From: Chen Ridong <chenridong@huawei.com> stable inclusion from stable-v6.6.76 commit 6f45ef616775b0ce7889b0f6077fc8d681ab30bc category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPBDP CVE: CVE-2025-21726 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit dd7d37ccf6b11f3d95e797ebe4e9e886d0332600 ] Although the previous patch can avoid ps and ps UAF for _do_serial, it can not avoid potential UAF issue for reorder_work. This issue can happen just as below: crypto_request crypto_request crypto_del_alg padata_do_serial ... padata_reorder // processes all remaining // requests then breaks while (1) { if (!padata) break; ... } padata_do_serial // new request added list_add // sees the new request queue_work(reorder_work) padata_reorder queue_work_on(squeue->work) ... <kworker context> padata_serial_worker // completes new request, // no more outstanding // requests crypto_del_alg // free pd <kworker context> invoke_padata_reorder // UAF of pd To avoid UAF for 'reorder_work', get 'pd' ref before put 'reorder_work' into the 'serial_wq' and put 'pd' ref until the 'serial_wq' finish. Fixes: bbefa1dd6a6d ("crypto: pcrypt - Avoid deadlock by using per-instance padata queues") Signed-off-by: Chen Ridong <chenridong@huawei.com> Acked-by: Daniel Jordan <daniel.m.jordan@oracle.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Zicheng Qu <quzicheng@huawei.com> --- kernel/padata.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/kernel/padata.c b/kernel/padata.c index d5c515b3058a..0e065e45e463 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -357,8 +357,14 @@ static void padata_reorder(struct parallel_data *pd) smp_mb(); reorder = per_cpu_ptr(pd->reorder_list, pd->cpu); - if (!list_empty(&reorder->list) && padata_find_next(pd, false)) + if (!list_empty(&reorder->list) && padata_find_next(pd, false)) { + /* + * Other context(eg. the padata_serial_worker) can finish the request. + * To avoid UAF issue, add pd ref here, and put pd ref after reorder_work finish. + */ + padata_get_pd(pd); queue_work(pinst->serial_wq, &pd->reorder_work); + } } static void invoke_padata_reorder(struct work_struct *work) @@ -369,6 +375,8 @@ static void invoke_padata_reorder(struct work_struct *work) pd = container_of(work, struct parallel_data, reorder_work); padata_reorder(pd); local_bh_enable(); + /* Pairs with putting the reorder_work in the serial_wq */ + padata_put_pd(pd); } static void padata_serial_worker(struct work_struct *serial_work) -- 2.34.1