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 541FDC33CB6 for ; Thu, 16 Jan 2020 23:46:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 19667206B7 for ; Thu, 16 Jan 2020 23:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579218376; bh=tSTT7czsVqE67MSHd+OyLSOcwk2po/pfGgxNVwE0rG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=RVm5mq69i2vWJnjSx18qdC90xkqGZ8UcDv7bpJCjOT6/D+7jdpmkQiC45IW0gQfhQ Wa1UjfKQKANadkvpeDvbzXM/IaDqFtnFeQBBp+uEKn+RQpTQDNW3vpHzOYXA8fChPV Ylbw/2pp1mAST1c6pMDBrTIQd2dEuQQCdrCPh6Ug= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391993AbgAPXqP (ORCPT ); Thu, 16 Jan 2020 18:46:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:49974 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390905AbgAPXWN (ORCPT ); Thu, 16 Jan 2020 18:22:13 -0500 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 11D3C2073A; Thu, 16 Jan 2020 23:22:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579216932; bh=tSTT7czsVqE67MSHd+OyLSOcwk2po/pfGgxNVwE0rG4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=PHYzm8UNtl16EINndx6QYrZms6VX6R1sCpJgbhRPUiCT7q2KFzMECmlVQ59JaQD2e PN48xhELSsBDgBVvFF0z/cPYohnA9aQcQItCqcsQ5favOj5jA8EGZfi0ONe9aIHyqM +R84ruSgTs2EcN2WythxYxMjKibIEPdDAYqdOTwc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , John Fastabend , "David S. Miller" Subject: [PATCH 5.4 079/203] bpf: skmsg, fix potential psock NULL pointer dereference Date: Fri, 17 Jan 2020 00:16:36 +0100 Message-Id: <20200116231751.508994827@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200116231745.218684830@linuxfoundation.org> References: <20200116231745.218684830@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: John Fastabend commit 8163999db445021f2651a8a47b5632483e8722ea upstream. Report from Dan Carpenter, net/core/skmsg.c:792 sk_psock_write_space() error: we previously assumed 'psock' could be null (see line 790) net/core/skmsg.c 789 psock = sk_psock(sk); 790 if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))) Check for NULL 791 schedule_work(&psock->work); 792 write_space = psock->saved_write_space; ^^^^^^^^^^^^^^^^^^^^^^^^ 793 rcu_read_unlock(); 794 write_space(sk); Ensure psock dereference on line 792 only occurs if psock is not null. Reported-by: Dan Carpenter Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: John Fastabend Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/skmsg.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/net/core/skmsg.c +++ b/net/core/skmsg.c @@ -793,15 +793,18 @@ static void sk_psock_strp_data_ready(str static void sk_psock_write_space(struct sock *sk) { struct sk_psock *psock; - void (*write_space)(struct sock *sk); + void (*write_space)(struct sock *sk) = NULL; rcu_read_lock(); psock = sk_psock(sk); - if (likely(psock && sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED))) - schedule_work(&psock->work); - write_space = psock->saved_write_space; + if (likely(psock)) { + if (sk_psock_test_state(psock, SK_PSOCK_TX_ENABLED)) + schedule_work(&psock->work); + write_space = psock->saved_write_space; + } rcu_read_unlock(); - write_space(sk); + if (write_space) + write_space(sk); } int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)