From: Fredric Cover <fredric.cover.lkernel@gmail.com> mainline inclusion from mainline-v7.3-rc1 commit b1b741cf8e7ce1b91d937e23decd3d3358748700 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18921 CVE: CVE-2026-89636 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When free_tgts() frees all structures in ce->tlist, ce->tgthint is left pointing to one of the freed cache_dfs_tgt structures. If ce->tgthint is not reset before it is used later, it results in a use-after-free. Set ce->tgthint to NULL in free_tgts() after the elements are freed to reflect that no elements remain. Fixes: 54be1f6c1c37 ("cifs: Add DFS cache routines") Cc: stable@vger.kernel.org # depends on: smb: client: harden DFS cache against invalid target hints Signed-off-by: Fredric Cover <fredric.cover.lkernel@gmail.com> Reviewed-by: ChenXiaoSong <chenxiaosong@kylinos.cn> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org> Signed-off-by: Paulo Alcantara <pc@manguebit.org> Conflicts: fs/cifs/dfs_cache.c fs/smb/client/dfs_cache.c [different files] Signed-off-by: Yifan Qiao <qiaoyifan4@huawei.com> --- fs/cifs/dfs_cache.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c index b83932175c83..9bdc9918b12e 100644 --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -118,6 +118,8 @@ static inline void free_tgts(struct cache_entry *ce) kfree(t->name); kfree(t); } + + WRITE_ONCE(ce->tgthint, NULL); } static inline void flush_cache_ent(struct cache_entry *ce) -- 2.52.0