From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C053DCD4F54 for ; Fri, 29 May 2026 14:02:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wSxnD-0004lP-6a; Fri, 29 May 2026 10:02:31 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSxnA-0004eL-I9 for qemu-devel@nongnu.org; Fri, 29 May 2026 10:02:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wSxn8-0007PJ-OM for qemu-devel@nongnu.org; Fri, 29 May 2026 10:02:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1780063346; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ekz0twJaJm7BEwRS/guT4u7IP0hcVDfUtKPhe48WhIk=; b=b8sk43ErcO5MtTByo7uLMVJNOh78KlFI9jOJAIVz4RLC6gQtFiHuZpFE9MVJbf0qd9brdR jrAEHYF6ok+ByWoo8JuEBVkJlx5+alROwikZcft0j7EKJIYhihvY7gGnlPK9wYgarLpM2X hT0nXlv/VZPtMFCO21iKKrNtcsUrGv8= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-613-RfAXXKMbPM6le8r0Gkicfg-1; Fri, 29 May 2026 10:02:22 -0400 X-MC-Unique: RfAXXKMbPM6le8r0Gkicfg-1 X-Mimecast-MFC-AGG-ID: RfAXXKMbPM6le8r0Gkicfg_1780063341 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 883901956067; Fri, 29 May 2026 14:02:21 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.95]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 22091176F; Fri, 29 May 2026 14:02:18 +0000 (UTC) Date: Fri, 29 May 2026 16:02:16 +0200 From: Kevin Wolf To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, qemu-stable@nongnu.org, "Michael S. Tsirkin" , Paolo Bonzini , Hanna Reitz , Feifan Qian Subject: Re: [PATCH] virtio-blk: add missing VIRTIO_BLK_T_SCSI_CMD size check (CVE-2026-48914) Message-ID: References: <20260526154957.1741622-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260526154957.1741622-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Am 26.05.2026 um 17:49 hat Stefan Hajnoczi geschrieben: > Check that the iovec containing struct virtio_scsi_inhdr is large enough > before storing an error value there. > > Feifan Qian pointed out that this can be used to > corrupt heap memory when the descriptor uses an MMIO address and a > length of 1, forcing QEMU to allocate a 1-byte heap bounce buffer. > virtio_stl_p() stores 4 bytes and therefore corrupts whatever is beyond > the bounce buffer. > > Fixes: CVE-2026-48914 > Fixes: f34e73cd69bd ("virtio-blk: report non-zero status when failing SG_IO requests") > Reported-by: Feifan Qian > Cc: Paolo Bonzini > Signed-off-by: Stefan Hajnoczi Reviewed-by: Kevin Wolf > diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c > index 9cb9f1fb2b..6b92066aff 100644 > --- a/hw/block/virtio-blk.c > +++ b/hw/block/virtio-blk.c > @@ -199,10 +199,16 @@ static void virtio_blk_handle_scsi(VirtIOBlockReq *req) > > /* > * The scsi inhdr is placed in the second-to-last input segment, just > - * before the regular inhdr. > + * before the regular inhdr. VIRTIO implementations normally do not rely on > + * the precise message framing, but legacy implementations did and so we do > + * too for the legacy virtio-blk SCSI request type. > * > * Just put anything nonzero so that the ioctl fails in the guest. > */ > + if (elem->in_sg[elem->in_num - 2].iov_len != sizeof(*scsi)) { > + status = VIRTIO_BLK_S_IOERR; > + goto fail; > + } > scsi = (void *)elem->in_sg[elem->in_num - 2].iov_base; > virtio_stl_p(vdev, &scsi->errors, 255); > status = VIRTIO_BLK_S_UNSUPP; What would the guest do if we didn't update scsi->errors, but just return VIRTIO_BLK_S_UNSUPP (i.e. remove this whole function)? Shouldn't that result in an error, too? Kevin