From nobody Sat Jul 25 22:33:44 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1783946415859936.6037807017051; Mon, 13 Jul 2026 05:40:15 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wjFwE-0007S4-TO; Mon, 13 Jul 2026 08:39:10 -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 1wj7Bb-0007qm-Io; Sun, 12 Jul 2026 23:18:27 -0400 Received: from mailgw.kylinos.cn ([124.126.103.232]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wj7BW-0005bT-9C; Sun, 12 Jul 2026 23:18:27 -0400 Received: from localhost.localdomain [(223.70.159.239)] by mailgw.kylinos.cn (envelope-from ) (Generic MTA with TLSv1.3 TLS_AES_256_GCM_SHA384 256/256) with ESMTP id 1769151953; Mon, 13 Jul 2026 11:18:05 +0800 X-UUID: 7701369e7e6911f1aa26b74ffac11d73-20260713 X-CTIC-Tags: HR_CC_COUNT, HR_CC_DOMAIN_COUNT, HR_CC_NAME, HR_CC_NO_NAME, HR_CTE_8B HR_CTT_MISS, HR_DATE_H, HR_DATE_WKD, HR_DATE_ZONE, HR_FROM_NAME HR_SJ_LANG, HR_SJ_LEN, HR_SJ_LETTER, HR_SJ_NOR_SYM, HR_SJ_PHRASE HR_SJ_PHRASE_LEN, HR_SJ_WS, HR_TO_COUNT, HR_TO_DOMAIN_COUNT, HR_TO_NO_NAME IP_TRUSTED, SRC_TRUSTED, DN_TRUSTED, SA_UNTRUSTED, SA_UNFAMILIAR SN_UNTRUSTED, SN_UNFAMILIAR, SPF_NOPASS, DKIM_NOPASS, DMARC_NOPASS UD_TRUSTED X-CID-UNFAMILIAR: 1 X-CID-O-RULE: Release_Ham X-CID-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.12, REQID:2b7b3e3f-594f-492a-9985-67708dece52c, IP:10, URL:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION :release,TS:10 X-CID-INFO: VERSION:1.3.12, REQID:2b7b3e3f-594f-492a-9985-67708dece52c, IP:10, UR L:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION:r elease,TS:10 X-CID-META: VersionHash:e7bac3a, CLOUDID:24c7b349e53b990c872a94f265e46534, BulkI D:260713111806Z3Y4OGOL,BulkQuantity:0,Recheck:0,SF:16|19|66|78|102|127|850 |865|898,TC:nil,Content:0|15|50,EDM:-3,IP:-2,URL:1,File:nil,RT:nil,Bulk:ni l,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE :0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR,TF_CID_SPAM_USA,TF_CID_SPAM_FSD,TF_CID_SPAM_ULS X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 7701369e7e6911f1aa26b74ffac11d73-20260713 X-User: malike@kylinos.cn From: malike To: qemu-devel@nongnu.org Cc: stefanha@redhat.com, kwolf@redhat.com, hreitz@redhat.com, qemu-block@nongnu.org, malike Subject: [PATCH] block/cloop: fix integer overflow in total_sectors calculation Date: Mon, 13 Jul 2026 11:17:50 +0800 Message-Id: <20260713031750.58448-1-malike@kylinos.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists1p.gnu.org; Received-SPF: pass client-ip=124.126.103.232; envelope-from=malike@kylinos.cn; helo=mailgw.kylinos.cn X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_PASS=-0.001, T_SPF_HELO_TEMPERROR=0.01, UNPARSEABLE_RELAY=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Mailman-Approved-At: Mon, 13 Jul 2026 08:39:04 -0400 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1783946419031158500 Content-Type: text/plain; charset="utf-8" The total_sectors is computed as n_blocks * sectors_per_block where both operands are uint32_t. The multiplication is performed in 32-bit arithmetic and can overflow when the product exceeds UINT32_MAX, producing a value much smaller than the true image size. The result is assigned to int64_t total_sectors but the 32-bit multiplication has already wrapped around, and the zero-extension to 64-bit does not recover the correct value. This causes the block layer to reject valid I/O requests (DoS) when the reported total_sectors is smaller than the actual image. Use 64-bit arithmetic by casting one operand to uint64_t so the multiplication is performed in 64-bit precision. Resolves: https://gitlab.com/qemu-project/qemu/-/work_items/3972 Signed-off-by: Ma Like --- block/cloop.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/cloop.c b/block/cloop.c index 443af1444e..a16f08e6ef 100644 --- a/block/cloop.c +++ b/block/cloop.c @@ -202,7 +202,8 @@ static int cloop_open(BlockDriverState *bs, QDict *opti= ons, int flags, s->current_block =3D s->n_blocks; =20 s->sectors_per_block =3D s->block_size/512; - bs->total_sectors =3D s->n_blocks * s->sectors_per_block; + /* Cast to uint64_t to prevent uint32_t overflow */ + bs->total_sectors =3D (uint64_t)s->n_blocks * s->sectors_per_block; qemu_co_mutex_init(&s->lock); return 0; =20 --=20 2.25.1