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 X-Spam-Level: X-Spam-Status: No, score=-17.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1300FC433E0 for ; Thu, 30 Jul 2020 13:08:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBC362074B for ; Thu, 30 Jul 2020 13:08:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=embeddedor.com header.i=@embeddedor.com header.b="JF8CA1C/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728671AbgG3NIE (ORCPT ); Thu, 30 Jul 2020 09:08:04 -0400 Received: from gateway32.websitewelcome.com ([192.185.145.115]:24008 "EHLO gateway32.websitewelcome.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726535AbgG3NID (ORCPT ); Thu, 30 Jul 2020 09:08:03 -0400 Received: from cm10.websitewelcome.com (cm10.websitewelcome.com [100.42.49.4]) by gateway32.websitewelcome.com (Postfix) with ESMTP id 0F841EEDE for ; Thu, 30 Jul 2020 08:07:32 -0500 (CDT) Received: from gator4166.hostgator.com ([108.167.133.22]) by cmsmtp with SMTP id 18GWkM1J8RQIV18GWknV3i; Thu, 30 Jul 2020 08:06:32 -0500 X-Authority-Reason: nr=8 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=embeddedor.com; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:Subject:From:References:Cc:To:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=0p2Wo7L4ooW+9Ky8FHANq9urEHVpRIv4/Heqml0lU6k=; b=JF8CA1C/TqyZK+tGxOF6BF8iht 1c//5Ei6DDMU8CsCMlV0GhMObxUCkb42UTX+Zqp4GNWqOslf8ZFm3IoWlqwXHjBwWXqTCee2kFqfu N6G5LBqK4iI4Kz5TOssLjfuauef2qj1qTkaShIHfZLVjF3wEj6EA5+fHakazhE030W9UrLP/aAAjU TvSjVvxny4Mf7nfSg7EfbfCh+YQjHKt+JK1DkI8G9SL+vOEeeqrTiXaZYLHRLavpWdJmglYWRLNam CXPPewiN146qtLaXZjpfltEy+vk/BjF+04tYLkhgGJuk1zW5bRWIOzN4zF6eWMZcaTRO1MqPQqvjD beCO/IZg==; Received: from 187-162-31-110.static.axtel.net ([187.162.31.110]:33846 helo=[192.168.15.3]) by gator4166.hostgator.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.93) (envelope-from ) id 1k18GW-003RPp-2W; Thu, 30 Jul 2020 08:06:32 -0500 To: Takashi Iwai , "Gustavo A. R. Silva" Cc: Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org References: <20200729221829.GA10623@embeddedor> From: "Gustavo A. R. Silva" Autocrypt: addr=gustavo@embeddedor.com; keydata= xsFNBFssHAwBEADIy3ZoPq3z5UpsUknd2v+IQud4TMJnJLTeXgTf4biSDSrXn73JQgsISBwG 2Pm4wnOyEgYUyJd5tRWcIbsURAgei918mck3tugT7AQiTUN3/5aAzqe/4ApDUC+uWNkpNnSV tjOx1hBpla0ifywy4bvFobwSh5/I3qohxDx+c1obd8Bp/B/iaOtnq0inli/8rlvKO9hp6Z4e DXL3PlD0QsLSc27AkwzLEc/D3ZaqBq7ItvT9Pyg0z3Q+2dtLF00f9+663HVC2EUgP25J3xDd 496SIeYDTkEgbJ7WYR0HYm9uirSET3lDqOVh1xPqoy+U9zTtuA9NQHVGk+hPcoazSqEtLGBk YE2mm2wzX5q2uoyptseSNceJ+HE9L+z1KlWW63HhddgtRGhbP8pj42bKaUSrrfDUsicfeJf6 m1iJRu0SXYVlMruGUB1PvZQ3O7TsVfAGCv85pFipdgk8KQnlRFkYhUjLft0u7CL1rDGZWDDr NaNj54q2CX9zuSxBn9XDXvGKyzKEZ4NY1Jfw+TAMPCp4buawuOsjONi2X0DfivFY+ZsjAIcx qQMglPtKk/wBs7q2lvJ+pHpgvLhLZyGqzAvKM1sVtRJ5j+ARKA0w4pYs5a5ufqcfT7dN6TBk LXZeD9xlVic93Ju08JSUx2ozlcfxq+BVNyA+dtv7elXUZ2DrYwARAQABzStHdXN0YXZvIEEu IFIuIFNpbHZhIDxndXN0YXZvYXJzQGtlcm5lbC5vcmc+wsGrBBMBCAA+FiEEkmRahXBSurMI g1YvRwW0y0cG2zEFAl6zFvQCGyMFCQlmAYAFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AAIQkQ RwW0y0cG2zEWIQSSZFqFcFK6swiDVi9HBbTLRwbbMZsEEACWjJyXLjtTAF21Vuf1VDoGzitP oE69rq9UhXIGR+e0KACyIFoB9ibG/1j/ESMa0RPSwLpJDLgfvi/I18H/9cKtdo2uz0XNbDT8 i3llIu0b43nzGIDzRudINBXC8Coeob+hrp/MMZueyzt0CUoAnY4XqpHQbQsTfTrpFeHT02Qz ITw6kTSmK7dNbJj2naH2vSrU11qGdU7aFzI7jnVvGgv4NVQLPxm/t4jTG1o+P1Xk4N6vKafP zqzkxj99JrUAPt+LyPS2VpNvmbSNq85PkQ9gpeTHpkio/D9SKsMW62njITPgy6M8TFAmx8JF ZAI6k8l1eU29F274WnlQ6ZokkJoNctwHa+88euWKHWUDolCmQpegJJ8932www83GLn1mdUZn NsymjFSdMWE+y8apWaV9QsDOKWf7pY2uBuE6GMPRhX7e7h5oQwa1lYeO2L9LTDeXkEOJe+hE qQdEEvkC/nok0eoRlBlZh433DQlv4+IvSsfN/uWld2TuQFyjDCLIm1CPRfe7z0TwiCM27F+O lHnUspCFSgpnrxqNH6CM4aj1EF4fEX+ZyknTSrKL9BGZ/qRz7Xe9ikU2/7M1ov6rOXCI4NR9 THsNax6etxCBMzZs2bdMHMcajP5XdRsOIARuN08ytRjDolR2r8SkTN2YMwxodxNWWDC3V8X2 RHZ4UwQw487BTQRbLBwMARAAsHCE31Ffrm6uig1BQplxMV8WnRBiZqbbsVJBH1AAh8tq2ULl 7udfQo1bsPLGGQboJSVN9rckQQNahvHAIK8ZGfU4Qj8+CER+fYPp/MDZj+t0DbnWSOrG7z9H IZo6PR9z4JZza3Hn/35jFggaqBtuydHwwBANZ7A6DVY+W0COEU4of7CAahQo5NwYiwS0lGis LTqks5R0Vh+QpvDVfuaF6I8LUgQR/cSgLkR//V1uCEQYzhsoiJ3zc1HSRyOPotJTApqGBq80 X0aCVj1LOiOF4rrdvQnj6iIlXQssdb+WhSYHeuJj1wD0ZlC7ds5zovXh+FfFl5qH5RFY/qVn 3mNIVxeO987WSF0jh+T5ZlvUNdhedGndRmwFTxq2Li6GNMaolgnpO/CPcFpDjKxY/HBUSmaE 9rNdAa1fCd4RsKLlhXda+IWpJZMHlmIKY8dlUybP+2qDzP2lY7kdFgPZRU+ezS/pzC/YTzAv CWM3tDgwoSl17vnZCr8wn2/1rKkcLvTDgiJLPCevqpTb6KFtZosQ02EGMuHQI6Zk91jbx96n rdsSdBLGH3hbvLvjZm3C+fNlVb9uvWbdznObqcJxSH3SGOZ7kCHuVmXUcqozol6ioMHMb+In rHPP16aVDTBTPEGwgxXI38f7SUEn+NpbizWdLNz2hc907DvoPm6HEGCanpcAEQEAAcLBZQQY AQgADwUCWywcDAIbDAUJCWYBgAAKCRBHBbTLRwbbMdsZEACUjmsJx2CAY+QSUMebQRFjKavw XB/xE7fTt2ahuhHT8qQ/lWuRQedg4baInw9nhoPE+VenOzhGeGlsJ0Ys52sdXvUjUocKgUQq 6ekOHbcw919nO5L9J2ejMf/VC/quN3r3xijgRtmuuwZjmmi8ct24TpGeoBK4WrZGh/1hAYw4 ieARvKvgjXRstcEqM5thUNkOOIheud/VpY+48QcccPKbngy//zNJWKbRbeVnimua0OpqRXhC rEVm/xomeOvl1WK1BVO7z8DjSdEBGzbV76sPDJb/fw+y+VWrkEiddD/9CSfgfBNOb1p1jVnT 2mFgGneIWbU0zdDGhleI9UoQTr0e0b/7TU+Jo6TqwosP9nbk5hXw6uR5k5PF8ieyHVq3qatJ 9K1jPkBr8YWtI5uNwJJjTKIA1jHlj8McROroxMdI6qZ/wZ1ImuylpJuJwCDCORYf5kW61fcr HEDlIvGc371OOvw6ejF8ksX5+L2zwh43l/pKkSVGFpxtMV6d6J3eqwTafL86YJWH93PN+ZUh 6i6Rd2U/i8jH5WvzR57UeWxE4P8bQc0hNGrUsHQH6bpHV2lbuhDdqo+cM9ehGZEO3+gCDFmK rjspZjkJbB5Gadzvts5fcWGOXEvuT8uQSvl+vEL0g6vczsyPBtqoBLa9SNrSVtSixD1uOgyt AP7RWS474w== Subject: Re: [PATCH][next] ALSA: vmaster: Use flex_array_size() helper in memcpy() Message-ID: <96ea053c-f4c9-56dd-0d44-b627b067405f@embeddedor.com> Date: Thu, 30 Jul 2020 08:12:33 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 187.162.31.110 X-Source-L: No X-Exim-ID: 1k18GW-003RPp-2W X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: 187-162-31-110.static.axtel.net ([192.168.15.3]) [187.162.31.110]:33846 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 6 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/30/20 03:41, Takashi Iwai wrote: > On Thu, 30 Jul 2020 00:18:29 +0200, > Gustavo A. R. Silva wrote: >> >> Make use of the flex_array_size() helper to calculate the size of a >> flexible array member within an enclosing structure. >> >> This helper offers defense-in-depth against potential integer overflows >> and makes it explicitly clear that we are dealing with a flexible array >> member. >> >> Signed-off-by: Gustavo A. R. Silva >> --- >> sound/core/vmaster.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c >> index ab36f9898711..21ce4082cb5f 100644 >> --- a/sound/core/vmaster.c >> +++ b/sound/core/vmaster.c >> @@ -262,7 +262,8 @@ int _snd_ctl_add_follower(struct snd_kcontrol *master, >> return -ENOMEM; >> srec->kctl = follower; >> srec->follower = *follower; >> - memcpy(srec->follower.vd, follower->vd, follower->count * sizeof(*follower->vd)); >> + memcpy(srec->follower.vd, follower->vd, flex_array_size(srec, follower.vd, >> + srec->follower.count)); > > Changing from follower->count to srec->follower.count isn't obvious, > so it should have been mentioned in the log; other than that, the code > change looks good. > Yeah; you're right. I'll include that in the changelog text. > But since the API isn't in Linus tree yet, I'll postpone the merge > until the API reaches to upstream. Maybe I can merge this during RC1 > merge window, as those are trivial. > The API is already in mainline, see: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/overflow.h#n320 > > BTW, looking at those patterns, I wonder whether it'd make sense to > make the whole memset() call as a macro like > > safe_copy_array(srec->follower.vd, follower->vd, follower->count); > > ? > Yep; I was actually thinking about that, yesterday. I might implement it for the next development cycle. :) Thanks for the feedback. -- Gustavo