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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 B5832C4320D for ; Tue, 24 Sep 2019 07:36:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82DC620640 for ; Tue, 24 Sep 2019 07:36:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="0K6Ytrl/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2502735AbfIXHgZ (ORCPT ); Tue, 24 Sep 2019 03:36:25 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:43049 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388489AbfIXHgZ (ORCPT ); Tue, 24 Sep 2019 03:36:25 -0400 Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 6c2e1b8c; Tue, 24 Sep 2019 06:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=from:to:cc :subject:date:message-id:mime-version:content-transfer-encoding; s=mail; bh=sxkr1GjA+CsTQ6F9imEHmeQRp90=; b=0K6Ytrl/QEsiaO1QZr6s +K7CfH2DPbhur/Qy3RFbGxcJzXNW2ugJbMgIhVnUMpZxVpzTgMqxE3lXYyHe30ZL 4KbwsIEZthGw9zi+qowGGpxDkB2XsaictHzT8vnq1txFDdUHf/nT9QKr7V8L3xJW O9QCKE00gkivk1hykqNT3obEgyeLL4YtLg+YM4RZGecvyPQIpGVIlidG2eDQgj9a kWUEtrBG8ArIyDxwZBFv6orgP5PWAS+RoENJWt677BNh4I39wIxYmKceGrBgBaqQ HdUvSDMxb3jWLCaKfXbf67t61bGhEOLbuOA2uMXD9SBrIaNFsXS9Ua6vnLMMjfne Zw== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 6493f950 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Tue, 24 Sep 2019 06:50:47 +0000 (UTC) From: "Jason A. Donenfeld" To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "Jason A. Donenfeld" , stable@vger.kernel.org Subject: [PATCH] ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule Date: Tue, 24 Sep 2019 09:36:15 +0200 Message-Id: <20190924073615.31704-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 7d9e5f422150 removed references from certain dsts, but accounting for this never translated down into the fib6 suppression code. This bug was triggered by WireGuard users who use wg-quick(8), which uses the "suppress-prefix" directive to ip-rule(8) for routing all of their internet traffic without routing loops. The test case in the link of this commit reliably triggers various crashes due to the use-after-free caused by the reference underflow. Cc: stable@vger.kernel.org Fixes: 7d9e5f422150 ("ipv6: convert major tx path to use RT6_LOOKUP_F_DST_NOREF") Test-case: https://git.zx2c4.com/WireGuard/commit/?id=ad66532000f7a20b149e47c5eb3a957362c8e161 Signed-off-by: Jason A. Donenfeld --- net/ipv6/fib6_rules.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv6/fib6_rules.c b/net/ipv6/fib6_rules.c index d22b6c140f23..f9e8fe3ff0c5 100644 --- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -287,7 +287,8 @@ static bool fib6_rule_suppress(struct fib_rule *rule, struct fib_lookup_arg *arg return false; suppress_route: - ip6_rt_put(rt); + if (!(arg->flags & FIB_LOOKUP_NOREF)) + ip6_rt_put(rt); return true; } -- 2.21.0