From patchwork Fri Jan 5 13:32:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Murilo_Opsfelder_Ara=C3=BAjo?= X-Patchwork-Id: 10146599 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id F40FB60153 for ; Fri, 5 Jan 2018 13:36:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E37A728887 for ; Fri, 5 Jan 2018 13:36:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D83EA2889C; Fri, 5 Jan 2018 13:36:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 30D9728887 for ; Fri, 5 Jan 2018 13:36:22 +0000 (UTC) Received: from localhost ([::1]:40325 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eXSAX-0005cg-TZ for patchwork-qemu-devel@patchwork.kernel.org; Fri, 05 Jan 2018 08:36:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58853) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eXS7z-0003Qg-4a for qemu-devel@nongnu.org; Fri, 05 Jan 2018 08:33:44 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eXS7u-0004yo-Tx for qemu-devel@nongnu.org; Fri, 05 Jan 2018 08:33:43 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42422 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eXS7u-0004yi-PY for qemu-devel@nongnu.org; Fri, 05 Jan 2018 08:33:38 -0500 Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id w05DSvDR006220 for ; Fri, 5 Jan 2018 08:33:36 -0500 Received: from e16.ny.us.ibm.com (e16.ny.us.ibm.com [129.33.205.206]) by mx0b-001b2d01.pphosted.com with ESMTP id 2fa968jtvq-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Fri, 05 Jan 2018 08:33:36 -0500 Received: from localhost by e16.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Fri, 5 Jan 2018 08:33:32 -0500 Received: from b01ledav005.gho.pok.ibm.com (b01ledav005.gho.pok.ibm.com [9.57.199.110]) by b01cxnp22033.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w05DXWDW39387346; Fri, 5 Jan 2018 13:33:32 GMT Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 85245AE034; Fri, 5 Jan 2018 08:34:41 -0500 (EST) Received: from kermit-br-ibm-com.ibmmodules.com (unknown [9.80.206.62]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTP id 64DAEAE03C; Fri, 5 Jan 2018 08:34:39 -0500 (EST) From: Murilo Opsfelder Araujo To: qemu-devel@nongnu.org Date: Fri, 5 Jan 2018 11:32:41 -0200 X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180105133241.14141-1-muriloo@linux.vnet.ibm.com> References: <20180105133241.14141-1-muriloo@linux.vnet.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 18010513-0024-0000-0000-0000030BF709 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00008323; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000244; SDB=6.00970607; UDB=6.00491595; IPR=6.00750578; BA=6.00005765; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00018889; XFM=3.00000015; UTC=2018-01-05 13:33:34 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18010513-0025-0000-0000-0000468529DD Message-Id: <20180105133241.14141-2-muriloo@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2018-01-05_06:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1801050190 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH 1/1] block/nbd: fix segmentation fault when .desc is not null-terminated X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-block@nongnu.org, R Nageswara Sastry , Max Reitz , qemu-ppc@nongnu.org, Paolo Bonzini , Murilo Opsfelder Araujo Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP The find_desc_by_name() from util/qemu-option.c relies on the .name not being NULL to call strcmp(). This check becomes unsafe when the list is not NULL-terminated, which is the case of nbd_runtime_opts in block/nbd.c, and can result in segmentation fault when strcmp() tries to access an invalid memory: #0 0x00007fff8c75f7d4 in __strcmp_power9 () from /lib64/libc.so.6 #1 0x00000000102d3ec8 in find_desc_by_name (desc=0x1036d6f0, name=0x28e46670 "server.path") at util/qemu-option.c:166 #2 0x00000000102d93e0 in qemu_opts_absorb_qdict (opts=0x28e47a80, qdict=0x28e469a0, errp=0x7fffec247c98) at util/qemu-option.c:1026 #3 0x000000001012a2e4 in nbd_open (bs=0x28e42290, options=0x28e469a0, flags=24578, errp=0x7fffec247d80) at block/nbd.c:406 #4 0x00000000100144e8 in bdrv_open_driver (bs=0x28e42290, drv=0x1036e070 , node_name=0x0, options=0x28e469a0, open_flags=24578, errp=0x7fffec247f50) at block.c:1135 #5 0x0000000010015b04 in bdrv_open_common (bs=0x28e42290, file=0x0, options=0x28e469a0, errp=0x7fffec247f50) at block.c:1395 From gdb, the desc[i].name was not NULL and resulted in strcmp() accessing an invalid memory: >>> p desc[5] $8 = { name = 0x1037f098 "R27A", type = 1561964883, help = 0xc0bbb23e , def_value_str = 0x2 } >>> p desc[6] $9 = { name = 0x103dac78 <__gcov0.do_qemu_init_bdrv_nbd_init> "\001", type = 272101528, help = 0x29ec0b754403e31f , def_value_str = 0x81f343b9 } This patch fixes the segmentation fault in strcmp() by adding a NULL element at the end of nbd_runtime_opts.desc list, which is the common practice to most of other structs like runtime_opts in block/null.c. Thus, the desc[i].name != NULL check becomes safe because it will not evaluate to true when .desc list reached its end. Reported-by: R. Nageswara Sastry Buglink: https://bugs.launchpad.net/qemu/+bug/1727259 Signed-off-by: Murilo Opsfelder Araujo Reviewed-by: Eric Blake --- block/nbd.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/nbd.c b/block/nbd.c index a50d24b50a..8b8ba56cdd 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -388,6 +388,7 @@ static QemuOptsList nbd_runtime_opts = { .type = QEMU_OPT_STRING, .help = "ID of the TLS credentials to use", }, + { /* end of list */ } }, };