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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 C6820C47084 for ; Mon, 24 May 2021 15:37:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A936261411 for ; Mon, 24 May 2021 15:37:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234172AbhEXPjF (ORCPT ); Mon, 24 May 2021 11:39:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:50500 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233874AbhEXPgV (ORCPT ); Mon, 24 May 2021 11:36:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E088B6140D; Mon, 24 May 2021 15:32:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621870353; bh=Wjlwndu3maWl4Pu3r737cwkled+6HVuNMWTYCHealns=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RXFyX0YBUyxMyS4hb9eVID7NzZHNjJX9mBrvHnq0qt3nInYSSvm5iqljfjEadNarz pz5Xozw4p3m3AefHkg/ek2F1M1y+8pa6EJB7Ek5+YYlfsnDDOGx6aTJOJew4BvZo+B jI421uaLCioDzmfCv+62kBud0Gd2F7W6PEhmcUA0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ferenc Bakonyi , Bartlomiej Zolnierkiewicz , Igor Matheus Andrade Torrente Subject: [PATCH 4.9 32/36] video: hgafb: fix potential NULL pointer dereference Date: Mon, 24 May 2021 17:25:17 +0200 Message-Id: <20210524152325.193367564@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210524152324.158146731@linuxfoundation.org> References: <20210524152324.158146731@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Igor Matheus Andrade Torrente commit dc13cac4862cc68ec74348a80b6942532b7735fa upstream. The return of ioremap if not checked, and can lead to a NULL to be assigned to hga_vram. Potentially leading to a NULL pointer dereference. The fix adds code to deal with this case in the error label and changes how the hgafb_probe handles the return of hga_card_detect. Cc: Ferenc Bakonyi Cc: Bartlomiej Zolnierkiewicz Cc: stable Signed-off-by: Igor Matheus Andrade Torrente Link: https://lore.kernel.org/r/20210503115736.2104747-40-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/hgafb.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) --- a/drivers/video/fbdev/hgafb.c +++ b/drivers/video/fbdev/hgafb.c @@ -285,6 +285,8 @@ static int hga_card_detect(void) hga_vram_len = 0x08000; hga_vram = ioremap(0xb0000, hga_vram_len); + if (!hga_vram) + return -ENOMEM; if (request_region(0x3b0, 12, "hgafb")) release_io_ports = 1; @@ -344,13 +346,18 @@ static int hga_card_detect(void) hga_type_name = "Hercules"; break; } - return 1; + return 0; error: if (release_io_ports) release_region(0x3b0, 12); if (release_io_port) release_region(0x3bf, 1); - return 0; + + iounmap(hga_vram); + + pr_err("hgafb: HGA card not detected.\n"); + + return -EINVAL; } /** @@ -548,13 +555,11 @@ static struct fb_ops hgafb_ops = { static int hgafb_probe(struct platform_device *pdev) { struct fb_info *info; + int ret; - if (! hga_card_detect()) { - printk(KERN_INFO "hgafb: HGA card not detected.\n"); - if (hga_vram) - iounmap(hga_vram); - return -EINVAL; - } + ret = hga_card_detect(); + if (!ret) + return ret; printk(KERN_INFO "hgafb: %s with %ldK of memory detected.\n", hga_type_name, hga_vram_len/1024);