On 17/10/2018 14:20, David Howells wrote:
David Howells <dhowells@xxxxxxxxxx> wrote:
I should probably check that the picked point is actually a mountpoint.
The root of the mount object at the path specified, that is, perhaps with
something like the attached.
David
I agree. I'm happy to see this is using the same check as do_remount().
* change filesystem flags. dir should be a physical root of filesystem.
* If you've mounted a non-root directory somewhere and want to do remount
* on it - tough luck.
*/
Thanks
Alan
---
diff --git a/fs/fsopen.c b/fs/fsopen.c
index f673e93ac456..aaaaa17a233c 100644
--- a/fs/fsopen.c
+++ b/fs/fsopen.c
@@ -186,6 +186,10 @@ SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags
if (ret < 0)
goto err;
+ ret = -EINVAL;
+ if (target.mnt->mnt_root != target.dentry)
+ goto err_path;
+
fc = vfs_new_fs_context(target.dentry->d_sb->s_type, target.dentry,
0, 0, FS_CONTEXT_FOR_RECONFIGURE);
if (IS_ERR(fc)) {
