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authorMiklos Szeredi <mszeredi@redhat.com>2016-06-29 10:54:23 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2016-06-30 23:28:09 -0400
commitb403f0e37a11f84f7ceaf40b0075499e5bcfd220 (patch)
tree50cece69d070007009655f40e488c20da578b990 /fs
parentb42b90d177d0c7f46f9c888c10c7900578ae7e09 (diff)
downloadlinux-b403f0e37a11f84f7ceaf40b0075499e5bcfd220.tar.gz
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/9p/vfs_file.c6
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);