From patchwork Tue Mar 17 23:27:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sven Eckelmann X-Patchwork-Id: 229168 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=-9.9 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,USER_AGENT_GIT autolearn=ham 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 27CBCC1975A for ; Tue, 17 Mar 2020 23:28:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDAB520738 for ; Tue, 17 Mar 2020 23:28:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=narfation.org header.i=@narfation.org header.b="xgvvUfo5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727136AbgCQX2I (ORCPT ); Tue, 17 Mar 2020 19:28:08 -0400 Received: from dvalin.narfation.org ([213.160.73.56]:53786 "EHLO dvalin.narfation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727071AbgCQX2I (ORCPT ); Tue, 17 Mar 2020 19:28:08 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=narfation.org; s=20121; t=1584487686; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=62DBp7+DAaVNKLZZN0SVrqWdYTSfNttg2+6dYKFYf3A=; b=xgvvUfo5Mlz0+RmStm2aSvcwHZ2CxtBCiaE2OzMKJVbUNMPGZPVzowwjYLNzKh14EK66Sm eH4PSof/qtTvq57YOY6T6XWnP9UeC6aVkqYt2knn+mGjtBS9FShqUvR4GHunc+3d6suiS/ PzYSg56cMFwt2WcCJoeICBLfOtU3Wjc= From: Sven Eckelmann To: stable@vger.kernel.org Cc: Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.4 25/48] batman-adv: Fix double free during fragment merge error Date: Wed, 18 Mar 2020 00:27:11 +0100 Message-Id: <20200317232734.6127-26-sven@narfation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200317232734.6127-1-sven@narfation.org> References: <20200317232734.6127-1-sven@narfation.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org commit 248e23b50e2da0753f3b5faa068939cbe9f8a75a upstream. The function batadv_frag_skb_buffer was supposed not to consume the skbuff on errors. This was followed in the helper function batadv_frag_insert_packet when the skb would potentially be inserted in the fragment queue. But it could happen that the next helper function batadv_frag_merge_packets would try to merge the fragments and fail. This results in a kfree_skb of all the enqueued fragments (including the just inserted one). batadv_recv_frag_packet would detect the error in batadv_frag_skb_buffer and try to free the skb again. The behavior of batadv_frag_skb_buffer (and its helper batadv_frag_insert_packet) must therefore be changed to always consume the skbuff to have a common behavior and avoid the double kfree_skb. Fixes: 610bfc6bc99b ("batman-adv: Receive fragmented packets and merge") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich Signed-off-by: Sven Eckelmann --- net/batman-adv/fragmentation.c | 6 ++++-- net/batman-adv/routing.c | 6 ++++++ 2 files changed, 10 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index d50c3b003dc9..8605e3c7958d 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -233,8 +233,10 @@ err_unlock: spin_unlock_bh(&chain->lock); err: - if (!ret) + if (!ret) { kfree(frag_entry_new); + kfree_skb(skb); + } return ret; } @@ -329,9 +331,9 @@ bool batadv_frag_skb_buffer(struct sk_buff **skb, goto out_err; out: - *skb = skb_out; ret = true; out_err: + *skb = skb_out; return ret; } diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 39b4c6ab3e71..6c3dfd65023f 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -1053,6 +1053,12 @@ int batadv_recv_frag_packet(struct sk_buff *skb, batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_RX); batadv_add_counter(bat_priv, BATADV_CNT_FRAG_RX_BYTES, skb->len); + /* batadv_frag_skb_buffer will always consume the skb and + * the caller should therefore never try to free the + * skb after this point + */ + ret = NET_RX_SUCCESS; + /* Add fragment to buffer and merge if possible. */ if (!batadv_frag_skb_buffer(&skb, orig_node_src)) goto out;