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,URIBL_BLOCKED,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 9F6B0C433E0 for ; Mon, 18 May 2020 18:07:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7777220884 for ; Mon, 18 May 2020 18:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589825244; bh=JnO/HTljguYyDlXacpcME3iHeEzv1y1UnnpJKpBEuR0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ih7mLhzpWWaQauDfUNfdFXhaSpow8JhnuOECjDNUpOGGCGVFjvyz7k7eU0jE1Us0O mEWYFb/EmG0aC6vCtt45KubixMG2xTglCIiN/aIMJv93SnZHaVzRMyVZZnBOVNOUp3 rW7JJteanGVbGiNPKsPfLjrDIZx8Qc+ulsyteUWc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733306AbgERSHY (ORCPT ); Mon, 18 May 2020 14:07:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:55988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733292AbgERSHR (ORCPT ); Mon, 18 May 2020 14:07:17 -0400 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 BD3D320873; Mon, 18 May 2020 18:07:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589825237; bh=JnO/HTljguYyDlXacpcME3iHeEzv1y1UnnpJKpBEuR0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mnrneoC7mOaGnzhlq5yYola4HXhteJLWsT+2aK/n415sRcINgKf5t4GgkG5GjOtYJ EE90sYwGycPc1VQt0boFQr+oqTVqHk++pZNk1XB2GT+NzjYRq6cCF2lS16cj4vDL7M REAtwcyCatFLS/ysPyscA7kGGU6TqB868FsFGRwo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Xiyu Yang , Xin Tan , Daniel Borkmann , Jakub Sitnicki Subject: [PATCH 5.6 184/194] bpf: Fix sk_psock refcnt leak when receiving message Date: Mon, 18 May 2020 19:37:54 +0200 Message-Id: <20200518173546.791738129@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173531.455604187@linuxfoundation.org> References: <20200518173531.455604187@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: 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(-) --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -121,14 +121,17 @@ int tcp_bpf_recvmsg(struct sock *sk, str 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);