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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 97547C4332E for ; Thu, 19 Mar 2020 13:11:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EBA320722 for ; Thu, 19 Mar 2020 13:11:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623514; bh=If8LOuZuwFEjouDXrY7qAUXtG8O0r9olz6X8s3nhxu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=s5ag8wYJJR7/BGQvnRG7WKsEZRgXnM5q5PJfLhjvtsamaQUDA67qFKG35rXH68mJR HUPSdxLYEHFDSfV7LlDeSkMADVnGSrFiFOdOVe5CbPRLC0kz8DzijmU9hXInYbGpVm XI3I1FVCo7vLOZDUQZBAFUsdAHDRzD+HhVV7voaM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728792AbgCSNLx (ORCPT ); Thu, 19 Mar 2020 09:11:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:57284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728219AbgCSNLt (ORCPT ); Thu, 19 Mar 2020 09:11:49 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7908A20722; Thu, 19 Mar 2020 13:11:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623508; bh=If8LOuZuwFEjouDXrY7qAUXtG8O0r9olz6X8s3nhxu8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tZI/AXDRcqFSXBGc3HvrNV3w9IlV/vdFmayqAlEcc+8lhgQaEnRa2/NLSBhI1Q7cf 9nwvr90K67N5yXI910I/N1jnUEDlHCisd0MaPtWaLfQPDbAEUE4U8eIjQ5OpIOAAsE 0HqdwpgCjWHNCZmcmIpzxEBhQgO3IRanE0z8kL+4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.9 51/90] batman-adv: Fix double free during fragment merge error Date: Thu, 19 Mar 2020 14:00:13 +0100 Message-Id: <20200319123944.264971850@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123928.635114118@linuxfoundation.org> References: <20200319123928.635114118@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sven Eckelmann 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: Greg Kroah-Hartman --- net/batman-adv/fragmentation.c | 8 +++++--- net/batman-adv/routing.c | 6 ++++++ 2 files changed, 11 insertions(+), 3 deletions(-) --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -232,8 +232,10 @@ err_unlock: spin_unlock_bh(&chain->lock); err: - if (!ret) + if (!ret) { kfree(frag_entry_new); + kfree_skb(skb); + } return ret; } @@ -305,7 +307,7 @@ free: * * There are three possible outcomes: 1) Packet is merged: Return true and * set *skb to merged packet; 2) Packet is buffered: Return true and set *skb - * to NULL; 3) Error: Return false and leave skb as is. + * to NULL; 3) Error: Return false and free skb. * * Return: true when packet is merged or buffered, false when skb is not not * used. @@ -330,9 +332,9 @@ bool batadv_frag_skb_buffer(struct sk_bu goto out_err; out: - *skb = skb_out; ret = true; out_err: + *skb = skb_out; return ret; } --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -1080,6 +1080,12 @@ int batadv_recv_frag_packet(struct sk_bu 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;