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=-6.9 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 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 D2029C33CA9 for ; Mon, 13 Jan 2020 22:42:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A076120678 for ; Mon, 13 Jan 2020 22:42:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="dwIyPyXf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728883AbgAMWmq (ORCPT ); Mon, 13 Jan 2020 17:42:46 -0500 Received: from mail-lf1-f68.google.com ([209.85.167.68]:36758 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728800AbgAMWmq (ORCPT ); Mon, 13 Jan 2020 17:42:46 -0500 Received: by mail-lf1-f68.google.com with SMTP id n12so8188456lfe.3 for ; Mon, 13 Jan 2020 14:42:45 -0800 (PST) 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=hYezfZM0vvLS3M5s++Lru0Dkzvjkxpc7Nto24AAXinM=; b=dwIyPyXfHowi/NcCWY7Kzdsig1ZmvIYBKaA6gNstjR8jNNxmJx2c576/8dzckEkosV eaOuv/hEFh3DkSjIX2Jn/e9unPzOGTq8ZA9AuVJKjP3uccUYN+5qftkqJI6nbeVrhU/o lAeuVVdROABPeu9c/HJPTRY7S93wUYdPgMFv0= 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=hYezfZM0vvLS3M5s++Lru0Dkzvjkxpc7Nto24AAXinM=; b=GVQSQtq2Kr6FXmwHmrmPYyP0CbUeVlbTZYzaH3wueYjx9Va/Cf+Meauc8j7H+TBCPG dSpc3R3xg7PPG9oXfi4JLdCVHGvbXR4JKjrh1Oh1f3sbhf3J8K05W+jfEW7dEcE6IF6z Z1GhYsTps0gzDCBLAzDNL8utmyaUtqJXpx6Z/MxnBYKw2anWi0ul8F6gO5FMupgeNypo SBPM+6xCKXEt1ytynheXUEGzf4ctdW/Iqtt8DGHmNhcGXgmkiBoy7Bz7Yu7Rq7O9jILF dM+8zfP5IFCJZ/StiTBg75qPdUwJQ8UXXLVQJLoMGfEdylH4ew435gktEMenlYGBmxEE XXrw== X-Gm-Message-State: APjAAAWJFg3I+iIjbcNL4ezFrZygEItb8K+4IHsSBWMus2U4c8vMUHuI GuQ70PSgRhOL1VmIHdRFi/OMYg== X-Google-Smtp-Source: APXvYqyQ+1cE+sTLxxgen+bJhJ8btjNu7hFcEEIPyCQ4ipolBW/T7Sv6MsE3yO+8YIebAk0PpFJpNQ== X-Received: by 2002:a19:5212:: with SMTP id m18mr11046342lfb.7.1578955364322; Mon, 13 Jan 2020 14:42:44 -0800 (PST) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id y25sm6279571lfy.59.2020.01.13.14.42.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jan 2020 14:42:43 -0800 (PST) References: <20200110105027.257877-1-jakub@cloudflare.com> <20200110105027.257877-5-jakub@cloudflare.com> <20200113222342.suypc3rgib7xbkjl@kafai-mbp.dhcp.thefacebook.com> User-agent: mu4e 1.1.0; emacs 26.3 From: Jakub Sitnicki To: Martin Lau Cc: "bpf\@vger.kernel.org" , "netdev\@vger.kernel.org" , "kernel-team\@cloudflare.com" , Eric Dumazet , "John Fastabend" , Lorenz Bauer Subject: Re: [PATCH bpf-next v2 04/11] tcp_bpf: Don't let child socket inherit parent protocol ops on copy In-reply-to: <20200113222342.suypc3rgib7xbkjl@kafai-mbp.dhcp.thefacebook.com> Date: Mon, 13 Jan 2020 23:42:42 +0100 Message-ID: <87ftgjrna5.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 Mon, Jan 13, 2020 at 11:23 PM CET, Martin Lau wrote: > On Fri, Jan 10, 2020 at 11:50:20AM +0100, Jakub Sitnicki wrote: >> Prepare for cloning listening sockets that have their protocol callbacks >> overridden by sk_msg. Child sockets must not inherit parent callbacks that >> access state stored in sk_user_data owned by the parent. >> >> Restore the child socket protocol callbacks before the it gets hashed and >> any of the callbacks can get invoked. >> >> Signed-off-by: Jakub Sitnicki >> --- >> include/net/tcp.h | 1 + >> net/ipv4/tcp_bpf.c | 13 +++++++++++++ >> net/ipv4/tcp_minisocks.c | 2 ++ >> 3 files changed, 16 insertions(+) >> >> diff --git a/include/net/tcp.h b/include/net/tcp.h >> index 9dd975be7fdf..7cbf9465bb10 100644 >> --- a/include/net/tcp.h >> +++ b/include/net/tcp.h >> @@ -2181,6 +2181,7 @@ int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, >> int nonblock, int flags, int *addr_len); >> int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock, >> struct msghdr *msg, int len, int flags); >> +void tcp_bpf_clone(const struct sock *sk, struct sock *child); >> >> /* Call BPF_SOCK_OPS program that returns an int. If the return value >> * is < 0, then the BPF op failed (for example if the loaded BPF >> diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c >> index f6c83747c71e..6f96320fb7cf 100644 >> --- a/net/ipv4/tcp_bpf.c >> +++ b/net/ipv4/tcp_bpf.c >> @@ -586,6 +586,19 @@ static void tcp_bpf_close(struct sock *sk, long timeout) >> saved_close(sk, timeout); >> } >> >> +/* If a child got cloned from a listening socket that had tcp_bpf >> + * protocol callbacks installed, we need to restore the callbacks to >> + * the default ones because the child does not inherit the psock state >> + * that tcp_bpf callbacks expect. >> + */ >> +void tcp_bpf_clone(const struct sock *sk, struct sock *newsk) >> +{ >> + struct proto *prot = newsk->sk_prot; >> + >> + if (prot->recvmsg == tcp_bpf_recvmsg) > A question not related to this patch (may be it is more for patch 6). > > How tcp_bpf_recvmsg may be used for a listening sock (sk here)? It can't be used. It's a way of checking if sock has tcp_bpf callbacks that I copied from sk_psock_get_checked: static inline struct sk_psock *sk_psock_get_checked(struct sock *sk) { struct sk_psock *psock; rcu_read_lock(); psock = sk_psock(sk); if (psock) { if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) { psock = ERR_PTR(-EBUSY); goto out; } ... This makes me think that perhaps it deserves a well-named helper. > >> + newsk->sk_prot = sk->sk_prot_creator; >> +} >> +