mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-01-11 09:00:12 +00:00
2b74209458
There exists a null pointer dereference in simple_xattrs_free() as part of the __kernfs_new_node() routine. Within __kernfs_new_node(), err_out4 calls simple_xattr_free(), but kn->iattr may be NULL if __kernfs_setattr() was never called. As a result, the first argument to simple_xattrs_free() may be NULL + 0x38, and no NULL check is done internally, causing an incorrect pointer dereference. Add a check to ensure kn->iattr is not NULL, meaning __kernfs_setattr() has been called and kn->iattr is allocated. Note that struct kernfs_node kn is allocated with kmem_cache_zalloc, so we can assume kn->iattr will be NULL if not allocated. An alternative fix could be to not call simple_xattrs_free() at all. As was previously discussed during the initial patch, simple_xattrs_free() is not strictly needed and is included to be consistent with kernfs_free_rcu(), which also helps the function maintain correctness if changes are made in __kernfs_new_node(). Reported-by: syzbot+6aaf7f48ae034ab0ea97@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=6aaf7f48ae034ab0ea97 Fixes: 382b1e8f30f7 ("kernfs: fix memory leak of kernfs_iattrs in __kernfs_new_node") Signed-off-by: Will Rosenberg <whrosenb@asu.edu> Link: https://patch.msgid.link/20251217060107.4171558-1-whrosenb@asu.edu Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>