From nobody Wed May 8 19:40:36 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1488540360041925.6392658750018; Fri, 3 Mar 2017 03:26:00 -0800 (PST) Received: from localhost ([::1]:57267 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cjlLS-0006zJ-Bx for importer@patchew.org; Fri, 03 Mar 2017 06:25:58 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cjlKk-0006y3-Mh for qemu-devel@nongnu.org; Fri, 03 Mar 2017 06:25:15 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cjlKg-0001BN-Oi for qemu-devel@nongnu.org; Fri, 03 Mar 2017 06:25:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:40814) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cjlKg-0001AG-Ij for qemu-devel@nongnu.org; Fri, 03 Mar 2017 06:25:10 -0500 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C30FBC05092E; Fri, 3 Mar 2017 11:25:09 +0000 (UTC) Received: from localhost.localdomain (ovpn-116-84.phx2.redhat.com [10.3.116.84]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v23BP6NA017178 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Fri, 3 Mar 2017 06:25:08 -0500 From: P J P To: Qemu Developers Date: Fri, 3 Mar 2017 16:55:03 +0530 Message-Id: <20170303112503.32277-1-ppandit@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 03 Mar 2017 11:25:09 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH] linux-user: limit number of arguments to execve 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: Riku Voipio , Prasad J Pandit , Jann Horn Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Prasad J Pandit Limit the number of arguments passed to execve(2) call from a user program, as large number of them could lead to a bad guest address error. Reported-by: Jann Horn Signed-off-by: Prasad J Pandit --- linux-user/syscall.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 9be8e95..c545c12 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -7766,6 +7766,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long = arg1, #endif case TARGET_NR_execve: { +#define ARG_MAX 65535 char **argp, **envp; int argc, envc; abi_ulong gp; @@ -7794,6 +7795,12 @@ abi_long do_syscall(void *cpu_env, int num, abi_long= arg1, envc++; } =20 + if (argc > ARG_MAX || envc > ARG_MAX) { + fprintf(stderr, + "argc(%d), envc(%d) exceed %d\n", argc, envc, ARG_= MAX); + ret =3D -TARGET_EFAULT; + break; + } argp =3D alloca((argc + 1) * sizeof(void *)); envp =3D alloca((envc + 1) * sizeof(void *)); =20 --=20 2.9.3