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 E2921C07E9D for ; Mon, 26 Sep 2022 13:29:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235370AbiIZN3t (ORCPT ); Mon, 26 Sep 2022 09:29:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235452AbiIZN2w (ORCPT ); Mon, 26 Sep 2022 09:28:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2DB81DB548; Mon, 26 Sep 2022 04:53:13 -0700 (PDT) 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 06F7460D30; Mon, 26 Sep 2022 10:37:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 094EBC43470; Mon, 26 Sep 2022 10:37:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1664188636; bh=oltk1OjiNQorMNCdlqIIDzftepr4ZhS75pVgiLfx544=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rcrG1LL4bw5KBHZVqQeveDNYS3bAKWg1dXx0PRYxJ+lxAwwSWdumeT+wJrivn2nJZ 2vR2YXWgzWVDyZT0XrMwRbDrxE0B5USvAFn13pc/+072Fex5pZdmelA+TN92F7ieGg HMyTcalAkMg9RsrwzEXfaQRy5CJ3a/Ir/D5Uwcas= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ludovic Cintrat , "David S. Miller" , Sasha Levin Subject: [PATCH 5.15 072/148] net: core: fix flow symmetric hash Date: Mon, 26 Sep 2022 12:11:46 +0200 Message-Id: <20220926100758.733849813@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220926100756.074519146@linuxfoundation.org> References: <20220926100756.074519146@linuxfoundation.org> User-Agent: quilt/0.67 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: Ludovic Cintrat [ Upstream commit 64ae13ed478428135cddc2f1113dff162d8112d4 ] __flow_hash_consistentify() wrongly swaps ipv4 addresses in few cases. This function is indirectly used by __skb_get_hash_symmetric(), which is used to fanout packets in AF_PACKET. Intrusion detection systems may be impacted by this issue. __flow_hash_consistentify() computes the addresses difference then swaps them if the difference is negative. In few cases src - dst and dst - src are both negative. The following snippet mimics __flow_hash_consistentify(): ``` #include #include int main(int argc, char** argv) { int diffs_d, diffd_s; uint32_t dst = 0xb225a8c0; /* 178.37.168.192 --> 192.168.37.178 */ uint32_t src = 0x3225a8c0; /* 50.37.168.192 --> 192.168.37.50 */ uint32_t dst2 = 0x3325a8c0; /* 51.37.168.192 --> 192.168.37.51 */ diffs_d = src - dst; diffd_s = dst - src; printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n", src, dst, diffs_d, diffs_d, diffd_s, diffd_s); diffs_d = src - dst2; diffd_s = dst2 - src; printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n", src, dst2, diffs_d, diffs_d, diffd_s, diffd_s); return 0; } ``` Results: src:3225a8c0 dst:b225a8c0, \ diff(s-d)=-2147483648(0x80000000) \ diff(d-s)=-2147483648(0x80000000) src:3225a8c0 dst:3325a8c0, \ diff(s-d)=-16777216(0xff000000) \ diff(d-s)=16777216(0x1000000) In the first case the addresses differences are always < 0, therefore __flow_hash_consistentify() always swaps, thus dst->src and src->dst packets have differents hashes. Fixes: c3f8324188fa8 ("net: Add full IPv6 addresses to flow_keys") Signed-off-by: Ludovic Cintrat Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/core/flow_dissector.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index bc50bd331d5b..1c34e2266578 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1519,9 +1519,8 @@ static inline void __flow_hash_consistentify(struct flow_keys *keys) switch (keys->control.addr_type) { case FLOW_DISSECTOR_KEY_IPV4_ADDRS: - addr_diff = (__force u32)keys->addrs.v4addrs.dst - - (__force u32)keys->addrs.v4addrs.src; - if (addr_diff < 0) + if ((__force u32)keys->addrs.v4addrs.dst < + (__force u32)keys->addrs.v4addrs.src) swap(keys->addrs.v4addrs.src, keys->addrs.v4addrs.dst); if ((__force u16)keys->ports.dst < -- 2.35.1