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,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 18E90C433DF for ; Tue, 9 Jun 2020 09:03:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4660206D5 for ; Tue, 9 Jun 2020 09:03:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="lETBsvPl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728217AbgFIJDu (ORCPT ); Tue, 9 Jun 2020 05:03:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbgFIJDs (ORCPT ); Tue, 9 Jun 2020 05:03:48 -0400 Received: from mail-ed1-x544.google.com (mail-ed1-x544.google.com [IPv6:2a00:1450:4864:20::544]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 705AEC05BD43 for ; Tue, 9 Jun 2020 02:03:48 -0700 (PDT) Received: by mail-ed1-x544.google.com with SMTP id t21so12998987edr.12 for ; Tue, 09 Jun 2020 02:03:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version; bh=9f22rJL4VIrAu8fDizdaN/kAIljAWzM52xMFa+9jhcE=; b=lETBsvPl/e6m7cD1GW80ZZstOjK1s+8vpzxkkt56DthnbNGvhoVJpuEhXvgqlodADS CdMQ73miTju/tPFRCg6+leMzxLZwNNkzsiB4LSJ2hTV2UBabUQzluHIS/D8WWT4u9U8P 17JymPfEoXvTcDmJyAXIp7BbttZ84+8/V1Z+Q= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version; bh=9f22rJL4VIrAu8fDizdaN/kAIljAWzM52xMFa+9jhcE=; b=fkf36VmS/fAmRzWuzO7fm2FtAjFH7+ABG07iysX+vrNAHePfVIhbytE2JBpL+tICRl KEWYn7+3v13o4pBlj0oJOGgH+GXg+YcmSfNZNTQDHj/OSD9j05ifQeYU/iRejws3jV3V 3eVNcu+Ge1JSAUubh2k4w2KPExaDsGxFQTDpUDOdCJLreVz0xNMPUIr8ZSR36QVUiJDX xtDxjAR0ZIljAJIRT+s7cvhtbV23bMDPJUm7KvRiP/BXCE2SmfgY9pQ3JxCjzGu9GIcm BiVm8g8JIMJ7J/f7dEVBN9JU4TmDu07IxlaNJuSid/PnCcQSGEiNRgLvS3S1485LjlKR CPCQ== X-Gm-Message-State: AOAM531R25XmcaP1r8QjdrZEbndq1W3UE8B3EThylfBIu7KADstj2kTX 4OCxZ1uFV/oYLhLkhK6PcxChv/1LHw8= X-Google-Smtp-Source: ABdhPJwmO5mlkYxhnPgEdMGvz+/409+hPu5jLZh2LYxy6w/sxaKeJWimzsdAz6wvi799qO2cj7C/IQ== X-Received: by 2002:aa7:c682:: with SMTP id n2mr25139091edq.18.1591693427077; Tue, 09 Jun 2020 02:03:47 -0700 (PDT) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id k23sm490495ejo.120.2020.06.09.02.03.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 Jun 2020 02:03:46 -0700 (PDT) References: <20200605084625.9783-1-anny.hu@linux.alibaba.com> User-agent: mu4e 1.1.0; emacs 26.3 From: Jakub Sitnicki To: dihu Cc: bpf@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg In-reply-to: <20200605084625.9783-1-anny.hu@linux.alibaba.com> Date: Tue, 09 Jun 2020 11:03:45 +0200 Message-ID: <874krk391q.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Jun 05, 2020 at 10:46 AM CEST, dihu wrote: > 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; > } Acked-by: Jakub Sitnicki