From patchwork Thu Mar 19 13:00:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 228948 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, URIBL_BLOCKED, 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 6A66FC4332E for ; Thu, 19 Mar 2020 13:37:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 423F920789 for ; Thu, 19 Mar 2020 13:37:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584625034; bh=PXYai1ZiJAgW5vL3Zh/m08qdMjBroO5ouphz7+nA/oI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Vie1/CXp9buCXOVJxhyncodZVcOqJCI/VXoz9j6qo1e7wCnTVhbEoX2jcHz88JOX/ ytlwcozl2MbZ3HjfFFzD7P2ug2A5zdJnrLEBuh60PXY14YyWBeh2snGl6TpeGM2yM0 CMZLikj39IYjLIVdKwReLR7R2rFn5tBk9L/eRxJk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727460AbgCSNhI (ORCPT ); Thu, 19 Mar 2020 09:37:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:52664 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727417AbgCSNI3 (ORCPT ); Thu, 19 Mar 2020 09:08:29 -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 47EFB20789; Thu, 19 Mar 2020 13:08:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584623308; bh=PXYai1ZiJAgW5vL3Zh/m08qdMjBroO5ouphz7+nA/oI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U0MhjwdQyoq9ifv6rbKAEPJYaZkHp2zValX5aOtRbqkqx0BDbAG3zqr314mq+xRoY UobdhL6wAbGiroiXBOLcAyRwWlkZIkM1RTD2f0oNpaoL7YmnfM2Jb0aSMWVCdqKLL2 6W27gE+m51a3BfrCz+lCy+qtOBgPja0adHphQ9LU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Sven Eckelmann , Simon Wunderlich Subject: [PATCH 4.4 62/93] batman-adv: Fix double free during fragment merge error Date: Thu, 19 Mar 2020 14:00:06 +0100 Message-Id: <20200319123944.598841370@linuxfoundation.org> X-Mailer: git-send-email 2.25.2 In-Reply-To: <20200319123924.795019515@linuxfoundation.org> References: <20200319123924.795019515@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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: Sven Eckelmann Signed-off-by: Greg Kroah-Hartman --- net/batman-adv/fragmentation.c | 6 ++++-- net/batman-adv/routing.c | 6 ++++++ 2 files changed, 10 insertions(+), 2 deletions(-) --- 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_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 @@ -1053,6 +1053,12 @@ 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;