From patchwork Wed Oct 15 13:48:07 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen Gang X-Patchwork-Id: 399996 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 50B7D140085 for ; Thu, 16 Oct 2014 00:49:20 +1100 (EST) Received: from localhost ([::1]:44845 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XeOx4-00025F-9f for incoming@patchwork.ozlabs.org; Wed, 15 Oct 2014 09:49:18 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48612) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XeOwd-0001km-94 for qemu-devel@nongnu.org; Wed, 15 Oct 2014 09:49:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XeOwU-0007AC-7x for qemu-devel@nongnu.org; Wed, 15 Oct 2014 09:48:51 -0400 Received: from mail-pa0-x22d.google.com ([2607:f8b0:400e:c03::22d]:62372) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XeOwB-00070b-QE; Wed, 15 Oct 2014 09:48:23 -0400 Received: by mail-pa0-f45.google.com with SMTP id rd3so1351287pab.4 for ; Wed, 15 Oct 2014 06:48:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :content-type:content-transfer-encoding; bh=EQHffkkZV+JWmxWG/5EdClClvbgVEOnowqB7vKi/8gk=; b=sN6y02eHKxkxfjoObKH75V6iX3pjYP5fuAhEXWw8Ym1wFiTg9ufiiF3jYuvUbjE60a p0h+C5inEQ0+vxOYpZXMeCtIbAmReo1/cQq12YI9iJ2q8ipAqhmhiww84MAW8gInUP9q 9bLVFCZEw946TjaUcY9gkEiHqnM+/wMXvZ2fauloG874wTaupMsouSallqHM6ph3WLM6 JNabPmJDIQcJQtCmxxmaWsFoxI85T61MEweaxKCVnH+9TnaI5nRChXKetUom3alBbj4e PZc+gb5HitGp1OtB41oxc2RrzHOk5+xMHfUzD/1feNI9ymoYQQ1D91+uzSfQKbfGptx7 Znaw== X-Received: by 10.70.102.162 with SMTP id fp2mr12894687pdb.112.1413380901109; Wed, 15 Oct 2014 06:48:21 -0700 (PDT) Received: from [192.168.1.103] ([223.72.65.123]) by mx.google.com with ESMTPSA id qj2sm17091190pbc.78.2014.10.15.06.48.17 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 15 Oct 2014 06:48:20 -0700 (PDT) Message-ID: <543E7B17.1050902@gmail.com> Date: Wed, 15 Oct 2014 21:48:07 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: agraf@suse.de, Paolo Bonzini X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2607:f8b0:400e:c03::22d Cc: qemu-ppc@nongnu.org, qemu-devel , kvm@vger.kernel.org Subject: [Qemu-devel] [PATCH v2] target-ppc: kvm: Fix memory overflow issue about strncat() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org strncat() will append additional '\0' to destination buffer, so need additional 1 byte for it, or may cause memory overflow, just like other area within QEMU have done. And can use g_strdup_printf() instead of strncat(), which may be more easier understanding. Signed-off-by: Chen Gang --- target-ppc/kvm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c index 66e7ce5..cea6a87 100644 --- a/target-ppc/kvm.c +++ b/target-ppc/kvm.c @@ -1782,7 +1782,7 @@ static int kvmppc_find_cpu_dt(char *buf, int buf_len) * format) */ static uint64_t kvmppc_read_int_cpu_dt(const char *propname) { - char buf[PATH_MAX]; + char buf[PATH_MAX], *tmp; union { uint32_t v32; uint64_t v64; @@ -1794,10 +1794,10 @@ static uint64_t kvmppc_read_int_cpu_dt(const char *propname) return -1; } - strncat(buf, "/", sizeof(buf) - strlen(buf)); - strncat(buf, propname, sizeof(buf) - strlen(buf)); + tmp = g_strdup_printf("%s/%s", buf, propname); - f = fopen(buf, "rb"); + f = fopen(tmp, "rb"); + g_free(tmp); if (!f) { return -1; }