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 2236EC43219 for ; Mon, 24 Jan 2022 19:26:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350717AbiAXTZO (ORCPT ); Mon, 24 Jan 2022 14:25:14 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:45504 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343689AbiAXTQX (ORCPT ); Mon, 24 Jan 2022 14:16:23 -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 dfw.source.kernel.org (Postfix) with ESMTPS id EF7A56131E; Mon, 24 Jan 2022 19:16:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAE33C340E5; Mon, 24 Jan 2022 19:16:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643051782; bh=FFc92ucDMk1pQ5zu/eaB0zb0C06jywc23rLv9Ce6chs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qAd2QmHKvqEZpJU+pt0u5MOMHeDsu4St9UlWL3O5/rgdU95VelllKkqsYTubYQcCC MgHJ3H1q+2PMQYUKzRqki1cM6SS4Pjrc0L08UJlvhQYOODE8p5SPNpN7IrIfHuufTz zYcd2wQlXZxsVd4Rc38QPDWobERZYWVyRLUR6Hn0= 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 4.19 086/239] pcmcia: rsrc_nonstatic: Fix a NULL pointer dereference in nonstatic_find_mem_region() Date: Mon, 24 Jan 2022 19:42:04 +0100 Message-Id: <20220124183945.853766473@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124183943.102762895@linuxfoundation.org> References: <20220124183943.102762895@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: 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 5cb29d6951df2..123420cac6b54 100644 --- a/drivers/pcmcia/rsrc_nonstatic.c +++ b/drivers/pcmcia/rsrc_nonstatic.c @@ -815,6 +815,9 @@ 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