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

commit 508c1314b342b78591f51c4b5dadee31a88335df upstream.

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: 194bb58c60 ("io_uring: add support for futex wake and wait")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe 2025-08-21 13:23:21 -06:00 committed by Greg Kroah-Hartman
parent 220c491490
commit d34c04152d

View File

@ -288,6 +288,7 @@ int io_futex_wait(struct io_kiocb *req, unsigned int issue_flags)
goto done_unlock; goto done_unlock;
} }
req->flags |= REQ_F_ASYNC_DATA;
req->async_data = ifd; req->async_data = ifd;
ifd->q = futex_q_init; ifd->q = futex_q_init;
ifd->q.bitset = iof->futex_mask; ifd->q.bitset = iof->futex_mask;
@ -309,6 +310,8 @@ done:
if (ret < 0) if (ret < 0)
req_set_fail(req); req_set_fail(req);
io_req_set_res(req, ret, 0); io_req_set_res(req, ret, 0);
req->async_data = NULL;
req->flags &= ~REQ_F_ASYNC_DATA;
kfree(ifd); kfree(ifd);
return IOU_COMPLETE; return IOU_COMPLETE;
} }