* Re: [PATCH 29/38] vfs: syscall: Add fsconfig() for configuring and managing a context [ver #10]
From: David Howells @ 2018-07-27 21:51 UTC (permalink / raw)
To: Andy Lutomirski
Cc: dhowells, Al Viro, Linux API, Linus Torvalds, Linux FS Devel,
LKML
In-Reply-To: <CALCETrUXsOexKcj+K_v_bsW6DkGFgyNOaEs_qVOAcdNGBbEb2w@mail.gmail.com>
Andy Lutomirski <luto@amacapital.net> wrote:
> Unless I'm rather confused, you have two or possibly three ways to
> pass in an open fd. Can you clarify what the difference is and/or
> remove all but one of them?
No, they're not equivalent.
> > (*) fsconfig_set_path: A non-empty path is specified. The parameter must
> > be expecting a path object. value points to a NUL-terminated string
> > that is the path and aux is a file descriptor at which to start a
> > relative lookup or AT_FDCWD.
So, an example:
fsconfig(fd, fsconfig_set_path, "source", "/dev/sda1", AT_FDCWD);
I don't want to require that the caller open /dev/sda1 and pass in an fd as
that might prevent the filesystem from "holding" it exclusively.
> > (*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH
> > implied.
You can't do:
fsconfig(fd, fsconfig_set_path, "source", "", dir_fd);
because AT_EMPTY_PATH cannot be specified directly[*]. What you do instead is:
fsconfig(fd, fsconfig_set_path_empty, "source", "", dir_fd);
[*] Not without a 6-arg syscall or some other way of passing it.
I *could* require that the caller must call open(O_PATH) or openat(O_PATH)
before calling fsconfig() - so you don't pass a string, but only a path-fd.
> > (*) fsconfig_set_fd: An open file descriptor is specified. value must
> > be NULL and aux indicates the file descriptor.
See fd=%u on fuse. I think it's cleaner to do:
fsconfig(fd, fsconfig_set_fd, "source", NULL, control_fd);
saying explicitly that there's an open file to be passed rather than:
fsconfig(fd, fsconfig_set_path, "source", NULL, control_fd);
which indicates that you are actually providing a path.
David
^ permalink raw reply
* Re: [PATCH 30/38] vfs: syscall: Add fsmount() to create a mount for a superblock [ver #10]
From: Andy Lutomirski @ 2018-07-27 19:43 UTC (permalink / raw)
To: David Howells; +Cc: Al Viro, Linux API, Linus Torvalds, Linux FS Devel, LKML
In-Reply-To: <D09916DC-DA22-48AA-A62B-F874BB3C15BC@amacapital.net>
On Fri, Jul 27, 2018 at 12:27 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>
>
>> On Jul 27, 2018, at 10:34 AM, David Howells <dhowells@redhat.com> wrote:
>>
>> Provide a system call by which a filesystem opened with fsopen() and
>> configured by a series of writes can be mounted:
>>
>> int ret = fsmount(int fsfd, unsigned int flags,
>> unsigned int ms_flags);
>>
>> where fsfd is the file descriptor returned by fsopen(). flags can be 0 or
>> FSMOUNT_CLOEXEC. ms_flags is a bitwise-OR of the following flags:
>
> I have a potentially silly objection. For the old timers, “mount” means to stick a reel of tape or some similar object onto a reader, which seems to imply that “mount” means to start up the filesystem. For younguns, this meaning is probably lost, and the more obvious meaning is to “mount” it into some location in the VFS hierarchy a la vfsmount. The patch description doesn’t disambiguate it, and obviously people used to mount(2)/mount(8) are just likely to be confused.
>
> At the very least, your description should make it absolutely clear what you mean. Even better IMO would be to drop the use of the word “mount” entirely and maybe rename the syscall.
>
> From a very brief reading, I think you are giving it the meaning that would be implied by fsstart(2).
>
After further reading, maybe what you actually mean is:
int mfd = fsmount(...);
where you pass in an fscontext fd and get out an fd referring to the
root of the filesystem? In this case, maybe fs_open_root(2) would be
a better name.
This *definitely* needs to be clearer in the description.
^ permalink raw reply
* Re: [PATCH 29/38] vfs: syscall: Add fsconfig() for configuring and managing a context [ver #10]
From: Andy Lutomirski @ 2018-07-27 19:42 UTC (permalink / raw)
To: David Howells; +Cc: Al Viro, Linux API, Linus Torvalds, Linux FS Devel, LKML
In-Reply-To: <153271287586.9458.6001928723332685410.stgit@warthog.procyon.org.uk>
On Fri, Jul 27, 2018 at 10:34 AM, David Howells <dhowells@redhat.com> wrote:
> (*) fsconfig_set_path: A non-empty path is specified. The parameter must
> be expecting a path object. value points to a NUL-terminated string
> that is the path and aux is a file descriptor at which to start a
> relative lookup or AT_FDCWD.
>
> (*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH
> implied.
>
> (*) fsconfig_set_fd: An open file descriptor is specified. value must
> be NULL and aux indicates the file descriptor.
Unless I'm rather confused, you have two or possibly three ways to
pass in an open fd. Can you clarify what the difference is and/or
remove all but one of them?
^ permalink raw reply
* Re: [PATCH 34/38] vfs: syscall: Add fsinfo() to query filesystem information [ver #10]
From: Andy Lutomirski @ 2018-07-27 19:35 UTC (permalink / raw)
To: David Howells; +Cc: Al Viro, Linux API, Linus Torvalds, Linux FS Devel, LKML
In-Reply-To: <153271291017.9458.7827028432894772673.stgit@warthog.procyon.org.uk>
On Fri, Jul 27, 2018 at 10:35 AM, David Howells <dhowells@redhat.com> wrote:
> Add a system call to allow filesystem information to be queried. A request
> value can be given to indicate the desired attribute. Support is provided
> for enumerating multi-value attributes.
Has anyone seriously reviewed this? It might make sense to defer this
to a followup patch set. Also:
> params->request indicates the attribute/attributes to be queried. This can
> be one of:
>
> fsinfo_attr_statfs - statfs-style info
> fsinfo_attr_fsinfo - Information about fsinfo()
Constants are almost always all caps. Is there any reason these are lowercase?
^ permalink raw reply
* Re: [PATCH 30/38] vfs: syscall: Add fsmount() to create a mount for a superblock [ver #10]
From: Andy Lutomirski @ 2018-07-27 19:27 UTC (permalink / raw)
To: David Howells; +Cc: viro, linux-api, torvalds, linux-fsdevel, linux-kernel
In-Reply-To: <153271288242.9458.18050138471208178879.stgit@warthog.procyon.org.uk>
> On Jul 27, 2018, at 10:34 AM, David Howells <dhowells@redhat.com> wrote:
>
> Provide a system call by which a filesystem opened with fsopen() and
> configured by a series of writes can be mounted:
>
> int ret = fsmount(int fsfd, unsigned int flags,
> unsigned int ms_flags);
>
> where fsfd is the file descriptor returned by fsopen(). flags can be 0 or
> FSMOUNT_CLOEXEC. ms_flags is a bitwise-OR of the following flags:
I have a potentially silly objection. For the old timers, “mount” means to stick a reel of tape or some similar object onto a reader, which seems to imply that “mount” means to start up the filesystem. For younguns, this meaning is probably lost, and the more obvious meaning is to “mount” it into some location in the VFS hierarchy a la vfsmount. The patch description doesn’t disambiguate it, and obviously people used to mount(2)/mount(8) are just likely to be confused.
At the very least, your description should make it absolutely clear what you mean. Even better IMO would be to drop the use of the word “mount” entirely and maybe rename the syscall.
From a very brief reading, I think you are giving it the meaning that would be implied by fsstart(2).
>
> MS_RDONLY
> MS_NOSUID
> MS_NODEV
> MS_NOEXEC
> MS_NOATIME
> MS_NODIRATIME
> MS_RELATIME
> MS_STRICTATIME
>
> MS_UNBINDABLE
> MS_PRIVATE
> MS_SLAVE
> MS_SHARED
>
> In the event that fsmount() fails, it may be possible to get an error
> message by calling read() on fsfd. If no message is available, ENODATA
> will be reported.
>
> Signed-off-by: David Howells <dhowells@redhat.com>
> cc: linux-api@vger.kernel.org
> ---
>
> arch/x86/entry/syscalls/syscall_32.tbl | 1
> arch/x86/entry/syscalls/syscall_64.tbl | 1
> fs/namespace.c | 140 +++++++++++++++++++++++++++++++-
> include/linux/syscalls.h | 1
> include/uapi/linux/fs.h | 2
> 5 files changed, 141 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index f9970310c126..c78b68256f8a 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -402,3 +402,4 @@
> 388 i386 move_mount sys_move_mount __ia32_sys_move_mount
> 389 i386 fsopen sys_fsopen __ia32_sys_fsopen
> 390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
> +391 i386 fsmount sys_fsmount __ia32_sys_fsmount
> diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
> index 4185d36e03bb..d44ead5d4368 100644
> --- a/arch/x86/entry/syscalls/syscall_64.tbl
> +++ b/arch/x86/entry/syscalls/syscall_64.tbl
> @@ -347,6 +347,7 @@
> 336 common move_mount __x64_sys_move_mount
> 337 common fsopen __x64_sys_fsopen
> 338 common fsconfig __x64_sys_fsconfig
> +339 common fsmount __x64_sys_fsmount
>
> #
> # x32-specific system call numbers start at 512 to avoid cache impact
> diff --git a/fs/namespace.c b/fs/namespace.c
> index ea07066a2731..b1661b90256d 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2503,7 +2503,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
>
> attached = mnt_has_parent(old);
> /*
> - * We need to allow open_tree(OPEN_TREE_CLONE) followed by
> + * We need to allow open_tree(OPEN_TREE_CLONE) or fsmount() followed by
> * move_mount(), but mustn't allow "/" to be moved.
> */
> if (old->mnt_ns && !attached)
> @@ -3348,9 +3348,141 @@ struct vfsmount *kern_mount(struct file_system_type *type)
> EXPORT_SYMBOL_GPL(kern_mount);
>
> /*
> - * Move a mount from one place to another.
> - * In combination with open_tree(OPEN_TREE_CLONE [| AT_RECURSIVE]) it can be
> - * used to copy a mount subtree.
> + * Create a kernel mount representation for a new, prepared superblock
> + * (specified by fs_fd) and attach to an open_tree-like file descriptor.
> + */
> +SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, ms_flags)
> +{
> + struct fs_context *fc;
> + struct file *file;
> + struct path newmount;
> + struct fd f;
> + unsigned int mnt_flags = 0;
> + long ret;
> +
> + if (!may_mount())
> + return -EPERM;
> +
> + if ((flags & ~(FSMOUNT_CLOEXEC)) != 0)
> + return -EINVAL;
> +
> + if (ms_flags & ~(MS_RDONLY | MS_NOSUID | MS_NODEV | MS_NOEXEC |
> + MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
> + MS_STRICTATIME))
> + return -EINVAL;
> +
> + if (ms_flags & MS_RDONLY)
> + mnt_flags |= MNT_READONLY;
> + if (ms_flags & MS_NOSUID)
> + mnt_flags |= MNT_NOSUID;
> + if (ms_flags & MS_NODEV)
> + mnt_flags |= MNT_NODEV;
> + if (ms_flags & MS_NOEXEC)
> + mnt_flags |= MNT_NOEXEC;
> + if (ms_flags & MS_NODIRATIME)
> + mnt_flags |= MNT_NODIRATIME;
> +
> + if (ms_flags & MS_STRICTATIME) {
> + if (ms_flags & MS_NOATIME)
> + return -EINVAL;
> + } else if (ms_flags & MS_NOATIME) {
> + mnt_flags |= MNT_NOATIME;
> + } else {
> + mnt_flags |= MNT_RELATIME;
> + }
> +
> + f = fdget(fs_fd);
> + if (!f.file)
> + return -EBADF;
> +
> + ret = -EINVAL;
> + if (f.file->f_op != &fscontext_fops)
> + goto err_fsfd;
> +
> + fc = f.file->private_data;
> +
> + /* There must be a valid superblock or we can't mount it */
> + ret = -EINVAL;
> + if (!fc->root)
> + goto err_fsfd;
> +
> + ret = -EPERM;
> + if (mount_too_revealing(fc->root->d_sb, &mnt_flags)) {
> + pr_warn("VFS: Mount too revealing\n");
> + goto err_fsfd;
> + }
> +
> + ret = mutex_lock_interruptible(&fc->uapi_mutex);
> + if (ret < 0)
> + goto err_fsfd;
> +
> + ret = -EBUSY;
> + if (fc->phase != FS_CONTEXT_AWAITING_MOUNT)
> + goto err_unlock;
> +
> + ret = -EPERM;
> + if ((fc->sb_flags & SB_MANDLOCK) && !may_mandlock())
> + goto err_unlock;
> +
> + newmount.mnt = vfs_create_mount(fc, mnt_flags);
> + if (IS_ERR(newmount.mnt)) {
> + ret = PTR_ERR(newmount.mnt);
> + goto err_unlock;
> + }
> + newmount.dentry = dget(fc->root);
> +
> + /* We've done the mount bit - now move the file context into more or
> + * less the same state as if we'd done an fspick(). We don't want to
> + * do any memory allocation or anything like that at this point as we
> + * don't want to have to handle any errors incurred.
> + */
> + if (fc->ops && fc->ops->free)
> + fc->ops->free(fc);
> + fc->fs_private = NULL;
> + fc->s_fs_info = NULL;
> + fc->sb_flags = 0;
> + fc->sloppy = false;
> + fc->silent = false;
> + security_fs_context_free(fc);
> + fc->security = NULL;
> + kfree(fc->subtype);
> + fc->subtype = NULL;
> + kfree(fc->source);
> + fc->source = NULL;
> +
> + fc->purpose = FS_CONTEXT_FOR_RECONFIGURE;
> + fc->phase = FS_CONTEXT_AWAITING_RECONF;
> +
> + /* Attach to an apparent O_PATH fd with a note that we need to unmount
> + * it, not just simply put it.
> + */
> + file = dentry_open(&newmount, O_PATH, fc->cred);
> + if (IS_ERR(file)) {
> + ret = PTR_ERR(file);
> + goto err_path;
> + }
> + file->f_mode |= FMODE_NEED_UNMOUNT;
> +
> + ret = get_unused_fd_flags((flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0);
> + if (ret >= 0)
> + fd_install(ret, file);
> + else
> + fput(file);
> +
> +err_path:
> + path_put(&newmount);
> +err_unlock:
> + mutex_unlock(&fc->uapi_mutex);
> +err_fsfd:
> + fdput(f);
> + return ret;
> +}
> +
> +/*
> + * Move a mount from one place to another. In combination with
> + * fsopen()/fsmount() this is used to install a new mount and in combination
> + * with open_tree(OPEN_TREE_CLONE [| AT_RECURSIVE]) it can be used to copy
> + * a mount subtree.
> *
> * Note the flags value is a combination of MOVE_MOUNT_* flags.
> */
> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
> index 9628d14a7ede..65db661cc2da 100644
> --- a/include/linux/syscalls.h
> +++ b/include/linux/syscalls.h
> @@ -907,6 +907,7 @@ asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
> asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
> asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key,
> const void __user *value, int aux);
> +asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
>
> /*
> * Architecture-specific system calls
> diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
> index 7c9e165e8689..297362908d01 100644
> --- a/include/uapi/linux/fs.h
> +++ b/include/uapi/linux/fs.h
> @@ -349,6 +349,8 @@ typedef int __bitwise __kernel_rwf_t;
> */
> #define FSOPEN_CLOEXEC 0x00000001
>
> +#define FSMOUNT_CLOEXEC 0x00000001
> +
> /*
> * The type of fsconfig() call made.
> */
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-api" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* [PATCH 34/38] vfs: syscall: Add fsinfo() to query filesystem information [ver #10]
From: David Howells @ 2018-07-27 17:35 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Add a system call to allow filesystem information to be queried. A request
value can be given to indicate the desired attribute. Support is provided
for enumerating multi-value attributes.
===============
NEW SYSTEM CALL
===============
The new system call looks like:
int ret = fsinfo(int dfd,
const char *filename,
const struct fsinfo_params *params,
void *buffer,
size_t buf_size);
The params parameter optionally points to a block of parameters:
struct fsinfo_params {
__u32 at_flags;
__u32 request;
__u32 Nth;
__u32 Mth;
__u32 __reserved[6];
};
If params is NULL, it is assumed params->request should be
fsinfo_attr_statfs, params->Nth should be 0, params->Mth should be 0 and
params->at_flags should be 0.
If params is given, all of params->__reserved[] must be 0.
dfd, filename and params->at_flags indicate the file to query. There is no
equivalent of lstat() as that can be emulated with fsinfo() by setting
AT_SYMLINK_NOFOLLOW in params->at_flags. There is also no equivalent of
fstat() as that can be emulated by passing a NULL filename to fsinfo() with
the fd of interest in dfd. AT_NO_AUTOMOUNT can also be used to an allow
automount point to be queried without triggering it.
params->request indicates the attribute/attributes to be queried. This can
be one of:
fsinfo_attr_statfs - statfs-style info
fsinfo_attr_fsinfo - Information about fsinfo()
fsinfo_attr_ids - Filesystem IDs
fsinfo_attr_limits - Filesystem limits
fsinfo_attr_supports - What's supported in statx(), IOC flags
fsinfo_attr_capabilities - Filesystem capabilities
fsinfo_attr_timestamp_info - Inode timestamp info
fsinfo_attr_volume_id - Volume ID (string)
fsinfo_attr_volume_uuid - Volume UUID
fsinfo_attr_volume_name - Volume name (string)
fsinfo_attr_cell_name - Cell name (string)
fsinfo_attr_domain_name - Domain name (string)
fsinfo_attr_realm_name - Realm name (string)
fsinfo_attr_server_name - Name of the Nth server (string)
fsinfo_attr_server_address - Mth address of the Nth server
fsinfo_attr_parameter - Nth mount parameter (string)
fsinfo_attr_source - Nth mount source name (string)
fsinfo_attr_name_encoding - Filename encoding (string)
fsinfo_attr_name_codepage - Filename codepage (string)
fsinfo_attr_io_size - I/O size hints
Some attributes (such as the servers backing a network filesystem) can have
multiple values. These can be enumerated by setting params->Nth and
params->Mth to 0, 1, ... until ENODATA is returned.
buffer and buf_size point to the reply buffer. The buffer is filled up to
the specified size, even if this means truncating the reply. The full size
of the reply is returned. In future versions, this will allow extra fields
to be tacked on to the end of the reply, but anyone not expecting them will
only get the subset they're expecting. If either buffer of buf_size are 0,
no copy will take place and the data size will be returned.
At the moment, this will only work on x86_64 and i386 as it requires the
system call to be wired up.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/statfs.c | 464 ++++++++++++++++++++++++++++
include/linux/fs.h | 4
include/linux/fsinfo.h | 40 ++
include/linux/syscalls.h | 4
include/uapi/linux/fsinfo.h | 234 ++++++++++++++
samples/statx/Makefile | 5
samples/statx/test-fsinfo.c | 539 ++++++++++++++++++++++++++++++++
9 files changed, 1291 insertions(+), 1 deletion(-)
create mode 100644 include/linux/fsinfo.h
create mode 100644 include/uapi/linux/fsinfo.h
create mode 100644 samples/statx/test-fsinfo.c
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index d1eb6c815790..806760188a31 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -404,3 +404,4 @@
390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
391 i386 fsmount sys_fsmount __ia32_sys_fsmount
392 i386 fspick sys_fspick __ia32_sys_fspick
+393 i386 fsinfo sys_fsinfo __ia32_sys_fsinfo
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index d3ab703c02bb..0823eed2b02e 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -349,6 +349,7 @@
338 common fsconfig __x64_sys_fsconfig
339 common fsmount __x64_sys_fsmount
340 common fspick __x64_sys_fspick
+341 common fsinfo __x64_sys_fsinfo
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/statfs.c b/fs/statfs.c
index 5b2a24f0f263..caf0773957e9 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -9,6 +9,7 @@
#include <linux/security.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
+#include <linux/fsinfo.h>
#include "internal.h"
static int flags_by_mnt(int mnt_flags)
@@ -384,3 +385,466 @@ COMPAT_SYSCALL_DEFINE2(ustat, unsigned, dev, struct compat_ustat __user *, u)
return 0;
}
#endif
+
+/*
+ * Get basic filesystem stats from statfs.
+ */
+static int fsinfo_generic_statfs(struct dentry *dentry,
+ struct fsinfo_statfs *p)
+{
+ struct super_block *sb;
+ struct kstatfs buf;
+ int ret;
+
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+
+ sb = dentry->d_sb;
+ p->f_blocks = buf.f_blocks;
+ p->f_bfree = buf.f_bfree;
+ p->f_bavail = buf.f_bavail;
+ p->f_files = buf.f_files;
+ p->f_ffree = buf.f_ffree;
+ p->f_favail = buf.f_ffree;
+ p->f_bsize = buf.f_bsize;
+ p->f_frsize = buf.f_frsize;
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_ids(struct dentry *dentry,
+ struct fsinfo_ids *p)
+{
+ struct super_block *sb;
+ struct kstatfs buf;
+ int ret;
+
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+
+ sb = dentry->d_sb;
+ p->f_fstype = sb->s_magic;
+ p->f_dev_major = MAJOR(sb->s_dev);
+ p->f_dev_minor = MINOR(sb->s_dev);
+ p->f_flags = ST_VALID | flags_by_sb(sb->s_flags);
+
+ memcpy(&p->f_fsid, &buf.f_fsid, sizeof(p->f_fsid));
+ strcpy(p->f_fs_name, dentry->d_sb->s_type->name);
+ return sizeof(*p);
+}
+
+static int fsinfo_generic_limits(struct dentry *dentry,
+ struct fsinfo_limits *lim)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ lim->max_file_size = sb->s_maxbytes;
+ lim->max_hard_links = sb->s_max_links;
+ lim->max_uid = UINT_MAX;
+ lim->max_gid = UINT_MAX;
+ lim->max_projid = UINT_MAX;
+ lim->max_filename_len = NAME_MAX;
+ lim->max_symlink_len = PAGE_SIZE;
+ lim->max_xattr_name_len = XATTR_NAME_MAX;
+ lim->max_xattr_body_len = XATTR_SIZE_MAX;
+ lim->max_dev_major = 0xffffff;
+ lim->max_dev_minor = 0xff;
+ return sizeof(*lim);
+}
+
+static int fsinfo_generic_supports(struct dentry *dentry,
+ struct fsinfo_supports *c)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ c->stx_mask = STATX_BASIC_STATS;
+ if (sb->s_d_op && sb->s_d_op->d_automount)
+ c->stx_attributes |= STATX_ATTR_AUTOMOUNT;
+ return sizeof(*c);
+}
+
+static int fsinfo_generic_capabilities(struct dentry *dentry,
+ struct fsinfo_capabilities *c)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ if (sb->s_mtd)
+ fsinfo_set_cap(c, fsinfo_cap_is_flash_fs);
+ else if (sb->s_bdev)
+ fsinfo_set_cap(c, fsinfo_cap_is_block_fs);
+
+ if (sb->s_quota_types & QTYPE_MASK_USR)
+ fsinfo_set_cap(c, fsinfo_cap_user_quotas);
+ if (sb->s_quota_types & QTYPE_MASK_GRP)
+ fsinfo_set_cap(c, fsinfo_cap_group_quotas);
+ if (sb->s_quota_types & QTYPE_MASK_PRJ)
+ fsinfo_set_cap(c, fsinfo_cap_project_quotas);
+ if (sb->s_d_op && sb->s_d_op->d_automount)
+ fsinfo_set_cap(c, fsinfo_cap_automounts);
+ if (sb->s_id[0])
+ fsinfo_set_cap(c, fsinfo_cap_volume_id);
+
+ fsinfo_set_cap(c, fsinfo_cap_has_atime);
+ fsinfo_set_cap(c, fsinfo_cap_has_ctime);
+ fsinfo_set_cap(c, fsinfo_cap_has_mtime);
+ return sizeof(*c);
+}
+
+static int fsinfo_generic_timestamp_info(struct dentry *dentry,
+ struct fsinfo_timestamp_info *ts)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ /* If unset, assume 1s granularity */
+ u16 mantissa = 1;
+ s8 exponent = 0;
+
+ ts->minimum_timestamp = S64_MIN;
+ ts->maximum_timestamp = S64_MAX;
+ if (sb->s_time_gran < 1000000000) {
+ if (sb->s_time_gran < 1000)
+ exponent = -9;
+ else if (sb->s_time_gran < 1000000)
+ exponent = -6;
+ else
+ exponent = -3;
+ }
+#define set_gran(x) \
+ do { \
+ ts->x##_mantissa = mantissa; \
+ ts->x##_exponent = exponent; \
+ } while (0)
+ set_gran(atime_gran);
+ set_gran(btime_gran);
+ set_gran(ctime_gran);
+ set_gran(mtime_gran);
+ return sizeof(*ts);
+}
+
+static int fsinfo_generic_volume_uuid(struct dentry *dentry,
+ struct fsinfo_volume_uuid *vu)
+{
+ struct super_block *sb = dentry->d_sb;
+
+ memcpy(vu, &sb->s_uuid, sizeof(*vu));
+ return sizeof(*vu);
+}
+
+static int fsinfo_generic_volume_id(struct dentry *dentry, char *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ size_t len = strlen(sb->s_id);
+
+ if (buf)
+ memcpy(buf, sb->s_id, len + 1);
+ return len;
+}
+
+static int fsinfo_generic_name_encoding(struct dentry *dentry, char *buf)
+{
+ static const char encoding[] = "utf8";
+
+ if (buf)
+ memcpy(buf, encoding, sizeof(encoding) - 1);
+ return sizeof(encoding) - 1;
+}
+
+static int fsinfo_generic_io_size(struct dentry *dentry,
+ struct fsinfo_io_size *c)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct kstatfs buf;
+ int ret;
+
+ if (sb->s_op->statfs == simple_statfs) {
+ c->dio_size_gran = 1;
+ c->dio_mem_align = 1;
+ } else {
+ ret = statfs_by_dentry(dentry, &buf);
+ if (ret < 0)
+ return ret;
+ c->dio_size_gran = buf.f_bsize;
+ c->dio_mem_align = buf.f_bsize;
+ }
+ return sizeof(*c);
+}
+
+/*
+ * Implement some queries generically from stuff in the superblock.
+ */
+int generic_fsinfo(struct dentry *dentry, struct fsinfo_kparams *params)
+{
+#define _gen(X) fsinfo_attr_##X: return fsinfo_generic_##X(dentry, params->buffer)
+
+ switch (params->request) {
+ case _gen(statfs);
+ case _gen(ids);
+ case _gen(limits);
+ case _gen(supports);
+ case _gen(capabilities);
+ case _gen(timestamp_info);
+ case _gen(volume_uuid);
+ case _gen(volume_id);
+ case _gen(name_encoding);
+ case _gen(io_size);
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+EXPORT_SYMBOL(generic_fsinfo);
+
+/*
+ * Retrieve the filesystem info. We make some stuff up if the operation is not
+ * supported.
+ */
+int vfs_fsinfo(const struct path *path, struct fsinfo_kparams *params)
+{
+ struct dentry *dentry = path->dentry;
+ int (*get_fsinfo)(struct dentry *, struct fsinfo_kparams *);
+ int ret;
+
+ if (params->request == fsinfo_attr_fsinfo) {
+ struct fsinfo_fsinfo *info = params->buffer;
+
+ info->max_attr = fsinfo_attr__nr;
+ info->max_cap = fsinfo_cap__nr;
+ return sizeof(*info);
+ }
+
+ get_fsinfo = dentry->d_sb->s_op->get_fsinfo;
+ if (!get_fsinfo) {
+ if (!dentry->d_sb->s_op->statfs)
+ return -EOPNOTSUPP;
+ get_fsinfo = generic_fsinfo;
+ }
+
+ ret = security_sb_statfs(dentry);
+ if (ret)
+ return ret;
+
+ ret = get_fsinfo(dentry, params);
+ if (ret < 0)
+ return ret;
+
+ if (params->request == fsinfo_attr_ids &&
+ params->buffer) {
+ struct fsinfo_ids *p = params->buffer;
+
+ p->f_flags |= flags_by_mnt(path->mnt->mnt_flags);
+ }
+ return ret;
+}
+
+static int vfs_fsinfo_path(int dfd, const char __user *filename,
+ struct fsinfo_kparams *params)
+{
+ struct path path;
+ unsigned lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+ int ret = -EINVAL;
+
+ if ((params->at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_NO_AUTOMOUNT |
+ AT_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ if (params->at_flags & AT_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (params->at_flags & AT_NO_AUTOMOUNT)
+ lookup_flags &= ~LOOKUP_AUTOMOUNT;
+ if (params->at_flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+ ret = user_path_at(dfd, filename, lookup_flags, &path);
+ if (ret)
+ goto out;
+
+ ret = vfs_fsinfo(&path, params);
+ path_put(&path);
+ if (retry_estale(ret, lookup_flags)) {
+ lookup_flags |= LOOKUP_REVAL;
+ goto retry;
+ }
+out:
+ return ret;
+}
+
+static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_kparams *params)
+{
+ struct fd f = fdget_raw(fd);
+ int ret = -EBADF;
+
+ if (f.file) {
+ ret = vfs_fsinfo(&f.file->f_path, params);
+ fdput(f);
+ }
+ return ret;
+}
+
+/*
+ * Return buffer information by requestable attribute.
+ *
+ * STRUCT indicates a fixed-size structure with only one instance.
+ * STRUCT_N indicates a fixed-size structure that may have multiple instances.
+ * STRING indicates a string with only one instance.
+ * STRING_N indicates a string that may have multiple instances.
+ * STRUCT_ARRAY indicates an array of fixed-size structs with only one instance.
+ * STRUCT_ARRAY_N as above that may have multiple instances.
+ *
+ * If an entry is marked STRUCT, STRUCT_N or STRUCT_NM then if no buffer is
+ * supplied to sys_fsinfo(), sys_fsinfo() will handle returning the buffer size
+ * without calling vfs_fsinfo() and the filesystem.
+ *
+ * No struct may have more than 252 bytes (ie. 0x3f * 4)
+ */
+#define FSINFO_STRING(N) [fsinfo_attr_##N] = 0x0000
+#define FSINFO_STRUCT(N) [fsinfo_attr_##N] = sizeof(struct fsinfo_##N)
+#define FSINFO_STRING_N(N) [fsinfo_attr_##N] = 0x4000
+#define FSINFO_STRUCT_N(N) [fsinfo_attr_##N] = 0x4000 | sizeof(struct fsinfo_##N)
+#define FSINFO_STRUCT_NM(N) [fsinfo_attr_##N] = 0x8000 | sizeof(struct fsinfo_##N)
+static const u16 fsinfo_buffer_sizes[fsinfo_attr__nr] = {
+ FSINFO_STRUCT (statfs),
+ FSINFO_STRUCT (fsinfo),
+ FSINFO_STRUCT (ids),
+ FSINFO_STRUCT (limits),
+ FSINFO_STRUCT (capabilities),
+ FSINFO_STRUCT (supports),
+ FSINFO_STRUCT (timestamp_info),
+ FSINFO_STRING (volume_id),
+ FSINFO_STRUCT (volume_uuid),
+ FSINFO_STRING (volume_name),
+ FSINFO_STRING (cell_name),
+ FSINFO_STRING (domain_name),
+ FSINFO_STRING (realm_name),
+ FSINFO_STRING_N (server_name),
+ FSINFO_STRUCT_NM (server_address),
+ FSINFO_STRING_N (parameter),
+ FSINFO_STRING_N (source),
+ FSINFO_STRING (name_encoding),
+ FSINFO_STRING (name_codepage),
+ FSINFO_STRUCT (io_size),
+};
+
+/**
+ * sys_fsinfo - System call to get filesystem information
+ * @dfd: Base directory to pathwalk from or fd referring to filesystem.
+ * @filename: Filesystem to query or NULL.
+ * @_params: Parameters to define request (or NULL for enhanced statfs).
+ * @_buffer: Result buffer.
+ * @buf_size: Size of result buffer.
+ *
+ * Get information on a filesystem. The filesystem attribute to be queried is
+ * indicated by @_params->request, and some of the attributes can have multiple
+ * values, indexed by @_params->Nth and @_params->Mth. If @_params is NULL,
+ * then the 0th fsinfo_attr_statfs attribute is queried. If an attribute does
+ * not exist, EOPNOTSUPP is returned; if the Nth,Mth value does not exist,
+ * ENODATA is returned.
+ *
+ * On success, the size of the attribute's value is returned. If @buf_size is
+ * 0 or @_buffer is NULL, only the size is returned. If the size of the value
+ * is larger than @buf_size, it will be truncated by the copy. If the size of
+ * the value is smaller than @buf_size then the excess buffer space will be
+ * cleared. The full size of the value will be returned, irrespective of how
+ * much data is actually placed in the buffer.
+ */
+SYSCALL_DEFINE5(fsinfo,
+ int, dfd, const char __user *, filename,
+ struct fsinfo_params __user *, _params,
+ void __user *, _buffer, size_t, buf_size)
+{
+ struct fsinfo_params user_params;
+ struct fsinfo_kparams params;
+ size_t size;
+ int ret;
+
+ if (_params) {
+ if (copy_from_user(&user_params, _params, sizeof(user_params)))
+ return -EFAULT;
+ if (user_params.__reserved[0] ||
+ user_params.__reserved[1] ||
+ user_params.__reserved[2] ||
+ user_params.__reserved[3] ||
+ user_params.__reserved[4] ||
+ user_params.__reserved[5])
+ return -EINVAL;
+ if (user_params.request >= fsinfo_attr__nr)
+ return -EOPNOTSUPP;
+ params.at_flags = user_params.at_flags;
+ params.request = user_params.request;
+ params.Nth = user_params.Nth;
+ params.Mth = user_params.Mth;
+ } else {
+ params.at_flags = 0;
+ params.request = fsinfo_attr_statfs;
+ params.Nth = 0;
+ params.Mth = 0;
+ }
+
+ if (!_buffer || !buf_size) {
+ buf_size = 0;
+ _buffer = NULL;
+ }
+
+ /* Allocate an appropriately-sized buffer. We will truncate the
+ * contents when we write the contents back to userspace.
+ */
+ size = fsinfo_buffer_sizes[params.request];
+ switch (size & 0xc000) {
+ case 0x0000:
+ if (params.Nth != 0)
+ return -ENODATA;
+ /* Fall through */
+ case 0x4000:
+ if (params.Mth != 0)
+ return -ENODATA;
+ /* Fall through */
+ case 0x8000:
+ break;
+ case 0xc000:
+ return -ENOBUFS;
+ }
+
+ size &= ~0xc000;
+ if (size == 0) {
+ size = 4096; /* String */
+ } else {
+ if (buf_size == 0)
+ return size; /* We know how big the buffer should be */
+
+ /* Clear any part of the buffer that we won't fill. */
+ if (buf_size > size &&
+ clear_user(_buffer, buf_size) != 0)
+ return -EFAULT;
+ }
+
+ if (buf_size > 0) {
+ params.buf_size = size;
+ params.buffer = kzalloc(size, GFP_KERNEL);
+ if (!params.buffer)
+ return -ENOMEM;
+ } else {
+ params.buf_size = 0;
+ params.buffer = NULL;
+ }
+
+ if (filename)
+ ret = vfs_fsinfo_path(dfd, filename, ¶ms);
+ else
+ ret = vfs_fsinfo_fd(dfd, ¶ms);
+ if (ret < 0)
+ goto error;
+
+ if (ret == 0) {
+ ret = -ENODATA;
+ goto error;
+ }
+
+ if (buf_size > ret)
+ buf_size = ret;
+
+ if (copy_to_user(_buffer, params.buffer, buf_size))
+ ret = -EFAULT;
+error:
+ kfree(params.buffer);
+ return ret;
+}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3e661d033163..053d53861995 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -64,6 +64,8 @@ struct fscrypt_operations;
struct fs_context;
struct fsconfig_parser;
struct fsconfig_param;
+struct fsinfo_kparams;
+enum fsinfo_attribute;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -1849,6 +1851,7 @@ struct super_operations {
int (*thaw_super) (struct super_block *);
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
+ int (*get_fsinfo) (struct dentry *, struct fsinfo_kparams *);
int (*remount_fs) (struct super_block *, int *, char *, size_t);
int (*reconfigure) (struct super_block *, struct fs_context *);
void (*umount_begin) (struct super_block *);
@@ -2226,6 +2229,7 @@ extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,
extern int vfs_statfs(const struct path *, struct kstatfs *);
extern int user_statfs(const char __user *, struct kstatfs *);
extern int fd_statfs(int, struct kstatfs *);
+extern int vfs_fsinfo(const struct path *, struct fsinfo_kparams *);
extern int freeze_super(struct super_block *super);
extern int thaw_super(struct super_block *super);
extern bool our_mnt(struct vfsmount *mnt);
diff --git a/include/linux/fsinfo.h b/include/linux/fsinfo.h
new file mode 100644
index 000000000000..c356391b4b2a
--- /dev/null
+++ b/include/linux/fsinfo.h
@@ -0,0 +1,40 @@
+/* Filesystem information query
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_FSINFO_H
+#define _LINUX_FSINFO_H
+
+#include <uapi/linux/fsinfo.h>
+
+struct fsinfo_kparams {
+ __u32 at_flags; /* AT_SYMLINK_NOFOLLOW and similar */
+ enum fsinfo_attribute request; /* What is being asking for */
+ __u32 Nth; /* Instance of it (some may have multiple) */
+ __u32 Mth; /* Subinstance */
+ void *buffer; /* Where to place the reply */
+ size_t buf_size; /* Size of the buffer */
+};
+
+extern int generic_fsinfo(struct dentry *, struct fsinfo_kparams *);
+
+static inline void fsinfo_set_cap(struct fsinfo_capabilities *c,
+ enum fsinfo_capability cap)
+{
+ c->capabilities[cap / 8] |= 1 << (cap % 8);
+}
+
+static inline void fsinfo_clear_cap(struct fsinfo_capabilities *c,
+ enum fsinfo_capability cap)
+{
+ c->capabilities[cap / 8] &= ~(1 << (cap % 8));
+}
+
+#endif /* _LINUX_FSINFO_H */
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 701522957a12..bc7173c09f4d 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -49,6 +49,7 @@ struct stat64;
struct statfs;
struct statfs64;
struct statx;
+struct fsinfo_params;
struct __sysctl_args;
struct sysinfo;
struct timespec;
@@ -909,6 +910,9 @@ asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key
const void __user *value, int aux);
asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
asmlinkage long sys_fspick(int dfd, const char __user *path, unsigned int flags);
+asmlinkage long sys_fsinfo(int dfd, const char __user *path,
+ struct fsinfo_params __user *params,
+ void __user *buffer, size_t buf_size);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fsinfo.h b/include/uapi/linux/fsinfo.h
new file mode 100644
index 000000000000..abcf414dd3be
--- /dev/null
+++ b/include/uapi/linux/fsinfo.h
@@ -0,0 +1,234 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/* fsinfo() definitions.
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+#ifndef _UAPI_LINUX_FSINFO_H
+#define _UAPI_LINUX_FSINFO_H
+
+#include <linux/types.h>
+#include <linux/socket.h>
+
+/*
+ * The filesystem attributes that can be requested. Note that some attributes
+ * may have multiple instances which can be switched in the parameter block.
+ */
+enum fsinfo_attribute {
+ fsinfo_attr_statfs = 0, /* statfs()-style state */
+ fsinfo_attr_fsinfo = 1, /* Information about fsinfo() */
+ fsinfo_attr_ids = 2, /* Filesystem IDs */
+ fsinfo_attr_limits = 3, /* Filesystem limits */
+ fsinfo_attr_supports = 4, /* What's supported in statx, iocflags, ... */
+ fsinfo_attr_capabilities = 5, /* Filesystem capabilities (bits) */
+ fsinfo_attr_timestamp_info = 6, /* Inode timestamp info */
+ fsinfo_attr_volume_id = 7, /* Volume ID (string) */
+ fsinfo_attr_volume_uuid = 8, /* Volume UUID (LE uuid) */
+ fsinfo_attr_volume_name = 9, /* Volume name (string) */
+ fsinfo_attr_cell_name = 10, /* Cell name (string) */
+ fsinfo_attr_domain_name = 11, /* Domain name (string) */
+ fsinfo_attr_realm_name = 12, /* Realm name (string) */
+ fsinfo_attr_server_name = 13, /* Name of the Nth server */
+ fsinfo_attr_server_address = 14, /* Mth address of the Nth server */
+ fsinfo_attr_parameter = 15, /* Nth mount parameter (string) */
+ fsinfo_attr_source = 16, /* Nth mount source name (string) */
+ fsinfo_attr_name_encoding = 17, /* Filename encoding (string) */
+ fsinfo_attr_name_codepage = 18, /* Filename codepage (string) */
+ fsinfo_attr_io_size = 19, /* Optimal I/O sizes */
+ fsinfo_attr__nr
+};
+
+/*
+ * Optional fsinfo() parameter structure.
+ *
+ * If this is not given, it is assumed that fsinfo_attr_statfs instance 0,0 is
+ * desired.
+ */
+struct fsinfo_params {
+ __u32 at_flags; /* AT_SYMLINK_NOFOLLOW and similar flags */
+ __u32 request; /* What is being asking for (enum fsinfo_attribute) */
+ __u32 Nth; /* Instance of it (some may have multiple) */
+ __u32 Mth; /* Subinstance of Nth instance */
+ __u32 __reserved[6]; /* Reserved params; all must be 0 */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_statfs).
+ * - This gives extended filesystem information.
+ */
+struct fsinfo_statfs {
+ __u64 f_blocks; /* Total number of blocks in fs */
+ __u64 f_bfree; /* Total number of free blocks */
+ __u64 f_bavail; /* Number of free blocks available to ordinary user */
+ __u64 f_files; /* Total number of file nodes in fs */
+ __u64 f_ffree; /* Number of free file nodes */
+ __u64 f_favail; /* Number of free file nodes available to ordinary user */
+ __u32 f_bsize; /* Optimal block size */
+ __u32 f_frsize; /* Fragment size */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_ids).
+ *
+ * List of basic identifiers as is normally found in statfs().
+ */
+struct fsinfo_ids {
+ char f_fs_name[15 + 1];
+ __u64 f_flags; /* Filesystem mount flags (MS_*) */
+ __u64 f_fsid; /* Short 64-bit Filesystem ID (as statfs) */
+ __u64 f_sb_id; /* Internal superblock ID for sbnotify()/mntnotify() */
+ __u32 f_fstype; /* Filesystem type from linux/magic.h [uncond] */
+ __u32 f_dev_major; /* As st_dev_* from struct statx [uncond] */
+ __u32 f_dev_minor;
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_limits).
+ *
+ * List of supported filesystem limits.
+ */
+struct fsinfo_limits {
+ __u64 max_file_size; /* Maximum file size */
+ __u64 max_uid; /* Maximum UID supported */
+ __u64 max_gid; /* Maximum GID supported */
+ __u64 max_projid; /* Maximum project ID supported */
+ __u32 max_dev_major; /* Maximum device major representable */
+ __u32 max_dev_minor; /* Maximum device minor representable */
+ __u32 max_hard_links; /* Maximum number of hard links on a file */
+ __u32 max_xattr_body_len; /* Maximum xattr content length */
+ __u32 max_xattr_name_len; /* Maximum xattr name length */
+ __u32 max_filename_len; /* Maximum filename length */
+ __u32 max_symlink_len; /* Maximum symlink content length */
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_supports).
+ *
+ * What's supported in various masks, such as statx() attribute and mask bits
+ * and IOC flags.
+ */
+struct fsinfo_supports {
+ __u64 stx_attributes; /* What statx::stx_attributes are supported */
+ __u32 stx_mask; /* What statx::stx_mask bits are supported */
+ __u32 ioc_flags; /* What FS_IOC_* flags are supported */
+ __u32 win_file_attrs; /* What DOS/Windows FILE_* attributes are supported */
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_capabilities).
+ *
+ * Bitmask indicating filesystem capabilities where renderable as single bits.
+ */
+enum fsinfo_capability {
+ fsinfo_cap_is_kernel_fs = 0, /* fs is kernel-special filesystem */
+ fsinfo_cap_is_block_fs = 1, /* fs is block-based filesystem */
+ fsinfo_cap_is_flash_fs = 2, /* fs is flash filesystem */
+ fsinfo_cap_is_network_fs = 3, /* fs is network filesystem */
+ fsinfo_cap_is_automounter_fs = 4, /* fs is automounter special filesystem */
+ fsinfo_cap_automounts = 5, /* fs supports automounts */
+ fsinfo_cap_adv_locks = 6, /* fs supports advisory file locking */
+ fsinfo_cap_mand_locks = 7, /* fs supports mandatory file locking */
+ fsinfo_cap_leases = 8, /* fs supports file leases */
+ fsinfo_cap_uids = 9, /* fs supports numeric uids */
+ fsinfo_cap_gids = 10, /* fs supports numeric gids */
+ fsinfo_cap_projids = 11, /* fs supports numeric project ids */
+ fsinfo_cap_id_names = 12, /* fs supports user names */
+ fsinfo_cap_id_guids = 13, /* fs supports user guids */
+ fsinfo_cap_windows_attrs = 14, /* fs has windows attributes */
+ fsinfo_cap_user_quotas = 15, /* fs has per-user quotas */
+ fsinfo_cap_group_quotas = 16, /* fs has per-group quotas */
+ fsinfo_cap_project_quotas = 17, /* fs has per-project quotas */
+ fsinfo_cap_xattrs = 18, /* fs has xattrs */
+ fsinfo_cap_journal = 19, /* fs has a journal */
+ fsinfo_cap_data_is_journalled = 20, /* fs is using data journalling */
+ fsinfo_cap_o_sync = 21, /* fs supports O_SYNC */
+ fsinfo_cap_o_direct = 22, /* fs supports O_DIRECT */
+ fsinfo_cap_volume_id = 23, /* fs has a volume ID */
+ fsinfo_cap_volume_uuid = 24, /* fs has a volume UUID */
+ fsinfo_cap_volume_name = 25, /* fs has a volume name */
+ fsinfo_cap_volume_fsid = 26, /* fs has a volume FSID */
+ fsinfo_cap_cell_name = 27, /* fs has a cell name */
+ fsinfo_cap_domain_name = 28, /* fs has a domain name */
+ fsinfo_cap_realm_name = 29, /* fs has a realm name */
+ fsinfo_cap_iver_all_change = 30, /* i_version represents data + meta changes */
+ fsinfo_cap_iver_data_change = 31, /* i_version represents data changes only */
+ fsinfo_cap_iver_mono_incr = 32, /* i_version incremented monotonically */
+ fsinfo_cap_symlinks = 33, /* fs supports symlinks */
+ fsinfo_cap_hard_links = 34, /* fs supports hard links */
+ fsinfo_cap_hard_links_1dir = 35, /* fs supports hard links in same dir only */
+ fsinfo_cap_device_files = 36, /* fs supports bdev, cdev */
+ fsinfo_cap_unix_specials = 37, /* fs supports pipe, fifo, socket */
+ fsinfo_cap_resource_forks = 38, /* fs supports resource forks/streams */
+ fsinfo_cap_name_case_indep = 39, /* Filename case independence is mandatory */
+ fsinfo_cap_name_non_utf8 = 40, /* fs has non-utf8 names */
+ fsinfo_cap_name_has_codepage = 41, /* fs has a filename codepage */
+ fsinfo_cap_sparse = 42, /* fs supports sparse files */
+ fsinfo_cap_not_persistent = 43, /* fs is not persistent */
+ fsinfo_cap_no_unix_mode = 44, /* fs does not support unix mode bits */
+ fsinfo_cap_has_atime = 45, /* fs supports access time */
+ fsinfo_cap_has_btime = 46, /* fs supports birth/creation time */
+ fsinfo_cap_has_ctime = 47, /* fs supports change time */
+ fsinfo_cap_has_mtime = 48, /* fs supports modification time */
+ fsinfo_cap__nr
+};
+
+struct fsinfo_capabilities {
+ __u8 capabilities[(fsinfo_cap__nr + 7) / 8];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_timestamp_info).
+ */
+struct fsinfo_timestamp_info {
+ __s64 minimum_timestamp; /* Minimum timestamp value in seconds */
+ __s64 maximum_timestamp; /* Maximum timestamp value in seconds */
+ __u16 atime_gran_mantissa; /* Granularity(secs) = mant * 10^exp */
+ __u16 btime_gran_mantissa;
+ __u16 ctime_gran_mantissa;
+ __u16 mtime_gran_mantissa;
+ __s8 atime_gran_exponent;
+ __s8 btime_gran_exponent;
+ __s8 ctime_gran_exponent;
+ __s8 mtime_gran_exponent;
+ __u32 __reserved[1];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_volume_uuid).
+ */
+struct fsinfo_volume_uuid {
+ __u8 uuid[16];
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_server_addresses).
+ *
+ * Find the Mth address of the Nth server for a network mount.
+ */
+struct fsinfo_server_address {
+ struct __kernel_sockaddr_storage address;
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_io_size).
+ *
+ * Retrieve I/O size hints for a filesystem.
+ */
+struct fsinfo_io_size {
+ __u32 dio_size_gran; /* Size granularity for O_DIRECT */
+ __u32 dio_mem_align; /* Memory alignment for O_DIRECT */
+};
+
+/*
+ * Information struct for fsinfo(fsinfo_attr_fsinfo).
+ *
+ * This gives information about fsinfo() itself.
+ */
+struct fsinfo_fsinfo {
+ __u32 max_attr; /* Number of supported attributes (fsinfo_attr__nr) */
+ __u32 max_cap; /* Number of supported capabilities (fsinfo_cap__nr) */
+};
+
+#endif /* _UAPI_LINUX_FSINFO_H */
diff --git a/samples/statx/Makefile b/samples/statx/Makefile
index 59df7c25a9d1..9cb9a88e3a10 100644
--- a/samples/statx/Makefile
+++ b/samples/statx/Makefile
@@ -1,7 +1,10 @@
# List of programs to build
-hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx
+hostprogs-$(CONFIG_SAMPLE_STATX) := test-statx test-fsinfo
# Tell kbuild to always build the programs
always := $(hostprogs-y)
HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include
+
+HOSTCFLAGS_test-fsinfo.o += -I$(objtree)/usr/include
+HOSTLOADLIBES_test-fsinfo += -lm
diff --git a/samples/statx/test-fsinfo.c b/samples/statx/test-fsinfo.c
new file mode 100644
index 000000000000..deab0081ecd1
--- /dev/null
+++ b/samples/statx/test-fsinfo.c
@@ -0,0 +1,539 @@
+/* Test the fsinfo() system call
+ *
+ * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define _GNU_SOURCE
+#define _ATFILE_SOURCE
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <ctype.h>
+#include <errno.h>
+#include <time.h>
+#include <math.h>
+#include <fcntl.h>
+#include <sys/syscall.h>
+#include <linux/fsinfo.h>
+#include <linux/socket.h>
+#include <sys/stat.h>
+
+static __attribute__((unused))
+ssize_t fsinfo(int dfd, const char *filename, struct fsinfo_params *params,
+ void *buffer, size_t buf_size)
+{
+ return syscall(__NR_fsinfo, dfd, filename, params, buffer, buf_size);
+}
+
+#define FSINFO_STRING(N) [fsinfo_attr_##N] = 0x00
+#define FSINFO_STRUCT(N) [fsinfo_attr_##N] = sizeof(struct fsinfo_##N)/sizeof(__u32)
+#define FSINFO_STRING_N(N) [fsinfo_attr_##N] = 0x40
+#define FSINFO_STRUCT_N(N) [fsinfo_attr_##N] = 0x40 | sizeof(struct fsinfo_##N)/sizeof(__u32)
+#define FSINFO_STRUCT_NM(N) [fsinfo_attr_##N] = 0x80 | sizeof(struct fsinfo_##N)/sizeof(__u32)
+static const __u8 fsinfo_buffer_sizes[fsinfo_attr__nr] = {
+ FSINFO_STRUCT (statfs),
+ FSINFO_STRUCT (fsinfo),
+ FSINFO_STRUCT (ids),
+ FSINFO_STRUCT (limits),
+ FSINFO_STRUCT (supports),
+ FSINFO_STRUCT (capabilities),
+ FSINFO_STRUCT (timestamp_info),
+ FSINFO_STRING (volume_id),
+ FSINFO_STRUCT (volume_uuid),
+ FSINFO_STRING (volume_name),
+ FSINFO_STRING (cell_name),
+ FSINFO_STRING (domain_name),
+ FSINFO_STRING (realm_name),
+ FSINFO_STRING_N (server_name),
+ FSINFO_STRUCT_NM (server_address),
+ FSINFO_STRING_N (parameter),
+ FSINFO_STRING_N (source),
+ FSINFO_STRING (name_encoding),
+ FSINFO_STRING (name_codepage),
+ FSINFO_STRUCT (io_size),
+};
+
+#define FSINFO_NAME(N) [fsinfo_attr_##N] = #N
+static const char *fsinfo_attr_names[fsinfo_attr__nr] = {
+ FSINFO_NAME(statfs),
+ FSINFO_NAME(fsinfo),
+ FSINFO_NAME(ids),
+ FSINFO_NAME(limits),
+ FSINFO_NAME(supports),
+ FSINFO_NAME(capabilities),
+ FSINFO_NAME(timestamp_info),
+ FSINFO_NAME(volume_id),
+ FSINFO_NAME(volume_uuid),
+ FSINFO_NAME(volume_name),
+ FSINFO_NAME(cell_name),
+ FSINFO_NAME(domain_name),
+ FSINFO_NAME(realm_name),
+ FSINFO_NAME(server_name),
+ FSINFO_NAME(server_address),
+ FSINFO_NAME(parameter),
+ FSINFO_NAME(source),
+ FSINFO_NAME(name_encoding),
+ FSINFO_NAME(name_codepage),
+ FSINFO_NAME(io_size),
+};
+
+union reply {
+ char buffer[4096];
+ struct fsinfo_statfs statfs;
+ struct fsinfo_fsinfo fsinfo;
+ struct fsinfo_ids ids;
+ struct fsinfo_limits limits;
+ struct fsinfo_supports supports;
+ struct fsinfo_capabilities caps;
+ struct fsinfo_timestamp_info timestamps;
+ struct fsinfo_volume_uuid uuid;
+ struct fsinfo_server_address srv_addr;
+ struct fsinfo_io_size io_size;
+};
+
+static void dump_hex(unsigned int *data, int from, int to)
+{
+ unsigned offset, print_offset = 1, col = 0;
+
+ from /= 4;
+ to = (to + 3) / 4;
+
+ for (offset = from; offset < to; offset++) {
+ if (print_offset) {
+ printf("%04x: ", offset * 8);
+ print_offset = 0;
+ }
+ printf("%08x", data[offset]);
+ col++;
+ if ((col & 3) == 0) {
+ printf("\n");
+ print_offset = 1;
+ } else {
+ printf(" ");
+ }
+ }
+
+ if (!print_offset)
+ printf("\n");
+}
+
+static void dump_attr_statfs(union reply *r, int size)
+{
+ struct fsinfo_statfs *f = &r->statfs;
+
+ printf("\n");
+ printf("\tblocks: n=%llu fr=%llu av=%llu\n",
+ (unsigned long long)f->f_blocks,
+ (unsigned long long)f->f_bfree,
+ (unsigned long long)f->f_bavail);
+
+ printf("\tfiles : n=%llu fr=%llu av=%llu\n",
+ (unsigned long long)f->f_files,
+ (unsigned long long)f->f_ffree,
+ (unsigned long long)f->f_favail);
+ printf("\tbsize : %u\n", f->f_bsize);
+ printf("\tfrsize: %u\n", f->f_frsize);
+}
+
+static void dump_attr_fsinfo(union reply *r, int size)
+{
+ struct fsinfo_fsinfo *f = &r->fsinfo;
+
+ printf("max_attr=%u max_cap=%u\n", f->max_attr, f->max_cap);
+}
+
+static void dump_attr_ids(union reply *r, int size)
+{
+ struct fsinfo_ids *f = &r->ids;
+
+ printf("\n");
+ printf("\tdev : %02x:%02x\n", f->f_dev_major, f->f_dev_minor);
+ printf("\tfs : type=%x name=%s\n", f->f_fstype, f->f_fs_name);
+ printf("\tflags : %llx\n", (unsigned long long)f->f_flags);
+ printf("\tfsid : %llx\n", (unsigned long long)f->f_fsid);
+}
+
+static void dump_attr_limits(union reply *r, int size)
+{
+ struct fsinfo_limits *f = &r->limits;
+
+ printf("\n");
+ printf("\tmax file size: %llx\n", f->max_file_size);
+ printf("\tmax ids : u=%llx g=%llx p=%llx\n",
+ f->max_uid, f->max_gid, f->max_projid);
+ printf("\tmax dev : maj=%x min=%x\n",
+ f->max_dev_major, f->max_dev_minor);
+ printf("\tmax links : %x\n", f->max_hard_links);
+ printf("\tmax xattr : n=%x b=%x\n",
+ f->max_xattr_name_len, f->max_xattr_body_len);
+ printf("\tmax len : file=%x sym=%x\n",
+ f->max_filename_len, f->max_symlink_len);
+}
+
+static void dump_attr_supports(union reply *r, int size)
+{
+ struct fsinfo_supports *f = &r->supports;
+
+ printf("\n");
+ printf("\tstx_attr=%llx\n", f->stx_attributes);
+ printf("\tstx_mask=%x\n", f->stx_mask);
+ printf("\tioc_flags=%x\n", f->ioc_flags);
+ printf("\twin_fattrs=%x\n", f->win_file_attrs);
+}
+
+#define FSINFO_CAP_NAME(C) [fsinfo_cap_##C] = #C
+static const char *fsinfo_cap_names[fsinfo_cap__nr] = {
+ FSINFO_CAP_NAME(is_kernel_fs),
+ FSINFO_CAP_NAME(is_block_fs),
+ FSINFO_CAP_NAME(is_flash_fs),
+ FSINFO_CAP_NAME(is_network_fs),
+ FSINFO_CAP_NAME(is_automounter_fs),
+ FSINFO_CAP_NAME(automounts),
+ FSINFO_CAP_NAME(adv_locks),
+ FSINFO_CAP_NAME(mand_locks),
+ FSINFO_CAP_NAME(leases),
+ FSINFO_CAP_NAME(uids),
+ FSINFO_CAP_NAME(gids),
+ FSINFO_CAP_NAME(projids),
+ FSINFO_CAP_NAME(id_names),
+ FSINFO_CAP_NAME(id_guids),
+ FSINFO_CAP_NAME(windows_attrs),
+ FSINFO_CAP_NAME(user_quotas),
+ FSINFO_CAP_NAME(group_quotas),
+ FSINFO_CAP_NAME(project_quotas),
+ FSINFO_CAP_NAME(xattrs),
+ FSINFO_CAP_NAME(journal),
+ FSINFO_CAP_NAME(data_is_journalled),
+ FSINFO_CAP_NAME(o_sync),
+ FSINFO_CAP_NAME(o_direct),
+ FSINFO_CAP_NAME(volume_id),
+ FSINFO_CAP_NAME(volume_uuid),
+ FSINFO_CAP_NAME(volume_name),
+ FSINFO_CAP_NAME(volume_fsid),
+ FSINFO_CAP_NAME(cell_name),
+ FSINFO_CAP_NAME(domain_name),
+ FSINFO_CAP_NAME(realm_name),
+ FSINFO_CAP_NAME(iver_all_change),
+ FSINFO_CAP_NAME(iver_data_change),
+ FSINFO_CAP_NAME(iver_mono_incr),
+ FSINFO_CAP_NAME(symlinks),
+ FSINFO_CAP_NAME(hard_links),
+ FSINFO_CAP_NAME(hard_links_1dir),
+ FSINFO_CAP_NAME(device_files),
+ FSINFO_CAP_NAME(unix_specials),
+ FSINFO_CAP_NAME(resource_forks),
+ FSINFO_CAP_NAME(name_case_indep),
+ FSINFO_CAP_NAME(name_non_utf8),
+ FSINFO_CAP_NAME(name_has_codepage),
+ FSINFO_CAP_NAME(sparse),
+ FSINFO_CAP_NAME(not_persistent),
+ FSINFO_CAP_NAME(no_unix_mode),
+ FSINFO_CAP_NAME(has_atime),
+ FSINFO_CAP_NAME(has_btime),
+ FSINFO_CAP_NAME(has_ctime),
+ FSINFO_CAP_NAME(has_mtime),
+};
+
+static void dump_attr_capabilities(union reply *r, int size)
+{
+ struct fsinfo_capabilities *f = &r->caps;
+ int i;
+
+ for (i = 0; i < sizeof(f->capabilities); i++)
+ printf("%02x", f->capabilities[i]);
+ printf("\n");
+ for (i = 0; i < fsinfo_cap__nr; i++)
+ if (f->capabilities[i / 8] & (1 << (i % 8)))
+ printf("\t- %s\n", fsinfo_cap_names[i]);
+}
+
+static void dump_attr_timestamp_info(union reply *r, int size)
+{
+ struct fsinfo_timestamp_info *f = &r->timestamps;
+
+ printf("range=%llx-%llx\n",
+ (unsigned long long)f->minimum_timestamp,
+ (unsigned long long)f->maximum_timestamp);
+
+#define print_time(G) \
+ printf("\t"#G"time : gran=%gs\n", \
+ (f->G##time_gran_mantissa * \
+ pow(10., f->G##time_gran_exponent)))
+ print_time(a);
+ print_time(b);
+ print_time(c);
+ print_time(m);
+}
+
+static void dump_attr_volume_uuid(union reply *r, int size)
+{
+ struct fsinfo_volume_uuid *f = &r->uuid;
+
+ printf("%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x"
+ "-%02x%02x%02x%02x%02x%02x\n",
+ f->uuid[ 0], f->uuid[ 1],
+ f->uuid[ 2], f->uuid[ 3],
+ f->uuid[ 4], f->uuid[ 5],
+ f->uuid[ 6], f->uuid[ 7],
+ f->uuid[ 8], f->uuid[ 9],
+ f->uuid[10], f->uuid[11],
+ f->uuid[12], f->uuid[13],
+ f->uuid[14], f->uuid[15]);
+}
+
+static void dump_attr_server_address(union reply *r, int size)
+{
+ struct fsinfo_server_address *f = &r->srv_addr;
+
+ printf("family=%u\n", f->address.ss_family);
+}
+
+static void dump_attr_io_size(union reply *r, int size)
+{
+ struct fsinfo_io_size *f = &r->io_size;
+
+ printf("dio_size=%u\n", f->dio_size_gran);
+}
+
+/*
+ *
+ */
+typedef void (*dumper_t)(union reply *r, int size);
+
+#define FSINFO_DUMPER(N) [fsinfo_attr_##N] = dump_attr_##N
+static const dumper_t fsinfo_attr_dumper[fsinfo_attr__nr] = {
+ FSINFO_DUMPER(statfs),
+ FSINFO_DUMPER(fsinfo),
+ FSINFO_DUMPER(ids),
+ FSINFO_DUMPER(limits),
+ FSINFO_DUMPER(supports),
+ FSINFO_DUMPER(capabilities),
+ FSINFO_DUMPER(timestamp_info),
+ FSINFO_DUMPER(volume_uuid),
+ FSINFO_DUMPER(server_address),
+ FSINFO_DUMPER(io_size),
+};
+
+static void dump_fsinfo(enum fsinfo_attribute attr, __u8 about,
+ union reply *r, int size)
+{
+ dumper_t dumper = fsinfo_attr_dumper[attr];
+ unsigned int len;
+
+ if (!dumper) {
+ printf("<no dumper>\n");
+ return;
+ }
+
+ len = (about & 0x3f) * sizeof(__u32);
+ if (size < len) {
+ printf("<short data %u/%u>\n", size, len);
+ return;
+ }
+
+ dumper(r, size);
+}
+
+/*
+ * Try one subinstance of an attribute.
+ */
+static int try_one(const char *file, struct fsinfo_params *params, bool raw)
+{
+ union reply r;
+ char *p;
+ int ret;
+ __u8 about;
+
+ memset(&r.buffer, 0xbd, sizeof(r.buffer));
+
+ errno = 0;
+ ret = fsinfo(AT_FDCWD, file, params, r.buffer, sizeof(r.buffer));
+ if (params->request >= fsinfo_attr__nr) {
+ if (ret == -1 && errno == EOPNOTSUPP)
+ exit(0);
+ fprintf(stderr, "Unexpected error for too-large command %u: %m\n",
+ params->request);
+ exit(1);
+ }
+
+ //printf("fsinfo(%s,%s,%u,%u) = %d: %m\n",
+ // file, fsinfo_attr_names[params->request],
+ // params->Nth, params->Mth, ret);
+
+ about = fsinfo_buffer_sizes[params->request];
+ if (ret == -1) {
+ if (errno == ENODATA) {
+ switch (about & 0xc0) {
+ case 0x00:
+ if (params->Nth == 0 && params->Mth == 0) {
+ fprintf(stderr,
+ "Unexpected ENODATA1 (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ break;
+ case 0x40:
+ if (params->Nth == 0 && params->Mth == 0) {
+ fprintf(stderr,
+ "Unexpected ENODATA2 (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ break;
+ }
+ return (params->Mth == 0) ? 2 : 1;
+ }
+ if (errno == EOPNOTSUPP) {
+ if (params->Nth > 0 || params->Mth > 0) {
+ fprintf(stderr,
+ "Should return -ENODATA (%u[%u][%u])\n",
+ params->request, params->Nth, params->Mth);
+ exit(1);
+ }
+ //printf("\e[33m%s\e[m: <not supported>\n",
+ // fsinfo_attr_names[attr]);
+ return 2;
+ }
+ perror(file);
+ exit(1);
+ }
+
+ if (raw) {
+ if (ret > 4096)
+ ret = 4096;
+ dump_hex((unsigned int *)&r.buffer, 0, ret);
+ return 0;
+ }
+
+ switch (about & 0xc0) {
+ case 0x00:
+ printf("\e[33m%s\e[m: ",
+ fsinfo_attr_names[params->request]);
+ break;
+ case 0x40:
+ printf("\e[33m%s[%u]\e[m: ",
+ fsinfo_attr_names[params->request],
+ params->Nth);
+ break;
+ case 0x80:
+ printf("\e[33m%s[%u][%u]\e[m: ",
+ fsinfo_attr_names[params->request],
+ params->Nth, params->Mth);
+ break;
+ }
+
+ switch (about) {
+ /* Struct */
+ case 0x01 ... 0x3f:
+ case 0x41 ... 0x7f:
+ case 0x81 ... 0xbf:
+ dump_fsinfo(params->request, about, &r, ret);
+ return 0;
+
+ /* String */
+ case 0x00:
+ case 0x40:
+ case 0x80:
+ if (ret >= 4096) {
+ ret = 4096;
+ r.buffer[4092] = '.';
+ r.buffer[4093] = '.';
+ r.buffer[4094] = '.';
+ r.buffer[4095] = 0;
+ } else {
+ r.buffer[ret] = 0;
+ }
+ for (p = r.buffer; *p; p++) {
+ if (!isprint(*p)) {
+ printf("<non-printable>\n");
+ continue;
+ }
+ }
+ printf("%s\n", r.buffer);
+ return 0;
+
+ default:
+ fprintf(stderr, "Fishy about %u %02x\n", params->request, about);
+ exit(1);
+ }
+}
+
+/*
+ *
+ */
+int main(int argc, char **argv)
+{
+ struct fsinfo_params params = {
+ .at_flags = AT_SYMLINK_NOFOLLOW,
+ };
+ unsigned int attr;
+ int raw = 0, opt, Nth, Mth;
+
+ while ((opt = getopt(argc, argv, "alr"))) {
+ switch (opt) {
+ case 'a':
+ params.at_flags |= AT_NO_AUTOMOUNT;
+ continue;
+ case 'l':
+ params.at_flags &= ~AT_SYMLINK_NOFOLLOW;
+ continue;
+ case 'r':
+ raw = 1;
+ continue;
+ }
+ break;
+ }
+
+ argc -= optind;
+ argv += optind;
+
+ if (argc != 1) {
+ printf("Format: test-fsinfo [-alr] <file>\n");
+ exit(2);
+ }
+
+ for (attr = 0; attr <= fsinfo_attr__nr; attr++) {
+ Nth = 0;
+ do {
+ Mth = 0;
+ do {
+ params.request = attr;
+ params.Nth = Nth;
+ params.Mth = Mth;
+
+ switch (try_one(argv[0], ¶ms, raw)) {
+ case 0:
+ continue;
+ case 1:
+ goto done_M;
+ case 2:
+ goto done_N;
+ }
+ } while (++Mth < 100);
+
+ done_M:
+ if (Mth >= 100) {
+ fprintf(stderr, "Fishy: Mth == %u\n", Mth);
+ break;
+ }
+
+ } while (++Nth < 100);
+
+ done_N:
+ if (Nth >= 100) {
+ fprintf(stderr, "Fishy: Nth == %u\n", Nth);
+ break;
+ }
+ }
+
+ return 0;
+}
^ permalink raw reply related
* [PATCH 31/38] vfs: syscall: Add fspick() to select a superblock for reconfiguration [ver #10]
From: David Howells @ 2018-07-27 17:34 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Provide an fspick() system call that can be used to pick an existing
mountpoint into an fs_context which can thereafter be used to reconfigure a
superblock (equivalent of the superblock side of -o remount).
This looks like:
int fd = fspick(AT_FDCWD, "/mnt",
FSPICK_CLOEXEC | FSPICK_NO_AUTOMOUNT);
fsconfig(fd, fsconfig_set_flag, "intr", NULL, 0);
fsconfig(fd, fsconfig_set_flag, "noac", NULL, 0);
fsconfig(fd, fsconfig_cmd_reconfigure, NULL, NULL, 0);
At the point of fspick being called, the file descriptor referring to the
filesystem context is in exactly the same state as the one that was created
by fsopen() after fsmount() has been successfully called.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
fs/fsopen.c | 58 ++++++++++++++++++++++++++++++++
include/linux/syscalls.h | 1 +
include/uapi/linux/fs.h | 5 +++
5 files changed, 66 insertions(+)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index c78b68256f8a..d1eb6c815790 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -403,3 +403,4 @@
389 i386 fsopen sys_fsopen __ia32_sys_fsopen
390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
391 i386 fsmount sys_fsmount __ia32_sys_fsmount
+392 i386 fspick sys_fspick __ia32_sys_fspick
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index d44ead5d4368..d3ab703c02bb 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -348,6 +348,7 @@
337 common fsopen __x64_sys_fsopen
338 common fsconfig __x64_sys_fsconfig
339 common fsmount __x64_sys_fsmount
+340 common fspick __x64_sys_fspick
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/fsopen.c b/fs/fsopen.c
index d2d23c02839a..51ce50904988 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -155,6 +155,64 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
return ret;
}
+/*
+ * Pick a superblock into a context for reconfiguration.
+ */
+SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags)
+{
+ struct fs_context *fc;
+ struct path target;
+ unsigned int lookup_flags;
+ int ret;
+
+ if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if ((flags & ~(FSPICK_CLOEXEC |
+ FSPICK_SYMLINK_NOFOLLOW |
+ FSPICK_NO_AUTOMOUNT |
+ FSPICK_EMPTY_PATH)) != 0)
+ return -EINVAL;
+
+ lookup_flags = LOOKUP_FOLLOW | LOOKUP_AUTOMOUNT;
+ if (flags & FSPICK_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (flags & FSPICK_NO_AUTOMOUNT)
+ lookup_flags &= ~LOOKUP_AUTOMOUNT;
+ if (flags & FSPICK_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+ ret = user_path_at(dfd, path, lookup_flags, &target);
+ if (ret < 0)
+ goto err;
+
+ ret = -EOPNOTSUPP;
+ if (!target.dentry->d_sb->s_op->reconfigure)
+ goto err_path;
+
+ fc = vfs_new_fs_context(target.dentry->d_sb->s_type, target.dentry,
+ 0, FS_CONTEXT_FOR_RECONFIGURE);
+ if (IS_ERR(fc)) {
+ ret = PTR_ERR(fc);
+ goto err_path;
+ }
+
+ fc->phase = FS_CONTEXT_RECONF_PARAMS;
+
+ ret = fscontext_alloc_log(fc);
+ if (ret < 0)
+ goto err_fc;
+
+ path_put(&target);
+ return fscontext_create_fd(fc, flags & FSPICK_CLOEXEC ? O_CLOEXEC : 0);
+
+err_fc:
+ put_fs_context(fc);
+err_path:
+ path_put(&target);
+err:
+ return ret;
+}
+
/*
* Check the state and apply the configuration. Note that this function is
* allowed to 'steal' the value by setting param->xxx to NULL before returning.
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 65db661cc2da..701522957a12 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -908,6 +908,7 @@ asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key,
const void __user *value, int aux);
asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
+asmlinkage long sys_fspick(int dfd, const char __user *path, unsigned int flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 297362908d01..be70cbac21b4 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -351,6 +351,11 @@ typedef int __bitwise __kernel_rwf_t;
#define FSMOUNT_CLOEXEC 0x00000001
+#define FSPICK_CLOEXEC 0x00000001
+#define FSPICK_SYMLINK_NOFOLLOW 0x00000002
+#define FSPICK_NO_AUTOMOUNT 0x00000004
+#define FSPICK_EMPTY_PATH 0x00000008
+
/*
* The type of fsconfig() call made.
*/
^ permalink raw reply related
* [PATCH 30/38] vfs: syscall: Add fsmount() to create a mount for a superblock [ver #10]
From: David Howells @ 2018-07-27 17:34 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Provide a system call by which a filesystem opened with fsopen() and
configured by a series of writes can be mounted:
int ret = fsmount(int fsfd, unsigned int flags,
unsigned int ms_flags);
where fsfd is the file descriptor returned by fsopen(). flags can be 0 or
FSMOUNT_CLOEXEC. ms_flags is a bitwise-OR of the following flags:
MS_RDONLY
MS_NOSUID
MS_NODEV
MS_NOEXEC
MS_NOATIME
MS_NODIRATIME
MS_RELATIME
MS_STRICTATIME
MS_UNBINDABLE
MS_PRIVATE
MS_SLAVE
MS_SHARED
In the event that fsmount() fails, it may be possible to get an error
message by calling read() on fsfd. If no message is available, ENODATA
will be reported.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/namespace.c | 140 +++++++++++++++++++++++++++++++-
include/linux/syscalls.h | 1
include/uapi/linux/fs.h | 2
5 files changed, 141 insertions(+), 4 deletions(-)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index f9970310c126..c78b68256f8a 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -402,3 +402,4 @@
388 i386 move_mount sys_move_mount __ia32_sys_move_mount
389 i386 fsopen sys_fsopen __ia32_sys_fsopen
390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
+391 i386 fsmount sys_fsmount __ia32_sys_fsmount
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 4185d36e03bb..d44ead5d4368 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -347,6 +347,7 @@
336 common move_mount __x64_sys_move_mount
337 common fsopen __x64_sys_fsopen
338 common fsconfig __x64_sys_fsconfig
+339 common fsmount __x64_sys_fsmount
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/namespace.c b/fs/namespace.c
index ea07066a2731..b1661b90256d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2503,7 +2503,7 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
attached = mnt_has_parent(old);
/*
- * We need to allow open_tree(OPEN_TREE_CLONE) followed by
+ * We need to allow open_tree(OPEN_TREE_CLONE) or fsmount() followed by
* move_mount(), but mustn't allow "/" to be moved.
*/
if (old->mnt_ns && !attached)
@@ -3348,9 +3348,141 @@ struct vfsmount *kern_mount(struct file_system_type *type)
EXPORT_SYMBOL_GPL(kern_mount);
/*
- * Move a mount from one place to another.
- * In combination with open_tree(OPEN_TREE_CLONE [| AT_RECURSIVE]) it can be
- * used to copy a mount subtree.
+ * Create a kernel mount representation for a new, prepared superblock
+ * (specified by fs_fd) and attach to an open_tree-like file descriptor.
+ */
+SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags, unsigned int, ms_flags)
+{
+ struct fs_context *fc;
+ struct file *file;
+ struct path newmount;
+ struct fd f;
+ unsigned int mnt_flags = 0;
+ long ret;
+
+ if (!may_mount())
+ return -EPERM;
+
+ if ((flags & ~(FSMOUNT_CLOEXEC)) != 0)
+ return -EINVAL;
+
+ if (ms_flags & ~(MS_RDONLY | MS_NOSUID | MS_NODEV | MS_NOEXEC |
+ MS_NOATIME | MS_NODIRATIME | MS_RELATIME |
+ MS_STRICTATIME))
+ return -EINVAL;
+
+ if (ms_flags & MS_RDONLY)
+ mnt_flags |= MNT_READONLY;
+ if (ms_flags & MS_NOSUID)
+ mnt_flags |= MNT_NOSUID;
+ if (ms_flags & MS_NODEV)
+ mnt_flags |= MNT_NODEV;
+ if (ms_flags & MS_NOEXEC)
+ mnt_flags |= MNT_NOEXEC;
+ if (ms_flags & MS_NODIRATIME)
+ mnt_flags |= MNT_NODIRATIME;
+
+ if (ms_flags & MS_STRICTATIME) {
+ if (ms_flags & MS_NOATIME)
+ return -EINVAL;
+ } else if (ms_flags & MS_NOATIME) {
+ mnt_flags |= MNT_NOATIME;
+ } else {
+ mnt_flags |= MNT_RELATIME;
+ }
+
+ f = fdget(fs_fd);
+ if (!f.file)
+ return -EBADF;
+
+ ret = -EINVAL;
+ if (f.file->f_op != &fscontext_fops)
+ goto err_fsfd;
+
+ fc = f.file->private_data;
+
+ /* There must be a valid superblock or we can't mount it */
+ ret = -EINVAL;
+ if (!fc->root)
+ goto err_fsfd;
+
+ ret = -EPERM;
+ if (mount_too_revealing(fc->root->d_sb, &mnt_flags)) {
+ pr_warn("VFS: Mount too revealing\n");
+ goto err_fsfd;
+ }
+
+ ret = mutex_lock_interruptible(&fc->uapi_mutex);
+ if (ret < 0)
+ goto err_fsfd;
+
+ ret = -EBUSY;
+ if (fc->phase != FS_CONTEXT_AWAITING_MOUNT)
+ goto err_unlock;
+
+ ret = -EPERM;
+ if ((fc->sb_flags & SB_MANDLOCK) && !may_mandlock())
+ goto err_unlock;
+
+ newmount.mnt = vfs_create_mount(fc, mnt_flags);
+ if (IS_ERR(newmount.mnt)) {
+ ret = PTR_ERR(newmount.mnt);
+ goto err_unlock;
+ }
+ newmount.dentry = dget(fc->root);
+
+ /* We've done the mount bit - now move the file context into more or
+ * less the same state as if we'd done an fspick(). We don't want to
+ * do any memory allocation or anything like that at this point as we
+ * don't want to have to handle any errors incurred.
+ */
+ if (fc->ops && fc->ops->free)
+ fc->ops->free(fc);
+ fc->fs_private = NULL;
+ fc->s_fs_info = NULL;
+ fc->sb_flags = 0;
+ fc->sloppy = false;
+ fc->silent = false;
+ security_fs_context_free(fc);
+ fc->security = NULL;
+ kfree(fc->subtype);
+ fc->subtype = NULL;
+ kfree(fc->source);
+ fc->source = NULL;
+
+ fc->purpose = FS_CONTEXT_FOR_RECONFIGURE;
+ fc->phase = FS_CONTEXT_AWAITING_RECONF;
+
+ /* Attach to an apparent O_PATH fd with a note that we need to unmount
+ * it, not just simply put it.
+ */
+ file = dentry_open(&newmount, O_PATH, fc->cred);
+ if (IS_ERR(file)) {
+ ret = PTR_ERR(file);
+ goto err_path;
+ }
+ file->f_mode |= FMODE_NEED_UNMOUNT;
+
+ ret = get_unused_fd_flags((flags & FSMOUNT_CLOEXEC) ? O_CLOEXEC : 0);
+ if (ret >= 0)
+ fd_install(ret, file);
+ else
+ fput(file);
+
+err_path:
+ path_put(&newmount);
+err_unlock:
+ mutex_unlock(&fc->uapi_mutex);
+err_fsfd:
+ fdput(f);
+ return ret;
+}
+
+/*
+ * Move a mount from one place to another. In combination with
+ * fsopen()/fsmount() this is used to install a new mount and in combination
+ * with open_tree(OPEN_TREE_CLONE [| AT_RECURSIVE]) it can be used to copy
+ * a mount subtree.
*
* Note the flags value is a combination of MOVE_MOUNT_* flags.
*/
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 9628d14a7ede..65db661cc2da 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -907,6 +907,7 @@ asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key,
const void __user *value, int aux);
+asmlinkage long sys_fsmount(int fs_fd, unsigned int flags, unsigned int ms_flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 7c9e165e8689..297362908d01 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -349,6 +349,8 @@ typedef int __bitwise __kernel_rwf_t;
*/
#define FSOPEN_CLOEXEC 0x00000001
+#define FSMOUNT_CLOEXEC 0x00000001
+
/*
* The type of fsconfig() call made.
*/
^ permalink raw reply related
* [PATCH 29/38] vfs: syscall: Add fsconfig() for configuring and managing a context [ver #10]
From: David Howells @ 2018-07-27 17:34 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Add a syscall for configuring a filesystem creation context and triggering
actions upon it, to be used in conjunction with fsopen, fspick and fsmount.
long fsconfig(int fs_fd, unsigned int cmd, const char *key,
const void *value, int aux);
Where fs_fd indicates the context, cmd indicates the action to take, key
indicates the parameter name for parameter-setting actions and, if needed,
value points to a buffer containing the value and aux can give more
information for the value.
The following command IDs are proposed:
(*) fsconfig_set_flag: No value is specified. The parameter must be
boolean in nature. The key may be prefixed with "no" to invert the
setting. value must be NULL and aux must be 0.
(*) fsconfig_set_string: A string value is specified. The parameter can
be expecting boolean, integer, string or take a path. A conversion to
an appropriate type will be attempted (which may include looking up as
a path). value points to a NUL-terminated string and aux must be 0.
(*) fsconfig_set_binary: A binary blob is specified. value points to
the blob and aux indicates its size. The parameter must be expecting
a blob.
(*) fsconfig_set_path: A non-empty path is specified. The parameter must
be expecting a path object. value points to a NUL-terminated string
that is the path and aux is a file descriptor at which to start a
relative lookup or AT_FDCWD.
(*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH
implied.
(*) fsconfig_set_fd: An open file descriptor is specified. value must
be NULL and aux indicates the file descriptor.
(*) fsconfig_cmd_create: Trigger superblock creation.
(*) fsconfig_cmd_reconfigure: Trigger superblock reconfiguration.
For the "set" command IDs, the idea is that the file_system_type will point
to a list of parameters and the types of value that those parameters expect
to take. The core code can then do the parse and argument conversion and
then give the LSM and FS a cooked option or array of options to use.
Source specification is also done the same way same way, using special keys
"source", "source1", "source2", etc..
[!] Note that, for the moment, the key and value are just glued back
together and handed to the filesystem. Every filesystem that uses options
uses match_token() and co. to do this, and this will need to be changed -
but not all at once.
Example usage:
fd = fsopen("ext4", FSOPEN_CLOEXEC);
fsconfig(fd, fsconfig_set_path, "source", "/dev/sda1", AT_FDCWD);
fsconfig(fd, fsconfig_set_path_empty, "journal_path", "", journal_fd);
fsconfig(fd, fsconfig_set_fd, "journal_fd", "", journal_fd);
fsconfig(fd, fsconfig_set_flag, "user_xattr", NULL, 0);
fsconfig(fd, fsconfig_set_flag, "noacl", NULL, 0);
fsconfig(fd, fsconfig_set_string, "sb", "1", 0);
fsconfig(fd, fsconfig_set_string, "errors", "continue", 0);
fsconfig(fd, fsconfig_set_string, "data", "journal", 0);
fsconfig(fd, fsconfig_set_string, "context", "unconfined_u:...", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC);
or:
fd = fsopen("ext4", FSOPEN_CLOEXEC);
fsconfig(fd, fsconfig_set_string, "source", "/dev/sda1", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC);
or:
fd = fsopen("afs", FSOPEN_CLOEXEC);
fsconfig(fd, fsconfig_set_string, "source", "#grand.central.org:root.cell", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC);
or:
fd = fsopen("jffs2", FSOPEN_CLOEXEC);
fsconfig(fd, fsconfig_set_string, "source", "mtd0", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(fd, FSMOUNT_CLOEXEC, MS_NOEXEC);
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/fsopen.c | 278 ++++++++++++++++++++++++++++++++
include/linux/syscalls.h | 2
include/uapi/linux/fs.h | 14 ++
5 files changed, 296 insertions(+)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 1647fefd2969..f9970310c126 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -401,3 +401,4 @@
387 i386 open_tree sys_open_tree __ia32_sys_open_tree
388 i386 move_mount sys_move_mount __ia32_sys_move_mount
389 i386 fsopen sys_fsopen __ia32_sys_fsopen
+390 i386 fsconfig sys_fsconfig __ia32_sys_fsconfig
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 235d33dbccb2..4185d36e03bb 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -346,6 +346,7 @@
335 common open_tree __x64_sys_open_tree
336 common move_mount __x64_sys_move_mount
337 common fsopen __x64_sys_fsopen
+338 common fsconfig __x64_sys_fsconfig
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/fsopen.c b/fs/fsopen.c
index 7a25b4c3bc18..d2d23c02839a 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -10,6 +10,7 @@
*/
#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
@@ -17,6 +18,7 @@
#include <linux/anon_inodes.h>
#include <linux/namei.h>
#include <linux/file.h>
+#include "internal.h"
#include "mount.h"
/*
@@ -152,3 +154,279 @@ SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
put_fs_context(fc);
return ret;
}
+
+/*
+ * Check the state and apply the configuration. Note that this function is
+ * allowed to 'steal' the value by setting param->xxx to NULL before returning.
+ */
+static int vfs_fsconfig(struct fs_context *fc, struct fs_parameter *param)
+{
+ int ret;
+
+ /* We need to reinitialise the context if we have reconfiguration
+ * pending after creation or a previous reconfiguration.
+ */
+ if (fc->phase == FS_CONTEXT_AWAITING_RECONF) {
+ if (fc->fs_type->init_fs_context) {
+ ret = fc->fs_type->init_fs_context(fc, fc->root);
+ if (ret < 0) {
+ fc->phase = FS_CONTEXT_FAILED;
+ return ret;
+ }
+ } else {
+ /* Leave legacy context ops in place */
+ }
+
+ /* Do the security check last because ->init_fs_context may
+ * change the namespace subscriptions.
+ */
+ ret = security_fs_context_alloc(fc, fc->root);
+ if (ret < 0) {
+ fc->phase = FS_CONTEXT_FAILED;
+ return ret;
+ }
+
+ fc->phase = FS_CONTEXT_RECONF_PARAMS;
+ }
+
+ if (fc->phase != FS_CONTEXT_CREATE_PARAMS &&
+ fc->phase != FS_CONTEXT_RECONF_PARAMS)
+ return -EBUSY;
+
+ return vfs_parse_fs_param(fc, param);
+}
+
+/*
+ * Perform an action on a context.
+ */
+static int vfs_fsconfig_action(struct fs_context *fc, enum fsconfig_command cmd)
+{
+ int ret = -EINVAL;
+
+ switch (cmd) {
+ case fsconfig_cmd_create:
+ if (fc->phase != FS_CONTEXT_CREATE_PARAMS)
+ return -EBUSY;
+ fc->phase = FS_CONTEXT_CREATING;
+ ret = vfs_get_tree(fc);
+ if (ret == 0)
+ fc->phase = FS_CONTEXT_AWAITING_MOUNT;
+ else
+ fc->phase = FS_CONTEXT_FAILED;
+ return ret;
+
+ default:
+ return -EOPNOTSUPP;
+ }
+}
+
+/**
+ * sys_fsconfig - Set parameters and trigger actions on a context
+ * @fd: The filesystem context to act upon
+ * @cmd: The action to take
+ * @_key: Where appropriate, the parameter key to set
+ * @_value: Where appropriate, the parameter value to set
+ * @aux: Additional information for the value
+ *
+ * This system call is used to set parameters on a context, including
+ * superblock settings, data source and security labelling.
+ *
+ * Actions include triggering the creation of a superblock and the
+ * reconfiguration of the superblock attached to the specified context.
+ *
+ * When setting a parameter, @cmd indicates the type of value being proposed
+ * and @_key indicates the parameter to be altered.
+ *
+ * @_value and @aux are used to specify the value, should a value be required:
+ *
+ * (*) fsconfig_set_flag: No value is specified. The parameter must be boolean
+ * in nature. The key may be prefixed with "no" to invert the
+ * setting. @_value must be NULL and @aux must be 0.
+ *
+ * (*) fsconfig_set_string: A string value is specified. The parameter can be
+ * expecting boolean, integer, string or take a path. A conversion to an
+ * appropriate type will be attempted (which may include looking up as a
+ * path). @_value points to a NUL-terminated string and @aux must be 0.
+ *
+ * (*) fsconfig_set_binary: A binary blob is specified. @_value points to the
+ * blob and @aux indicates its size. The parameter must be expecting a
+ * blob.
+ *
+ * (*) fsconfig_set_path: A non-empty path is specified. The parameter must be
+ * expecting a path object. @_value points to a NUL-terminated string that
+ * is the path and @aux is a file descriptor at which to start a relative
+ * lookup or AT_FDCWD.
+ *
+ * (*) fsconfig_set_path_empty: As fsconfig_set_path, but with AT_EMPTY_PATH
+ * implied.
+ *
+ * (*) fsconfig_set_fd: An open file descriptor is specified. @_value must be
+ * NULL and @aux indicates the file descriptor.
+ */
+SYSCALL_DEFINE5(fsconfig,
+ int, fd,
+ unsigned int, cmd,
+ const char __user *, _key,
+ const void __user *, _value,
+ int, aux)
+{
+ struct fs_context *fc;
+ struct fd f;
+ int ret;
+
+ struct fs_parameter param = {
+ .type = fs_value_is_undefined,
+ };
+
+ if (fd < 0)
+ return -EINVAL;
+
+ switch (cmd) {
+ case fsconfig_set_flag:
+ if (!_key || _value || aux)
+ return -EINVAL;
+ break;
+ case fsconfig_set_string:
+ if (!_key || !_value || aux)
+ return -EINVAL;
+ break;
+ case fsconfig_set_binary:
+ if (!_key || !_value || aux <= 0 || aux > 1024 * 1024)
+ return -EINVAL;
+ break;
+ case fsconfig_set_path:
+ case fsconfig_set_path_empty:
+ if (!_key || !_value || (aux != AT_FDCWD && aux < 0))
+ return -EINVAL;
+ break;
+ case fsconfig_set_fd:
+ if (!_key || _value || aux < 0)
+ return -EINVAL;
+ break;
+ case fsconfig_cmd_create:
+ case fsconfig_cmd_reconfigure:
+ if (_key || _value || aux)
+ return -EINVAL;
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ f = fdget(fd);
+ if (!f.file)
+ return -EBADF;
+ ret = -EINVAL;
+ if (f.file->f_op != &fscontext_fops)
+ goto out_f;
+
+ fc = f.file->private_data;
+ if (fc->ops == &legacy_fs_context_ops) {
+ switch (cmd) {
+ case fsconfig_set_binary:
+ case fsconfig_set_path:
+ case fsconfig_set_path_empty:
+ case fsconfig_set_fd:
+ ret = -EOPNOTSUPP;
+ goto out_f;
+ }
+ }
+
+ if (_key) {
+ param.key = strndup_user(_key, 256);
+ if (IS_ERR(param.key)) {
+ ret = PTR_ERR(param.key);
+ goto out_f;
+ }
+ }
+
+ switch (cmd) {
+ case fsconfig_set_string:
+ param.type = fs_value_is_string;
+ param.string = strndup_user(_value, 256);
+ if (IS_ERR(param.string)) {
+ ret = PTR_ERR(param.string);
+ goto out_key;
+ }
+ param.size = strlen(param.string);
+ break;
+ case fsconfig_set_binary:
+ param.type = fs_value_is_blob;
+ param.size = aux;
+ param.blob = memdup_user_nul(_value, aux);
+ if (IS_ERR(param.blob)) {
+ ret = PTR_ERR(param.blob);
+ goto out_key;
+ }
+ break;
+ case fsconfig_set_path:
+ param.type = fs_value_is_filename;
+ param.name = getname_flags(_value, 0, NULL);
+ if (IS_ERR(param.name)) {
+ ret = PTR_ERR(param.name);
+ goto out_key;
+ }
+ param.dirfd = aux;
+ param.size = strlen(param.name->name);
+ break;
+ case fsconfig_set_path_empty:
+ param.type = fs_value_is_filename_empty;
+ param.name = getname_flags(_value, LOOKUP_EMPTY, NULL);
+ if (IS_ERR(param.name)) {
+ ret = PTR_ERR(param.name);
+ goto out_key;
+ }
+ param.dirfd = aux;
+ param.size = strlen(param.name->name);
+ break;
+ case fsconfig_set_fd:
+ param.type = fs_value_is_file;
+ ret = -EBADF;
+ param.file = fget(aux);
+ if (!param.file)
+ goto out_key;
+ break;
+ default:
+ break;
+ }
+
+ ret = mutex_lock_interruptible(&fc->uapi_mutex);
+ if (ret == 0) {
+ switch (cmd) {
+ case fsconfig_cmd_create:
+ case fsconfig_cmd_reconfigure:
+ ret = vfs_fsconfig_action(fc, cmd);
+ break;
+ default:
+ ret = vfs_fsconfig(fc, ¶m);
+ break;
+ }
+ mutex_unlock(&fc->uapi_mutex);
+ }
+
+ /* Clean up the our record of any value that we obtained from
+ * userspace. Note that the value may have been stolen by the LSM or
+ * filesystem, in which case the value pointer will have been cleared.
+ */
+ switch (cmd) {
+ case fsconfig_set_string:
+ case fsconfig_set_binary:
+ kfree(param.string);
+ break;
+ case fsconfig_set_path:
+ case fsconfig_set_path_empty:
+ if (param.name)
+ putname(param.name);
+ break;
+ case fsconfig_set_fd:
+ if (param.file)
+ fput(param.file);
+ break;
+ default:
+ break;
+ }
+out_key:
+ kfree(param.key);
+out_f:
+ fdput(f);
+ return ret;
+}
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index ad6c7ff33c01..9628d14a7ede 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -905,6 +905,8 @@ asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
int to_dfd, const char __user *to_path,
unsigned int ms_flags);
asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
+asmlinkage long sys_fsconfig(int fs_fd, unsigned int cmd, const char __user *key,
+ const void __user *value, int aux);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index f8818e6cddd6..7c9e165e8689 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -349,4 +349,18 @@ typedef int __bitwise __kernel_rwf_t;
*/
#define FSOPEN_CLOEXEC 0x00000001
+/*
+ * The type of fsconfig() call made.
+ */
+enum fsconfig_command {
+ fsconfig_set_flag, /* Set parameter, supplying no value */
+ fsconfig_set_string, /* Set parameter, supplying a string value */
+ fsconfig_set_binary, /* Set parameter, supplying a binary blob value */
+ fsconfig_set_path, /* Set parameter, supplying an object by path */
+ fsconfig_set_path_empty, /* Set parameter, supplying an object by (empty) path */
+ fsconfig_set_fd, /* Set parameter, supplying an object by fd */
+ fsconfig_cmd_create, /* Invoke superblock creation */
+ fsconfig_cmd_reconfigure, /* Invoke superblock reconfiguration */
+};
+
#endif /* _UAPI_LINUX_FS_H */
^ permalink raw reply related
* [PATCH 26/38] vfs: syscall: Add fsopen() to prepare for superblock creation [ver #10]
From: David Howells @ 2018-07-27 17:34 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Provide an fsopen() system call that starts the process of preparing to
create a superblock that will then be mountable, using an fd as a context
handle. fsopen() is given the name of the filesystem that will be used:
int mfd = fsopen(const char *fsname, unsigned int flags);
where flags can be 0 or FSOPEN_CLOEXEC.
For example:
sfd = fsopen("ext4", FSOPEN_CLOEXEC);
fsconfig(sfd, fsconfig_set_path, "source", "/dev/sda1", AT_FDCWD);
fsconfig(sfd, fsconfig_set_flag, "noatime", NULL, 0);
fsconfig(sfd, fsconfig_set_flag, "acl", NULL, 0);
fsconfig(sfd, fsconfig_set_flag, "user_xattr", NULL, 0);
fsconfig(sfd, fsconfig_set_string, "sb", "1", 0);
fsconfig(sfd, fsconfig_cmd_create, NULL, NULL, 0);
fsinfo(sfd, NULL, ...); // query new superblock attributes
mfd = fsmount(sfd, FSMOUNT_CLOEXEC, MS_RELATIME);
move_mount(mfd, "", sfd, AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH);
sfd = fsopen("afs", -1);
fsconfig(fd, fsconfig_set_string, "source", "#grand.central.org:root.cell", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(sfd, 0, MS_NODEV);
move_mount(mfd, "", sfd, AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH);
If an error is reported at any step, an error message may be available to be
read() back (ENODATA will be reported if there isn't an error available) in
the form:
"e <subsys>:<problem>"
"e SELinux:Mount on mountpoint not permitted"
Once fsmount() has been called, further fsconfig() calls will incur EBUSY,
even if the fsmount() fails. read() is still possible to retrieve error
information.
The fsopen() syscall creates a mount context and hangs it of the fd that it
returns.
Netlink is not used because it is optional and would make the core VFS
dependent on the networking layer and also potentially add network
namespace issues.
Note that, for the moment, the caller must have SYS_CAP_ADMIN to use
fsopen().
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/Makefile | 2 -
fs/fs_context.c | 4 +
fs/fsopen.c | 87 ++++++++++++++++++++++++++++++++
include/linux/fs_context.h | 4 +
include/linux/syscalls.h | 1
include/uapi/linux/fs.h | 5 ++
8 files changed, 104 insertions(+), 1 deletion(-)
create mode 100644 fs/fsopen.c
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 76d092b7d1b0..1647fefd2969 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -400,3 +400,4 @@
386 i386 rseq sys_rseq __ia32_sys_rseq
387 i386 open_tree sys_open_tree __ia32_sys_open_tree
388 i386 move_mount sys_move_mount __ia32_sys_move_mount
+389 i386 fsopen sys_fsopen __ia32_sys_fsopen
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 37ba4e65eee6..235d33dbccb2 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -345,6 +345,7 @@
334 common rseq __x64_sys_rseq
335 common open_tree __x64_sys_open_tree
336 common move_mount __x64_sys_move_mount
+337 common fsopen __x64_sys_fsopen
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/Makefile b/fs/Makefile
index ae681523b4b1..e3ea8093b178 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -13,7 +13,7 @@ obj-y := open.o read_write.o file_table.o super.o \
seq_file.o xattr.o libfs.o fs-writeback.o \
pnode.o splice.o sync.o utimes.o d_path.o \
stack.o fs_struct.o statfs.o fs_pin.o nsfs.o \
- fs_context.o fs_parser.o
+ fs_context.o fs_parser.o fsopen.o
ifeq ($(CONFIG_BLOCK),y)
obj-y += buffer.o block_dev.o direct-io.o mpage.o
diff --git a/fs/fs_context.c b/fs/fs_context.c
index c298cbfb62a2..7259caf42c24 100644
--- a/fs/fs_context.c
+++ b/fs/fs_context.c
@@ -263,6 +263,8 @@ struct fs_context *vfs_new_fs_context(struct file_system_type *fs_type,
fc->fs_type = get_filesystem(fs_type);
fc->cred = get_current_cred();
+ mutex_init(&fc->uapi_mutex);
+
switch (purpose) {
case FS_CONTEXT_FOR_KERNEL_MOUNT:
fc->sb_flags |= SB_KERNMOUNT;
@@ -347,6 +349,8 @@ struct fs_context *vfs_dup_fs_context(struct fs_context *src_fc)
if (!fc)
return ERR_PTR(-ENOMEM);
+ mutex_init(&fc->uapi_mutex);
+
fc->fs_private = NULL;
fc->s_fs_info = NULL;
fc->source = NULL;
diff --git a/fs/fsopen.c b/fs/fsopen.c
new file mode 100644
index 000000000000..f30080e1ebc4
--- /dev/null
+++ b/fs/fsopen.c
@@ -0,0 +1,87 @@
+/* Filesystem access-by-fd.
+ *
+ * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/fs_context.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/security.h>
+#include <linux/anon_inodes.h>
+#include <linux/namei.h>
+#include <linux/file.h>
+#include "mount.h"
+
+static int fscontext_release(struct inode *inode, struct file *file)
+{
+ struct fs_context *fc = file->private_data;
+
+ if (fc) {
+ file->private_data = NULL;
+ put_fs_context(fc);
+ }
+ return 0;
+}
+
+const struct file_operations fscontext_fops = {
+ .release = fscontext_release,
+ .llseek = no_llseek,
+};
+
+/*
+ * Attach a filesystem context to a file and an fd.
+ */
+static int fscontext_create_fd(struct fs_context *fc, unsigned int o_flags)
+{
+ int fd;
+
+ fd = anon_inode_getfd("fscontext", &fscontext_fops, fc,
+ O_RDWR | o_flags);
+ if (fd < 0)
+ put_fs_context(fc);
+ return fd;
+}
+
+/*
+ * Open a filesystem by name so that it can be configured for mounting.
+ *
+ * We are allowed to specify a container in which the filesystem will be
+ * opened, thereby indicating which namespaces will be used (notably, which
+ * network namespace will be used for network filesystems).
+ */
+SYSCALL_DEFINE2(fsopen, const char __user *, _fs_name, unsigned int, flags)
+{
+ struct file_system_type *fs_type;
+ struct fs_context *fc;
+ const char *fs_name;
+
+ if (!ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (flags & ~FSOPEN_CLOEXEC)
+ return -EINVAL;
+
+ fs_name = strndup_user(_fs_name, PAGE_SIZE);
+ if (IS_ERR(fs_name))
+ return PTR_ERR(fs_name);
+
+ fs_type = get_fs_type(fs_name);
+ kfree(fs_name);
+ if (!fs_type)
+ return -ENODEV;
+
+ fc = vfs_new_fs_context(fs_type, NULL, 0, FS_CONTEXT_FOR_USER_MOUNT);
+ put_filesystem(fs_type);
+ if (IS_ERR(fc))
+ return PTR_ERR(fc);
+
+ fc->phase = FS_CONTEXT_CREATE_PARAMS;
+ return fscontext_create_fd(fc, flags & FSOPEN_CLOEXEC ? O_CLOEXEC : 0);
+}
diff --git a/include/linux/fs_context.h b/include/linux/fs_context.h
index 8d812fcc5f54..488d30de1f4f 100644
--- a/include/linux/fs_context.h
+++ b/include/linux/fs_context.h
@@ -14,6 +14,7 @@
#include <linux/kernel.h>
#include <linux/errno.h>
+#include <linux/mutex.h>
struct cred;
struct dentry;
@@ -87,6 +88,7 @@ struct fs_parameter {
*/
struct fs_context {
const struct fs_context_operations *ops;
+ struct mutex uapi_mutex; /* Userspace access mutex */
struct file_system_type *fs_type;
void *fs_private; /* The filesystem's context */
struct dentry *root; /* The root and superblock */
@@ -142,6 +144,8 @@ extern int vfs_get_super(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
+extern const struct file_operations fscontext_fops;
+
#define logfc(FC, FMT, ...) pr_notice(FMT, ## __VA_ARGS__)
/**
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3c0855d9b105..ad6c7ff33c01 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -904,6 +904,7 @@ asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags);
asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
int to_dfd, const char __user *to_path,
unsigned int ms_flags);
+asmlinkage long sys_fsopen(const char __user *fs_name, unsigned int flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 1c982eb44ff4..f8818e6cddd6 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -344,4 +344,9 @@ typedef int __bitwise __kernel_rwf_t;
#define RWF_SUPPORTED (RWF_HIPRI | RWF_DSYNC | RWF_SYNC | RWF_NOWAIT |\
RWF_APPEND)
+/*
+ * Flags for fsopen() and co.
+ */
+#define FSOPEN_CLOEXEC 0x00000001
+
#endif /* _UAPI_LINUX_FS_H */
^ permalink raw reply related
* [PATCH 02/38] vfs: syscall: Add move_mount(2) to move mounts around [ver #10]
From: David Howells @ 2018-07-27 17:31 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
Add a move_mount() system call that will move a mount from one place to
another and, in the next commit, allow to attach an unattached mount tree.
The new system call looks like the following:
int move_mount(int from_dfd, const char *from_path,
int to_dfd, const char *to_path,
unsigned int flags);
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/namespace.c | 102 ++++++++++++++++++++++++++------
include/linux/lsm_hooks.h | 6 ++
include/linux/security.h | 7 ++
include/linux/syscalls.h | 3 +
include/uapi/linux/mount.h | 11 +++
security/security.c | 5 ++
8 files changed, 118 insertions(+), 18 deletions(-)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index ea1b413afd47..76d092b7d1b0 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -399,3 +399,4 @@
385 i386 io_pgetevents sys_io_pgetevents __ia32_compat_sys_io_pgetevents
386 i386 rseq sys_rseq __ia32_sys_rseq
387 i386 open_tree sys_open_tree __ia32_sys_open_tree
+388 i386 move_mount sys_move_mount __ia32_sys_move_mount
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 0545bed581dc..37ba4e65eee6 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -344,6 +344,7 @@
333 common io_pgetevents __x64_sys_io_pgetevents
334 common rseq __x64_sys_rseq
335 common open_tree __x64_sys_open_tree
+336 common move_mount __x64_sys_move_mount
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/namespace.c b/fs/namespace.c
index a4a01ecbcacd..e2934a4f342b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2447,43 +2447,37 @@ static inline int tree_contains_unbindable(struct mount *mnt)
return 0;
}
-static int do_move_mount(struct path *path, const char *old_name)
+static int do_move_mount(struct path *old_path, struct path *new_path)
{
- struct path old_path, parent_path;
+ struct path parent_path = {.mnt = NULL, .dentry = NULL};
struct mount *p;
struct mount *old;
struct mountpoint *mp;
int err;
- if (!old_name || !*old_name)
- return -EINVAL;
- err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
- if (err)
- return err;
- mp = lock_mount(path);
+ mp = lock_mount(new_path);
err = PTR_ERR(mp);
if (IS_ERR(mp))
goto out;
- old = real_mount(old_path.mnt);
- p = real_mount(path->mnt);
+ old = real_mount(old_path->mnt);
+ p = real_mount(new_path->mnt);
err = -EINVAL;
if (!check_mnt(p) || !check_mnt(old))
goto out1;
- if (old->mnt.mnt_flags & MNT_LOCKED)
+ if (!mnt_has_parent(old))
goto out1;
- err = -EINVAL;
- if (old_path.dentry != old_path.mnt->mnt_root)
+ if (old->mnt.mnt_flags & MNT_LOCKED)
goto out1;
- if (!mnt_has_parent(old))
+ if (old_path->dentry != old_path->mnt->mnt_root)
goto out1;
- if (d_is_dir(path->dentry) !=
- d_is_dir(old_path.dentry))
+ if (d_is_dir(new_path->dentry) !=
+ d_is_dir(old_path->dentry))
goto out1;
/*
* Don't move a mount residing in a shared parent.
@@ -2501,7 +2495,8 @@ static int do_move_mount(struct path *path, const char *old_name)
if (p == old)
goto out1;
- err = attach_recursive_mnt(old, real_mount(path->mnt), mp, &parent_path);
+ err = attach_recursive_mnt(old, real_mount(new_path->mnt), mp,
+ &parent_path);
if (err)
goto out1;
@@ -2513,6 +2508,22 @@ static int do_move_mount(struct path *path, const char *old_name)
out:
if (!err)
path_put(&parent_path);
+ return err;
+}
+
+static int do_move_mount_old(struct path *path, const char *old_name)
+{
+ struct path old_path;
+ int err;
+
+ if (!old_name || !*old_name)
+ return -EINVAL;
+
+ err = kern_path(old_name, LOOKUP_FOLLOW, &old_path);
+ if (err)
+ return err;
+
+ err = do_move_mount(&old_path, path);
path_put(&old_path);
return err;
}
@@ -2934,7 +2945,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE | MS_UNBINDABLE))
retval = do_change_type(&path, flags);
else if (flags & MS_MOVE)
- retval = do_move_mount(&path, dev_name);
+ retval = do_move_mount_old(&path, dev_name);
else
retval = do_new_mount(&path, type_page, sb_flags, mnt_flags,
dev_name, data_page, data_size);
@@ -3169,6 +3180,61 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
return ksys_mount(dev_name, dir_name, type, flags, data);
}
+/*
+ * Move a mount from one place to another.
+ *
+ * Note the flags value is a combination of MOVE_MOUNT_* flags.
+ */
+SYSCALL_DEFINE5(move_mount,
+ int, from_dfd, const char *, from_pathname,
+ int, to_dfd, const char *, to_pathname,
+ unsigned int, flags)
+{
+ struct path from_path, to_path;
+ unsigned int lflags;
+ int ret = 0;
+
+ if (!may_mount())
+ return -EPERM;
+
+ if (flags & ~MOVE_MOUNT__MASK)
+ return -EINVAL;
+
+ /* If someone gives a pathname, they aren't permitted to move
+ * from an fd that requires unmount as we can't get at the flag
+ * to clear it afterwards.
+ */
+ lflags = 0;
+ if (flags & MOVE_MOUNT_F_SYMLINKS) lflags |= LOOKUP_FOLLOW;
+ if (flags & MOVE_MOUNT_F_AUTOMOUNTS) lflags |= LOOKUP_AUTOMOUNT;
+ if (flags & MOVE_MOUNT_F_EMPTY_PATH) lflags |= LOOKUP_EMPTY;
+
+ ret = user_path_at(from_dfd, from_pathname, lflags, &from_path);
+ if (ret < 0)
+ return ret;
+
+ lflags = 0;
+ if (flags & MOVE_MOUNT_T_SYMLINKS) lflags |= LOOKUP_FOLLOW;
+ if (flags & MOVE_MOUNT_T_AUTOMOUNTS) lflags |= LOOKUP_AUTOMOUNT;
+ if (flags & MOVE_MOUNT_T_EMPTY_PATH) lflags |= LOOKUP_EMPTY;
+
+ ret = user_path_at(to_dfd, to_pathname, lflags, &to_path);
+ if (ret < 0)
+ goto out_from;
+
+ ret = security_move_mount(&from_path, &to_path);
+ if (ret < 0)
+ goto out_to;
+
+ ret = do_move_mount(&from_path, &to_path);
+
+out_to:
+ path_put(&to_path);
+out_from:
+ path_put(&from_path);
+ return ret;
+}
+
/*
* Return true if path is reachable from root
*
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index b43bbc893074..924424e7be8f 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -147,6 +147,10 @@
* Parse a string of security data filling in the opts structure
* @options string containing all mount options known by the LSM
* @opts binary data structure usable by the LSM
+ * @move_mount:
+ * Check permission before a mount is moved.
+ * @from_path indicates the mount that is going to be moved.
+ * @to_path indicates the mountpoint that will be mounted upon.
* @dentry_init_security:
* Compute a context for a dentry as the inode is not yet available
* since NFSv4 has no label backed by an EA anyway.
@@ -1480,6 +1484,7 @@ union security_list_options {
unsigned long kern_flags,
unsigned long *set_kern_flags);
int (*sb_parse_opts_str)(char *options, struct security_mnt_opts *opts);
+ int (*move_mount)(const struct path *from_path, const struct path *to_path);
int (*dentry_init_security)(struct dentry *dentry, int mode,
const struct qstr *name, void **ctx,
u32 *ctxlen);
@@ -1811,6 +1816,7 @@ struct security_hook_heads {
struct hlist_head sb_set_mnt_opts;
struct hlist_head sb_clone_mnt_opts;
struct hlist_head sb_parse_opts_str;
+ struct hlist_head move_mount;
struct hlist_head dentry_init_security;
struct hlist_head dentry_create_files_as;
#ifdef CONFIG_SECURITY_PATH
diff --git a/include/linux/security.h b/include/linux/security.h
index 1498b9e0539b..9bb5bc6d596c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -245,6 +245,7 @@ int security_sb_clone_mnt_opts(const struct super_block *oldsb,
unsigned long kern_flags,
unsigned long *set_kern_flags);
int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts);
+int security_move_mount(const struct path *from_path, const struct path *to_path);
int security_dentry_init_security(struct dentry *dentry, int mode,
const struct qstr *name, void **ctx,
u32 *ctxlen);
@@ -599,6 +600,12 @@ static inline int security_sb_parse_opts_str(char *options, struct security_mnt_
return 0;
}
+static inline int security_move_mount(const struct path *from_path,
+ const struct path *to_path)
+{
+ return 0;
+}
+
static inline int security_inode_alloc(struct inode *inode)
{
return 0;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 3cc6b8f8bd2f..3c0855d9b105 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -901,6 +901,9 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
int flags, uint32_t sig);
asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags);
+asmlinkage long sys_move_mount(int from_dfd, const char __user *from_path,
+ int to_dfd, const char __user *to_path,
+ unsigned int ms_flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h
index e8db2911adca..89adf0d731ab 100644
--- a/include/uapi/linux/mount.h
+++ b/include/uapi/linux/mount.h
@@ -7,4 +7,15 @@
#define OPEN_TREE_CLONE 1 /* Clone the target tree and attach the clone */
#define OPEN_TREE_CLOEXEC O_CLOEXEC /* Close the file on execve() */
+/*
+ * move_mount() flags.
+ */
+#define MOVE_MOUNT_F_SYMLINKS 0x00000001 /* Follow symlinks on from path */
+#define MOVE_MOUNT_F_AUTOMOUNTS 0x00000002 /* Follow automounts on from path */
+#define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 /* Empty from path permitted */
+#define MOVE_MOUNT_T_SYMLINKS 0x00000010 /* Follow symlinks on to path */
+#define MOVE_MOUNT_T_AUTOMOUNTS 0x00000020 /* Follow automounts on to path */
+#define MOVE_MOUNT_T_EMPTY_PATH 0x00000040 /* Empty to path permitted */
+#define MOVE_MOUNT__MASK 0x00000077
+
#endif /* _UAPI_LINUX_MOUNT_H */
diff --git a/security/security.c b/security/security.c
index 7cafc1c90d16..5149c2cbe8a7 100644
--- a/security/security.c
+++ b/security/security.c
@@ -439,6 +439,11 @@ int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts)
}
EXPORT_SYMBOL(security_sb_parse_opts_str);
+int security_move_mount(const struct path *from_path, const struct path *to_path)
+{
+ return call_int_hook(move_mount, 0, from_path, to_path);
+}
+
int security_inode_alloc(struct inode *inode)
{
inode->i_security = NULL;
^ permalink raw reply related
* [PATCH 01/38] vfs: syscall: Add open_tree(2) to reference or clone a mount [ver #10]
From: David Howells @ 2018-07-27 17:31 UTC (permalink / raw)
To: viro; +Cc: linux-api, torvalds, dhowells, linux-fsdevel, linux-kernel
In-Reply-To: <153271267980.9458.7640156373438016898.stgit@warthog.procyon.org.uk>
From: Al Viro <viro@zeniv.linux.org.uk>
open_tree(dfd, pathname, flags)
Returns an O_PATH-opened file descriptor or an error.
dfd and pathname specify the location to open, in usual
fashion (see e.g. fstatat(2)). flags should be an OR of
some of the following:
* AT_PATH_EMPTY, AT_NO_AUTOMOUNT, AT_SYMLINK_NOFOLLOW -
same meanings as usual
* OPEN_TREE_CLOEXEC - make the resulting descriptor
close-on-exec
* OPEN_TREE_CLONE or OPEN_TREE_CLONE | AT_RECURSIVE -
instead of opening the location in question, create a detached
mount tree matching the subtree rooted at location specified by
dfd/pathname. With AT_RECURSIVE the entire subtree is cloned,
without it - only the part within in the mount containing the
location in question. In other words, the same as mount --rbind
or mount --bind would've taken. The detached tree will be
dissolved on the final close of obtained file. Creation of such
detached trees requires the same capabilities as doing mount --bind.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1
arch/x86/entry/syscalls/syscall_64.tbl | 1
fs/file_table.c | 9 +-
fs/internal.h | 1
fs/namespace.c | 132 +++++++++++++++++++++++++++-----
include/linux/fs.h | 3 +
include/linux/syscalls.h | 1
include/uapi/linux/fcntl.h | 2
include/uapi/linux/mount.h | 10 ++
9 files changed, 135 insertions(+), 25 deletions(-)
create mode 100644 include/uapi/linux/mount.h
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 3cf7b533b3d1..ea1b413afd47 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -398,3 +398,4 @@
384 i386 arch_prctl sys_arch_prctl __ia32_compat_sys_arch_prctl
385 i386 io_pgetevents sys_io_pgetevents __ia32_compat_sys_io_pgetevents
386 i386 rseq sys_rseq __ia32_sys_rseq
+387 i386 open_tree sys_open_tree __ia32_sys_open_tree
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index f0b1709a5ffb..0545bed581dc 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -343,6 +343,7 @@
332 common statx __x64_sys_statx
333 common io_pgetevents __x64_sys_io_pgetevents
334 common rseq __x64_sys_rseq
+335 common open_tree __x64_sys_open_tree
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/fs/file_table.c b/fs/file_table.c
index 7ec0b3e5f05d..7480271a0d21 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -189,6 +189,7 @@ static void __fput(struct file *file)
struct dentry *dentry = file->f_path.dentry;
struct vfsmount *mnt = file->f_path.mnt;
struct inode *inode = file->f_inode;
+ fmode_t mode = file->f_mode;
might_sleep();
@@ -209,14 +210,14 @@ static void __fput(struct file *file)
file->f_op->release(inode, file);
security_file_free(file);
if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL &&
- !(file->f_mode & FMODE_PATH))) {
+ !(mode & FMODE_PATH))) {
cdev_put(inode->i_cdev);
}
fops_put(file->f_op);
put_pid(file->f_owner.pid);
- if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+ if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
i_readcount_dec(inode);
- if (file->f_mode & FMODE_WRITER) {
+ if (mode & FMODE_WRITER) {
put_write_access(inode);
__mnt_drop_write(mnt);
}
@@ -224,6 +225,8 @@ static void __fput(struct file *file)
file->f_path.mnt = NULL;
file->f_inode = NULL;
file_free(file);
+ if (unlikely(mode & FMODE_NEED_UNMOUNT))
+ dissolve_on_fput(mnt);
dput(dentry);
mntput(mnt);
}
diff --git a/fs/internal.h b/fs/internal.h
index 56533b08532e..383ee4724f77 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -85,6 +85,7 @@ extern void __mnt_drop_write(struct vfsmount *);
extern void __mnt_drop_write_file(struct file *);
extern void mnt_drop_write_file_path(struct file *);
+extern void dissolve_on_fput(struct vfsmount *);
/*
* fs_struct.c
*/
diff --git a/fs/namespace.c b/fs/namespace.c
index 03cc3b5bcf00..a4a01ecbcacd 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -20,12 +20,14 @@
#include <linux/init.h> /* init_rootfs */
#include <linux/fs_struct.h> /* get_fs_root et.al. */
#include <linux/fsnotify.h> /* fsnotify_vfsmount_delete */
+#include <linux/file.h>
#include <linux/uaccess.h>
#include <linux/proc_ns.h>
#include <linux/magic.h>
#include <linux/bootmem.h>
#include <linux/task_work.h>
#include <linux/sched/task.h>
+#include <uapi/linux/mount.h>
#include "pnode.h"
#include "internal.h"
@@ -1840,6 +1842,16 @@ struct vfsmount *collect_mounts(const struct path *path)
return &tree->mnt;
}
+void dissolve_on_fput(struct vfsmount *mnt)
+{
+ namespace_lock();
+ lock_mount_hash();
+ mntget(mnt);
+ umount_tree(real_mount(mnt), UMOUNT_SYNC);
+ unlock_mount_hash();
+ namespace_unlock();
+}
+
void drop_collected_mounts(struct vfsmount *mnt)
{
namespace_lock();
@@ -2199,6 +2211,30 @@ static bool has_locked_children(struct mount *mnt, struct dentry *dentry)
return false;
}
+static struct mount *__do_loopback(struct path *old_path, int recurse)
+{
+ struct mount *mnt = ERR_PTR(-EINVAL), *old = real_mount(old_path->mnt);
+
+ if (IS_MNT_UNBINDABLE(old))
+ return mnt;
+
+ if (!check_mnt(old) && old_path->dentry->d_op != &ns_dentry_operations)
+ return mnt;
+
+ if (!recurse && has_locked_children(old, old_path->dentry))
+ return mnt;
+
+ if (recurse)
+ mnt = copy_tree(old, old_path->dentry, CL_COPY_MNT_NS_FILE);
+ else
+ mnt = clone_mnt(old, old_path->dentry, 0);
+
+ if (!IS_ERR(mnt))
+ mnt->mnt.mnt_flags &= ~MNT_LOCKED;
+
+ return mnt;
+}
+
/*
* do loopback mount.
*/
@@ -2206,7 +2242,7 @@ static int do_loopback(struct path *path, const char *old_name,
int recurse)
{
struct path old_path;
- struct mount *mnt = NULL, *old, *parent;
+ struct mount *mnt = NULL, *parent;
struct mountpoint *mp;
int err;
if (!old_name || !*old_name)
@@ -2220,38 +2256,21 @@ static int do_loopback(struct path *path, const char *old_name,
goto out;
mp = lock_mount(path);
- err = PTR_ERR(mp);
- if (IS_ERR(mp))
+ if (IS_ERR(mp)) {
+ err = PTR_ERR(mp);
goto out;
+ }
- old = real_mount(old_path.mnt);
parent = real_mount(path->mnt);
-
- err = -EINVAL;
- if (IS_MNT_UNBINDABLE(old))
- goto out2;
-
if (!check_mnt(parent))
goto out2;
- if (!check_mnt(old) && old_path.dentry->d_op != &ns_dentry_operations)
- goto out2;
-
- if (!recurse && has_locked_children(old, old_path.dentry))
- goto out2;
-
- if (recurse)
- mnt = copy_tree(old, old_path.dentry, CL_COPY_MNT_NS_FILE);
- else
- mnt = clone_mnt(old, old_path.dentry, 0);
-
+ mnt = __do_loopback(&old_path, recurse);
if (IS_ERR(mnt)) {
err = PTR_ERR(mnt);
goto out2;
}
- mnt->mnt.mnt_flags &= ~MNT_LOCKED;
-
err = graft_tree(mnt, parent, mp);
if (err) {
lock_mount_hash();
@@ -2265,6 +2284,75 @@ static int do_loopback(struct path *path, const char *old_name,
return err;
}
+SYSCALL_DEFINE3(open_tree, int, dfd, const char *, filename, unsigned, flags)
+{
+ struct file *file;
+ struct path path;
+ int lookup_flags = LOOKUP_AUTOMOUNT | LOOKUP_FOLLOW;
+ bool detached = flags & OPEN_TREE_CLONE;
+ int error;
+ int fd;
+
+ BUILD_BUG_ON(OPEN_TREE_CLOEXEC != O_CLOEXEC);
+
+ if (flags & ~(AT_EMPTY_PATH | AT_NO_AUTOMOUNT | AT_RECURSIVE |
+ AT_SYMLINK_NOFOLLOW | OPEN_TREE_CLONE |
+ OPEN_TREE_CLOEXEC))
+ return -EINVAL;
+
+ if ((flags & (AT_RECURSIVE | OPEN_TREE_CLONE)) == AT_RECURSIVE)
+ return -EINVAL;
+
+ if (flags & AT_NO_AUTOMOUNT)
+ lookup_flags &= ~LOOKUP_AUTOMOUNT;
+ if (flags & AT_SYMLINK_NOFOLLOW)
+ lookup_flags &= ~LOOKUP_FOLLOW;
+ if (flags & AT_EMPTY_PATH)
+ lookup_flags |= LOOKUP_EMPTY;
+
+ if (detached && !may_mount())
+ return -EPERM;
+
+ fd = get_unused_fd_flags(flags & O_CLOEXEC);
+ if (fd < 0)
+ return fd;
+
+ error = user_path_at(dfd, filename, lookup_flags, &path);
+ if (error)
+ goto out;
+
+ if (detached) {
+ struct mount *mnt = __do_loopback(&path, flags & AT_RECURSIVE);
+ if (IS_ERR(mnt)) {
+ error = PTR_ERR(mnt);
+ goto out2;
+ }
+ mntput(path.mnt);
+ path.mnt = &mnt->mnt;
+ }
+
+ file = dentry_open(&path, O_PATH, current_cred());
+ if (IS_ERR(file)) {
+ error = PTR_ERR(file);
+ goto out3;
+ }
+
+ if (detached)
+ file->f_mode |= FMODE_NEED_UNMOUNT;
+ path_put(&path);
+ fd_install(fd, file);
+ return fd;
+
+out3:
+ if (detached)
+ dissolve_on_fput(path.mnt);
+out2:
+ path_put(&path);
+out:
+ put_unused_fd(fd);
+ return error;
+}
+
static int change_mount_flags(struct vfsmount *mnt, int ms_flags)
{
int error = 0;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e3a18cddb74e..067f0e31aec7 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -154,6 +154,9 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
/* File is capable of returning -EAGAIN if I/O will block */
#define FMODE_NOWAIT ((__force fmode_t)0x8000000)
+/* File represents mount that needs unmounting */
+#define FMODE_NEED_UNMOUNT ((__force fmode_t)0x10000000)
+
/*
* Flag for rw_copy_check_uvector and compat_rw_copy_check_uvector
* that indicates that they should check the contents of the iovec are
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 73810808cdf2..3cc6b8f8bd2f 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -900,6 +900,7 @@ asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
unsigned mask, struct statx __user *buffer);
asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
int flags, uint32_t sig);
+asmlinkage long sys_open_tree(int dfd, const char __user *path, unsigned flags);
/*
* Architecture-specific system calls
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index 6448cdd9a350..594b85f7cb86 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -90,5 +90,7 @@
#define AT_STATX_FORCE_SYNC 0x2000 /* - Force the attributes to be sync'd with the server */
#define AT_STATX_DONT_SYNC 0x4000 /* - Don't sync attributes with the server */
+#define AT_RECURSIVE 0x8000 /* Apply to the entire subtree */
+
#endif /* _UAPI_LINUX_FCNTL_H */
diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h
new file mode 100644
index 000000000000..e8db2911adca
--- /dev/null
+++ b/include/uapi/linux/mount.h
@@ -0,0 +1,10 @@
+#ifndef _UAPI_LINUX_MOUNT_H
+#define _UAPI_LINUX_MOUNT_H
+
+/*
+ * open_tree() flags.
+ */
+#define OPEN_TREE_CLONE 1 /* Clone the target tree and attach the clone */
+#define OPEN_TREE_CLOEXEC O_CLOEXEC /* Close the file on execve() */
+
+#endif /* _UAPI_LINUX_MOUNT_H */
^ permalink raw reply related
* [PATCH 00/38] VFS: Introduce filesystem context [ver #10]
From: David Howells @ 2018-07-27 17:31 UTC (permalink / raw)
To: viro
Cc: John Johansen, Tejun Heo, Eric W. Biederman, selinux, Paul Moore,
Li Zefan, linux-api, apparmor, Casey Schaufler, fenghua.yu,
Greg Kroah-Hartman, Eric Biggers, linux-security-module,
Tetsuo Handa, Johannes Weiner, Stephen Smalley, tomoyo-dev-en,
cgroups, torvalds, dhowells, linux-fsdevel, linux-kernel
Hi Al,
[!] NOTE: This is a preview of the patches; Apparmor is currently broken and
needs fixing.
Here are a set of patches to create a filesystem context prior to setting
up a new mount, populating it with the parsed options/binary data, creating
the superblock and then effecting the mount. This is also used for remount
since much of the parsing stuff is common in many filesystems.
This allows namespaces and other information to be conveyed through the
mount procedure.
This also allows Miklós Szeredi's idea of doing:
fd = fsopen("nfs");
fsconfig(fd, fsconfig_set_string, "option", "val", 0);
fsconfig(fd, fsconfig_cmd_create, NULL, NULL, 0);
mfd = fsmount(fd, MS_NODEV);
move_mount(mfd, "", AT_FDCWD, "/mnt", MOVE_MOUNT_F_EMPTY_PATH);
that he presented at LSF-2017 to be implemented (see the relevant patches
in the series).
I didn't use netlink as that would make the core kernel depend on
CONFIG_NET and CONFIG_NETLINK and would introduce network namespacing
issues.
I've implemented filesystem context handling for procfs, nfs, mqueue,
cpuset, kernfs, sysfs, cgroup and afs filesystems.
Unconverted filesystems are handled by a legacy filesystem wrapper.
====================
WHY DO WE WANT THIS?
====================
Firstly, there's a bunch of problems with the mount(2) syscall:
(1) It's actually six or seven different interfaces rolled into one and weird
combinations of flags make it do different things beyond the original
specification of the syscall.
(2) It produces a particularly large and diverse set of errors, which have to
be mapped back to a small error code. Yes, there's dmesg - if you have
it configured - but you can't necessarily see that if you're doing a
mount inside of a container.
(3) It copies a PAGE_SIZE block of data for each of the type, device name and
options.
(4) The size of the buffers is PAGE_SIZE - and this is arch dependent.
(5) You can't mount into another mount namespace. I could, for example,
build a container without having to be in that container's namespace if I
can do it from outside.
(6) It's not really geared for the specification of multiple sources, but
some filesystems really want that - overlayfs, for example.
and some problems in the internal kernel api:
(1) There's no defined way to supply namespace configuration for the
superblock - so, for instance, I can't say that I want to create a
superblock in a particular network namespace (on automount, say).
NFS hacks around this by creating multiple shadow file_system_types with
different ->mount() ops.
(2) When calling mount internally, unless you have NFS-like hacks, you have
to generate or otherwise provide text config data which then gets parsed,
when some of the time you could bypass the parsing stage entirely.
(3) The amount of data in the data buffer is not known, but the data buffer
might be on a kernel stack somewhere, leading to the possibility of
tripping the stack underrun guard.
and other issues too:
(1) Superblock remount in some filesystems applies options on an as-parsed
basis, so if there's a parse failure, a partial alteration with no
rollback is effected.
(2) Under some circumstances, the mount data may get copied multiple times so
that it can have multiple parsers applied to it or because it has to be
parsed multiple times - for instance, once to get the preliminary info
required to access the on-disk superblock and then again to update the
superblock record in the kernel.
I want to be able to add support for a bunch of things:
(1) UID, GID and Project ID mapping/translation. I want to be able to
install a translation table of some sort on the superblock to translate
source identifiers (which may be foreign numeric UIDs/GIDs, text names,
GUIDs) into system identifiers. This needs to be done before the
superblock is published[*].
Note that this may, for example, involve using the context and the
superblock held therein to issue an RPC to a server to look up
translations.
[*] By "published" I mean made available through mount so that other
userspace processes can access it by path.
Maybe specifying a translation range element with something like:
fsconfig(fd, fsconfig_translate_uid, "<srcuid> <nsuid> <count>", 0, 0);
The translation information also needs to propagate over an automount in
some circumstances.
(2) Namespace configuration. I want to be able to tell the superblock
creation process what namespaces should be applied when it created (in
particular the userns and netns) for containerisation purposes, e.g.:
fsconfig(fd, fsconfig_set_namespace, "user", 0, userns_fd);
fsconfig(fd, fsconfig_set_namespace, "net", 0, netns_fd);
(3) Namespace propagation. I want to have a properly defined mechanism for
propagating namespace configuration over automounts within the kernel.
This will be particularly useful for network filesystems.
(4) Pre-mount attribute query. A chunk of the changes is actually the
fsinfo() syscall to query attributes of the filesystem beyond what's
available in statx() and statfs(). This will allow a created superblock
to be queried before it is published.
(5) Upcall for configuration. I would like to be able to query configuration
that's stored in userspace when an automount is made. For instance, to
look up network parameters for NFS or to find a cache selector for
fscache.
The internal fs_context could be passed to the upcall process or the
kernel could read a config file directly if named appropriately for the
superblock, perhaps:
[/etc/fscontext.d/afs/example.com/cell.cfg]
realm = EXAMPLE.COM
translation = uid,3000,4000,100
fscache = tag=fred
(6) Event notifications. I want to be able to install a watch on a
superblock before it is published to catch things like quota events and
EIO.
(7) Large and binary parameters. There might be at some point a need to pass
large/binary objects like Microsoft PACs around. If I understand PACs
correctly, you can obtain these from the Kerberos server and then pass
them to the file server when you connect.
Having it possible to pass large or binary objects as individual fsconfig
calls make parsing these trivial. OTOH, some or all of this can
potentially be handled with the use of the keyrings interface - as the afs
filesystem does for passing kerberos tokens around; it's just that that
seems overkill for a parameter you may only need once.
===================
SIGNIFICANT CHANGES
===================
ver #10:
(*) Renamed "option" to "parameter" in a number of places.
(*) Replaced the use of write() to drive the configuration with an fsconfig()
syscall. This also allows at-style paths and fds to be presented as typed
object.
(*) Routed the key=value parameter concept all the way through from the
fsconfig() system call to the LSM and filesystem.
(*) Added a parameter-description concept and helper functions to help
interpret a parameter and possibly convert the value.
(*) Made it possible to query the parameter description using the fsinfo()
syscall. Added a test-fs-query sample to dump the parameters used by a
filesystem.
ver #9:
(*) Dropped the fd cookie stuff and the FMODE_*/O_* split stuff.
(*) Al added an open_tree() system call to allow a mount tree to be picked
referenced or cloned into an O_PATH-style fd. This can then be used
with sys_move_mount(). Dropped the O_CLONE_MOUNT and O_NON_RECURSIVE
open() flags.
(*) Brought error logging back in, though only in the fs_context and not
in the task_struct.
(*) Separated MS_REMOUNT|MS_BIND handling from MS_REMOUNT handling.
(*) Used anon_inodes for the fd returned by fsopen() and fspick(). This
requires making it unconditional.
(*) Fixed lots of bugs. Especial thanks to Al and Eric Biggers for
finding them and providing patches.
(*) Wrote manual pages, which I'll post separately.
ver #8:
(*) Changed the way fsmount() mounts into the namespace according to some
of Al's ideas.
(*) Put better typing on the fd cookie obtained from __fdget() & co..
(*) Stored the fd cookie in struct nameidata rather than the dfd number.
(*) Changed sys_fsmount() to return an O_PATH-style fd rather than
actually mounting into the mount namespace.
(*) Separated internal FMODE_* handling from O_* handling to free up
certain O_* flag numbers.
(*) Added two new open flags (O_CLONE_MOUNT and O_NON_RECURSIVE) for use
with open(O_PATH) to copy a mount or mount-subtree to an O_PATH fd.
(*) Added a new syscall, sys_move_mount(), to move a mount from an
dfd+path source to a dfd+path destination.
(*) Added a file->f_mode flag (FMODE_NEED_UNMOUNT) that indicates that the
vfsmount attached to file->f_path needs 'unmounting' if set.
(*) Made sys_move_mount() clear FMODE_NEED_UNMOUNT if successful.
[!] This doesn't work quite right.
(*) Added a new syscall, fsinfo(), to query information about a
filesystem. The idea being that this will, in future, work with the
fd from fsopen() too and permit querying of the parameters and
metadata before fsmount() is called.
ver #7:
(*) Undo an incorrect MS_* -> SB_* conversion.
(*) Pass the mount data buffer size to all the mount-related functions that
take the data pointer. This fixes a problem where someone (say SELinux)
tries to copy the mount data, assuming it to be a page in size, and
overruns the buffer - thereby incurring an oops by hitting a guard page.
(*) Made the AFS filesystem use them as an example. This is a much easier to
deal with than with NFS or Ext4 as there are very few mount options.
ver #6:
(*) Dropped the supplementary error string facility for the moment.
(*) Dropped the NFS patches for the moment.
(*) Dropped the reserved file descriptor argument from fsopen() and
replaced it with three reserved pointers that must be NULL.
ver #5:
(*) Renamed sb_config -> fs_context and adjusted variable names.
(*) Differentiated the flags in sb->s_flags (now named SB_*) from those
passed to mount(2) (named MS_*).
(*) Renamed __vfs_new_fs_context() to vfs_new_fs_context() and made the
caller always provide a struct file_system_type pointer and the
parameters required.
(*) Got rid of vfs_submount_fc() in favour of passing
FS_CONTEXT_FOR_SUBMOUNT to vfs_new_fs_context(). The purpose is now
used more.
(*) Call ->validate() on the remount path.
(*) Got rid of the inode locking in sys_fsmount().
(*) Call security_sb_mountpoint() in the mount(2) path.
ver #4:
(*) Split the sb_config patch up somewhat.
(*) Made the supplementary error string facility something attached to the
task_struct rather than the sb_config so that error messages can be
obtained from NFS doing a mount-root-and-pathwalk inside the
nfs_get_tree() operation.
Further, made this managed and read by prctl rather than through the
mount fd so that it's more generally available.
ver #3:
(*) Rebased on 4.12-rc1.
(*) Split the NFS patch up somewhat.
ver #2:
(*) Removed the ->fill_super() from sb_config_operations and passed it in
directly to functions that want to call it. NFS now calls
nfs_fill_super() directly rather than jumping through a pointer to it
since there's only the one option at the moment.
(*) Removed ->mnt_ns and ->sb from sb_config and moved ->pid_ns into
proc_sb_config.
(*) Renamed create_super -> get_tree.
(*) Renamed struct mount_context to struct sb_config and amended various
variable names.
(*) sys_fsmount() acquired AT_* flags and MS_* flags (for MNT_* flags)
arguments.
ver #1:
(*) Split the sb_config stuff out into its own header.
(*) Support non-context aware filesystems through a special set of
sb_config operations.
(*) Stored the created superblock and root dentry into the sb_config after
creation rather than directly into a vfsmount. This allows some
arguments to be removed to various NFS functions.
(*) Added an explicit superblock-creation step. This allows a created
superblock to then be mounted multiple times.
(*) Added a flag to say that the sb_config is degraded and cannot have
another go at having a superblock creation whilst getting rid of the
one that says it's already mounted.
Possible further developments:
(*) Implement sb reconfiguration (for now it returns ENOANO).
(*) Implement mount context support in more filesystems, ext4 being next
on my list.
(*) Move the walk-from-root stuff that nfs has to generic code so that you
can do something akin to:
mount /dev/sda1:/foo/bar /mnt
See nfs_follow_remote_path() and mount_subtree(). This is slightly
tricky in NFS as we have to prevent referral loops.
(*) Work out how to get at the error message incurred by submounts
encountered during nfs_follow_remote_path().
Should the error message be moved to task_struct and made more
general, perhaps retrieved with a prctl() function?
(*) Clean up/consolidate the security functions. Possibly add a
validation hook to be called at the same time as the mount context
validate op.
The patches can be found here also:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
on branch:
mount-api
David
---
Al Viro (2):
vfs: syscall: Add open_tree(2) to reference or clone a mount
teach move_mount(2) to work with OPEN_TREE_CLONE
David Howells (36):
vfs: syscall: Add move_mount(2) to move mounts around
vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled
vfs: Introduce the basic header for the new mount API's filesystem context
vfs: Introduce logging functions
vfs: Add configuration parser helpers
vfs: Add LSM hooks for the new mount API
selinux: Implement the new mount API LSM hooks
smack: Implement filesystem context security hooks
apparmor: Implement security hooks for the new mount API
vfs: Pass key and value into LSM and FS and provide a helper parser
tomoyo: Implement security hooks for the new mount API
vfs: Separate changing mount flags full remount
vfs: Implement a filesystem superblock creation/configuration context
vfs: Remove unused code after filesystem context changes
procfs: Move proc_fill_super() to fs/proc/root.c
proc: Add fs_context support to procfs
ipc: Convert mqueue fs to fs_context
cpuset: Use fs_context
kernfs, sysfs, cgroup, intel_rdt: Support fs_context
hugetlbfs: Convert to fs_context
vfs: Remove kern_mount_data()
vfs: Provide documentation for new mount API
Make anon_inodes unconditional
vfs: syscall: Add fsopen() to prepare for superblock creation
vfs: Implement logging through fs_context
vfs: Add some logging to the core users of the fs_context log
vfs: syscall: Add fsconfig() for configuring and managing a context
vfs: syscall: Add fsmount() to create a mount for a superblock
vfs: syscall: Add fspick() to select a superblock for reconfiguration
afs: Add fs_context support
afs: Use fs_context to pass parameters over automount
vfs: syscall: Add fsinfo() to query filesystem information
afs: Add fsinfo support
vfs: Add a sample program for the new mount API
vfs: Allow fsinfo() to query what's in an fs_context
vfs: Allow fsinfo() to be used to query an fs parameter description
Documentation/filesystems/mount_api.txt | 706 ++++++++++++++++++++++++
arch/arc/kernel/setup.c | 1
arch/arm/kernel/atags_parse.c | 1
arch/sh/kernel/setup.c | 1
arch/sparc/kernel/setup_32.c | 1
arch/sparc/kernel/setup_64.c | 1
arch/x86/entry/syscalls/syscall_32.tbl | 7
arch/x86/entry/syscalls/syscall_64.tbl | 7
arch/x86/kernel/cpu/intel_rdt.h | 15 +
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 184 ++++--
arch/x86/kernel/setup.c | 1
drivers/base/devtmpfs.c | 1
fs/Kconfig | 7
fs/Makefile | 5
fs/afs/internal.h | 9
fs/afs/mntpt.c | 148 +++--
fs/afs/super.c | 605 ++++++++++++++-------
fs/afs/volume.c | 4
fs/f2fs/super.c | 2
fs/file_table.c | 9
fs/filesystems.c | 4
fs/fs_context.c | 778 +++++++++++++++++++++++++++
fs/fs_parser.c | 476 ++++++++++++++++
fs/fsopen.c | 490 +++++++++++++++++
fs/hugetlbfs/inode.c | 392 ++++++++------
fs/internal.h | 13
fs/kernfs/mount.c | 89 +--
fs/libfs.c | 19 +
fs/namei.c | 4
fs/namespace.c | 866 +++++++++++++++++++++++-------
fs/pnode.c | 1
fs/proc/inode.c | 51 --
fs/proc/internal.h | 6
fs/proc/root.c | 245 ++++++--
fs/statfs.c | 574 ++++++++++++++++++++
fs/super.c | 368 ++++++++++---
fs/sysfs/mount.c | 67 ++
include/linux/cgroup.h | 3
include/linux/fs.h | 25 +
include/linux/fs_context.h | 207 +++++++
include/linux/fs_parser.h | 116 ++++
include/linux/fsinfo.h | 40 +
include/linux/kernfs.h | 39 +
include/linux/lsm_hooks.h | 70 ++
include/linux/module.h | 6
include/linux/mount.h | 5
include/linux/security.h | 61 ++
include/linux/syscalls.h | 13
include/uapi/linux/fcntl.h | 2
include/uapi/linux/fs.h | 82 +--
include/uapi/linux/fsinfo.h | 301 ++++++++++
include/uapi/linux/mount.h | 75 +++
init/Kconfig | 10
init/do_mounts.c | 1
init/do_mounts_initrd.c | 1
ipc/mqueue.c | 121 +++-
kernel/cgroup/cgroup-internal.h | 50 +-
kernel/cgroup/cgroup-v1.c | 347 +++++++-----
kernel/cgroup/cgroup.c | 256 ++++++---
kernel/cgroup/cpuset.c | 68 ++
samples/Kconfig | 7
samples/Makefile | 2
samples/mount_api/Makefile | 7
samples/mount_api/test-fsmount.c | 118 ++++
samples/statx/Makefile | 7
samples/statx/test-fs-query.c | 137 +++++
samples/statx/test-fsinfo.c | 539 +++++++++++++++++++
security/apparmor/include/mount.h | 11
security/apparmor/lsm.c | 106 ++++
security/apparmor/mount.c | 47 ++
security/security.c | 51 ++
security/selinux/hooks.c | 311 ++++++++++-
security/smack/smack.h | 11
security/smack/smack_lsm.c | 370 ++++++++++++-
security/tomoyo/common.h | 3
security/tomoyo/mount.c | 46 ++
security/tomoyo/tomoyo.c | 15 +
77 files changed, 8375 insertions(+), 1470 deletions(-)
create mode 100644 Documentation/filesystems/mount_api.txt
create mode 100644 fs/fs_context.c
create mode 100644 fs/fs_parser.c
create mode 100644 fs/fsopen.c
create mode 100644 include/linux/fs_context.h
create mode 100644 include/linux/fs_parser.h
create mode 100644 include/linux/fsinfo.h
create mode 100644 include/uapi/linux/fsinfo.h
create mode 100644 include/uapi/linux/mount.h
create mode 100644 samples/mount_api/Makefile
create mode 100644 samples/mount_api/test-fsmount.c
create mode 100644 samples/statx/test-fs-query.c
create mode 100644 samples/statx/test-fsinfo.c
^ permalink raw reply
* Re: [PATCH 4/4] mm: proc/pid/smaps_rollup: convert to single value seq_file
From: Alexey Dobriyan @ 2018-07-26 16:26 UTC (permalink / raw)
To: Vlastimil Babka
Cc: Andrew Morton, Daniel Colascione, linux-mm, linux-kernel,
linux-fsdevel, linux-api
In-Reply-To: <cb1d1965-9a13-e80f-dfde-a5d3bf9f510c@suse.cz>
On Wed, Jul 25, 2018 at 08:53:53AM +0200, Vlastimil Babka wrote:
> I moved the reply to this thread since the "added to -mm tree"
> notification Alexey replied to in <20180724182908.GD27053@avx2> has
> reduced CC list and is not linked to the patch postings.
>
> On 07/24/2018 08:29 PM, Alexey Dobriyan wrote:
> > On Mon, Jul 23, 2018 at 04:55:48PM -0700, akpm@linux-foundation.org wrote:
> >> The patch titled
> >> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
> >> has been added to the -mm tree. Its filename is
> >> mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
> >
> >> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
> >>
> >> The /proc/pid/smaps_rollup file is currently implemented via the
> >> m_start/m_next/m_stop seq_file iterators shared with the other maps files,
> >> that iterate over vma's. However, the rollup file doesn't print anything
> >> for each vma, only accumulate the stats.
> >
> > What I don't understand why keep seq_ops then and not do all the work in
> > ->show hook. Currently /proc/*/smaps_rollup is at ~500 bytes so with
> > minimum 1 page seq buffer, no buffer resizing is possible.
>
> Hmm IIUC seq_file also provides the buffer and handles feeding the data
> from there to the user process, which might have called read() with a smaller
> buffer than that. So I would rather not avoid the seq_file infrastructure.
> Or you're saying it could be converted to single_open()? Maybe, with more work.
Prefereably yes.
There are 2 ways to using seq_file:
* introduce seq_operations and iterate over objects printing them one by one,
* use single_open and 1 ->show hook and do all the work of collecting
data there and print once.
/proc/*/smaps_rollup is suited for variant 2 because variant 1 is
designed for printing arbitrary amount of data.
> >> +static int show_smaps_rollup(struct seq_file *m, void *v)
> >> +{
> >> + struct proc_maps_private *priv = m->private;
> >> + struct mem_size_stats *mss = priv->rollup;
> >> + struct vm_area_struct *vma;
> >> +
> >> + /*
> >> + * We might be called multiple times when e.g. the seq buffer
> >> + * overflows. Gather the stats only once.
> >
> > It doesn't!
>
> Because the buffer is 1 page and the data is ~500 bytes as you said above?
> Agreed, but I wouldn't want to depend on data not growing in the future or
> the initial buffer not getting smaller. I could extend the comment that this
> is theoretical for now?
Given the rate of growth I wouldn't be concerned.
> >> + if (!mss->finished) {
> >> + for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
> >> + smap_gather_stats(vma, mss);
> >> + mss->last_vma_end = vma->vm_end;
> >> }
> >> - last_vma = !m_next_vma(priv, vma);
> >> - } else {
> >> - rollup_mode = false;
> >> - memset(&mss_stack, 0, sizeof(mss_stack));
> >> - mss = &mss_stack;
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 04/10] audit: add support for non-syscall auxiliary records
From: Richard Guy Briggs @ 2018-07-26 14:30 UTC (permalink / raw)
To: Paul Moore
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <CAHC9VhTX99Gqnv5SQbm1_3KON7g2R83qSt=bM3KJibDnORBXzQ@mail.gmail.com>
On 2018-07-24 17:57, Paul Moore wrote:
> On Tue, Jul 24, 2018 at 3:40 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > On 2018-07-20 18:14, Paul Moore wrote:
> > > On Wed, Jun 6, 2018 at 1:01 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > Standalone audit records have the timestamp and serial number generated
> > > > on the fly and as such are unique, making them standalone. This new
> > > > function audit_alloc_local() generates a local audit context that will
> > > > be used only for a standalone record and its auxiliary record(s). The
> > > > context is discarded immediately after the local associated records are
> > > > produced.
> > > >
> > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > ---
> > > > include/linux/audit.h | 8 ++++++++
> > > > kernel/auditsc.c | 25 +++++++++++++++++++++++--
> > > > 2 files changed, 31 insertions(+), 2 deletions(-)
>
> ...
>
> > > > + struct audit_context *context;
> > > > +
> > > > + if (!audit_ever_enabled)
> > > > + return NULL; /* Return if not auditing. */
> > > > +
> > > > + context = audit_alloc_context(AUDIT_RECORD_CONTEXT);
> > > > + if (!context)
> > > > + return NULL;
> > > > + context->serial = audit_serial();
> > > > + context->ctime = current_kernel_time64();
> > > > + context->in_syscall = 1;
> > >
> > > Setting in_syscall is both interesting and a bit troubling, if for no
> > > other reason than I expect most (all?) callers to be in an interrupt
> > > context when audit_alloc_local() is called. Setting in_syscall would
> > > appear to be conceptually in this case. Can you help explain why this
> > > is the right thing to do, or necessary to ensure things are handled
> > > correctly?
> >
> > I'll admit this is cheating a bit, but seemed harmless. It is needed so
> > that auditsc_get_stamp() from audit_get_stamp() from audit_log_start()
> > doesn't bail on me without giving me its already assigned time and
> > serial values rather than generating a new one. I did look to see if
> > there were any other undesireable side effects and found none, so I'm
> > tmepted to rename the ->in_syscall to something a bit more helpful. I
> > could add a new audit_context structure member to make
> > auditsc_get_stamp() co-operative, but this seems wasteful and
> > unnecessary.
>
> That's what I suspected.
>
> Let's look into renaming the "in_syscall" field, it borderline
> confusing now, and hijacking it for something which is very obviously
> not "in syscall" is A Very Bad Thing.
Ok, looking more carefully, I'm not going to touch in_syscall, since it
does more than I remember discovering when investigating why the
existing stamp wasn't being used. I don't want to change the existing
behaviour. I'll somewhat reluctantly grow the context struct and add a
"local" boolean to it so that auditsc_get_stamp knows to use the
existing stamp in both the in_syscall and local cases.
> paul moore
- RGB
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 07/10] audit: add support for containerid to network namespaces
From: Richard Guy Briggs @ 2018-07-26 13:33 UTC (permalink / raw)
To: Paul Moore
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <CAHC9VhSuczaFi49-3SrVM9vND=vT=U1Aj0G6kOyJ3rAFnvi6VA@mail.gmail.com>
On 2018-07-24 16:33, Paul Moore wrote:
> On Tue, Jul 24, 2018 at 10:06 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> > On 2018-07-20 18:14, Paul Moore wrote:
> > > On Wed, Jun 6, 2018 at 1:03 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > Audit events could happen in a network namespace outside of a task
> > > > context due to packets received from the net that trigger an auditing
> > > > rule prior to being associated with a running task. The network
> > > > namespace could in use by multiple containers by association to the
> > > > tasks in that network namespace. We still want a way to attribute
> > > > these events to any potential containers. Keep a list per network
> > > > namespace to track these audit container identifiiers.
> > > >
> > > > Add/increment the audit container identifier on:
> > > > - initial setting of the audit container identifier via /proc
> > > > - clone/fork call that inherits an audit container identifier
> > > > - unshare call that inherits an audit container identifier
> > > > - setns call that inherits an audit container identifier
> > > > Delete/decrement the audit container identifier on:
> > > > - an inherited audit container identifier dropped when child set
> > > > - process exit
> > > > - unshare call that drops a net namespace
> > > > - setns call that drops a net namespace
> > > >
> > > > See: https://github.com/linux-audit/audit-kernel/issues/92
> > > > See: https://github.com/linux-audit/audit-testsuite/issues/64
> > > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > ---
> > > > include/linux/audit.h | 23 ++++++++++++++++
> > > > kernel/audit.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > > > kernel/auditsc.c | 5 ++++
> > > > kernel/nsproxy.c | 4 +++
> > > > 4 files changed, 104 insertions(+)
>
> ...
>
> > > > + }
> > > > + if (!found)
> > > > + return;
> > > > + list_del(&cont->list);
> > > > + if (refcount_dec_and_test(&cont->refcount))
> > > > + kfree(cont);
> > >
> > > Don't you want to dec_and_test first and only remove it from the list
> > > if there are no other references?
> >
> > I don't think so. Let me try to describe it in prose to see if I
> > understood this properly and see if this makes more sense: I want to
> > remove this audit_contid list member from this net's audit_contid list
> > and decrement unconditionally this member's refcount so it knows there
> > is one less thing pointing at it and when there is no longer anything
> > pointing at it, free it.
>
> Yep, sorry, my mistake, I was thinking the other way around (netns
> going away) ... which actually, this patchset doesn't handle that does
> it (I don't see any new code in audit_net_exit())? Is is in a later
> patch? If so, it really should be in the same patch as this code to
> prevent bisect nasties.
I don't think any code is needed in audit_net_exit() other than a WARN()
that the contid list is empty, since if a netns is going away, all its
tasks would have exited (removing its contid from the list) or moved to
a new nstns (moving its contid from this list to another netns).
At worst, this is a memory leak and not a bad pointer dereference.
> paul moore
- RGB
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 02/10] audit: log container info of syscalls
From: Richard Guy Briggs @ 2018-07-26 0:51 UTC (permalink / raw)
To: Paul Moore
Cc: sgrubb, cgroups, containers, linux-api, linux-audit,
linux-fsdevel, linux-kernel, netdev, ebiederm, luto, carlos,
dhowells, viro, simo, Eric Paris, serge
In-Reply-To: <CAHC9VhTkuf+2BwJp399-NzSgQyp21GgY1SZVDboDdXgpvEV=pQ@mail.gmail.com>
On 2018-07-23 14:31, Paul Moore wrote:
> On Mon, Jul 23, 2018 at 12:48 PM Steve Grubb <sgrubb@redhat.com> wrote:
> > On Monday, July 23, 2018 11:11:48 AM EDT Richard Guy Briggs wrote:
> > > On 2018-07-23 09:19, Steve Grubb wrote:
> > > > On Sunday, July 22, 2018 4:55:10 PM EDT Richard Guy Briggs wrote:
> > > > > On 2018-07-22 09:32, Steve Grubb wrote:
> > > > > > On Saturday, July 21, 2018 4:29:30 PM EDT Richard Guy Briggs wrote:
> > > > > > > > > + * audit_log_contid - report container info
> > > > > > > > > + * @tsk: task to be recorded
> > > > > > > > > + * @context: task or local context for record
> > > > > > > > > + * @op: contid string description
> > > > > > > > > + */
> > > > > > > > > +int audit_log_contid(struct task_struct *tsk,
> > > > > > > > > + struct audit_context *context,
> > > > > > > > > char
> > > > > > > > > *op)
> > > > > > > > > +{
> > > > > > > > > + struct audit_buffer *ab;
> > > > > > > > > +
> > > > > > > > > + if (!audit_contid_set(tsk))
> > > > > > > > > + return 0;
> > > > > > > > > + /* Generate AUDIT_CONTAINER record with container ID */
> > > > > > > > > + ab = audit_log_start(context, GFP_KERNEL,
> > > > > > > > > AUDIT_CONTAINER);
> > > > > > > > > + if (!ab)
> > > > > > > > > + return -ENOMEM;
> > > > > > > > > + audit_log_format(ab, "op=%s contid=%llu",
> > > > > > > > > + op, audit_get_contid(tsk));
> > > > > > > >
> > > > > > > > Can you explain your reason for including an "op" field in this
> > > > > > > > record
> > > > > > > > type? I've been looking at the rest of the patches in this
> > > > > > > > patchset
> > > > > > > > and it seems to be used more as an indicator of the record's
> > > > > > > > generating context rather than any sort of audit container ID
> > > > > > > > operation.
> > > > > > >
> > > > > > > "action" might work, but that's netfilter and numeric... "kind"?
> > > > > > > Nothing else really seems to fit from a field name, type or lack of
> > > > > > > searchability perspective.
> > > > > > >
> > > > > > > Steve, do you have an opinion?
> > > > > >
> > > > > > We only have 1 sample event where we have op=task. What are the other
> > > > > > possible values?
> > > > >
> > > > > For the AUDIT_CONTAINER record we have op= "task", "target" (from the
> > > > > ptrace and signals patch), "tty".
> > > > >
> > > > > For the AUDIT_CONTAINER_ID record we have "op=set".
> > > >
> > > > Since the purpose of this record is to log the container id, I think that
> > > > is all that is needed. We can get the context from the other records in
> > > > the event. I'd suggest dropping the "op" field.
> > >
> > > Ok, the information above it for two different audit container
> > > identifier records. Which one should drop the "op=" field? Both? Or
> > > just the AUDIT_CONTAINER record? The AUDIT_CONTAINER_ID record (which
> > > might be renamed) could use it to distinguish a "set" record from a
> > > dropped audit container identifier that is no longer registered by any
> > > task or namespace.
> >
> > Neither of them need it. All they need to do is state the container that is
> > being acted upon.
>
> I think we should keep the "op" field for audit container ID
> management operations, even though we really only have a "set"
> operation at the moment, but the others should drop the "op" field
> (see my previous emails in this thread).
In fact, I'd like to question the wisdom of dropping this field and
perhaps fine a better or new name for it, since these contid records
could be multiple and different from the primary task that is generating
this record. In particular, there are extra contid records generated by
the ptrace/signals patch that could be from other processes in other
containers that I mentioned in a branch thread that got dropped
including the auc_pids data and the target_pid also attached to the
primary task's audit context.
> paul moore
> www.paul-moore.com
- RGB
--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
^ permalink raw reply
* Re: [PATCH v9 00/24] ILP32 for ARM64
From: Andreas Schwab @ 2018-07-25 9:48 UTC (permalink / raw)
To: Yury Norov
Cc: Catalin Marinas, Arnd Bergmann, linux-arm-kernel, linux-kernel,
linux-doc, linux-arch, linux-api, Adam Borowski, Alexander Graf,
Alexey Klimov, Andrew Pinski, Bamvor Zhangjian, Chris Metcalf,
Christoph Muellner, Dave Martin, David S . Miller, Florian Weimer,
Geert Uytterhoeven, Heiko Carstens, James Hogan
In-Reply-To: <20180724173957.GA22106@yury-thinkpad>
On Jul 24 2018, Yury Norov <ynorov@caviumnetworks.com> wrote:
> This is the update of the series based on 4.17 kernel
> https://github.com/norov/linux/tree/ilp32-4.17
Note that commit 947bd8e7cd (arm64: ilp32: add
is_ilp32_compat_{task,thread} and TIF_32BIT_AARCH64) conflicts with
commit 9dd9614f54 (arm64: ssbd: Introduce thread flag to control
userspace mitigation) (which has been backported to stable).
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."
^ permalink raw reply
* Re: [PATCH 4/4] mm: proc/pid/smaps_rollup: convert to single value seq_file
From: Vlastimil Babka @ 2018-07-25 6:53 UTC (permalink / raw)
To: Andrew Morton, Alexey Dobriyan
Cc: Daniel Colascione, linux-mm, linux-kernel, linux-fsdevel,
linux-api
In-Reply-To: <20180723111933.15443-5-vbabka@suse.cz>
I moved the reply to this thread since the "added to -mm tree"
notification Alexey replied to in <20180724182908.GD27053@avx2> has
reduced CC list and is not linked to the patch postings.
On 07/24/2018 08:29 PM, Alexey Dobriyan wrote:
> On Mon, Jul 23, 2018 at 04:55:48PM -0700, akpm@linux-foundation.org wrote:
>> The patch titled
>> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
>> has been added to the -mm tree. Its filename is
>> mm-proc-pid-smaps_rollup-convert-to-single-value-seq_file.patch
>
>> Subject: mm: /proc/pid/smaps_rollup: convert to single value seq_file
>>
>> The /proc/pid/smaps_rollup file is currently implemented via the
>> m_start/m_next/m_stop seq_file iterators shared with the other maps files,
>> that iterate over vma's. However, the rollup file doesn't print anything
>> for each vma, only accumulate the stats.
>
> What I don't understand why keep seq_ops then and not do all the work in
> ->show hook. Currently /proc/*/smaps_rollup is at ~500 bytes so with
> minimum 1 page seq buffer, no buffer resizing is possible.
Hmm IIUC seq_file also provides the buffer and handles feeding the data
from there to the user process, which might have called read() with a smaller
buffer than that. So I would rather not avoid the seq_file infrastructure.
Or you're saying it could be converted to single_open()? Maybe, with more work.
>> +static int show_smaps_rollup(struct seq_file *m, void *v)
>> +{
>> + struct proc_maps_private *priv = m->private;
>> + struct mem_size_stats *mss = priv->rollup;
>> + struct vm_area_struct *vma;
>> +
>> + /*
>> + * We might be called multiple times when e.g. the seq buffer
>> + * overflows. Gather the stats only once.
>
> It doesn't!
Because the buffer is 1 page and the data is ~500 bytes as you said above?
Agreed, but I wouldn't want to depend on data not growing in the future or
the initial buffer not getting smaller. I could extend the comment that this
is theoretical for now?
>> + if (!mss->finished) {
>> + for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
>> + smap_gather_stats(vma, mss);
>> + mss->last_vma_end = vma->vm_end;
>> }
>> - last_vma = !m_next_vma(priv, vma);
>> - } else {
>> - rollup_mode = false;
>> - memset(&mss_stack, 0, sizeof(mss_stack));
>> - mss = &mss_stack;
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 04/10] audit: add support for non-syscall auxiliary records
From: Paul Moore @ 2018-07-24 21:57 UTC (permalink / raw)
To: rgb
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <20180724193725.k27la4ubg2g2n4qm@madcap2.tricolour.ca>
On Tue, Jul 24, 2018 at 3:40 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-07-20 18:14, Paul Moore wrote:
> > On Wed, Jun 6, 2018 at 1:01 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Standalone audit records have the timestamp and serial number generated
> > > on the fly and as such are unique, making them standalone. This new
> > > function audit_alloc_local() generates a local audit context that will
> > > be used only for a standalone record and its auxiliary record(s). The
> > > context is discarded immediately after the local associated records are
> > > produced.
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > > include/linux/audit.h | 8 ++++++++
> > > kernel/auditsc.c | 25 +++++++++++++++++++++++--
> > > 2 files changed, 31 insertions(+), 2 deletions(-)
...
> > > + struct audit_context *context;
> > > +
> > > + if (!audit_ever_enabled)
> > > + return NULL; /* Return if not auditing. */
> > > +
> > > + context = audit_alloc_context(AUDIT_RECORD_CONTEXT);
> > > + if (!context)
> > > + return NULL;
> > > + context->serial = audit_serial();
> > > + context->ctime = current_kernel_time64();
> > > + context->in_syscall = 1;
> >
> > Setting in_syscall is both interesting and a bit troubling, if for no
> > other reason than I expect most (all?) callers to be in an interrupt
> > context when audit_alloc_local() is called. Setting in_syscall would
> > appear to be conceptually in this case. Can you help explain why this
> > is the right thing to do, or necessary to ensure things are handled
> > correctly?
>
> I'll admit this is cheating a bit, but seemed harmless. It is needed so
> that auditsc_get_stamp() from audit_get_stamp() from audit_log_start()
> doesn't bail on me without giving me its already assigned time and
> serial values rather than generating a new one. I did look to see if
> there were any other undesireable side effects and found none, so I'm
> tmepted to rename the ->in_syscall to something a bit more helpful. I
> could add a new audit_context structure member to make
> auditsc_get_stamp() co-operative, but this seems wasteful and
> unnecessary.
That's what I suspected.
Let's look into renaming the "in_syscall" field, it borderline
confusing now, and hijacking it for something which is very obviously
not "in syscall" is A Very Bad Thing.
--
paul moore
www.paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 01/10] audit: add container id
From: Paul Moore @ 2018-07-24 21:54 UTC (permalink / raw)
To: rgb
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <20180724190613.ww6yhsqpa7n4s62k@madcap2.tricolour.ca>
On Tue, Jul 24, 2018 at 3:09 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-07-20 18:13, Paul Moore wrote:
> > On Wed, Jun 6, 2018 at 1:00 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Implement the proc fs write to set the audit container identifier of a
> > > process, emitting an AUDIT_CONTAINER_ID record to document the event.
> > >
> > > This is a write from the container orchestrator task to a proc entry of
> > > the form /proc/PID/audit_containerid where PID is the process ID of the
> > > newly created task that is to become the first task in a container, or
> > > an additional task added to a container.
> > >
> > > The write expects up to a u64 value (unset: 18446744073709551615).
> > >
> > > The writer must have capability CAP_AUDIT_CONTROL.
> > >
> > > This will produce a record such as this:
> > > type=CONTAINER_ID msg=audit(2018-06-06 12:39:29.636:26949) : op=set opid=2209 old-contid=18446744073709551615 contid=123456 pid=628 auid=root uid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=bash exe=/usr/bin/bash res=yes
> > >
> > > The "op" field indicates an initial set. The "pid" to "ses" fields are
> > > the orchestrator while the "opid" field is the object's PID, the process
> > > being "contained". Old and new audit container identifier values are
> > > given in the "contid" fields, while res indicates its success.
> > >
> > > It is not permitted to unset or re-set the audit container identifier.
> > > A child inherits its parent's audit container identifier, but then can
> > > be set only once after.
> > >
> > > See: https://github.com/linux-audit/audit-kernel/issues/90
> > > See: https://github.com/linux-audit/audit-userspace/issues/51
> > > See: https://github.com/linux-audit/audit-testsuite/issues/64
> > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > > fs/proc/base.c | 37 ++++++++++++++++++++++++
> > > include/linux/audit.h | 25 ++++++++++++++++
> > > include/uapi/linux/audit.h | 2 ++
> > > kernel/auditsc.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++
> > > 4 files changed, 135 insertions(+)
...
> > > @@ -2112,6 +2116,73 @@ int audit_set_loginuid(kuid_t loginuid)
> > > }
> > >
> > > /**
> > > + * audit_set_contid - set current task's audit_context contid
> > > + * @contid: contid value
> > > + *
> > > + * Returns 0 on success, -EPERM on permission failure.
> > > + *
> > > + * Called (set) from fs/proc/base.c::proc_contid_write().
> > > + */
> > > +int audit_set_contid(struct task_struct *task, u64 contid)
> > > +{
> > > + u64 oldcontid;
> > > + int rc = 0;
> > > + struct audit_buffer *ab;
> > > + uid_t uid;
> > > + struct tty_struct *tty;
> > > + char comm[sizeof(current->comm)];
> > > +
> > > + /* Can't set if audit disabled */
> > > + if (!task->audit)
> > > + return -ENOPROTOOPT;
> > > + oldcontid = audit_get_contid(task);
> > > + /* Don't allow the audit containerid to be unset */
> > > + if (!cid_valid(contid))
> > > + rc = -EINVAL;
> > > + /* if we don't have caps, reject */
> > > + else if (!capable(CAP_AUDIT_CONTROL))
> > > + rc = -EPERM;
> > > + /* if task has children or is not single-threaded, deny */
> > > + else if (!list_empty(&task->children))
> > > + rc = -EBUSY;
> >
> > Is this safe without holding tasklist_lock? I worry we might be
> > vulnerable to a race with fork().
> >
> > > + else if (!(thread_group_leader(task) && thread_group_empty(task)))
> > > + rc = -EALREADY;
> >
> > Similar concern here as well, although related to threads.
>
> I think you are correct here and tasklist_lock should cover both. Do we
> also want rcu_read_lock() immediately preceeding it?
You'll need to take a closer look and determine the locking scheme. I
simply took a quick look while reviewing this patch to see what of the
existing locks, if any, would be most applicable here; tasklist_lock
seemed like a good starting point.
It looks like tasklist_lock is defined as a rwlock_t so I'm not sure
it would make sense to use it with a RCU protected structure
(typically it's RCU+spinlock), but maybe that is the case with a
task_struct, you'll need to check.
> > > + /* it is already set, and not inherited from the parent, reject */
> > > + else if (cid_valid(oldcontid) && !task->audit->inherited)
> > > + rc = -EEXIST;
> >
> > Maybe I'm missing something, but why do we care about preventing
> > reassigning the audit container ID in this case? The task is single
> > threaded and has no descendants at this point so it should be safe,
> > yes? So long as the task changing the audit container ID has
> > capable(CAP_AUDIT_CONTOL) it shouldn't matter, right?
>
> Because we hammered out this idea 6 months ago in the design phase and I
> thought we all firmly agreed that the audit container identifier could
> only be set once. Has any significant discussion happenned since then
> to change that wisdom? I just wonder why this is coming up now.
Implementation, and time, can change how one looks at an earlier
design. I believe this is why most well reasoned specifications have
a reference design.
Remind me why the design had the restriction of write once for the
audit container ID? At this point given the CAP_AUDIT_CONTROL and the
single-thread, no-children restrictions I'm not sure what harm there
is in allowing the value to be written multiple times (so long as the
changes are audited of course).
> > Related, I'm questioning if we would ever care if the audit container
> > ID was inherited or not?
>
> We do since that is the only way we can tell if the value has been set
> once already or inherited unless we check if the parent's audit
> container identifier is identical (which tells us it was inherited).
Tied to the above question. If we don't care about multiple changes,
given the other constraints, we probably don't need the inherited
flag.
--
paul moore
www.paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 08/10] audit: NETFILTER_PKT: record each container ID associated with a netNS
From: Richard Guy Briggs @ 2018-07-24 20:55 UTC (permalink / raw)
To: Paul Moore
Cc: cgroups, luto, jlayton, carlos, linux-api, containers,
linux-kernel, viro, dhowells, linux-audit, ebiederm, simo, netdev,
linux-fsdevel, Eric Paris, serge
In-Reply-To: <CAHC9VhRiqp5ttCfh1EttLgbpPowr5P_B7nC6sP4pq=XBfEYqJg@mail.gmail.com>
On 2018-07-24 16:22, Paul Moore wrote:
> On Tue, Jul 24, 2018 at 3:48 PM Steve Grubb <sgrubb@redhat.com> wrote:
> > On Friday, July 20, 2018 6:15:00 PM EDT Paul Moore wrote:
> > > On Wed, Jun 6, 2018 at 1:03 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > > Add audit container identifier auxiliary record(s) to NETFILTER_PKT
> > > > event standalone records. Iterate through all potential audit container
> > > > identifiers associated with a network namespace.
> > > >
> > > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > > ---
> > > > include/linux/audit.h | 5 +++++
> > > > kernel/audit.c | 20 +++++++++++++++++++-
> > > > kernel/auditsc.c | 2 ++
> > > > net/netfilter/xt_AUDIT.c | 12 ++++++++++--
> > > > 4 files changed, 36 insertions(+), 3 deletions(-)
> > >
> > > ...
> > >
> > > > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > > > index 7e2e51c..4560a4e 100644
> > > > --- a/include/linux/audit.h
> > > > +++ b/include/linux/audit.h
> > > > @@ -167,6 +167,8 @@ extern int audit_log_contid(struct audit_context
> > > > *context, extern void audit_contid_add(struct net *net, u64 contid);
> > > > extern void audit_contid_del(struct net *net, u64 contid);
> > > > extern void audit_switch_task_namespaces(struct nsproxy *ns, struct
> > > > task_struct *p); +extern void audit_log_contid_list(struct net *net,
> > > > + struct audit_context *context);
> > >
> > > See my comment in previous patches about changing the function name to
> > > better indicate it's dedicate use for network namespaces.
> > >
> > > > extern int audit_update_lsm_rules(void);
> > > >
> > > > @@ -231,6 +233,9 @@ static inline void audit_contid_del(struct net *net,
> > > > u64 contid) { }
> > > > static inline void audit_switch_task_namespaces(struct nsproxy *ns,
> > > > struct task_struct *p) { }
> > > > +static inline void audit_log_contid_list(struct net *net,
> > > > + struct audit_context *context)
> > > > +{ }
> > > >
> > > > #define audit_enabled 0
> > > > #endif /* CONFIG_AUDIT */
> > > > diff --git a/kernel/audit.c b/kernel/audit.c
> > > > index ecd2de4..8cca41a 100644
> > > > --- a/kernel/audit.c
> > > > +++ b/kernel/audit.c
> > > > @@ -382,6 +382,20 @@ void audit_switch_task_namespaces(struct nsproxy
> > > > *ns, struct task_struct *p) audit_contid_add(new->net_ns, contid);
> > > > }
> > > >
> > > > +void audit_log_contid_list(struct net *net, struct audit_context
> > > > *context) +{
> > > > + struct audit_contid *cont;
> > > > + int i = 0;
> > > > +
> > > > + list_for_each_entry(cont, audit_get_contid_list(net), list) {
> > > > + char buf[14];
> > > > +
> > > > + sprintf(buf, "net%u", i++);
> > > > + audit_log_contid(context, buf, cont->id);
> > >
> > > Hmm. It looks like this will generate multiple audit container ID
> > > records with "op=netX contid=Y" (X=netns number, Y=audit container
> > > ID), is that what we want? I've mentioned my concern around the "op"
> > > values in these records earlier in the patchset, that still applies
> > > here, but now I'm also concerned about the multiple records. I'm
> > > thinking we might be better served with a single record with either
> > > multiple "contid" fields, or a single "contid" field with a set of
> > > comma separated values (or some other delimiter that Steve's tools
> > > will tolerate).
> > >
> > > Steve, thoughts?
> >
> > A single record is best. Maybe pattern this after the args listed in an
> > execve record.
>
> I'm concerned that an execve-like approach might not scale very well
> as would could potentially have a lot of containers sharing a single
> network namespace ("a%d=%d" vs ",%d"). Further, with execve we log
> the argument position in addition to the argument itself, that isn't
> something we need to worry about with the audit container IDs.
I think a comma-separated list would be most efficient, but could
potentially overload one record. The "netX" labels are pretty
meaningless unless they are that netNS' inode number (with qualifying
dev, of course), but that would be elsewhere in another record.
> paul moore
- RGB
--
Richard Guy Briggs <rgb@redhat.com>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 05/10] audit: add containerid support for tty_audit
From: Paul Moore @ 2018-07-24 20:36 UTC (permalink / raw)
To: rgb
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <20180724140721.yyi5e7y3czxsjwug@madcap2.tricolour.ca>
On Tue, Jul 24, 2018 at 10:10 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-07-20 18:14, Paul Moore wrote:
> > On Wed, Jun 6, 2018 at 1:04 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Add audit container identifier auxiliary record to tty logging rule
> > > event standalone records.
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > > drivers/tty/tty_audit.c | 5 ++++-
> > > 1 file changed, 4 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/tty/tty_audit.c b/drivers/tty/tty_audit.c
> > > index e30aa6b..66bd850 100644
> > > --- a/drivers/tty/tty_audit.c
> > > +++ b/drivers/tty/tty_audit.c
> > > @@ -66,8 +66,9 @@ static void tty_audit_log(const char *description, dev_t dev,
> > > uid_t uid = from_kuid(&init_user_ns, task_uid(tsk));
> > > uid_t loginuid = from_kuid(&init_user_ns, audit_get_loginuid(tsk));
> > > unsigned int sessionid = audit_get_sessionid(tsk);
> > > + struct audit_context *context = audit_alloc_local();
> >
> > We should be using current's audit_context in tty_audit_log().
> > Actually, we should probably just get rid of the tsk variable in
> > tty_audit_log() and use current directly to make things a bit more
> > obvious.
>
> Ok, agreed. At this point, it it current passed in anyways so no harm
> other than efficiency.
>
> > <time passes>
> >
> > I did some digging and I have a two year old, half-baked patch that
> > cleans up this tsk/current usage as well as a few others. I just
> > rebased it against audit/next and surprisingly it seems to pass a
> > basic smoke test (kernel boots and audit-testsuite passes); I'll post
> > it to the list as a RFC once I'm done reviewing these patches.
>
> I'll leave this patch the way it is since there should be no difference
> and trust this other patch will work its way through the system and
> solve that.
Yep, that's a merge issue I'll deal with when we get to that point.
Although, I would expect that when you post an updated patchset that
it applies cleanly to the then-current audit/next tree (or Linus'
tree, but audit/next is preferable). In other words, please rebase
your development branch before doing your final dev testing and
posting.
> > > - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY);
> > > + ab = audit_log_start(context, GFP_KERNEL, AUDIT_TTY);
> > > if (ab) {
> > > char name[sizeof(tsk->comm)];
> > >
> > > @@ -80,6 +81,8 @@ static void tty_audit_log(const char *description, dev_t dev,
> > > audit_log_n_hex(ab, data, size);
> > > audit_log_end(ab);
> > > }
> > > + audit_log_contid(context, "tty", audit_get_contid(tsk));
> > > + audit_free_context(context);
> > > }
> >
> > --
> > paul moore
> > www.paul-moore.com
>
> - RGB
>
> --
> Richard Guy Briggs <rgb@redhat.com>
> Sr. S/W Engineer, Kernel Security, Base Operating Systems
> Remote, Ottawa, Red Hat Canada
> IRC: rgb, SunRaycer
> Voice: +1.647.777.2635, Internal: (81) 32635
--
paul moore
www.paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 07/10] audit: add support for containerid to network namespaces
From: Paul Moore @ 2018-07-24 20:33 UTC (permalink / raw)
To: rgb
Cc: cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <20180724140309.i6o2yjdoif5krxtw@madcap2.tricolour.ca>
On Tue, Jul 24, 2018 at 10:06 AM Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-07-20 18:14, Paul Moore wrote:
> > On Wed, Jun 6, 2018 at 1:03 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Audit events could happen in a network namespace outside of a task
> > > context due to packets received from the net that trigger an auditing
> > > rule prior to being associated with a running task. The network
> > > namespace could in use by multiple containers by association to the
> > > tasks in that network namespace. We still want a way to attribute
> > > these events to any potential containers. Keep a list per network
> > > namespace to track these audit container identifiiers.
> > >
> > > Add/increment the audit container identifier on:
> > > - initial setting of the audit container identifier via /proc
> > > - clone/fork call that inherits an audit container identifier
> > > - unshare call that inherits an audit container identifier
> > > - setns call that inherits an audit container identifier
> > > Delete/decrement the audit container identifier on:
> > > - an inherited audit container identifier dropped when child set
> > > - process exit
> > > - unshare call that drops a net namespace
> > > - setns call that drops a net namespace
> > >
> > > See: https://github.com/linux-audit/audit-kernel/issues/92
> > > See: https://github.com/linux-audit/audit-testsuite/issues/64
> > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > > include/linux/audit.h | 23 ++++++++++++++++
> > > kernel/audit.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > > kernel/auditsc.c | 5 ++++
> > > kernel/nsproxy.c | 4 +++
> > > 4 files changed, 104 insertions(+)
...
> > > + }
> > > + if (!found)
> > > + return;
> > > + list_del(&cont->list);
> > > + if (refcount_dec_and_test(&cont->refcount))
> > > + kfree(cont);
> >
> > Don't you want to dec_and_test first and only remove it from the list
> > if there are no other references?
>
> I don't think so. Let me try to describe it in prose to see if I
> understood this properly and see if this makes more sense: I want to
> remove this audit_contid list member from this net's audit_contid list
> and decrement unconditionally this member's refcount so it knows there
> is one less thing pointing at it and when there is no longer anything
> pointing at it, free it.
Yep, sorry, my mistake, I was thinking the other way around (netns
going away) ... which actually, this patchset doesn't handle that does
it (I don't see any new code in audit_net_exit())? Is is in a later
patch? If so, it really should be in the same patch as this code to
prevent bisect nasties.
--
paul moore
www.paul-moore.com
^ permalink raw reply
* Re: [RFC PATCH ghak90 (was ghak32) V3 08/10] audit: NETFILTER_PKT: record each container ID associated with a netNS
From: Paul Moore @ 2018-07-24 20:22 UTC (permalink / raw)
To: sgrubb
Cc: rgb, cgroups, containers, linux-api, linux-audit, linux-fsdevel,
linux-kernel, netdev, ebiederm, luto, jlayton, carlos, dhowells,
viro, simo, Eric Paris, serge
In-Reply-To: <1748819.SHaROlQLoH@x2>
On Tue, Jul 24, 2018 at 3:48 PM Steve Grubb <sgrubb@redhat.com> wrote:
> On Friday, July 20, 2018 6:15:00 PM EDT Paul Moore wrote:
> > On Wed, Jun 6, 2018 at 1:03 PM Richard Guy Briggs <rgb@redhat.com> wrote:
> > > Add audit container identifier auxiliary record(s) to NETFILTER_PKT
> > > event standalone records. Iterate through all potential audit container
> > > identifiers associated with a network namespace.
> > >
> > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > > ---
> > > include/linux/audit.h | 5 +++++
> > > kernel/audit.c | 20 +++++++++++++++++++-
> > > kernel/auditsc.c | 2 ++
> > > net/netfilter/xt_AUDIT.c | 12 ++++++++++--
> > > 4 files changed, 36 insertions(+), 3 deletions(-)
> >
> > ...
> >
> > > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > > index 7e2e51c..4560a4e 100644
> > > --- a/include/linux/audit.h
> > > +++ b/include/linux/audit.h
> > > @@ -167,6 +167,8 @@ extern int audit_log_contid(struct audit_context
> > > *context, extern void audit_contid_add(struct net *net, u64 contid);
> > > extern void audit_contid_del(struct net *net, u64 contid);
> > > extern void audit_switch_task_namespaces(struct nsproxy *ns, struct
> > > task_struct *p); +extern void audit_log_contid_list(struct net *net,
> > > + struct audit_context *context);
> >
> > See my comment in previous patches about changing the function name to
> > better indicate it's dedicate use for network namespaces.
> >
> > > extern int audit_update_lsm_rules(void);
> > >
> > > @@ -231,6 +233,9 @@ static inline void audit_contid_del(struct net *net,
> > > u64 contid) { }
> > > static inline void audit_switch_task_namespaces(struct nsproxy *ns,
> > > struct task_struct *p) { }
> > > +static inline void audit_log_contid_list(struct net *net,
> > > + struct audit_context *context)
> > > +{ }
> > >
> > > #define audit_enabled 0
> > > #endif /* CONFIG_AUDIT */
> > > diff --git a/kernel/audit.c b/kernel/audit.c
> > > index ecd2de4..8cca41a 100644
> > > --- a/kernel/audit.c
> > > +++ b/kernel/audit.c
> > > @@ -382,6 +382,20 @@ void audit_switch_task_namespaces(struct nsproxy
> > > *ns, struct task_struct *p) audit_contid_add(new->net_ns, contid);
> > > }
> > >
> > > +void audit_log_contid_list(struct net *net, struct audit_context
> > > *context) +{
> > > + struct audit_contid *cont;
> > > + int i = 0;
> > > +
> > > + list_for_each_entry(cont, audit_get_contid_list(net), list) {
> > > + char buf[14];
> > > +
> > > + sprintf(buf, "net%u", i++);
> > > + audit_log_contid(context, buf, cont->id);
> >
> > Hmm. It looks like this will generate multiple audit container ID
> > records with "op=netX contid=Y" (X=netns number, Y=audit container
> > ID), is that what we want? I've mentioned my concern around the "op"
> > values in these records earlier in the patchset, that still applies
> > here, but now I'm also concerned about the multiple records. I'm
> > thinking we might be better served with a single record with either
> > multiple "contid" fields, or a single "contid" field with a set of
> > comma separated values (or some other delimiter that Steve's tools
> > will tolerate).
> >
> > Steve, thoughts?
>
> A single record is best. Maybe pattern this after the args listed in an
> execve record.
I'm concerned that an execve-like approach might not scale very well
as would could potentially have a lot of containers sharing a single
network namespace ("a%d=%d" vs ",%d"). Further, with execve we log
the argument position in addition to the argument itself, that isn't
something we need to worry about with the audit container IDs.
--
paul moore
www.paul-moore.com
^ permalink raw reply
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