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 lists.gnu.org (lists.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 697D0C3DA7F for ; Wed, 31 Jul 2024 15:00:51 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sZAoN-0005ou-6E; Wed, 31 Jul 2024 11:00:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sZAoK-0005nq-JZ for qemu-devel@nongnu.org; Wed, 31 Jul 2024 11:00:16 -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 1sZAoD-0000cG-1k for qemu-devel@nongnu.org; Wed, 31 Jul 2024 11:00:16 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722438007; 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=5UQANs8DPXnGU/DEvo+pFarUfp6jcExKXPzs7NcN1M4=; b=YF1TYRWXOPsSc4O5r28Ie1Bcgtabu4H8TSnISxEbWfSY+NHFuMfQxBXIuYNCD+KqdAPziM 9z16VcUjUCAGI5FcU1+JCd/fa7uRL17DlP4I3uXhGfq3SaSiPEYoJZKnIQIPuYHjCMUd8B mgofqCgXHLpZaWbVY+Dz4lygrXYBgvM= Received: from mx-prod-mc-01.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-593-vKOAmP_HNYi1zlbbDmZVAA-1; Wed, 31 Jul 2024 10:59:54 -0400 X-MC-Unique: vKOAmP_HNYi1zlbbDmZVAA-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0E3101955BEE; Wed, 31 Jul 2024 14:59:53 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.1]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6FFED1955D42; Wed, 31 Jul 2024 14:59:50 +0000 (UTC) Date: Wed, 31 Jul 2024 16:59:48 +0200 From: Kevin Wolf To: Peter Maydell Cc: qemu-devel@nongnu.org, Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , John Snow , Stefan Weil , "Richard W.M. Jones" , Hanna Reitz , qemu-block@nongnu.org Subject: Re: [PATCH 1/7] block/vdi.c: Avoid potential overflow when calculating size of write Message-ID: References: <20240731143617.3391947-1-peter.maydell@linaro.org> <20240731143617.3391947-2-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240731143617.3391947-2-peter.maydell@linaro.org> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.126, 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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: 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 31.07.2024 um 16:36 hat Peter Maydell geschrieben: > In vdi_co_pwritev() we multiply a sector count by SECTOR_SIZE to > get the size to write in bytes. Coverity notes that this means that > we do the multiply as a 32x32->32 multiply before converting to > 64 bits, which has the potential to overflow. > > This is very unlikely to happen, since the block map has 4 bytes per > block and the maximum number of blocks in the image must fit into a > 32-bit integer. But we can keep Coverity happy by including a cast > so we do a 64-bit multiply here. > > Resolves: Coverity CID 1508076 > Signed-off-by: Peter Maydell > --- > block/vdi.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/block/vdi.c b/block/vdi.c > index 6363da08cee..27c60ba18d0 100644 > --- a/block/vdi.c > +++ b/block/vdi.c > @@ -728,7 +728,7 @@ nonallocating_write: > logout("will write %u block map sectors starting from entry %u\n", > n_sectors, bmap_first); > ret = bdrv_co_pwrite(bs->file, bmap_offset * SECTOR_SIZE, > - n_sectors * SECTOR_SIZE, base, 0); > + n_sectors * (uint64_t)SECTOR_SIZE, base, 0); > } I wonder if we shouldn't just make VDI's SECTOR_SIZE 64 bits like BDRV_SECTOR_SIZE. It's easy to miss the cast in individual places. Kevin