Commit 508c1314 authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring/futex: ensure io_futex_wait() cleans up properly on failure 



The io_futex_data is allocated upfront and assigned to the io_kiocb
async_data field, but the request isn't marked with REQ_F_ASYNC_DATA
at that point. Those two should always go together, as the flag tells
io_uring whether the field is valid or not.

Additionally, on failure cleanup, the futex handler frees the data but
does not clear ->async_data. Clear the data and the flag in the error
path as well.

Thanks to Trend Micro Zero Day Initiative and particularly ReDress for
reporting this.

Cc: stable@vger.kernel.org
Fixes: 194bb58c ("io_uring: add support for futex wake and wait")
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9d83e1f0

io_uring/futex.c

+3 −0
Original line number Diff line number Diff line
@@ -288,6 +288,7 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) 
		goto done_unlock;

	}



	req->flags |= REQ_F_ASYNC_DATA;

	req->async_data = ifd;

	ifd->q = futex_q_init;

	ifd->q.bitset = iof->futex_mask;
@@ -309,6 +310,8 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags) 
	if (ret < 0)

		req_set_fail(req);

	io_req_set_res(req, ret, 0);

	req->async_data = NULL;

	req->flags &= ~REQ_F_ASYNC_DATA;

	kfree(ifd);

	return IOU_COMPLETE;

}