From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751917AbeDHHUm (ORCPT ); Sun, 8 Apr 2018 03:20:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:41151 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751524AbeDHHUl (ORCPT ); Sun, 8 Apr 2018 03:20:41 -0400 From: Takashi Iwai To: Andrew Morton Cc: Ram Pai , Bjorn Helgaas , Michael Henders , linux-kernel@vger.kernel.org Subject: [PATCH v2] resource: Fix integer overflow at reallocation Date: Sun, 8 Apr 2018 09:20:26 +0200 Message-Id: <20180408072026.27365-1-tiwai@suse.de> X-Mailer: git-send-email 2.16.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We've got a bug report indicating a kernel panic at booting on an x86-32 system, and it turned out to be the invalid resource assigned after PCI resource reallocation. __find_resource() first aligns the resource start address and resets the end address with start+size-1 accordingly, then checks whether it's contained. Here the end address may overflow the integer, although resource_contains() still returns true because the function validates only start and end address. So this ends up with returning an invalid resource (start > end). There was already an attempt to cover such a problem in the commit 47ea91b4052d ("Resource: fix wrong resource window calculation"), but this case is an overseen one. This patch adds the validity check in resource_contains() to see whether the given resource has a valid range for avoiding the integer overflow problem. Bugzilla: http://bugzilla.opensuse.org/show_bug.cgi?id=1086739 Fixes: 23c570a67448 ("resource: ability to resize an allocated resource") Reported-and-tested-by: Michael Henders Reviewed-by: Ram Pai Cc: Signed-off-by: Takashi Iwai --- Andrew, could you pick this? It's still in a wild west... Thanks! v1->v2: check in resource_contains() instead of in __find_resource() include/linux/ioport.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/ioport.h b/include/linux/ioport.h index da0ebaec25f0..466d7be046eb 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -212,6 +212,9 @@ static inline bool resource_contains(struct resource *r1, struct resource *r2) return false; if (r1->flags & IORESOURCE_UNSET || r2->flags & IORESOURCE_UNSET) return false; + /* sanity check whether it's a valid resource range */ + if (r2->end < r2->start) + return false; return r1->start <= r2->start && r1->end >= r2->end; } -- 2.16.3