From patchwork Wed May 1 14:50:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= X-Patchwork-Id: 1093735 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 44vLxR3Krnz9s55 for ; Thu, 2 May 2019 00:53:31 +1000 (AEST) Received: from localhost ([127.0.0.1]:60312 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLqbx-0007wc-Hq for incoming@patchwork.ozlabs.org; Wed, 01 May 2019 10:53:29 -0400 Received: from eggs.gnu.org ([209.51.188.92]:55275) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLqZZ-0006ZS-Ts for qemu-devel@nongnu.org; Wed, 01 May 2019 10:51:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hLqZW-0003ns-LH for qemu-devel@nongnu.org; Wed, 01 May 2019 10:51:01 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43424) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hLqZW-0003n1-Cg for qemu-devel@nongnu.org; Wed, 01 May 2019 10:50:58 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 250B1C0467E4 for ; Wed, 1 May 2019 14:50:57 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-112-28.ams2.redhat.com [10.36.112.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6E93E10018E0; Wed, 1 May 2019 14:50:53 +0000 (UTC) From: =?utf-8?q?Daniel_P=2E_Berrang=C3=A9?= To: qemu-devel@nongnu.org Date: Wed, 1 May 2019 15:50:52 +0100 Message-Id: <20190501145052.12579-1-berrange@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 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]); Wed, 01 May 2019 14:50:57 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2] sockets: avoid string truncation warnings when copying UNIX path 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: Gerd Hoffmann Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" In file included from /usr/include/string.h:494, from include/qemu/osdep.h:101, from util/qemu-sockets.c:18: In function ‘strncpy’, inlined from ‘unix_connect_saddr.isra.0’ at util/qemu-sockets.c:925:5: /usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ specified bound 108 equals destination size [-Wstringop-truncation] 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function ‘strncpy’, inlined from ‘unix_listen_saddr.isra.0’ at util/qemu-sockets.c:880:5: /usr/include/bits/string_fortified.h:106:10: warning: ‘__builtin_strncpy’ specified bound 108 equals destination size [-Wstringop-truncation] 106 | return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest)); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We are already validating the UNIX socket path length earlier in the functions. If we save this string length when we first check it, then we can simply use memcpy instead of strcpy later, avoiding the gcc truncation warnings. Signed-off-by: Daniel P. Berrangé Reviewed-by: Eric Blake Reviewed-by: Stefano Garzarella --- util/qemu-sockets.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c index 9705051690..ba6335e71a 100644 --- a/util/qemu-sockets.c +++ b/util/qemu-sockets.c @@ -830,6 +830,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, int sock, fd; char *pathbuf = NULL; const char *path; + size_t pathlen; sock = qemu_socket(PF_UNIX, SOCK_STREAM, 0); if (sock < 0) { @@ -845,7 +846,8 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, path = pathbuf = g_strdup_printf("%s/qemu-socket-XXXXXX", tmpdir); } - if (strlen(path) > sizeof(un.sun_path)) { + pathlen = strlen(path); + if (pathlen > sizeof(un.sun_path)) { error_setg(errp, "UNIX socket path '%s' is too long", path); error_append_hint(errp, "Path must be less than %zu bytes\n", sizeof(un.sun_path)); @@ -877,7 +879,7 @@ static int unix_listen_saddr(UnixSocketAddress *saddr, memset(&un, 0, sizeof(un)); un.sun_family = AF_UNIX; - strncpy(un.sun_path, path, sizeof(un.sun_path)); + memcpy(un.sun_path, path, pathlen); if (bind(sock, (struct sockaddr*) &un, sizeof(un)) < 0) { error_setg_errno(errp, errno, "Failed to bind socket to %s", path); @@ -901,6 +903,7 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) { struct sockaddr_un un; int sock, rc; + size_t pathlen; if (saddr->path == NULL) { error_setg(errp, "unix connect: no path specified"); @@ -913,7 +916,8 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) return -1; } - if (strlen(saddr->path) > sizeof(un.sun_path)) { + pathlen = strlen(saddr->path); + if (pathlen > sizeof(un.sun_path)) { error_setg(errp, "UNIX socket path '%s' is too long", saddr->path); error_append_hint(errp, "Path must be less than %zu bytes\n", sizeof(un.sun_path)); @@ -922,7 +926,7 @@ static int unix_connect_saddr(UnixSocketAddress *saddr, Error **errp) memset(&un, 0, sizeof(un)); un.sun_family = AF_UNIX; - strncpy(un.sun_path, saddr->path, sizeof(un.sun_path)); + memcpy(un.sun_path, saddr->path, pathlen); /* connect to peer */ do {