From patchwork Fri Jun 25 10:23:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Skripkin X-Patchwork-Id: 467313 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, 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 86D6FC2B9F4 for ; Fri, 25 Jun 2021 10:24:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60ACE61434 for ; Fri, 25 Jun 2021 10:24:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231193AbhFYK0W (ORCPT ); Fri, 25 Jun 2021 06:26:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229956AbhFYK0V (ORCPT ); Fri, 25 Jun 2021 06:26:21 -0400 Received: from mail-lf1-x129.google.com (mail-lf1-x129.google.com [IPv6:2a00:1450:4864:20::129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D81BC061574; Fri, 25 Jun 2021 03:24:00 -0700 (PDT) Received: by mail-lf1-x129.google.com with SMTP id d16so15437219lfn.3; Fri, 25 Jun 2021 03:24:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=mA4MK7Qr8XHELuEKqiootlu+LOQg/7ijOx7HOstIiJ4=; b=FLY+8QuEnlw0aXi+0Z/K7u5MBSA0emdjGCxiSFOOVOx2UVbkAHwOaSlJXeSRa+QfEQ HSCg/CclfLPIw2ldxVHDTHF+mmp7fm9xP9f1jULV6hPMYnVMa8uWjSfnv+dNilsMlJ/l f6yBKMPBH0PSiDgAP6Y3fdUVJDeh175EJZJ/HGkpLbZaN2oW1ZoDbBqnMKUny2npK9Xj 6oIJx/lWCgXvpP1/359x7/HCQ6OzrNYMm77NUbglvFLSNW7Y3FF5cWLUc9F3q6tz100H H1XLmoFbFcETuGCKB9yrkak+vK9oESwEcU9OhJoTjzFL7tH8uxbs9M32wdRgJnuYkbSn M7wQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=mA4MK7Qr8XHELuEKqiootlu+LOQg/7ijOx7HOstIiJ4=; b=WjC3blmLvC6VzZoJef2n5P86tm9CSxeYr5+E4rwGJBK93SwofjcQ9NCkxglLqqY+VF reMXL5ci69qNXXyhjaAjZdNmxVr1HLS61DcLoowVQ5lHiDyuSwsrO9rfuUZ1DgYO5UH5 8gGd/4aF9QB2FAp6hzOU8RBBIpXhyN6T0IZ4/vIKKQjfehbOUrcrsAph/0CpTjJa3kop uu2TyO7wVeh8EyX7NBGUz39xFTfz0GwPVsfVgVfde9RqodrPmczRvnyQAQwgQZ5LluEk iEhRf0hjKRkjMcsEC28rBtRqlu4xK8y/cAgMLkYODKiU+Cdo31eKrCudYmtRHqK0KH/r UbTg== X-Gm-Message-State: AOAM5311d5+n+LueeNOU5VjylpXidGGPPHqMynJXW/SuqF1m6gFX3Jg0 dQ3UyYMdrA0YwA4J5qwRat2TVUWpA3RfIw== X-Google-Smtp-Source: ABdhPJzP8BIojsyjcuITH5Yh5F7FsZh5MrEOdEg7PEgv+7lhTdVafj4BjC5luipLHqpCvczgohsedw== X-Received: by 2002:a19:650f:: with SMTP id z15mr7471186lfb.511.1624616638682; Fri, 25 Jun 2021 03:23:58 -0700 (PDT) Received: from localhost.localdomain ([94.103.225.155]) by smtp.gmail.com with ESMTPSA id f13sm474904lfc.157.2021.06.25.03.23.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 25 Jun 2021 03:23:58 -0700 (PDT) From: Pavel Skripkin To: steffen.klassert@secunet.com, herbert@gondor.apana.org.au, davem@davemloft.net, 0x7f454c46@gmail.com Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kernel-mentees@lists.linuxfoundation.org, Pavel Skripkin , syzbot+fb347cf82c73a90efcca@syzkaller.appspotmail.com Subject: [PATCH] net: xfrm: fix memory leak in xfrm_user_rcv_msg Date: Fri, 25 Jun 2021 13:23:54 +0300 Message-Id: <20210625102354.18266-1-paskripkin@gmail.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Syzbot reported memory leak in xfrm_user_rcv_msg(). The problem was is non-freed skb's frag_list. In skb_release_all() skb_release_data() will be called only in case of skb->head != NULL, but netlink_skb_destructor() sets head to NULL. So, allocated frag_list skb should be freed manualy, since consume_skb() won't take care of it Fixes: 5106f4a8acff ("xfrm/compat: Add 32=>64-bit messages translator") Reported-and-tested-by: syzbot+fb347cf82c73a90efcca@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin --- One thing I'm not sure about is did I choose the rigth place to free this skb, maybe we can move this clean up a little bit deeper, like in xfrm_alloc_userspi()? --- net/xfrm/xfrm_user.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index f0aecee4d539..ff60ff804074 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2811,6 +2811,16 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, err = link->doit(skb, nlh, attrs); + /* We need to free skb allocated in xfrm_alloc_compat() before + * returning from this function, because consume_skb() won't take + * care of frag_list since netlink destructor sets + * sbk->head to NULL. (see netlink_skb_destructor()) + */ + if (skb_has_frag_list(skb)) { + kfree_skb(skb_shinfo(skb)->frag_list); + skb_shinfo(skb)->frag_list = NULL; + } + err: kvfree(nlh64); return err;