From patchwork Thu Aug 4 12:41:25 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheyu Ma X-Patchwork-Id: 595408 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 6BEEFC19F2D for ; Thu, 4 Aug 2022 12:42:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239737AbiHDMmC (ORCPT ); Thu, 4 Aug 2022 08:42:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239734AbiHDMly (ORCPT ); Thu, 4 Aug 2022 08:41:54 -0400 Received: from mail-pg1-x52d.google.com (mail-pg1-x52d.google.com [IPv6:2607:f8b0:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D9B92AE36; Thu, 4 Aug 2022 05:41:51 -0700 (PDT) Received: by mail-pg1-x52d.google.com with SMTP id 13so3395663pgc.8; Thu, 04 Aug 2022 05:41:51 -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=IqELUni7yOqBktpdBBbucmyGM38f0JGBlZ/P93Fp8ag=; b=oBx+siF17fjl9i5BvuQZ1qdK+rLtEzpUk3uCVRXEgskaRkyISP+iIlQ/giaOVIkrjI DPz9ffqSLfP6X23W/ejCdA0cHjdTajv5ZfB1JtrOqFFzYggakVhJNuyRdXM5xbYVQkgl FmW/0YPo2cmc7/vmgIsBSLBP3DlTQwPEWWb4qqNYgpHQXTyzRl2vns7C0LKp2Y+6UTn5 SCmWIea5jDUf8jIiSHCOqmUlTa/HV5QTMluEe/494XOSjLsXKHQLHwh6EdjCLwd0hlXp UCrEc7VNk3jN0/Ie+66c/4j2NaDf30FsSvABj3QtrD4Jk2ZtzdGdXowveIvnqTxgXoM8 XQtQ== 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=IqELUni7yOqBktpdBBbucmyGM38f0JGBlZ/P93Fp8ag=; b=QUS57aUr0Z/QqCNfHR3umsmtgilQJRIEHQ4ND+9ISQgDJQWbfJtZ4dZFas88j3alNh qzPmogL+irs/9WVNshAydxePj8Nc+3vcpFuT36dJll0J4bUrPxpqpSuTVNJTtp08Wkyn Cc7aghcYFN2T5mqIDQeqtuquHJlnzr+44YpfD4FO0Mi6BxfUiVYsND1FMCKD1ODRoEU2 d0K+Fw6K7qjhn625d9w5Yihq33WtpgAcHAKZr+0/Qh5TPbKBbccB7JueYWjWL7bwOPV0 KIeHBK0OePILFT0JRF+LJ4YQBnbzkhZEdfy5t50swsD0gZ6ktuZ6Qae3KvlEqAPXT7qf PM+A== X-Gm-Message-State: ACgBeo0znInLhi70XCswTYsssiWtdPVi+aA3vR3xW6uuA1MZR1p8tZY6 3DDV84M8+6sYnfL20n5aGw== X-Google-Smtp-Source: AA6agR7gwCQb5q3QUQuJgu3QIPH6DlUeRZ3KtvNPz5dZcndSktas2nIs8wSYnDaG/RC6A1skS2l6mA== X-Received: by 2002:a05:6a00:17a8:b0:52e:6e3e:9ff with SMTP id s40-20020a056a0017a800b0052e6e3e09ffmr1828954pfg.42.1659616910895; Thu, 04 Aug 2022 05:41:50 -0700 (PDT) Received: from localhost.localdomain ([166.111.133.51]) by smtp.gmail.com with ESMTPSA id i8-20020a63bf48000000b0041b672e93c2sm1070769pgo.17.2022.08.04.05.41.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Aug 2022 05:41:50 -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 3/3] video: fbdev: s3fb: Check the size of screen before memset_io() Date: Thu, 4 Aug 2022 20:41:25 +0800 Message-Id: <20220804124125.3506755-4-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 s3fb_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: [ 54.083733] BUG: unable to handle page fault for address: ffffc90003000000 [ 54.083742] #PF: supervisor write access in kernel mode [ 54.083744] #PF: error_code(0x0002) - not-present page [ 54.083760] RIP: 0010:memset_orig+0x33/0xb0 [ 54.083782] Call Trace: [ 54.083788] s3fb_set_par+0x1ec6/0x4040 [ 54.083806] fb_set_var+0x604/0xeb0 [ 54.083836] do_fb_ioctl+0x234/0x670 Fix the this by checking the value of 'screen_size' before memset_io(). Fixes: a268422de8bf ("[PATCH] fbdev driver for S3 Trio/Virge") Signed-off-by: Zheyu Ma --- drivers/video/fbdev/s3fb.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/video/fbdev/s3fb.c b/drivers/video/fbdev/s3fb.c index b93c8eb02336..5069f6f67923 100644 --- a/drivers/video/fbdev/s3fb.c +++ b/drivers/video/fbdev/s3fb.c @@ -905,6 +905,8 @@ static int s3fb_set_par(struct fb_info *info) value = clamp((htotal + hsstart + 1) / 2 + 2, hsstart + 4, htotal + 1); svga_wcrt_multi(par->state.vgabase, s3_dtpc_regs, value); + 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);