From patchwork Mon May 3 11:57:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 430782 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=-19.4 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, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 4E0CFC433ED for ; Mon, 3 May 2021 12:02:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1695761186 for ; Mon, 3 May 2021 12:02:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234179AbhECMDE (ORCPT ); Mon, 3 May 2021 08:03:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:37390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234122AbhECMCS (ORCPT ); Mon, 3 May 2021 08:02:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B707261249; Mon, 3 May 2021 12:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620043285; bh=FjgRy3LbQ5R6fhTMkrxeHZfE0dybG9CT8NVNTbrJ6ok=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zjgySv1q7WL8EONWlSFhe3V6l/D91/uJg6JKlgP7PxtFQ4cvtiVGUf2KOpMhxkIXl my5AEyAk5VRZTDEATEo06634B90KznhZGCercAxjyvZuZeab2fp0ViRSDMzYXyHQfl 0KXA9060WOW49rFVZ8tQjUCjmFnofb/wQJ+lYnGg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Igor Matheus Andrade Torrente , Ferenc Bakonyi , Bartlomiej Zolnierkiewicz , stable , Greg Kroah-Hartman Subject: [PATCH 39/69] video: hgafb: fix potential NULL pointer dereference Date: Mon, 3 May 2021 13:57:06 +0200 Message-Id: <20210503115736.2104747-40-gregkh@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210503115736.2104747-1-gregkh@linuxfoundation.org> References: <20210503115736.2104747-1-gregkh@linuxfoundation.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Igor Matheus Andrade Torrente 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 Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/hgafb.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c index fca29f219f8b..cc8e62ae93f6 100644 --- 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 const 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);