Received: by 2002:ab2:6a05:0:b0:1f8:1780:a4ed with SMTP id w5csp1472621lqo; Sun, 12 May 2024 04:17:58 -0700 (PDT) X-Forwarded-Encrypted: i=3; AJvYcCWL4uxU4by810KpPwOIdBhy7ASBI9C8tadEAwSQdJBGvRfF2+07fDJqMIlaH3S1gwVE/yFKfIGFrfh4qPUoslfRClakvtxTmu96XAgrzQ== X-Google-Smtp-Source: AGHT+IFq+tw7zgcil5OnTTXyVLTRBLyg48xtX7p847SFyS7gOEtTgjGarNHXnkkRIl7Fy3wsx61Q X-Received: by 2002:a05:6a20:244f:b0:1a9:cd98:5cd7 with SMTP id adf61e73a8af0-1afde1b707cmr9355021637.39.1715512678284; Sun, 12 May 2024 04:17:58 -0700 (PDT) Return-Path: Received: from sy.mirrors.kernel.org (sy.mirrors.kernel.org. [2604:1380:40f1:3f00::1]) by mx.google.com with ESMTPS id 41be03b00d2f7-6341276eea7si6984440a12.613.2024.05.12.04.17.57 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 May 2024 04:17:58 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-bluetooth+bounces-4539-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1; Authentication-Results: mx.google.com; dkim=pass header.i=@outlook.com header.s=selector1 header.b=mdauEvtd; arc=fail (signature failed); spf=pass (google.com: domain of linux-bluetooth+bounces-4539-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) smtp.mailfrom="linux-bluetooth+bounces-4539-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=outlook.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sy.mirrors.kernel.org (Postfix) with ESMTPS id C78AFB20DFA for ; Sun, 12 May 2024 11:17:56 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 55FC420B20; Sun, 12 May 2024 11:17:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=outlook.com header.i=@outlook.com header.b="mdauEvtd" X-Original-To: linux-bluetooth@vger.kernel.org Received: from EUR05-DB8-obe.outbound.protection.outlook.com (mail-db8eur05olkn2065.outbound.protection.outlook.com [40.92.89.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A25FF14265; Sun, 12 May 2024 11:17:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.92.89.65 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715512666; cv=fail; b=L8LZ5RudCA9Ypg//+1x/95BjvX9q8aakx9frSctWT0yFvdQVBP11kmZfT6x/8NKU87ACU4kBjaUI7BTPvP4QiHWSxQE3NkHoKpr3PcSbFczh6/NotEMynITkOPA6Jtm17KXIaZ7Bq6hdqfdEbGVC5hMpMTe40PIfM69MOH3ee50= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715512666; c=relaxed/simple; bh=Twy+4qL0i4LfjKxgj17PnOo/nbEK16vNz1Fsru+7EFw=; h=From:To:Cc:Subject:Date:Message-ID:Content-Type:MIME-Version; b=tRsZuN0yzYUerv+G5BwZyWbOL7IZQje+D/lRjSi524zanIDRknXfrtP/K36DHa9tqHU6tbF06RjPInFb6SEPx9p5xOJjaWdpfEkDAXRa0guy0cFqiBf/B3m4QkcRgM2zmEsJ9bPe46c6AIbuzK7+Wen6fwn5F9ChM5OstSlY/EU= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=outlook.com; spf=pass smtp.mailfrom=outlook.com; dkim=pass (2048-bit key) header.d=outlook.com header.i=@outlook.com header.b=mdauEvtd; arc=fail smtp.client-ip=40.92.89.65 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=outlook.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=outlook.com ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=aIAL/egdSVq8/BVSm7Mm1qu4BHPMHHGZz6Gx/hTUdUOCmon+ppldECdmU8ocQjINnVkVCpRsQe9a0GehSVaT0e1Az0/wJObPys2506SWCfEWN+EanycRyg8YGoah38HBRWLJOYPBR3rsT1YoDpZ+Vzu3O3S65bL+y6QG1mOn0vOVgzikCQtnGTQiQZNrGRraJfp/BEpiuoYpxh35abk95rqbAHdIhHdR5y9L7aG8zHO/Tr4InZVcROxuIp3KBRVmdfY9BeVt5JZqZZUU8oSw49EN0PyWsexC9e3GDJaqSU3XQXZ/5wuindS+Lk9YeKCXvitQsHmsvF6R4tMUr+JjUA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=d8vtJ2YZxXrunO7ONFn1rxg0QbT1LwStAoKpgMrB2vo=; b=CkdyNyPeSOPoE3KCKRbVr95h4/sn5QUOu2c0RUOy9FgM4Qwuf7y8Zx35di7ktaXuQMgU3XMg0OyDQdeUvSa7O+ngWxnOJvIgZraZDruQoEYtJ73ZeJVbN/vM10FB5V2sf9W2JEsnmRggAQSk65Gdkz/ck/AIZF2rI4PAPpQAzijCFjtrG7fU5CaMUyR2cRCnXuoHHaqV+eH22jtN1X4FozI16oCvuX2FQ6fo7iL6WpZcpXigRlkNmuR0VAb+gQ+sBmSjtWuqz5yfPUjXveAH23oTYI2FPzrwCGLVGbYm7me4O2Keu4vkqcwoB2+VOctAe8Ghu6nShZ/Sx1hq9IZYNw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=none; dmarc=none; dkim=none; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=outlook.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=d8vtJ2YZxXrunO7ONFn1rxg0QbT1LwStAoKpgMrB2vo=; b=mdauEvtdWnYkrbgHHB2P8frO3DnBmu8RpTDjw1NTpo8tWOk2RAsbPDwe4o4TAkRtXPDWdp7EqMTYqCdwU7+39Sr93x2C34ZUyE5WrQQoMJ9/9ycg84hDPeHrRe28nzaq2Oq3C+2DlKs96MRdMoRmQPZbg6/h2A6BJ2q8j0/QYd6KCVg5aINANYhTtLiE+M4DZTyg2G1KABFBrneQxFHXiTXnz7g1XAVpJWffmPh8HA8+jSv5EL0dAntCgCnax9Vd8gj4YdMlb4hUECBrzk21gZdUjacJdZz/XN4vqmtBXLXrfe7qV8H24uJ98jdEc1v5WQCYs9KAxfx1xah/blH85Q== Received: from AS8PR02MB7237.eurprd02.prod.outlook.com (2603:10a6:20b:3f1::10) by GVXPR02MB10690.eurprd02.prod.outlook.com (2603:10a6:150:14d::16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7544.55; Sun, 12 May 2024 11:17:41 +0000 Received: from AS8PR02MB7237.eurprd02.prod.outlook.com ([fe80::409b:1407:979b:f658]) by AS8PR02MB7237.eurprd02.prod.outlook.com ([fe80::409b:1407:979b:f658%5]) with mapi id 15.20.7544.052; Sun, 12 May 2024 11:17:41 +0000 From: Erick Archer To: Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kees Cook , "Gustavo A. R. Silva" , Nathan Chancellor , Nick Desaulniers , Bill Wendling , Justin Stitt , "Jiri Slaby (SUSE)" , Greg Kroah-Hartman , Geert Uytterhoeven Cc: Erick Archer , linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, llvm@lists.linux.dev Subject: [PATCH v2] tty: rfcomm: prefer struct_size over open coded arithmetic Date: Sun, 12 May 2024 13:17:24 +0200 Message-ID: X-Mailer: git-send-email 2.25.1 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-TMN: [+No29rggw54oDwiDwNbYhS2boQGTnUq4] X-ClientProxiedBy: MA2P292CA0011.ESPP292.PROD.OUTLOOK.COM (2603:10a6:250:1::15) To AS8PR02MB7237.eurprd02.prod.outlook.com (2603:10a6:20b:3f1::10) X-Microsoft-Original-Message-ID: <20240512111724.5660-1-erick.archer@outlook.com> Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AS8PR02MB7237:EE_|GVXPR02MB10690:EE_ X-MS-Office365-Filtering-Correlation-Id: b9e7f092-dbf6-4107-6eeb-08dc72752341 X-Microsoft-Antispam: BCL:0;ARA:14566002|461199019|1602099003|440099019|3412199016|1710799017; X-Microsoft-Antispam-Message-Info: 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 X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JXH39S/gWMh1ErEmQM/HmkXIHcjIF1VEMJ4KZYl6y1upxXt12K7RQvV1Jt3a?= =?us-ascii?Q?8YrX6m1+ww6nH3LyOP+DB2MOKfu0Ay2VeEsY9QkkPxgiD+vsEVJRpkx7TJkV?= =?us-ascii?Q?3Sk6PASO0MKcAE0uxg1TG19Mzb5p2GqbAAkhN0L8HGwxcAB6XBlW8sHH8l9b?= =?us-ascii?Q?xk5vUWVcBgnrbr0ukvov/Rvmr3Lf/qNrGOdQUzjeLAwkxthsAyhv7BjaD/HC?= =?us-ascii?Q?UI7Eu5NoFSxg3887hFOXzI57EJWnhYEnA9TSv0UivrhajHKNaIxGFMUMBlpa?= =?us-ascii?Q?e3HQ1ILIUHeL9Ysodo4SiFMcL/rEfwAAdtQB8KTLVgkw4xmltT9jvJot/esH?= =?us-ascii?Q?Ji4RRNKdqtJJ/NdFaTb0eWQFLl27r4t66d4wmDlSv9un0BvsHPTZTGJUzPXG?= =?us-ascii?Q?e9aOxsOYcvyOXSQJLtEd6TFoQZg1JcxclCPuXS8d9c0k7+RT3oVf9eDtB6G1?= =?us-ascii?Q?o/D4vjs3lD01IKPv0yPjBQ5rHK5/kB+6fdcvmDVwiL1T1AnHH1v6bfLPbpo9?= =?us-ascii?Q?yyLyfdgbleGuXVGZ9/3YviD/2SAiEAUpHuOCJ1/3uNVUwwyeBeWzVizkXZi8?= =?us-ascii?Q?dTCGgm2bajpggK5I0v2DXZu1UY19DIGf2atdPdZO4qGjqBi6Z8fGL8ijdSl5?= =?us-ascii?Q?8N8RxWfqf8Fj1b0zQ1FKUMOr3+a0aWoGBlXwVD+PxCbh2jNmjSY7KpUyL45w?= =?us-ascii?Q?47aYfYDAicJajU3susbS5/Pv4UeVPoH0uzdsDKtaIXTBq1GI1J+Mb8sx3+LJ?= =?us-ascii?Q?RjsypqTH0z8c8AFAKmn164DVK9P/YqIp7ESOQwIM/ds0eV9B2dHenQATWY7B?= =?us-ascii?Q?byXLV2dgHMj6hDZ0/2bwM4Vf15cQu2zrnFakipBekCQGJOYV1sOUev1sAqV8?= =?us-ascii?Q?c7xk581bV4mgDxp2ya49LuGWLCvCtf5gQ6//0PG4HWcU4vciSRv7h1wkfJf4?= =?us-ascii?Q?h+K5LPfu3MX0U/tTYSMj5UlGM9uEqn8G+ptOgn+S+UbRWMQcUdwQYKN73Wp/?= =?us-ascii?Q?RopL1bEAhe01y09SIAgR2Bxuinf5/QyPtaIGB9zARQFZ6oK1tE97690I2Gyf?= =?us-ascii?Q?JUlyApKmujQMunNMJAbDZ9fDtUB/2qny7cCpxswHiAidk11IKyLQwsRz58PI?= =?us-ascii?Q?nPQAkmJmpEm2u0q1EEKWjKNpBDMFIR+exoeplVC3DYU2K3mMWXOLupjaOJat?= =?us-ascii?Q?t9tyAoWdRYQLcQonF7Zie6Wo8G+SZOc7GH3fogjiUMysk4SsWMPNSlq46h3y?= =?us-ascii?Q?FASBtBSX93Ckz4QS7r0r?= X-OriginatorOrg: outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: b9e7f092-dbf6-4107-6eeb-08dc72752341 X-MS-Exchange-CrossTenant-AuthSource: AS8PR02MB7237.eurprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 May 2024 11:17:41.1723 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg: 00000000-0000-0000-0000-000000000000 X-MS-Exchange-Transport-CrossTenantHeadersStamped: GVXPR02MB10690 This is an effort to get rid of all multiplications from allocation functions in order to prevent integer overflows [1][2]. As the "dl" variable is a pointer to "struct rfcomm_dev_list_req" and this structure ends in a flexible array: struct rfcomm_dev_list_req { [...] struct rfcomm_dev_info dev_info[]; }; the preferred way in the kernel is to use the struct_size() helper to do the arithmetic instead of the calculation "size + count * size" in the kzalloc() and copy_to_user() functions. At the same time, prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). In this case, it is important to note that the logic needs a little refactoring to ensure that the "dev_num" member is initialized before the first access to the flex array. Specifically, add the assignment before the list_for_each_entry() loop. Also remove the "size" variable as it is no longer needed and refactor the list_for_each_entry() loop to use di[n] instead of (di + n). This way, the code is more readable, idiomatic and safer. This code was detected with the help of Coccinelle, and audited and modified manually. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1] Link: https://github.com/KSPP/linux/issues/160 [2] Signed-off-by: Erick Archer --- Changes in v2: - Add the __counted_by() attribute (Kees Cook). - Refactor the list_for_each_entry() loop to use di[n] instead of (di + n) (Kees Cook). Previous versions: v1 -> https://lore.kernel.org/linux-hardening/AS8PR02MB723725E0069F7AE8F64E876E8B142@AS8PR02MB7237.eurprd02.prod.outlook.com/ --- include/net/bluetooth/rfcomm.h | 2 +- net/bluetooth/rfcomm/tty.c | 23 ++++++++++------------- 2 files changed, 11 insertions(+), 14 deletions(-) diff --git a/include/net/bluetooth/rfcomm.h b/include/net/bluetooth/rfcomm.h index 99d26879b02a..c05882476900 100644 --- a/include/net/bluetooth/rfcomm.h +++ b/include/net/bluetooth/rfcomm.h @@ -355,7 +355,7 @@ struct rfcomm_dev_info { struct rfcomm_dev_list_req { u16 dev_num; - struct rfcomm_dev_info dev_info[]; + struct rfcomm_dev_info dev_info[] __counted_by(dev_num); }; int rfcomm_dev_ioctl(struct sock *sk, unsigned int cmd, void __user *arg); diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c index 69c75c041fe1..af80d599c337 100644 --- a/net/bluetooth/rfcomm/tty.c +++ b/net/bluetooth/rfcomm/tty.c @@ -504,7 +504,7 @@ static int rfcomm_get_dev_list(void __user *arg) struct rfcomm_dev *dev; struct rfcomm_dev_list_req *dl; struct rfcomm_dev_info *di; - int n = 0, size, err; + int n = 0, err; u16 dev_num; BT_DBG(""); @@ -515,12 +515,11 @@ static int rfcomm_get_dev_list(void __user *arg) if (!dev_num || dev_num > (PAGE_SIZE * 4) / sizeof(*di)) return -EINVAL; - size = sizeof(*dl) + dev_num * sizeof(*di); - - dl = kzalloc(size, GFP_KERNEL); + dl = kzalloc(struct_size(dl, dev_info, dev_num), GFP_KERNEL); if (!dl) return -ENOMEM; + dl->dev_num = dev_num; di = dl->dev_info; mutex_lock(&rfcomm_dev_lock); @@ -528,12 +527,12 @@ static int rfcomm_get_dev_list(void __user *arg) list_for_each_entry(dev, &rfcomm_dev_list, list) { if (!tty_port_get(&dev->port)) continue; - (di + n)->id = dev->id; - (di + n)->flags = dev->flags; - (di + n)->state = dev->dlc->state; - (di + n)->channel = dev->channel; - bacpy(&(di + n)->src, &dev->src); - bacpy(&(di + n)->dst, &dev->dst); + di[n].id = dev->id; + di[n].flags = dev->flags; + di[n].state = dev->dlc->state; + di[n].channel = dev->channel; + bacpy(&di[n].src, &dev->src); + bacpy(&di[n].dst, &dev->dst); tty_port_put(&dev->port); if (++n >= dev_num) break; @@ -542,9 +541,7 @@ static int rfcomm_get_dev_list(void __user *arg) mutex_unlock(&rfcomm_dev_lock); dl->dev_num = n; - size = sizeof(*dl) + n * sizeof(*di); - - err = copy_to_user(arg, dl, size); + err = copy_to_user(arg, dl, struct_size(dl, dev_info, n)); kfree(dl); return err ? -EFAULT : 0; -- 2.25.1