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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,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 4CF4BC433E0 for ; Tue, 9 Jun 2020 00:38:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29DA1206C3 for ; Tue, 9 Jun 2020 00:38:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591663109; bh=X7FpV+JC98CvjiH85Qi4hqa20p22Tnz7RmdeG4ZzTk0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=GxfgKyz9lzgDXU1MAbEy9hQ8Vp/gNeQhwuBWdpJKhiOYTT5sfaH/+J1o0Lg7EOINg TpA7+Jb90t24LKxCMWSHLrVdMRyzYPq0U0iGBiWvnVyvt/HPNfwnYxYYaJl0C+ELVr Nkv7r8KESQjYQucKraT1P8exAZ4tor3upxfjpYls= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728646AbgFIAh7 (ORCPT ); Mon, 8 Jun 2020 20:37:59 -0400 Received: from mail.kernel.org ([198.145.29.99]:33398 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729520AbgFHXNe (ORCPT ); Mon, 8 Jun 2020 19:13:34 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 15C1C21508; Mon, 8 Jun 2020 23:13:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658014; bh=X7FpV+JC98CvjiH85Qi4hqa20p22Tnz7RmdeG4ZzTk0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=brrh6MaN1SdjZ2qD9RdMS0e+NQ7k91InovUL1ntk0OlZIxahNmBA/0F6FxCGLvrYu 8TEAn4Akjp2r5w0ebCdYoiMT5xSXrGyki+hbBEzqr45Fs2oRL2mEbCJldchNlOLAGi aMzQzOS5P/ZpQnBysyN2ULdmQ3Mt3hprzoRNXHh4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Xiyu Yang , Xin Tan , Daniel Borkmann , Jakub Sitnicki , Greg Kroah-Hartman , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 068/606] bpf: Fix sk_psock refcnt leak when receiving message Date: Mon, 8 Jun 2020 19:03:13 -0400 Message-Id: <20200608231211.3363633-68-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Xiyu Yang commit 18f02ad19e2c2a1d9e1d55a4e1c0cbf51419151c upstream. tcp_bpf_recvmsg() invokes sk_psock_get(), which returns a reference of the specified sk_psock object to "psock" with increased refcnt. When tcp_bpf_recvmsg() returns, local variable "psock" becomes invalid, so the refcount should be decreased to keep refcount balanced. The reference counting issue happens in several exception handling paths of tcp_bpf_recvmsg(). When those error scenarios occur such as "flags" includes MSG_ERRQUEUE, the function forgets to decrease the refcnt increased by sk_psock_get(), causing a refcnt leak. Fix this issue by calling sk_psock_put() or pulling up the error queue read handling when those error scenarios occur. Fixes: e7a5f1f1cd000 ("bpf/sockmap: Read psock ingress_msg before sk_receive_queue") Signed-off-by: Xiyu Yang Signed-off-by: Xin Tan Signed-off-by: Daniel Borkmann Reviewed-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/1587872115-42805-1-git-send-email-xiyuyang19@fudan.edu.cn Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_bpf.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 19bd10e6ab83..69b025408390 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -121,14 +121,17 @@ int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, struct sk_psock *psock; int copied, ret; + if (unlikely(flags & MSG_ERRQUEUE)) + return inet_recv_error(sk, msg, len, addr_len); + psock = sk_psock_get(sk); if (unlikely(!psock)) return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); - if (unlikely(flags & MSG_ERRQUEUE)) - return inet_recv_error(sk, msg, len, addr_len); if (!skb_queue_empty(&sk->sk_receive_queue) && - sk_psock_queue_empty(psock)) + sk_psock_queue_empty(psock)) { + sk_psock_put(sk, psock); return tcp_recvmsg(sk, msg, len, nonblock, flags, addr_len); + } lock_sock(sk); msg_bytes_ready: copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags); -- 2.25.1