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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 3A8E3C43462 for ; Thu, 1 Apr 2021 17:51:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28F796115C for ; Thu, 1 Apr 2021 17:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237328AbhDARvZ (ORCPT ); Thu, 1 Apr 2021 13:51:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234817AbhDARkZ (ORCPT ); Thu, 1 Apr 2021 13:40:25 -0400 Received: from ustc.edu.cn (email6.ustc.edu.cn [IPv6:2001:da8:d800::8]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 021B1C0613AE; Thu, 1 Apr 2021 04:58:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mail.ustc.edu.cn; s=dkim; h=Received:From:To:Cc:Subject:Date: Message-Id:MIME-Version:Content-Transfer-Encoding; bh=CWklXCL+YD Y2PYR5Ag06YNYFH//f8R5Tm4EPbzqTnEU=; b=o3ghQiqfYhiAzCfXAPKmxKmsRx vIRaQkLAMkZkkiqMZBnyQrBPS69dtKc0FLZ4pSyXdlZKqExNxjFS3Cv3U0s62CC8 IBXXW5CXEtzHVRatWC34w+FAY0jlrprnxs/1ileqLUJLtHMdhPb4E4EVauIPWQcE VgC/V0ExDRBnCy5fs= Received: from ubuntu.localdomain (unknown [202.38.69.14]) by newmailweb.ustc.edu.cn (Coremail) with SMTP id LkAmygCHjaVFtWVgWIeBAA--.1831S4; Thu, 01 Apr 2021 19:57:57 +0800 (CST) From: Lv Yunlong To: philipp.reisner@linbit.com, lars.ellenberg@linbit.com, axboe@kernel.dk Cc: drbd-dev@lists.linbit.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, Lv Yunlong Subject: [PATCH] drbd: Fix a use after free in get_initial_state Date: Thu, 1 Apr 2021 04:57:53 -0700 Message-Id: <20210401115753.3684-1-lyl2019@mail.ustc.edu.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: LkAmygCHjaVFtWVgWIeBAA--.1831S4 X-Coremail-Antispam: 1UD129KBjvJXoW7tryDJrWDJFW8KFWkGF43Awb_yoW8Xr4fpa yUW3sIkFs8Ka18uFy3Kw18ZF909a1kGr9xGrWjq343AFnxtrn3Za40yFWYyFWFkr9xGF4r t3W2vw1DGayDK3DanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUvl14x267AKxVW8JVW5JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26F1j6w1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAac4AC62xK8xCEY4vEwIxC4wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC 0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr 1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IE rcIFxwCY02Avz4vE14v_Gw4l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr 1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE 14v26r126r1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7 IYx2IY6xkF7I0E14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvE x4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvj DU0xZFpf9x0JUDb1bUUUUU= X-CM-SenderInfo: ho1ojiyrz6zt1loo32lwfovvfxof0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In get_initial_state, it calls notify_initial_state_done(skb,..) if cb->args[5]==1. I see that if genlmsg_put() failed in notify_initial_state_done(), the skb will be freed by nlmsg_free(skb). Then get_initial_state will goto out and the freed skb will be used by return value skb->len. My patch lets skb_len = skb->len and return the skb_len to avoid the uaf. Fixes: a29728463b254 ("drbd: Backport the "events2" command") Signed-off-by: Lv Yunlong --- drivers/block/drbd/drbd_nl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c index bf7de4c7b96c..474f84675d0a 100644 --- a/drivers/block/drbd/drbd_nl.c +++ b/drivers/block/drbd/drbd_nl.c @@ -4905,6 +4905,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) struct drbd_state_change *state_change = (struct drbd_state_change *)cb->args[0]; unsigned int seq = cb->args[2]; unsigned int n; + unsigned int skb_len = skb->len; enum drbd_notification_type flags = 0; /* There is no need for taking notification_mutex here: it doesn't @@ -4915,7 +4916,7 @@ static int get_initial_state(struct sk_buff *skb, struct netlink_callback *cb) cb->args[5]--; if (cb->args[5] == 1) { notify_initial_state_done(skb, seq); - goto out; + return skb_len; } n = cb->args[4]++; if (cb->args[4] < cb->args[3]) -- 2.25.1