[PATCH 5.4 07/67] io_uring: Fix use-after-free in io_sq_wq_submit_work()

From: Guoyu Huang hgy5945@gmail.com

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 Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/io_uring.c | 1 + 1 file changed, 1 insertion(+)

--- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2232,6 +2232,7 @@ restart: if (io_req_needs_user(req) && !cur_mm) { if (!mmget_not_zero(ctx->sqo_mm)) { ret = -EFAULT; + goto end_req; } else { cur_mm = ctx->sqo_mm; use_mm(cur_mm);