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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 D088CC433E0 for ; Tue, 9 Jun 2020 17:58:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF1D3206D5 for ; Tue, 9 Jun 2020 17:58:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="OmBAdQqV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387676AbgFIR6i (ORCPT ); Tue, 9 Jun 2020 13:58:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387671AbgFIR6f (ORCPT ); Tue, 9 Jun 2020 13:58:35 -0400 Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DEE67C05BD1E; Tue, 9 Jun 2020 10:58:34 -0700 (PDT) Received: by mail-lf1-x142.google.com with SMTP id e125so13043612lfd.1; Tue, 09 Jun 2020 10:58:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=0JzUAxIlsQW/ouIYhILjNkmM8ALrEBKdaPizi9XIUts=; b=OmBAdQqVJo/UkEguvL0veslfTRmVGDkO+kCcUMFN8ZxxgjTZGwkCdldMGUK46cR/8C 0NfmB7Y0ytbIgJn5WooEzSbY+yGIOdqRcBlj2CQpU+dbhY10/UcCMGUy0LKGQkfE44FF E8VnrAhi3nk9qvTWT1J7P2KS2xsSeQGkzUq3j94sQMYAlA+G9H9fGe7ICDa3g3mr/qHf IK42wAmjvN0QRwY72z439GBSp5YgihOyUxxRxvCRRwIP5KPQRVdFL+B7MAaWheIT51Mm 0sFJrYbBpFEOCiV1fUyq/dncNYaDkpEN6CbsQ+VOd62qP7Y5Mq1nWk8l/QppEAt11QEm 1paw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0JzUAxIlsQW/ouIYhILjNkmM8ALrEBKdaPizi9XIUts=; b=DsRBP3ERiZrIlIn9m8bSyvt/IhWjN2qx0veBWllQlXnKbq/2dRDoGozHPbaRcaZ8VY b6fsD5MrKMTdbuWsTHLWvE9v0U3hjr+q9qiegVM7ZPYjGJrvuyTLdmI5HkbHyaB0aw47 cWLEHrat97dYogeQN2PASJUQUnMlEfqZ1OgD3A4tohcNILAkN5CsrSyh1+aMSC9Pf7Tg zJIzPFo2D93nqqb1LqR82HaN1RRvRYgS/MhiXnMko/5C1ODir8txPR9U3V1JvKEq5HSy yu1GEEndK3+un9W4zxeYkonbZ0YAUgU7DlNQiJwqKFpW67mLxv7eGWD9u0RKzVWnZ3MM lyZg== X-Gm-Message-State: AOAM532irvFydesgVr7MhGpf882GrJajakFreUT8ULxsq8OfPM2DvoVM vSlZLKEtlW9bZErHC9xZQw5wUs9SvD9+LFZ4Wgo= X-Google-Smtp-Source: ABdhPJx4hAMylYWqsvOWovuEqBqM/loHIH21/XI5rH1uFSOQRP1lt0bTZtoR2Ml14/cy5k/DV95g1CRpu4qpGizjYck= X-Received: by 2002:a19:103:: with SMTP id 3mr15580721lfb.196.1591725513341; Tue, 09 Jun 2020 10:58:33 -0700 (PDT) MIME-Version: 1.0 References: <20200605084625.9783-1-anny.hu@linux.alibaba.com> <874krk391q.fsf@cloudflare.com> In-Reply-To: <874krk391q.fsf@cloudflare.com> From: Alexei Starovoitov Date: Tue, 9 Jun 2020 10:58:21 -0700 Message-ID: Subject: Re: [PATCH] bpf/sockmap: fix kernel panic at __tcp_bpf_recvmsg To: Jakub Sitnicki Cc: dihu , bpf , Network Development Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Jun 9, 2020 at 2:04 AM Jakub Sitnicki wrote: > > 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 Applied. Thanks