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| author | Miklos Szeredi <mszeredi@redhat.com> | 2016-06-29 11:54:23 +0300 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-07-01 06:28:09 +0300 |
| commit | b403f0e37a11f84f7ceaf40b0075499e5bcfd220 (patch) | |
| tree | 50cece69d070007009655f40e488c20da578b990 | |
| parent | b42b90d177d0c7f46f9c888c10c7900578ae7e09 (diff) | |
| download | linux-b403f0e37a11f84f7ceaf40b0075499e5bcfd220.tar.xz | |
9p: use file_dentry()
v9fs may be used as lower layer of overlayfs and accessing f_path.dentry
can lead to a crash. In this case it's a NULL pointer dereference in
p9_fid_create().
Fix by replacing direct access of file->f_path.dentry with the
file_dentry() accessor, which will always return a native object.
Reported-by: Alessio Igor Bogani <alessioigorbogani@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Tested-by: Alessio Igor Bogani <alessioigorbogani@gmail.com>
Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay and f_inode to the underlay")
Cc: <stable@vger.kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| -rw-r--r-- | fs/9p/vfs_file.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c index b84c291ba1eb..d7b78d531e63 100644 --- a/fs/9p/vfs_file.c +++ b/fs/9p/vfs_file.c @@ -74,7 +74,7 @@ int v9fs_file_open(struct inode *inode, struct file *file) v9fs_proto_dotu(v9ses)); fid = file->private_data; if (!fid) { - fid = v9fs_fid_clone(file->f_path.dentry); + fid = v9fs_fid_clone(file_dentry(file)); if (IS_ERR(fid)) return PTR_ERR(fid); @@ -100,7 +100,7 @@ int v9fs_file_open(struct inode *inode, struct file *file) * because we want write after unlink usecase * to work. */ - fid = v9fs_writeback_fid(file->f_path.dentry); + fid = v9fs_writeback_fid(file_dentry(file)); if (IS_ERR(fid)) { err = PTR_ERR(fid); mutex_unlock(&v9inode->v_mutex); @@ -516,7 +516,7 @@ v9fs_mmap_file_mmap(struct file *filp, struct vm_area_struct *vma) * because we want write after unlink usecase * to work. */ - fid = v9fs_writeback_fid(filp->f_path.dentry); + fid = v9fs_writeback_fid(file_dentry(filp)); if (IS_ERR(fid)) { retval = PTR_ERR(fid); mutex_unlock(&v9inode->v_mutex); |