* [PULL 1/2] virtiofsd: passthrough_ll: cleanup getxattr/listxattr
2020-03-03 15:16 [PULL 0/2] virtiofs queue Dr. David Alan Gilbert (git)
@ 2020-03-03 15:16 ` Dr. David Alan Gilbert (git)
2020-03-03 15:16 ` [PULL 2/2] virtiofsd: Fix xattr operations Dr. David Alan Gilbert (git)
2020-03-03 17:23 ` [PULL 0/2] virtiofs queue Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert (git) @ 2020-03-03 15:16 UTC (permalink / raw)
To: qemu-devel
From: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
This is a cleanup patch to simplify the following xattr fix and
there is no functional changes.
- Move memory allocation to head of the function
- Unify fgetxattr/flistxattr call for both size == 0 and
size != 0 case
- Remove redundant lo_inode_put call in error path
(Note: second call is ignored now since @inode is already NULL)
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20200227055927.24566-2-misono.tomohiro@jp.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
tools/virtiofsd/passthrough_ll.c | 54 +++++++++++++-------------------
1 file changed, 22 insertions(+), 32 deletions(-)
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 02ff01fad0..4690a97947 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -2195,34 +2195,30 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
goto out;
}
+ if (size) {
+ value = malloc(size);
+ if (!value) {
+ goto out_err;
+ }
+ }
+
sprintf(procname, "%i", inode->fd);
fd = openat(lo->proc_self_fd, procname, O_RDONLY);
if (fd < 0) {
goto out_err;
}
+ ret = fgetxattr(fd, name, value, size);
+ if (ret == -1) {
+ goto out_err;
+ }
if (size) {
- value = malloc(size);
- if (!value) {
- goto out_err;
- }
-
- ret = fgetxattr(fd, name, value, size);
- if (ret == -1) {
- goto out_err;
- }
saverr = 0;
if (ret == 0) {
goto out;
}
-
fuse_reply_buf(req, value, ret);
} else {
- ret = fgetxattr(fd, name, NULL, 0);
- if (ret == -1) {
- goto out_err;
- }
-
fuse_reply_xattr(req, ret);
}
out_free:
@@ -2238,7 +2234,6 @@ out_free:
out_err:
saverr = errno;
out:
- lo_inode_put(lo, &inode);
fuse_reply_err(req, saverr);
goto out_free;
}
@@ -2273,34 +2268,30 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
goto out;
}
+ if (size) {
+ value = malloc(size);
+ if (!value) {
+ goto out_err;
+ }
+ }
+
sprintf(procname, "%i", inode->fd);
fd = openat(lo->proc_self_fd, procname, O_RDONLY);
if (fd < 0) {
goto out_err;
}
+ ret = flistxattr(fd, value, size);
+ if (ret == -1) {
+ goto out_err;
+ }
if (size) {
- value = malloc(size);
- if (!value) {
- goto out_err;
- }
-
- ret = flistxattr(fd, value, size);
- if (ret == -1) {
- goto out_err;
- }
saverr = 0;
if (ret == 0) {
goto out;
}
-
fuse_reply_buf(req, value, ret);
} else {
- ret = flistxattr(fd, NULL, 0);
- if (ret == -1) {
- goto out_err;
- }
-
fuse_reply_xattr(req, ret);
}
out_free:
@@ -2316,7 +2307,6 @@ out_free:
out_err:
saverr = errno;
out:
- lo_inode_put(lo, &inode);
fuse_reply_err(req, saverr);
goto out_free;
}
--
2.24.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PULL 2/2] virtiofsd: Fix xattr operations
2020-03-03 15:16 [PULL 0/2] virtiofs queue Dr. David Alan Gilbert (git)
2020-03-03 15:16 ` [PULL 1/2] virtiofsd: passthrough_ll: cleanup getxattr/listxattr Dr. David Alan Gilbert (git)
@ 2020-03-03 15:16 ` Dr. David Alan Gilbert (git)
2020-03-03 17:23 ` [PULL 0/2] virtiofs queue Peter Maydell
2 siblings, 0 replies; 4+ messages in thread
From: Dr. David Alan Gilbert (git) @ 2020-03-03 15:16 UTC (permalink / raw)
To: qemu-devel
From: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Current virtiofsd has problems about xattr operations and
they does not work properly for directory/symlink/special file.
The fundamental cause is that virtiofsd uses openat() + f...xattr()
systemcalls for xattr operation but we should not open symlink/special
file in the daemon. Therefore the function is restricted.
Fix this problem by:
1. during setup of each thread, call unshare(CLONE_FS)
2. in xattr operations (i.e. lo_getxattr), if inode is not a regular
file or directory, use fchdir(proc_loot_fd) + ...xattr() +
fchdir(root.fd) instead of openat() + f...xattr()
(Note: for a regular file/directory openat() + f...xattr()
is still used for performance reason)
With this patch, xfstests generic/062 passes on virtiofs.
This fix is suggested by Miklos Szeredi and Stefan Hajnoczi.
The original discussion can be found here:
https://www.redhat.com/archives/virtio-fs/2019-October/msg00046.html
Signed-off-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Message-Id: <20200227055927.24566-3-misono.tomohiro@jp.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
tools/virtiofsd/fuse_virtio.c | 13 ++++
tools/virtiofsd/passthrough_ll.c | 105 +++++++++++++++++--------------
tools/virtiofsd/seccomp.c | 6 ++
3 files changed, 77 insertions(+), 47 deletions(-)
diff --git a/tools/virtiofsd/fuse_virtio.c b/tools/virtiofsd/fuse_virtio.c
index dd1c605dbf..3b6d16a041 100644
--- a/tools/virtiofsd/fuse_virtio.c
+++ b/tools/virtiofsd/fuse_virtio.c
@@ -426,6 +426,8 @@ err:
return ret;
}
+static __thread bool clone_fs_called;
+
/* Process one FVRequest in a thread pool */
static void fv_queue_worker(gpointer data, gpointer user_data)
{
@@ -441,6 +443,17 @@ static void fv_queue_worker(gpointer data, gpointer user_data)
assert(se->bufsize > sizeof(struct fuse_in_header));
+ if (!clone_fs_called) {
+ int ret;
+
+ /* unshare FS for xattr operation */
+ ret = unshare(CLONE_FS);
+ /* should not fail */
+ assert(ret == 0);
+
+ clone_fs_called = true;
+ }
+
/*
* An element contains one request and the space to send our response
* They're spread over multiple descriptors in a scatter/gather set
diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c
index 4690a97947..4f259aac70 100644
--- a/tools/virtiofsd/passthrough_ll.c
+++ b/tools/virtiofsd/passthrough_ll.c
@@ -123,7 +123,7 @@ struct lo_inode {
pthread_mutex_t plock_mutex;
GHashTable *posix_locks; /* protected by lo_inode->plock_mutex */
- bool is_symlink;
+ mode_t filetype;
};
struct lo_cred {
@@ -695,7 +695,7 @@ static int utimensat_empty(struct lo_data *lo, struct lo_inode *inode,
struct lo_inode *parent;
char path[PATH_MAX];
- if (inode->is_symlink) {
+ if (S_ISLNK(inode->filetype)) {
res = utimensat(inode->fd, "", tv, AT_EMPTY_PATH);
if (res == -1 && errno == EINVAL) {
/* Sorry, no race free way to set times on symlink. */
@@ -928,7 +928,8 @@ static int lo_do_lookup(fuse_req_t req, fuse_ino_t parent, const char *name,
goto out_err;
}
- inode->is_symlink = S_ISLNK(e->attr.st_mode);
+ /* cache only filetype */
+ inode->filetype = (e->attr.st_mode & S_IFMT);
/*
* One for the caller and one for nlookup (released in
@@ -1135,7 +1136,7 @@ static int linkat_empty_nofollow(struct lo_data *lo, struct lo_inode *inode,
struct lo_inode *parent;
char path[PATH_MAX];
- if (inode->is_symlink) {
+ if (S_ISLNK(inode->filetype)) {
res = linkat(inode->fd, "", dfd, name, AT_EMPTY_PATH);
if (res == -1 && (errno == ENOENT || errno == EINVAL)) {
/* Sorry, no race free way to hard-link a symlink. */
@@ -2189,12 +2190,6 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
fuse_log(FUSE_LOG_DEBUG, "lo_getxattr(ino=%" PRIu64 ", name=%s size=%zd)\n",
ino, name, size);
- if (inode->is_symlink) {
- /* Sorry, no race free way to getxattr on symlink. */
- saverr = EPERM;
- goto out;
- }
-
if (size) {
value = malloc(size);
if (!value) {
@@ -2203,12 +2198,25 @@ static void lo_getxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
}
sprintf(procname, "%i", inode->fd);
- fd = openat(lo->proc_self_fd, procname, O_RDONLY);
- if (fd < 0) {
- goto out_err;
+ /*
+ * It is not safe to open() non-regular/non-dir files in file server
+ * unless O_PATH is used, so use that method for regular files/dir
+ * only (as it seems giving less performance overhead).
+ * Otherwise, call fchdir() to avoid open().
+ */
+ if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) {
+ fd = openat(lo->proc_self_fd, procname, O_RDONLY);
+ if (fd < 0) {
+ goto out_err;
+ }
+ ret = fgetxattr(fd, name, value, size);
+ } else {
+ /* fchdir should not fail here */
+ assert(fchdir(lo->proc_self_fd) == 0);
+ ret = getxattr(procname, name, value, size);
+ assert(fchdir(lo->root.fd) == 0);
}
- ret = fgetxattr(fd, name, value, size);
if (ret == -1) {
goto out_err;
}
@@ -2262,12 +2270,6 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
fuse_log(FUSE_LOG_DEBUG, "lo_listxattr(ino=%" PRIu64 ", size=%zd)\n", ino,
size);
- if (inode->is_symlink) {
- /* Sorry, no race free way to listxattr on symlink. */
- saverr = EPERM;
- goto out;
- }
-
if (size) {
value = malloc(size);
if (!value) {
@@ -2276,12 +2278,19 @@ static void lo_listxattr(fuse_req_t req, fuse_ino_t ino, size_t size)
}
sprintf(procname, "%i", inode->fd);
- fd = openat(lo->proc_self_fd, procname, O_RDONLY);
- if (fd < 0) {
- goto out_err;
+ if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) {
+ fd = openat(lo->proc_self_fd, procname, O_RDONLY);
+ if (fd < 0) {
+ goto out_err;
+ }
+ ret = flistxattr(fd, value, size);
+ } else {
+ /* fchdir should not fail here */
+ assert(fchdir(lo->proc_self_fd) == 0);
+ ret = listxattr(procname, value, size);
+ assert(fchdir(lo->root.fd) == 0);
}
- ret = flistxattr(fd, value, size);
if (ret == -1) {
goto out_err;
}
@@ -2335,20 +2344,21 @@ static void lo_setxattr(fuse_req_t req, fuse_ino_t ino, const char *name,
fuse_log(FUSE_LOG_DEBUG, "lo_setxattr(ino=%" PRIu64
", name=%s value=%s size=%zd)\n", ino, name, value, size);
- if (inode->is_symlink) {
- /* Sorry, no race free way to setxattr on symlink. */
- saverr = EPERM;
- goto out;
- }
-
sprintf(procname, "%i", inode->fd);
- fd = openat(lo->proc_self_fd, procname, O_RDWR);
- if (fd < 0) {
- saverr = errno;
- goto out;
+ if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) {
+ fd = openat(lo->proc_self_fd, procname, O_RDONLY);
+ if (fd < 0) {
+ saverr = errno;
+ goto out;
+ }
+ ret = fsetxattr(fd, name, value, size, flags);
+ } else {
+ /* fchdir should not fail here */
+ assert(fchdir(lo->proc_self_fd) == 0);
+ ret = setxattr(procname, name, value, size, flags);
+ assert(fchdir(lo->root.fd) == 0);
}
- ret = fsetxattr(fd, name, value, size, flags);
saverr = ret == -1 ? errno : 0;
out:
@@ -2383,20 +2393,21 @@ static void lo_removexattr(fuse_req_t req, fuse_ino_t ino, const char *name)
fuse_log(FUSE_LOG_DEBUG, "lo_removexattr(ino=%" PRIu64 ", name=%s)\n", ino,
name);
- if (inode->is_symlink) {
- /* Sorry, no race free way to setxattr on symlink. */
- saverr = EPERM;
- goto out;
- }
-
sprintf(procname, "%i", inode->fd);
- fd = openat(lo->proc_self_fd, procname, O_RDWR);
- if (fd < 0) {
- saverr = errno;
- goto out;
+ if (S_ISREG(inode->filetype) || S_ISDIR(inode->filetype)) {
+ fd = openat(lo->proc_self_fd, procname, O_RDONLY);
+ if (fd < 0) {
+ saverr = errno;
+ goto out;
+ }
+ ret = fremovexattr(fd, name);
+ } else {
+ /* fchdir should not fail here */
+ assert(fchdir(lo->proc_self_fd) == 0);
+ ret = removexattr(procname, name);
+ assert(fchdir(lo->root.fd) == 0);
}
- ret = fremovexattr(fd, name);
saverr = ret == -1 ? errno : 0;
out:
@@ -2796,7 +2807,7 @@ static void setup_root(struct lo_data *lo, struct lo_inode *root)
exit(1);
}
- root->is_symlink = false;
+ root->filetype = S_IFDIR;
root->fd = fd;
root->key.ino = stat.st_ino;
root->key.dev = stat.st_dev;
diff --git a/tools/virtiofsd/seccomp.c b/tools/virtiofsd/seccomp.c
index 2d9d4a7ec0..bd9e7b083c 100644
--- a/tools/virtiofsd/seccomp.c
+++ b/tools/virtiofsd/seccomp.c
@@ -41,6 +41,7 @@ static const int syscall_whitelist[] = {
SCMP_SYS(exit),
SCMP_SYS(exit_group),
SCMP_SYS(fallocate),
+ SCMP_SYS(fchdir),
SCMP_SYS(fchmodat),
SCMP_SYS(fchownat),
SCMP_SYS(fcntl),
@@ -62,7 +63,9 @@ static const int syscall_whitelist[] = {
SCMP_SYS(getpid),
SCMP_SYS(gettid),
SCMP_SYS(gettimeofday),
+ SCMP_SYS(getxattr),
SCMP_SYS(linkat),
+ SCMP_SYS(listxattr),
SCMP_SYS(lseek),
SCMP_SYS(madvise),
SCMP_SYS(mkdirat),
@@ -85,6 +88,7 @@ static const int syscall_whitelist[] = {
SCMP_SYS(recvmsg),
SCMP_SYS(renameat),
SCMP_SYS(renameat2),
+ SCMP_SYS(removexattr),
SCMP_SYS(rt_sigaction),
SCMP_SYS(rt_sigprocmask),
SCMP_SYS(rt_sigreturn),
@@ -98,10 +102,12 @@ static const int syscall_whitelist[] = {
SCMP_SYS(setresuid32),
#endif
SCMP_SYS(set_robust_list),
+ SCMP_SYS(setxattr),
SCMP_SYS(symlinkat),
SCMP_SYS(time), /* Rarely needed, except on static builds */
SCMP_SYS(tgkill),
SCMP_SYS(unlinkat),
+ SCMP_SYS(unshare),
SCMP_SYS(utimensat),
SCMP_SYS(write),
SCMP_SYS(writev),
--
2.24.1
^ permalink raw reply related [flat|nested] 4+ messages in thread