From patchwork Mon Apr 4 08:47:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheyu Ma X-Patchwork-Id: 12800005 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 5031BC433F5 for ; Mon, 4 Apr 2022 08:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241587AbiDDItz (ORCPT ); Mon, 4 Apr 2022 04:49:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241450AbiDDItn (ORCPT ); Mon, 4 Apr 2022 04:49:43 -0400 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2644B3B56D; Mon, 4 Apr 2022 01:47:48 -0700 (PDT) Received: by mail-pl1-x629.google.com with SMTP id s11so3160240pla.8; Mon, 04 Apr 2022 01:47:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=se5gGj4gIJ4vBWROJp5FA4oTC1hFkItwaNy9Koid500=; b=FAWD5yFE3Vc1iB03y75UnpfQijI3kB8ErWFbZSX3sTvLpWWs8B9bNUKAqt1J9AUjua +8qiSwoCtM81wPcqTXMLNWNi51npg2coAdhvntqlt8jzubrZcqpdPAzkPEP+df7LxRF6 SU/2nl+b/D/Gfs5CGKOKbs5elEtIeGAeh1vYKYwyk5CpJxaYBG8ynXrXQISO+XQXwJNX oE8ZKXL7BUqPKahtHTTiFy1jsLmyVr/BiTJP0GWcFgyCkIBCLNn18/nIU9Zwz5uqdArj DfJQTbq4JSXt26CYu/+j4MreZdnQKpxzeh6b3w+GBv8DtX0UKPkv1dSkxJmCK0ViTutb oKNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=se5gGj4gIJ4vBWROJp5FA4oTC1hFkItwaNy9Koid500=; b=CobhGj/r+mwThlSgE8fzOmLa+kg4Uil3KZ+fymShwYPENEv1ayMN4Y4niHJEVQsVvW 23Hd6bXkFDtU3UBvYwehKa9lbO+q9ODPfoilEjl5F/ZM+nHXr8k8OAw/9J04ECOatRk2 JDBLNuaW21PzGS+Hvz8aPSfLJ28QxpL1FPivQVBcsPCc7aXp0JhpO4GLb3/6MKoL4HbM MI2GIiLvucd+f4SSur3sJ5ImMdGRLskwzaaLQw9D2OiPCWp8kG4NIdy7z9q5DDROKzdt jyE9vnoFy8oMyGe86UjEy1tyFqnhq/GOAO7owEwm68OeBpVxeXYY9W6vqFc/qG7vzDrk CWpA== X-Gm-Message-State: AOAM5316LIcphnbxG3eStPKw+ybpO2b1XKxi74xOCCZS7lVz5MfgENK9 +jYKjZ2JXzA4cMH+YQu2pkFPA9tFupimSmVkzg== X-Google-Smtp-Source: ABdhPJymLqxgqm2NQFE6WKf9I6xeVeCxVVNJO1ePEFu5Dx3u2IlfUF8NYPn6xZ6W5qBnlwa3LUtr8w== X-Received: by 2002:a17:902:ecd2:b0:156:9992:5892 with SMTP id a18-20020a170902ecd200b0015699925892mr5803329plh.7.1649062067669; Mon, 04 Apr 2022 01:47:47 -0700 (PDT) Received: from localhost.localdomain ([144.202.91.207]) by smtp.gmail.com with ESMTPSA id u6-20020a17090a3fc600b001ca88b0bdfesm3991960pjm.13.2022.04.04.01.47.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 04 Apr 2022 01:47:47 -0700 (PDT) From: Zheyu Ma To: deller@gmx.de Cc: linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Zheyu Ma Subject: [PATCH 1/7] video: fbdev: i740fb: Error out if 'pixclock' equals zero Date: Mon, 4 Apr 2022 16:47:17 +0800 Message-Id: <20220404084723.79089-2-zheyuma97@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220404084723.79089-1-zheyuma97@gmail.com> References: <20220404084723.79089-1-zheyuma97@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org The userspace program could pass any values to the driver through ioctl() interface. If the driver doesn't check the value of 'pixclock', it may cause divide error. Fix this by checking whether 'pixclock' is zero in the function i740fb_check_var(). The following log reveals it: divide error: 0000 [#1] PREEMPT SMP KASAN PTI RIP: 0010:i740fb_decode_var drivers/video/fbdev/i740fb.c:444 [inline] RIP: 0010:i740fb_set_par+0x272f/0x3bb0 drivers/video/fbdev/i740fb.c:739 Call Trace: fb_set_var+0x604/0xeb0 drivers/video/fbdev/core/fbmem.c:1036 do_fb_ioctl+0x234/0x670 drivers/video/fbdev/core/fbmem.c:1112 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1191 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] Signed-off-by: Zheyu Ma --- drivers/video/fbdev/i740fb.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/video/fbdev/i740fb.c b/drivers/video/fbdev/i740fb.c index 52cce0db8bd3..b595437a5752 100644 --- a/drivers/video/fbdev/i740fb.c +++ b/drivers/video/fbdev/i740fb.c @@ -657,6 +657,9 @@ static int i740fb_decode_var(const struct fb_var_screeninfo *var, static int i740fb_check_var(struct fb_var_screeninfo *var, struct fb_info *info) { + if (!var->pixclock) + return -EINVAL; + switch (var->bits_per_pixel) { case 8: var->red.offset = var->green.offset = var->blue.offset = 0;