diff mbox series

io_uring: Fix use-after-free in io_sq_wq_submit_work()

Message ID 20200805034042.GA29805@ubuntu (mailing list archive)
State New, archived
Headers show
Series io_uring: Fix use-after-free in io_sq_wq_submit_work() | expand

Commit Message

Guoyu Huang Aug. 5, 2020, 3:40 a.m. UTC 
when ctx->sqo_mm is zero, io_sq_wq_submit_work() frees 'req'
without deleting it from 'task_list'. After that, 'req' is
accessed in io_ring_ctx_wait_and_kill() which lead to
a use-after-free.

Signed-off-by: Guoyu Huang <hgy5945@gmail.com>
---
 fs/io_uring.c | 1 +
 1 file changed, 1 insertion(+)

--
2.25.1

Comments

Jens Axboe Aug. 5, 2020, 7:10 p.m. UTC | #1 
On 8/4/20 9:40 PM, Guoyu Huang wrote:
> when ctx->sqo_mm is zero, io_sq_wq_submit_work() frees 'req'
> without deleting it from 'task_list'. After that, 'req' is
> accessed in io_ring_ctx_wait_and_kill() which lead to
> a use-after-free.

This looks like an old one, that affects 5.4 only. I've massaged
it to apply on top of another fix, will ask to get it queued up for
stable. Thanks!
diff mbox series

Patch

diff --git a/fs/io_uring.c b/fs/io_uring.c
index e0200406765c..4b5ac381c67f 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2242,6 +2242,7 @@  static void io_sq_wq_submit_work(struct work_struct *work)
 		if (io_sqe_needs_user(sqe) && !cur_mm) {
 			if (!mmget_not_zero(ctx->sqo_mm)) {
 				ret = -EFAULT;
+				goto end_req;
 			} else {
 				cur_mm = ctx->sqo_mm;
 				use_mm(cur_mm);