The locks_remove_posix() function in fcntl_setlk/fcntl_setlk64 is designed to reliably remove locks when an fcntl/close race is detected. However, it was passing in the wrong filelock owner, it looks like a mistake and resulting in a failure to remove locks. More critically, if the lock removal fails, it could lead to a uaf issue while traversing the locks.
This problem occurs only in the 4.19/5.4 stable version.
Fixes: 4c43ad4ab416 ("filelock: Fix fcntl/close race recovery compat path") Fixes: dc2ce1dfceaa ("filelock: Remove locks reliably when fcntl/close race is detected") Cc: stable@vger.kernel.org Signed-off-by: Long Li leo.lilong@huawei.com --- fs/locks.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/locks.c b/fs/locks.c index 85c8af53d4eb..cf6ed857664b 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2542,7 +2542,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd, f = fcheck(fd); spin_unlock(¤t->files->file_lock); if (f != filp) { - locks_remove_posix(filp, ¤t->files); + locks_remove_posix(filp, current->files); error = -EBADF; } } @@ -2672,7 +2672,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd, f = fcheck(fd); spin_unlock(¤t->files->file_lock); if (f != filp) { - locks_remove_posix(filp, ¤t->files); + locks_remove_posix(filp, current->files); error = -EBADF; } }