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 25BE0C433F5 for ; Mon, 14 Feb 2022 09:29:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243248AbiBNJ3T (ORCPT ); Mon, 14 Feb 2022 04:29:19 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:41256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243079AbiBNJ3B (ORCPT ); Mon, 14 Feb 2022 04:29:01 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 50E2D60AAF; Mon, 14 Feb 2022 01:28:54 -0800 (PST) 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 E107160F87; Mon, 14 Feb 2022 09:28:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A4135C340E9; Mon, 14 Feb 2022 09:28:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1644830933; bh=De5s6O1Q/mpgBB7MSS/zLALmsk1o5Msqf9qPTvT22tM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KmlyN04+IyMnt/fLbuzBm8oQIxzWfjB6Oq/NErOrXQPTz/ZXYuvSNqarmULwjZs8l cMMVIDW5tTtYEpLA3TUcSqeS2rGWaAYFeRonA9HzjIBlZiknnc3Ffz3hJS4pHgB5Zs SFbXn5gS3YhYmSgfnZItQ7hhZ8u9aGivAMuHEVuk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paolo Abeni , Vlad Buslov , Antoine Tenart , "David S. Miller" , Sasha Levin Subject: [PATCH 4.9 19/34] net: do not keep the dst cache when uncloning an skb dst and its metadata Date: Mon, 14 Feb 2022 10:25:45 +0100 Message-Id: <20220214092446.567775131@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220214092445.946718557@linuxfoundation.org> References: <20220214092445.946718557@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: Antoine Tenart [ Upstream commit cfc56f85e72f5b9c5c5be26dc2b16518d36a7868 ] When uncloning an skb dst and its associated metadata a new dst+metadata is allocated and the tunnel information from the old metadata is copied over there. The issue is the tunnel metadata has references to cached dst, which are copied along the way. When a dst+metadata refcount drops to 0 the metadata is freed including the cached dst entries. As they are also referenced in the initial dst+metadata, this ends up in UaFs. In practice the above did not happen because of another issue, the dst+metadata was never freed because its refcount never dropped to 0 (this will be fixed in a subsequent patch). Fix this by initializing the dst cache after copying the tunnel information from the old metadata to also unshare the dst cache. Fixes: d71785ffc7e7 ("net: add dst_cache to ovs vxlan lwtunnel") Cc: Paolo Abeni Reported-by: Vlad Buslov Tested-by: Vlad Buslov Signed-off-by: Antoine Tenart Acked-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- include/net/dst_metadata.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/include/net/dst_metadata.h b/include/net/dst_metadata.h index 5a23535a5018d..33ca53057f318 100644 --- a/include/net/dst_metadata.h +++ b/include/net/dst_metadata.h @@ -97,6 +97,19 @@ static inline struct metadata_dst *tun_dst_unclone(struct sk_buff *skb) memcpy(&new_md->u.tun_info, &md_dst->u.tun_info, sizeof(struct ip_tunnel_info) + md_size); +#ifdef CONFIG_DST_CACHE + /* Unclone the dst cache if there is one */ + if (new_md->u.tun_info.dst_cache.cache) { + int ret; + + ret = dst_cache_init(&new_md->u.tun_info.dst_cache, GFP_ATOMIC); + if (ret) { + metadata_dst_free(new_md); + return ERR_PTR(ret); + } + } +#endif + skb_dst_drop(skb); dst_hold(&new_md->dst); skb_dst_set(skb, &new_md->dst); -- 2.34.1