From patchwork Fri Jun 26 00:09:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 217091 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=-17.6 required=3.0 tests=DKIMWL_WL_MED, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 0BAD7C433E1 for ; Fri, 26 Jun 2020 00:09:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBF4E2072E for ; Fri, 26 Jun 2020 00:09:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="cvv3oOX5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725957AbgFZAJe (ORCPT ); Thu, 25 Jun 2020 20:09:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725884AbgFZAJd (ORCPT ); Thu, 25 Jun 2020 20:09:33 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5FB3C08C5DB for ; Thu, 25 Jun 2020 17:09:32 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id w9so7942208ybt.2 for ; Thu, 25 Jun 2020 17:09:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=vkDmfyOJtnFtYzWvfEgCd9QelFOIV4Uf9bIpqIS45QQ=; b=cvv3oOX5TSfIrmzMS63S0JIxCqqxGEr+RjFTxaMoPlfiWlmI3IDQkzBchu3Zl1VuEn C6DRg0J+qkG1UfuIqfnb9fl9AiKmgXiCyXVu3pbKZQ9fxh/pM0GWm1nIE5HKFb8bgF6g 0gDlZjdZ7hrSWq45PDw4d44rbVl7YC98dT/dPMrPEMOGxKA6Y8Ntx+cTd7afFM8M8f3o IBsWhd0M2gJLF7s9mVF6Ak3EVIta5OlePGkbr93/vAmoRGgATMqvYdTtqspb+CzGi/9y JApVMpyI0BSF/IpRHpcJht52iC58S6u4HMxOp0fvxeLp52cUHHYSB+V6ooWEI/cRNbPh Y05Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=vkDmfyOJtnFtYzWvfEgCd9QelFOIV4Uf9bIpqIS45QQ=; b=Q6menkYBdq7/BmIBmxK1HT/giBFtEIwU91EUChHMHuK7L7rN4YXUP2ppMt/4Ozqcx5 Tx+bXUT9sZOVP00P5cwrNiPF4Rj0SUUdc3kphq/ZZiil9ECb/xR8qBFOoNI6QxAhFrmT LYSggAEMX/LoCA4VR63BoA1jemDbm0QSKokA+WNLPaInytcn3H/dxES9+4TGskeKPk0N aNLQhhgusAiZ+IrJHMT0sJWo564FkA4DL7V1wxczdAkm0AQeh4moN8zmJl58nbczvgN/ j262qQulTjC4RRjRmA97QFkNf9xkEzmx+QPyxF7IbS1HpJSx8H8ZsS6mV2GYrqrXW40s tNUw== X-Gm-Message-State: AOAM530xSWHifm2f+t/PNzaOMoMqJzotj5jsJEerOzjSG22QuO+gXjZ8 HAo3O7kJNgR2E0zqj1Xh8abDMq0tnIr+oFEYyFQ5hNQ//aM64yN1x+bfAGNoldCwoG6vMWdS2OI dzeWD6/iAGif5yeips+olObQQEI1XSfZIiLKh/kSjWtbrG04F+0Gb0Q== X-Google-Smtp-Source: ABdhPJwn7cFeIjhdrEPyiYpK8kPTuvvISD5PrZu5UQ6OipDyT8ufD9F7LzQjg562e0i7O8m5xsQBLeE= X-Received: by 2002:a25:18d5:: with SMTP id 204mr608318yby.209.1593130171514; Thu, 25 Jun 2020 17:09:31 -0700 (PDT) Date: Thu, 25 Jun 2020 17:09:26 -0700 Message-Id: <20200626000929.217930-1-sdf@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.27.0.111.gc72c7da667-goog Subject: [PATCH bpf-next 1/4] bpf: add BPF_CGROUP_INET_SOCK_RELEASE hook From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Sometimes it's handy to know when the socket gets freed. In particular, we'd like to try to use a smarter allocation of ports for bpf_bind and explore the possibility of limiting the number of SOCK_DGRAM sockets the process can have. Adding a release pair to existing BPF_CGROUP_INET_SOCK_CREATE can unlock both of the mentioned features. The only questionable part here is the sock->sk check in the inet_release. Looking at the places where we do 'sock->sk = NULL', I don't understand how it can race with inet_release and why the check is there (it's been there since the initial git import). Otherwise, the change itself is pretty simple, we add a BPF hook to the inet_release and avoid calling it for kernel sockets. Signed-off-by: Stanislav Fomichev --- include/linux/bpf-cgroup.h | 3 +++ include/uapi/linux/bpf.h | 1 + kernel/bpf/syscall.c | 3 +++ net/core/filter.c | 1 + net/ipv4/af_inet.c | 3 +++ 5 files changed, 11 insertions(+) diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index c66c545e161a..b4fd09fe67bd 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -210,6 +210,9 @@ int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, #define BPF_CGROUP_RUN_PROG_INET_SOCK(sk) \ BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_CREATE) +#define BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk) \ + BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET_SOCK_RELEASE) + #define BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk) \ BPF_CGROUP_RUN_SK_PROG(sk, BPF_CGROUP_INET4_POST_BIND) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index c65b374a5090..d7aea1d0167a 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -226,6 +226,7 @@ enum bpf_attach_type { BPF_CGROUP_INET4_GETSOCKNAME, BPF_CGROUP_INET6_GETSOCKNAME, BPF_XDP_DEVMAP, + BPF_CGROUP_INET_SOCK_RELEASE, __MAX_BPF_ATTACH_TYPE }; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 4d530b1d5683..2a3d4b8f95c7 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -1994,6 +1994,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type, case BPF_PROG_TYPE_CGROUP_SOCK: switch (expected_attach_type) { case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET_SOCK_RELEASE: case BPF_CGROUP_INET4_POST_BIND: case BPF_CGROUP_INET6_POST_BIND: return 0; @@ -2792,6 +2793,7 @@ attach_type_to_prog_type(enum bpf_attach_type attach_type) return BPF_PROG_TYPE_CGROUP_SKB; break; case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET_SOCK_RELEASE: case BPF_CGROUP_INET4_POST_BIND: case BPF_CGROUP_INET6_POST_BIND: return BPF_PROG_TYPE_CGROUP_SOCK; @@ -2942,6 +2944,7 @@ static int bpf_prog_query(const union bpf_attr *attr, case BPF_CGROUP_INET_INGRESS: case BPF_CGROUP_INET_EGRESS: case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET_SOCK_RELEASE: case BPF_CGROUP_INET4_BIND: case BPF_CGROUP_INET6_BIND: case BPF_CGROUP_INET4_POST_BIND: diff --git a/net/core/filter.c b/net/core/filter.c index 209482a4eaa2..7bcac182383c 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6855,6 +6855,7 @@ static bool __sock_filter_check_attach_type(int off, case offsetof(struct bpf_sock, priority): switch (attach_type) { case BPF_CGROUP_INET_SOCK_CREATE: + case BPF_CGROUP_INET_SOCK_RELEASE: goto full_access; default: return false; diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 02aa5cb3a4fd..965a96ea1168 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -411,6 +411,9 @@ int inet_release(struct socket *sock) if (sk) { long timeout; + if (!sk->sk_kern_sock) + BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk); + /* Applications forget to leave groups before exiting */ ip_mc_drop_socket(sk);