From patchwork Sun May 8 13:21:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Wunderlich X-Patchwork-Id: 12842381 X-Patchwork-Delegate: kuba@kernel.org 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 8BD9EC433FE for ; Sun, 8 May 2022 13:30:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233538AbiEHNeP (ORCPT ); Sun, 8 May 2022 09:34:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233495AbiEHNeO (ORCPT ); Sun, 8 May 2022 09:34:14 -0400 Received: from simonwunderlich.de (simonwunderlich.de [23.88.38.48]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6FE2BDF92 for ; Sun, 8 May 2022 06:30:24 -0700 (PDT) Received: from kero.packetmixer.de (p200300fa271A310000945df34724C077.dip0.t-ipconnect.de [IPv6:2003:fa:271a:3100:94:5df3:4724:c077]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simonwunderlich.de (Postfix) with ESMTPSA id 4C7FAFA1FC; Sun, 8 May 2022 15:21:15 +0200 (CEST) From: Simon Wunderlich To: davem@davemloft.net, kuba@kernel.org Cc: netdev@vger.kernel.org, b.a.t.m.a.n@lists.open-mesh.org, Sven Eckelmann , Felix Kaechele , Simon Wunderlich Subject: [PATCH 1/1] batman-adv: Don't skb_split skbuffs with frag_list Date: Sun, 8 May 2022 15:21:10 +0200 Message-Id: <20220508132110.20451-2-sw@simonwunderlich.de> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220508132110.20451-1-sw@simonwunderlich.de> References: <20220508132110.20451-1-sw@simonwunderlich.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org From: Sven Eckelmann The receiving interface might have used GRO to receive more fragments than MAX_SKB_FRAGS fragments. In this case, these will not be stored in skb_shinfo(skb)->frags but merged into the frag list. batman-adv relies on the function skb_split to split packets up into multiple smaller packets which are not larger than the MTU on the outgoing interface. But this function cannot handle frag_list entries and is only operating on skb_shinfo(skb)->frags. If it is still trying to split such an skb and xmit'ing it on an interface without support for NETIF_F_FRAGLIST, then validate_xmit_skb() will try to linearize it. But this fails due to inconsistent information. And __pskb_pull_tail will trigger a BUG_ON after skb_copy_bits() returns an error. In case of entries in frag_list, just linearize the skb before operating on it with skb_split(). Reported-by: Felix Kaechele Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol") Signed-off-by: Sven Eckelmann Tested-by: Felix Kaechele Signed-off-by: Simon Wunderlich --- net/batman-adv/fragmentation.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index 0899a729a23f..c120c7c6d25f 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -475,6 +475,17 @@ int batadv_frag_send_packet(struct sk_buff *skb, goto free_skb; } + /* GRO might have added fragments to the fragment list instead of + * frags[]. But this is not handled by skb_split and must be + * linearized to avoid incorrect length information after all + * batman-adv fragments were created and submitted to the + * hard-interface + */ + if (skb_has_frag_list(skb) && __skb_linearize(skb)) { + ret = -ENOMEM; + goto free_skb; + } + /* Create one header to be copied to all fragments */ frag_header.packet_type = BATADV_UNICAST_FRAG; frag_header.version = BATADV_COMPAT_VERSION;