From patchwork Thu Aug 4 12:41:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheyu Ma X-Patchwork-Id: 12936332 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 0C27EC19F2A for ; Thu, 4 Aug 2022 12:41:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239158AbiHDMlv (ORCPT ); Thu, 4 Aug 2022 08:41:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239405AbiHDMlu (ORCPT ); Thu, 4 Aug 2022 08:41:50 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51E972B188; Thu, 4 Aug 2022 05:41:48 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id b4so9247937pji.4; Thu, 04 Aug 2022 05:41:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=CCsyUyjtcxiqdAio61EdLoryAiVvM5FMmKPvH5Lk+7M=; b=p5VexO3soXHRkRquHKXZkC8JYq5rp2/+hH5cdP/9ybw6xveovaMm7vq9DULzixLiIm 2zQcITt0lDLza3JpyfTFtjiOf0ZjmkAYHl4dKyTmQHDnE5c264USvOJ3qUjPd8re+1o7 zMBGJm0vtdWGJhS35PJZI4FYub9oNCtlU5UqZpszGvlk3jzNvYf6EHshWdYWHXhjPxW/ hLb7yHDT1MRtKEEJgwiC1xcwkMDg6y7w4BivcoGWlgniNUlUueoeqLrT4pMYt0A0z4+G UnV3o+nvdprd6/CrmPtNzyvie7pw4bPdGQYISWpnMsWAxhHFAoD+J5qGzNQVecUS11rp fYYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=CCsyUyjtcxiqdAio61EdLoryAiVvM5FMmKPvH5Lk+7M=; b=eDHr/FFsIxqaf/DjBTtQDZvLT01o3pP2SEJ/ReZHSavgBH/B9dM/7a6L5O/XriSq2K 5XRV1JzfRtvBEmpXeUpP1T85yF93vaJVW1NoKAP1rbW3LuwhFa+plzgLPRvBKUiVPYcs /vSu/i4diOBw03dxPhpWESdhsRVtjtaEFmeMtiOI8XKtPio/bo+tiT+GKhN767wIkAj7 HrGx8iya/Xldf0DE00ARMcjirPA++FT4JwIcZOXEg3sV7+j5AwU07eobVddUh+rSedqs OGjYW2NEXL4zluiZyxocL1xl1+mDBMUJehMhzO2Lco+wvHXvfdp8nIbcqKWR8B9E2r6H pYng== X-Gm-Message-State: ACgBeo11c+6WLoLY9RcTje3W9O1qSuU6sbP63cUP5Y+yfMxEkGmd8Xxy v+S2tll+EtuQstNnJAbrbA== X-Google-Smtp-Source: AA6agR4X8s+bYDtMYD6EK98FWif6GTdlWCPPlzexQu4yKAsAh28bchh+1VCurElhJCelSbWYzUEB1g== X-Received: by 2002:a17:90a:fc91:b0:1f3:1f3a:54d5 with SMTP id ci17-20020a17090afc9100b001f31f3a54d5mr2006808pjb.74.1659616907801; Thu, 04 Aug 2022 05:41:47 -0700 (PDT) Received: from localhost.localdomain ([166.111.133.51]) by smtp.gmail.com with ESMTPSA id i8-20020a63bf48000000b0041b672e93c2sm1070769pgo.17.2022.08.04.05.41.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Aug 2022 05:41:47 -0700 (PDT) From: Zheyu Ma To: deller@gmx.de, adaplas@gmail.com, santiago@crfreenet.org, akpm@linux-foundation.org Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Zheyu Ma Subject: [PATCH 2/3] video: fbdev: arkfb: Check the size of screen before memset_io() Date: Thu, 4 Aug 2022 20:41:24 +0800 Message-Id: <20220804124125.3506755-3-zheyuma97@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220804124125.3506755-1-zheyuma97@gmail.com> References: <20220804124125.3506755-1-zheyuma97@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org In the function arkfb_set_par(), the value of 'screen_size' is calculated by the user input. If the user provides the improper value, the value of 'screen_size' may larger than 'info->screen_size', which may cause the following bug: [ 659.399066] BUG: unable to handle page fault for address: ffffc90003000000 [ 659.399077] #PF: supervisor write access in kernel mode [ 659.399079] #PF: error_code(0x0002) - not-present page [ 659.399094] RIP: 0010:memset_orig+0x33/0xb0 [ 659.399116] Call Trace: [ 659.399122] arkfb_set_par+0x143f/0x24c0 [ 659.399130] fb_set_var+0x604/0xeb0 [ 659.399161] do_fb_ioctl+0x234/0x670 [ 659.399189] fb_ioctl+0xdd/0x130 Fix the this by checking the value of 'screen_size' before memset_io(). Fixes: 681e14730c73 ("arkfb: new framebuffer driver for ARK Logic cards") Signed-off-by: Zheyu Ma --- drivers/video/fbdev/arkfb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/arkfb.c b/drivers/video/fbdev/arkfb.c index eb3e47c58c5f..de4002914f9e 100644 --- a/drivers/video/fbdev/arkfb.c +++ b/drivers/video/fbdev/arkfb.c @@ -792,6 +792,8 @@ static int arkfb_set_par(struct fb_info *info) value = ((value * hmul / hdiv) / 8) - 5; vga_wcrt(par->state.vgabase, 0x42, (value + 1) / 2); + if (screen_size > info->screen_size) + screen_size = info->screen_size; memset_io(info->screen_base, 0x00, screen_size); /* Device and screen back on */ svga_wcrt_mask(par->state.vgabase, 0x17, 0x80, 0x80);