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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,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 55ACBC48BE5 for ; Mon, 21 Jun 2021 16:17:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41BA161001 for ; Mon, 21 Jun 2021 16:17:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230512AbhFUQTX (ORCPT ); Mon, 21 Jun 2021 12:19:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:39350 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230454AbhFUQTP (ORCPT ); Mon, 21 Jun 2021 12:19:15 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id D3D90611BD; Mon, 21 Jun 2021 16:16:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1624292220; bh=sSqpAn7G0ikQJoVp8p7II5Rh1NHr2QgcB5MqOwTUOHc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rQr7ymdGoo0lBnwU1rT+t1sWtgdLdpTJawaTYhQLe9LFAGx33mXMMZ08n1otlvke8 vVbzp5XZffoMKp62r3fV4y5hj6e3YZzNJY+RG5ASNE5dIKhFJKxvqO6ujgHlkOnze8 Yv4LCWyAh0v84MapPmfJcmPk/8W1nAjHbjHo2rFU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Skripkin , =?UTF-8?q?H=C3=A5kon=20Bugge?= , Santosh Shilimkar , "David S. Miller" , Sasha Levin , syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com Subject: [PATCH 5.4 10/90] net: rds: fix memory leak in rds_recvmsg Date: Mon, 21 Jun 2021 18:14:45 +0200 Message-Id: <20210621154904.498202287@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210621154904.159672728@linuxfoundation.org> References: <20210621154904.159672728@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pavel Skripkin [ Upstream commit 49bfcbfd989a8f1f23e705759a6bb099de2cff9f ] Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | } Fixes: bdbe6fbc6a2f ("RDS: recv.c") Reported-and-tested-by: syzbot+5134cdf021c4ed5aaa5f@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Reviewed-by: Håkon Bugge Acked-by: Santosh Shilimkar Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/rds/recv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rds/recv.c b/net/rds/recv.c index aba4afe4dfed..967d115f97ef 100644 --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -714,7 +714,7 @@ int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; - goto out; + break; } rds_recvmsg_zcookie(rs, msg); -- 2.30.2