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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32F71C83F12 for ; Tue, 29 Aug 2023 17:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237679AbjH2RMR (ORCPT ); Tue, 29 Aug 2023 13:12:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48466 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237662AbjH2RLo (ORCPT ); Tue, 29 Aug 2023 13:11:44 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.15.15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7621FD; Tue, 29 Aug 2023 10:11:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1693329085; x=1693933885; i=deller@gmx.de; bh=Am0z4fpqq3gPWNH7evU/PjMIRGxd6gp6/fsCQ/0L66o=; h=X-UI-Sender-Class:Date:Subject:To:Cc:References:From:In-Reply-To; b=U4nedsHCoA/1LmSlRHSeHbWXHxCkCzF/0fMB5MMNEqbkl8Aq7pZFV3O13JP6z0lzBDPu78y eaiF+0agzmwjfKKGZ5PQ7lw9wDnC0irnyigLmIJrWgCUpsFNp9VKQqqn85kPj6748BRfbrlP7 y1DVOVfAa5nmC5KXpZ5k5K0dXhnIp8+iG0W8okM3AcO/MP97drELEzqITWhyCYWKln8CKDyAf MRy37VFMc5DN2lFRzgrWR6JhrMxlg9hsojGEZcI+otkmNiuXM3xz4tcvK9So9hiqz8Da/Nt76 PyDFQZV3AiR/Mq2W1bNlnYShwKCP5OJjn7C8i4FFBanF50GxKNQA== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [192.168.20.60] ([94.134.153.221]) by mail.gmx.net (mrgmx004 [212.227.17.190]) with ESMTPSA (Nemesis) id 1N5VDE-1pdHfz2KqY-016u5T; Tue, 29 Aug 2023 19:11:25 +0200 Message-ID: <9d2bb495-0c1d-0d1b-96ea-4b1110d45b79@gmx.de> Date: Tue, 29 Aug 2023 19:11:25 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: truncation in drivers/video/fbdev/neofb.c Content-Language: en-US To: Nick Desaulniers Cc: linux-fbdev@vger.kernel.org, dri-devel , clang-built-linux , LKML , Andrew Morton , Nathan Chancellor References: From: Helge Deller In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:nLhGJZGsPhbosIqFBHO4HTSsCDwh7B/34489wZUsEU4guozePTn iVOOt2b9v3YsEHpW1OfD88PAgAHTEbgFfXELfw2Ebm4znjRHVRWmhvb30OA9LZfWVLqEctA 4i7B1n7/aiRqpcY2BV1834zhck4UJb5ZmSKJauk4jQlc8J8DDWkDxocVBO3wZc5Y606xQYk qFFgxBkyI0OWmLlJMksaA== UI-OutboundReport: notjunk:1;M01:P0:NdvL8Q8qicY=;IRYB6GgUXLgy8IgJ3ESMKXhKypa khB8z5GixgdUdVJoaHINNn7L3sjLTdUwFpz4ml1HsEVwJK+tTpMgKw5YLNysd7U89fYcEqpyT Oz/r4xGSsObPFwEDk09fN62yK+pc26pTymOdTbnmCbNuyLj2Xd2ENaNGsvQEORVYafgu+6JM9 fIElepZdS+WmmrPSxBX9jWqoj0dmVi585iCmWfGHC40jbgmqyBVGKHUv049SpZbBocTLwkXHK DtKllaqG8GPfLfoOM2rOQ07w2/IhgUpouqADoGRMLa60RgG2KWAYvzfatosiH62nGgXrhMvio BVnnIQhj0/dS3sWRpPYJPv0ez+FIJWnuydCzf6qpKn2IcYOEv4Tts+O3fLZSseSHQePrTJOT2 CTfZbZS4MO6ThePqBbj3fyjPouhRtDXLs7xnigrNgcK9U+PNo9MGKNdc3jnb5p09yuUkt1oOn Htkz6eDrAqQ0hP5TZGb2Zf4E/BckybE4SQznt2FMV18OY5xja3mwlLx2k5ogCJTAy9+H+xXs1 EBoNbTAz9mReLc9f1XEwEgd2ISsZHysnNCV1lzgil21B07cfwiwyONK0LnrcZJ/udfd01vsfi XxUFhCBgzFfXJh3lOlTpsq6I5R5XMzPkEuYr9LZVqAjJX36ie3iOhv2bhyrRZ3oKr0PAB3xZk flPHwr/AwLrYv48h1iEDvvkiRWQLhhBQaxDFmWqvptavPQv1WjsjDQNqo0U/DQOAr7lfwjRvy 7yXoQ7PdUcNVJiYSBYGEvXFw/KqEl5ejG2CZoGnVnaKT4bhrxeyHdre/hkTbWjwWzqIu/XEAj L2GZawpRtuTA68msObmx5/dLj4RM4kEsBHMpXvZ/1j9/A8ej18clE6ujLJzMVBJauSrNeTSLr VE3R0z/1QSdcNwQZ6Tbo4rOM3TLpMxKIAk5wkT7ogK6IZCVcpnhJojsJmaycO0yKHVaXOBEA7 2mjR+w== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 8/29/23 18:45, Nick Desaulniers wrote: > Helge, > A recent change in clang made it better about spotting snprintf that > will result in truncation. Nathan reported the following instances: > > drivers/video/fbdev/neofb.c:1959:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 17 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1963:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 18 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1967:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 17 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1971:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 17 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1978:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 18 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1985:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 17 [-Wfortify-source] > drivers/video/fbdev/neofb.c:1992:3: warning: 'snprintf' will always be > truncated; specified size is 16, but format string expands to at least > 18 [-Wfortify-source] > > https://github.com/ClangBuiltLinux/linux/issues/1923 > > Clang is right here. `info->fix.id` is declared as `char id[16];` so > indeed string literals like "MagicGraph 256AV+" indeed lead to > truncation. But this is declared in include/uapi/linux/fb.h; I assume > those headers cant be changed? Can the strings be shortened then? Is > it perhaps time to delete this driver? > > I see AKPM mentioned alluded to this in > commit 0e90454 ("neofb: avoid overwriting fb_info fields") > > (Also, snprintf probably isn't necessary for string literals that > don't contain format strings) It's just an ID field, so I don't think we need the full name of the card. So using strscpy() and shorten the name, e.g. "MagicGr. 256XL+" instead of "MagicGraph 256XL+" is probably the most simple solution? Anyone want to send a patch? Helge