From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15D13C433EF for ; Wed, 29 Sep 2021 17:45:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA4BA614C8 for ; Wed, 29 Sep 2021 17:45:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345019AbhI2RrD (ORCPT ); Wed, 29 Sep 2021 13:47:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344502AbhI2RrC (ORCPT ); Wed, 29 Sep 2021 13:47:02 -0400 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AFCFC06161C; Wed, 29 Sep 2021 10:45:21 -0700 (PDT) Received: by mail-ed1-x52a.google.com with SMTP id v10so11844324edj.10; Wed, 29 Sep 2021 10:45:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=FIySyrXxkEKwm26jEVGIMsY7wJRMxgw98emBJrp8y6k=; b=TPaJQTAmcDitxf8sdYRG0suoD9OHN+sqJSpRUZK8MeJi++z5D1ptjyVQYeiOQb0xRz q/12yatXna9nstDHjtX91d0WHkcHgEAmqP9KMZqwMfGcdSq7xnaER0/LWjNOXtpP9FKn F3+D2FaUshkIzokd6Ze1bOk/b9cs9UH1g7G0Ksb88yXanQlTAXv2ypXxRprYdArK4k0G Xn+kJjK5+UFvUyGSF2oJM/6kx8z9D3NMPMQN/uBU+/8OO7orSgyv8a58AwQYVQpBjb3A 18cLyXbIvuY44Xrh/FnXl+PelNAiW3VaJSNiucUy2QkJmmJ3Hh60DV5sVavSCgo0lUb8 A+Ug== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=FIySyrXxkEKwm26jEVGIMsY7wJRMxgw98emBJrp8y6k=; b=bwTpLIRvO8V7/spP36xvwJ4PbNUS7gG2Vsrf2zLJ4FLJpmD7AZGqmA8C/jyg09A2au vXt4p8KAAX7K02XDtWsUqICafmz+KBJqK860EsJP7SqXnbeA01VPyZkKJn9G2gWOHo7d nZEfhKxFfkBN27/FoJltM1wRqMgWtMPfRGDjp0Xp5udoimmKBnMZSWkF6VMANqoHJ+Re r4PTWmZ63nBcgpECIENwKmhCkntap83iQ3xQ4lgCXqbnvmdIN+qnqKaaN4SWl3zlBO5L 3VkCdGHR+C1TPjJb7+WuFXjHanPEGjJ/6GIj/P4/mvILBlgrZF5Y11WY3ACdd+z38pR9 3NBw== X-Gm-Message-State: AOAM531MHijAAd/9isynwPi8J8V5whxOlJaWBTZDOA7yLwONWtl2vMPn Jh+GZlt+Dpjt55r8luaHeFpMX4m6bZ0= X-Google-Smtp-Source: ABdhPJyv6MYqHGEXqX5DmaZbUP++IQh7gQRcGMZL91Fz4wXLE2Arze2Mh7vp5GGyw/Lnk8fL/qPVcw== X-Received: by 2002:a50:fa89:: with SMTP id w9mr1411930edr.113.1632937519918; Wed, 29 Sep 2021 10:45:19 -0700 (PDT) Received: from [192.168.0.108] ([176.228.98.2]) by smtp.gmail.com with ESMTPSA id dt4sm350760ejb.27.2021.09.29.10.45.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 Sep 2021 10:45:19 -0700 (PDT) Subject: Re: [PATCH][net-next] net/mlx4: Use array_size() helper in copy_to_user() To: Eric Dumazet , "Gustavo A. R. Silva" , Tariq Toukan , "David S. Miller" , Jakub Kicinski Cc: netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20210928201733.GA268467@embeddedor> <283d239b-9af9-d3a3-72be-9138c032ef63@gmail.com> <16ae2d2d-3aba-82b2-0bd8-90f7d0367a62@gmail.com> From: Tariq Toukan Message-ID: Date: Wed, 29 Sep 2021 20:45:17 +0300 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <16ae2d2d-3aba-82b2-0bd8-90f7d0367a62@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On 9/29/2021 8:21 PM, Eric Dumazet wrote: > > > On 9/29/21 3:24 AM, Tariq Toukan wrote: >> >> >> On 9/28/2021 11:17 PM, Gustavo A. R. Silva wrote: >>> Use array_size() helper instead of the open-coded version in >>> copy_to_user(). These sorts of multiplication factors need >>> to be wrapped in array_size(). >>> >>> Link: https://github.com/KSPP/linux/issues/160 >>> Signed-off-by: Gustavo A. R. Silva >>> --- >>>   drivers/net/ethernet/mellanox/mlx4/cq.c | 3 ++- >>>   1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/net/ethernet/mellanox/mlx4/cq.c b/drivers/net/ethernet/mellanox/mlx4/cq.c >>> index f7053a74e6a8..4d4f9cf9facb 100644 >>> --- a/drivers/net/ethernet/mellanox/mlx4/cq.c >>> +++ b/drivers/net/ethernet/mellanox/mlx4/cq.c >>> @@ -314,7 +314,8 @@ static int mlx4_init_user_cqes(void *buf, int entries, int cqe_size) >>>               buf += PAGE_SIZE; >>>           } >>>       } else { >>> -        err = copy_to_user((void __user *)buf, init_ents, entries * cqe_size) ? >>> +        err = copy_to_user((void __user *)buf, init_ents, >>> +                   array_size(entries, cqe_size)) ? >>>               -EFAULT : 0; >>>       } >>> >> >> Thanks for your patch. >> Reviewed-by: Tariq Toukan > > Not sure why avoiding size_t overflows would make this code safer. > init_ents contains PAGE_SIZE bytes... > > BTW > > Is @entries guaranteed to be a power of two ? Yes. > > This function seems to either copy one chunk ( <= PAGE_SIZE), > or a number of full pages. > Exactly. No remainder handling is needed, for the reason you mentioned above.