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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 D4A74C433DF for ; Fri, 29 May 2020 09:05:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B954F206C3 for ; Fri, 29 May 2020 09:05:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725795AbgE2JFT (ORCPT ); Fri, 29 May 2020 05:05:19 -0400 Received: from out30-45.freemail.mail.aliyun.com ([115.124.30.45]:53928 "EHLO out30-45.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725775AbgE2JFS (ORCPT ); Fri, 29 May 2020 05:05:18 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=anny.hu@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0TzyLLYT_1590743112; Received: from 30.25.84.75(mailfrom:anny.hu@linux.alibaba.com fp:SMTPD_---0TzyLLYT_1590743112) by smtp.aliyun-inc.com(127.0.0.1); Fri, 29 May 2020 17:05:13 +0800 Subject: Re: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg To: John Fastabend , Eric Dumazet , Daniel Borkmann , Jakub Sitnicki , Lorenz Bauer , "David S. Miller" , Alexey Kuznetsov , Hideaki YOSHIFUJI , Jakub Kicinski , Alexei Starovoitov , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , KP Singh , netdev , bpf , linux-kernel References: <5ecd85c7a21fd_35792ad4115a05b8a9@john-XPS-13-9370.notmuch> From: dihu Message-ID: Date: Fri, 29 May 2020 17:05:12 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.8.1 MIME-Version: 1.0 In-Reply-To: <5ecd85c7a21fd_35792ad4115a05b8a9@john-XPS-13-9370.notmuch> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On 2020/5/27 5:10, John Fastabend wrote: > dihu wrote: >> From 865a45747de6b68fd02a0ff128a69a5c8feb73c3 Mon Sep 17 00:00:00 2001 >> From: dihu >> Date: Mon, 25 May 2020 17:23:16 +0800 >> Subject: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg >> >> When user application calls read() with MSG_PEEK flag to read data >> of bpf sockmap socket, kernel panic happens at >> __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg >> queue after read out under MSG_PEEK flag is set. Because it's not >> judged whether sk_msg is the last msg of ingress_msg queue, the next >> sk_msg may be the head of ingress_msg queue, whose memory address of >> sg page is invalid. So it's necessary to add check codes to prevent >> this problem. >> >> [20759.125457] BUG: kernel NULL pointer dereference, address: >> 0000000000000008 >> [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G E >> 5.4.32 #1 >> [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS >> 4.1.12 06/18/2017 >> [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 >> [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 >> [20759.276099] tcp_bpf_recvmsg+0x113/0x370 >> [20759.281137] inet_recvmsg+0x55/0xc0 >> [20759.285734] __sys_recvfrom+0xc8/0x130 >> [20759.290566] ? __audit_syscall_entry+0x103/0x130 >> [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 >> [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 >> [20759.307235] __x64_sys_recvfrom+0x24/0x30 >> [20759.312226] do_syscall_64+0x55/0x1b0 >> [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> >> Signed-off-by: dihu >> --- >> net/ipv4/tcp_bpf.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c >> index 5a05327..c0d4624 100644 >> --- a/net/ipv4/tcp_bpf.c >> +++ b/net/ipv4/tcp_bpf.c >> @@ -64,6 +64,9 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, >> } while (i != msg_rx->sg.end); >> >> if (unlikely(peek)) { >> + if (msg_rx == list_last_entry(&psock->ingress_msg, >> + struct sk_msg, list)) >> + break; > > Thanks. Change looks good but spacing is a bit off . Can we > turn those spaces into tabs? Otherwise adding fixes tag and > my ack would be great. > > Fixes: 02c558b2d5d67 ("bpf: sockmap, support for msg_peek in sk_msg with redirect ingress") > Acked-by: John Fastabend From 127a334fa5e5d029353ceb1a0414886c527f4be5 Mon Sep 17 00:00:00 2001 From: dihu Date: Fri, 29 May 2020 16:38:50 +0800 Subject: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg When user application calls read() with MSG_PEEK flag to read data of bpf sockmap socket, kernel panic happens at __tcp_bpf_recvmsg+0x12c/0x350. sk_msg is not removed from ingress_msg queue after read out under MSG_PEEK flag is set. Because it's not judged whether sk_msg is the last msg of ingress_msg queue, the next sk_msg may be the head of ingress_msg queue, whose memory address of sg page is invalid. So it's necessary to add check codes to prevent this problem. [20759.125457] BUG: kernel NULL pointer dereference, address: 0000000000000008 [20759.132118] CPU: 53 PID: 51378 Comm: envoy Tainted: G            E 5.4.32 #1 [20759.140890] Hardware name: Inspur SA5212M4/YZMB-00370-109, BIOS 4.1.12 06/18/2017 [20759.149734] RIP: 0010:copy_page_to_iter+0xad/0x300 [20759.270877] __tcp_bpf_recvmsg+0x12c/0x350 [20759.276099] tcp_bpf_recvmsg+0x113/0x370 [20759.281137] inet_recvmsg+0x55/0xc0 [20759.285734] __sys_recvfrom+0xc8/0x130 [20759.290566] ? __audit_syscall_entry+0x103/0x130 [20759.296227] ? syscall_trace_enter+0x1d2/0x2d0 [20759.301700] ? __audit_syscall_exit+0x1e4/0x290 [20759.307235] __x64_sys_recvfrom+0x24/0x30 [20759.312226] do_syscall_64+0x55/0x1b0 [20759.316852] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Signed-off-by: dihu ---  net/ipv4/tcp_bpf.c | 3 +++  1 file changed, 3 insertions(+) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 5a05327..b82e4c3 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -64,6 +64,9 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,          } while (i != msg_rx->sg.end);          if (unlikely(peek)) { +            if (msg_rx == list_last_entry(&psock->ingress_msg, +                              struct sk_msg, list)) +                break;              msg_rx = list_next_entry(msg_rx, list);              continue;          } -- 1.8.3.1