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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9BC63C433EF for ; Mon, 24 Jan 2022 20:33:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1385566AbiAXUdf (ORCPT ); Mon, 24 Jan 2022 15:33:35 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:33392 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1381964AbiAXUZA (ORCPT ); Mon, 24 Jan 2022 15:25:00 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5C63DB8122A; Mon, 24 Jan 2022 20:24:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9406AC340E5; Mon, 24 Jan 2022 20:24:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643055898; bh=HDH01BdQbtjtxDwLkE394xgNnK/+LbYUX8kUZZULQ84=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=00jsZ7gA0QbH4Gc8wkhCi2tN4Z5gyOJktE04AYr3MLKzBg8ch4cweqZ6iYH5QgXxN 4W8Eq3Hu4saAyIxc6Lfw5Mz8GrqNsOFdOv1mAjA5bq8reFbOCG0E1AuY46dCAL/mrT FTSG3sOtLjfrLE0M9nArOkD5oq2A0lyVh1fugOtc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zhou Qingyang , Dominik Brodowski , Sasha Levin Subject: [PATCH 5.15 303/846] pcmcia: rsrc_nonstatic: Fix a NULL pointer dereference in nonstatic_find_mem_region() Date: Mon, 24 Jan 2022 19:37:00 +0100 Message-Id: <20220124184111.353215825@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184100.867127425@linuxfoundation.org> References: <20220124184100.867127425@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: stable@vger.kernel.org From: Zhou Qingyang [ Upstream commit 977d2e7c63c3d04d07ba340b39987742e3241554 ] In nonstatic_find_mem_region(), pcmcia_make_resource() is assigned to res and used in pci_bus_alloc_resource(). There a dereference of res in pci_bus_alloc_resource(), which could lead to a NULL pointer dereference on failure of pcmcia_make_resource(). Fix this bug by adding a check of res. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_PCCARD_NONSTATIC=y show no new warnings, and our static analyzer no longer warns about this code. Fixes: 49b1153adfe1 ("pcmcia: move all pcmcia_resource_ops providers into one module") Signed-off-by: Zhou Qingyang Signed-off-by: Dominik Brodowski Signed-off-by: Sasha Levin --- drivers/pcmcia/rsrc_nonstatic.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pcmcia/rsrc_nonstatic.c b/drivers/pcmcia/rsrc_nonstatic.c index 827ca6e9ee54a..1cac528707111 100644 --- a/drivers/pcmcia/rsrc_nonstatic.c +++ b/drivers/pcmcia/rsrc_nonstatic.c @@ -812,6 +812,9 @@ static struct resource *nonstatic_find_mem_region(u_long base, u_long num, unsigned long min, max; int ret, i, j; + if (!res) + return NULL; + low = low || !(s->features & SS_CAP_PAGE_REGS); data.mask = align - 1; -- 2.34.1