From: Prasad J Pandit <p...@fedoraproject.org> While processing SCSI i/o requests in mptsas_process_scsi_io_request(), the Megaraid emulator appends new MPTSASRequest object 'req' to the 's->pending' queue. In case of an error, this same object gets dequeued in mptsas_free_request() only if SCSIRequest object 'req->sreq' is initialised. This may lead to a use-after-free issue. Unconditionally dequeue 'req' object from 's->pending' to avoid it.
Fixes: CVE-2021-3392 Buglink: https://bugs.launchpad.net/qemu/+bug/1914236 Reported-by: Cheolwoo Myung <cwmy...@snu.ac.kr> Signed-off-by: Prasad J Pandit <p...@fedoraproject.org> --- hw/scsi/mptsas.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/scsi/mptsas.c b/hw/scsi/mptsas.c index f86616544b..adff5b0bf2 100644 --- a/hw/scsi/mptsas.c +++ b/hw/scsi/mptsas.c @@ -257,8 +257,8 @@ static void mptsas_free_request(MPTSASRequest *req) req->sreq->hba_private = NULL; scsi_req_unref(req->sreq); req->sreq = NULL; - QTAILQ_REMOVE(&s->pending, req, next); } + QTAILQ_REMOVE(&s->pending, req, next); qemu_sglist_destroy(&req->qsg); g_free(req); } -- 2.29.2
