From: Amir Goldstein <amir73il@gmail.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Vivek Goyal <vgoyal@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org
Subject: [PATCH 2/4] ovl: use generic vfs_ioc_setflags_prepare() helper
Date: Mon, 15 Jul 2019 16:38:37 +0300 [thread overview]
Message-ID: <20190715133839.9878-3-amir73il@gmail.com> (raw)
In-Reply-To: <20190715133839.9878-1-amir73il@gmail.com>
Canonalize to ioctl FS_* flags instead of inode S_* flags.
Note that we do not call the helper vfs_ioc_fssetxattr_check()
for FS_IOC_FSSETXATTR ioctl. The reason is that underlying filesystem
will perform all the checks. We only need to perform the capability
check before overriding credentials.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
fs/overlayfs/file.c | 62 ++++++++++++++++++++++-----------------------
1 file changed, 30 insertions(+), 32 deletions(-)
diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
index c6426e4d3f1f..1ba40845fba0 100644
--- a/fs/overlayfs/file.c
+++ b/fs/overlayfs/file.c
@@ -406,12 +406,28 @@ static long ovl_real_ioctl(struct file *file, unsigned int cmd,
return ret;
}
+static unsigned int ovl_iflags_to_fsflags(unsigned int iflags)
+{
+ unsigned int flags = 0;
+
+ if (iflags & S_SYNC)
+ flags |= FS_SYNC_FL;
+ if (iflags & S_APPEND)
+ flags |= FS_APPEND_FL;
+ if (iflags & S_IMMUTABLE)
+ flags |= FS_IMMUTABLE_FL;
+ if (iflags & S_NOATIME)
+ flags |= FS_NOATIME_FL;
+
+ return flags;
+}
+
static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
- unsigned long arg, unsigned int iflags)
+ unsigned long arg, unsigned int flags)
{
long ret;
struct inode *inode = file_inode(file);
- unsigned int old_iflags;
+ unsigned int oldflags;
if (!inode_owner_or_capable(inode))
return -EACCES;
@@ -423,10 +439,9 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
inode_lock(inode);
/* Check the capability before cred override */
- ret = -EPERM;
- old_iflags = READ_ONCE(inode->i_flags);
- if (((iflags ^ old_iflags) & (S_APPEND | S_IMMUTABLE)) &&
- !capable(CAP_LINUX_IMMUTABLE))
+ oldflags = ovl_iflags_to_fsflags(READ_ONCE(inode->i_flags));
+ ret = vfs_ioc_setflags_prepare(inode, oldflags, flags);
+ if (ret)
goto unlock;
ret = ovl_maybe_copy_up(file_dentry(file), O_WRONLY);
@@ -445,22 +460,6 @@ static long ovl_ioctl_set_flags(struct file *file, unsigned int cmd,
}
-static unsigned int ovl_fsflags_to_iflags(unsigned int flags)
-{
- unsigned int iflags = 0;
-
- if (flags & FS_SYNC_FL)
- iflags |= S_SYNC;
- if (flags & FS_APPEND_FL)
- iflags |= S_APPEND;
- if (flags & FS_IMMUTABLE_FL)
- iflags |= S_IMMUTABLE;
- if (flags & FS_NOATIME_FL)
- iflags |= S_NOATIME;
-
- return iflags;
-}
-
static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
unsigned long arg)
{
@@ -469,24 +468,23 @@ static long ovl_ioctl_set_fsflags(struct file *file, unsigned int cmd,
if (get_user(flags, (int __user *) arg))
return -EFAULT;
- return ovl_ioctl_set_flags(file, cmd, arg,
- ovl_fsflags_to_iflags(flags));
+ return ovl_ioctl_set_flags(file, cmd, arg, flags);
}
-static unsigned int ovl_fsxflags_to_iflags(unsigned int xflags)
+static unsigned int ovl_fsxflags_to_fsflags(unsigned int xflags)
{
- unsigned int iflags = 0;
+ unsigned int flags = 0;
if (xflags & FS_XFLAG_SYNC)
- iflags |= S_SYNC;
+ flags |= FS_SYNC_FL;
if (xflags & FS_XFLAG_APPEND)
- iflags |= S_APPEND;
+ flags |= FS_APPEND_FL;
if (xflags & FS_XFLAG_IMMUTABLE)
- iflags |= S_IMMUTABLE;
+ flags |= FS_IMMUTABLE_FL;
if (xflags & FS_XFLAG_NOATIME)
- iflags |= S_NOATIME;
+ flags |= FS_NOATIME_FL;
- return iflags;
+ return flags;
}
static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
@@ -499,7 +497,7 @@ static long ovl_ioctl_set_fsxflags(struct file *file, unsigned int cmd,
return -EFAULT;
return ovl_ioctl_set_flags(file, cmd, arg,
- ovl_fsxflags_to_iflags(fa.fsx_xflags));
+ ovl_fsxflags_to_fsflags(fa.fsx_xflags));
}
long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
--
2.17.1
next prev parent reply other threads:[~2019-07-15 13:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 13:38 [PFC][PATCH 0/4] Overlayfs SHUTDOWN ioctl Amir Goldstein
2019-07-15 13:38 ` [PATCH 1/4] ovl: support [S|G]ETFLAGS ioctl for directories Amir Goldstein
2019-07-26 6:57 ` Amir Goldstein
2019-07-15 13:38 ` Amir Goldstein [this message]
2019-07-15 13:38 ` [PATCH 3/4] ovl: add pre/post access hooks to underlying layers Amir Goldstein
2019-07-15 13:38 ` [PATCH 4/4] ovl: add support for SHUTDOWN ioctl Amir Goldstein
2019-07-16 5:35 ` [PFC][PATCH 0/4] Overlayfs " Amir Goldstein
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