From patchwork Tue May 5 20:27:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 1283931 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20161025 header.b=aUQN3yW1; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49GrrH4tntz9sRf for ; Wed, 6 May 2020 06:27:43 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729198AbgEEU1m (ORCPT ); Tue, 5 May 2020 16:27:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50934 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1729165AbgEEU1m (ORCPT ); Tue, 5 May 2020 16:27:42 -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 A193CC061A0F for ; Tue, 5 May 2020 13:27:40 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id j4so3754719ybj.20 for ; Tue, 05 May 2020 13:27:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=vR6JSXZj19+euZPVSEfIpnQIGh60prv9Ojq+fdLFVQI=; b=aUQN3yW1/gLtNfbzGYQpLYcP62xT66Y9HfoAI32RHT9jcmuyKe1slsLFq3JLsV2wL+ A3y1MXSI+qJmwJyoxyDArylPRxEt+Hav8ahO6I0Be6/sW4fPhPe3bP/CVjWrMk3KdND7 thb+q3zqoKtugss712hXcyFgki8w3aBShZowLAt8M5/5wOXdXixzranbjVkyZj4DG485 phlWFoNvX9YbHqHaIFbfIEjB66ULavPTjM54ARiVHIZcLPaYC22jZngYVwyJkaS4hJGH i2S6wqNGmoLWMJie0OGk4BR2m5w1sxXn4T5lyqfUY587RVtGlRXMNstLx2aoEoqI/aWy lyGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=vR6JSXZj19+euZPVSEfIpnQIGh60prv9Ojq+fdLFVQI=; b=eLGyMMHlP7he/dfSJa9P60JnGh+V2GlRi7pjbsAcJIvFNc/EXWBa6t8Ew0qIEVFVkW 4omnlh3l8nNMtaM0hYwpRooiDw1ExpXTLpy6A0FxUQQKhz1iIasUF5rQcrE54OkVojf7 48UTOr56Ct5Pi3V47bd0+rQgPWEzupuHTTkQajt8NZkG8XYe+Vs2bu1YynBe3gD6/g6o 5uaX5CWGLD6rrdW228FgnGDUhAmgjizQJI03DED7p1VZqYzh9IsFzEL00e9iEbrh0NTk N3/+Tj4h8CGT05vZ1z3AQTH7gi1EXH2RYuLjr8/dnq89wqFTRJBB7iBvGuJMkZbzY2VP +n8w== X-Gm-Message-State: AGi0PubWLEhF4uE/SUGQHCgTWVBfle+oFLx2CoSkvVqGjpbo0WzzOMdN fRNuj8YdkKwpm2jbtA+1aiWLkRk= X-Google-Smtp-Source: APiQypJvJxyFPgUa+PHZTvcamb1wkUqtGRzQMpJ8g2sDMKmuF8Zklnk7EzN1MfuttgFAyv7yvpwliJE= X-Received: by 2002:a25:ba81:: with SMTP id s1mr7936893ybg.114.1588710459884; Tue, 05 May 2020 13:27:39 -0700 (PDT) Date: Tue, 5 May 2020 13:27:29 -0700 In-Reply-To: <20200505202730.70489-1-sdf@google.com> Message-Id: <20200505202730.70489-5-sdf@google.com> Mime-Version: 1.0 References: <20200505202730.70489-1-sdf@google.com> X-Mailer: git-send-email 2.26.2.526.g744177e7f7-goog Subject: [PATCH bpf-next v2 4/5] bpf: allow any port in bpf_bind helper From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev , Andrey Ignatov Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org We want to have a tighter control on what ports we bind to in the BPF_CGROUP_INET{4,6}_CONNECT hooks even if it means connect() becomes slightly more expensive. The expensive part comes from the fact that we now need to call inet_csk_get_port() that verifies that the port is not used and allocates an entry in the hash table for it. Since we can't rely on "snum || !bind_address_no_port" to prevent us from calling POST_BIND hook anymore, let's add another bind flag to indicate that the call site is BPF program. v2: * Update documentation (Andrey Ignatov) * Pass BIND_FORCE_ADDRESS_NO_PORT conditionally (Andrey Ignatov) Cc: Andrey Ignatov Signed-off-by: Stanislav Fomichev Acked-by: Andrey Ignatov --- include/net/inet_common.h | 2 + include/uapi/linux/bpf.h | 9 +- net/core/filter.c | 18 ++- net/ipv4/af_inet.c | 10 +- net/ipv6/af_inet6.c | 12 +- tools/include/uapi/linux/bpf.h | 9 +- .../bpf/prog_tests/connect_force_port.c | 104 ++++++++++++++++++ .../selftests/bpf/progs/connect_force_port4.c | 28 +++++ .../selftests/bpf/progs/connect_force_port6.c | 28 +++++ 9 files changed, 192 insertions(+), 28 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/connect_force_port.c create mode 100644 tools/testing/selftests/bpf/progs/connect_force_port4.c create mode 100644 tools/testing/selftests/bpf/progs/connect_force_port6.c diff --git a/include/net/inet_common.h b/include/net/inet_common.h index c38f4f7d660a..cb2818862919 100644 --- a/include/net/inet_common.h +++ b/include/net/inet_common.h @@ -39,6 +39,8 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len); #define BIND_FORCE_ADDRESS_NO_PORT (1 << 0) /* Grab and release socket lock. */ #define BIND_WITH_LOCK (1 << 1) +/* Called from BPF program. */ +#define BIND_FROM_BPF (1 << 2) int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, u32 flags); int inet_getname(struct socket *sock, struct sockaddr *uaddr, diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index b3643e27e264..14b5518a3d5b 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1994,10 +1994,11 @@ union bpf_attr { * * This helper works for IPv4 and IPv6, TCP and UDP sockets. The * domain (*addr*\ **->sa_family**) must be **AF_INET** (or - * **AF_INET6**). Looking for a free port to bind to can be - * expensive, therefore binding to port is not permitted by the - * helper: *addr*\ **->sin_port** (or **sin6_port**, respectively) - * must be set to zero. + * **AF_INET6**). It's advised to pass zero port (**sin_port** + * or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like + * behavior and lets the kernel reuse the same source port + * as long as 4-tuple is unique. Passing non-zero port might + * lead to degraded performance. * Return * 0 on success, or a negative error in case of failure. * diff --git a/net/core/filter.c b/net/core/filter.c index fa9ddab5dd1f..da0634979f53 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4525,32 +4525,28 @@ BPF_CALL_3(bpf_bind, struct bpf_sock_addr_kern *, ctx, struct sockaddr *, addr, { #ifdef CONFIG_INET struct sock *sk = ctx->sk; + u32 flags = BIND_FROM_BPF; int err; - /* Binding to port can be expensive so it's prohibited in the helper. - * Only binding to IP is supported. - */ err = -EINVAL; if (addr_len < offsetofend(struct sockaddr, sa_family)) return err; if (addr->sa_family == AF_INET) { if (addr_len < sizeof(struct sockaddr_in)) return err; - if (((struct sockaddr_in *)addr)->sin_port != htons(0)) - return err; - return __inet_bind(sk, addr, addr_len, - BIND_FORCE_ADDRESS_NO_PORT); + if (((struct sockaddr_in *)addr)->sin_port == htons(0)) + flags |= BIND_FORCE_ADDRESS_NO_PORT; + return __inet_bind(sk, addr, addr_len, flags); #if IS_ENABLED(CONFIG_IPV6) } else if (addr->sa_family == AF_INET6) { if (addr_len < SIN6_LEN_RFC2133) return err; - if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0)) - return err; + if (((struct sockaddr_in6 *)addr)->sin6_port == htons(0)) + flags |= BIND_FORCE_ADDRESS_NO_PORT; /* ipv6_bpf_stub cannot be NULL, since it's called from * bpf_cgroup_inet6_connect hook and ipv6 is already loaded */ - return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, - BIND_FORCE_ADDRESS_NO_PORT); + return ipv6_bpf_stub->inet6_bind(sk, addr, addr_len, flags); #endif /* CONFIG_IPV6 */ } #endif /* CONFIG_INET */ diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 68e74b1b0f26..fcf0d12a407a 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -526,10 +526,12 @@ int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, err = -EADDRINUSE; goto out_release_sock; } - err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk); - if (err) { - inet->inet_saddr = inet->inet_rcv_saddr = 0; - goto out_release_sock; + if (!(flags & BIND_FROM_BPF)) { + err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk); + if (err) { + inet->inet_saddr = inet->inet_rcv_saddr = 0; + goto out_release_sock; + } } } diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index 552c2592b81c..771a462a8322 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -407,11 +407,13 @@ static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len, err = -EADDRINUSE; goto out; } - err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk); - if (err) { - sk->sk_ipv6only = saved_ipv6only; - inet_reset_saddr(sk); - goto out; + if (!(flags & BIND_FROM_BPF)) { + err = BPF_CGROUP_RUN_PROG_INET6_POST_BIND(sk); + if (err) { + sk->sk_ipv6only = saved_ipv6only; + inet_reset_saddr(sk); + goto out; + } } } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index b3643e27e264..14b5518a3d5b 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1994,10 +1994,11 @@ union bpf_attr { * * This helper works for IPv4 and IPv6, TCP and UDP sockets. The * domain (*addr*\ **->sa_family**) must be **AF_INET** (or - * **AF_INET6**). Looking for a free port to bind to can be - * expensive, therefore binding to port is not permitted by the - * helper: *addr*\ **->sin_port** (or **sin6_port**, respectively) - * must be set to zero. + * **AF_INET6**). It's advised to pass zero port (**sin_port** + * or **sin6_port**) which triggers IP_BIND_ADDRESS_NO_PORT-like + * behavior and lets the kernel reuse the same source port + * as long as 4-tuple is unique. Passing non-zero port might + * lead to degraded performance. * Return * 0 on success, or a negative error in case of failure. * diff --git a/tools/testing/selftests/bpf/prog_tests/connect_force_port.c b/tools/testing/selftests/bpf/prog_tests/connect_force_port.c new file mode 100644 index 000000000000..97104e6410b6 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/connect_force_port.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include "cgroup_helpers.h" +#include "network_helpers.h" + +static int verify_port(int family, int fd, int expected) +{ + struct sockaddr_storage addr; + socklen_t len = sizeof(addr); + __u16 port; + + + if (getsockname(fd, (struct sockaddr *)&addr, &len)) { + log_err("Failed to get server addr"); + return -1; + } + + if (family == AF_INET) + port = ((struct sockaddr_in *)&addr)->sin_port; + else + port = ((struct sockaddr_in6 *)&addr)->sin6_port; + + if (ntohs(port) != expected) { + log_err("Unexpected port %d, expected %d", ntohs(port), + expected); + return -1; + } + + return 0; +} + +static int run_test(int cgroup_fd, int server_fd, int family) +{ + struct bpf_prog_load_attr attr = { + .prog_type = BPF_PROG_TYPE_CGROUP_SOCK_ADDR, + }; + struct bpf_object *obj; + int expected_port; + int prog_fd; + int err; + int fd; + + if (family == AF_INET) { + attr.file = "./connect_force_port4.o"; + attr.expected_attach_type = BPF_CGROUP_INET4_CONNECT; + expected_port = 22222; + } else { + attr.file = "./connect_force_port6.o"; + attr.expected_attach_type = BPF_CGROUP_INET6_CONNECT; + expected_port = 22223; + } + + err = bpf_prog_load_xattr(&attr, &obj, &prog_fd); + if (err) { + log_err("Failed to load BPF object"); + return -1; + } + + err = bpf_prog_attach(prog_fd, cgroup_fd, attr.expected_attach_type, + 0); + if (err) { + log_err("Failed to attach BPF program"); + goto close_bpf_object; + } + + fd = connect_to_fd(family, server_fd); + if (fd < 0) { + err = -1; + goto close_bpf_object; + } + + err = verify_port(family, fd, expected_port); + + close(fd); + +close_bpf_object: + bpf_object__close(obj); + return err; +} + +void test_connect_force_port(void) +{ + int server_fd, cgroup_fd; + + cgroup_fd = test__join_cgroup("/connect_force_port"); + if (CHECK_FAIL(cgroup_fd < 0)) + return; + + server_fd = start_server_thread(AF_INET); + if (CHECK_FAIL(server_fd < 0)) + goto close_cgroup_fd; + CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET)); + stop_server_thread(server_fd); + + server_fd = start_server_thread(AF_INET6); + if (CHECK_FAIL(server_fd < 0)) + goto close_cgroup_fd; + CHECK_FAIL(run_test(cgroup_fd, server_fd, AF_INET6)); + stop_server_thread(server_fd); + +close_cgroup_fd: + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/connect_force_port4.c b/tools/testing/selftests/bpf/progs/connect_force_port4.c new file mode 100644 index 000000000000..1b8eb34b2db0 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/connect_force_port4.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +#include +#include +#include +#include + +#include +#include + +char _license[] SEC("license") = "GPL"; +int _version SEC("version") = 1; + +SEC("cgroup/connect4") +int _connect4(struct bpf_sock_addr *ctx) +{ + struct sockaddr_in sa = {}; + + sa.sin_family = AF_INET; + sa.sin_port = bpf_htons(22222); + sa.sin_addr.s_addr = bpf_htonl(0x7f000001); /* 127.0.0.1 */ + + if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0) + return 0; + + return 1; +} diff --git a/tools/testing/selftests/bpf/progs/connect_force_port6.c b/tools/testing/selftests/bpf/progs/connect_force_port6.c new file mode 100644 index 000000000000..8cd1a9e81f64 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/connect_force_port6.c @@ -0,0 +1,28 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +#include +#include +#include +#include + +#include +#include + +char _license[] SEC("license") = "GPL"; +int _version SEC("version") = 1; + +SEC("cgroup/connect6") +int _connect6(struct bpf_sock_addr *ctx) +{ + struct sockaddr_in6 sa = {}; + + sa.sin6_family = AF_INET; + sa.sin6_port = bpf_htons(22223); + sa.sin6_addr.s6_addr32[3] = bpf_htonl(1); /* ::1 */ + + if (bpf_bind(ctx, (struct sockaddr *)&sa, sizeof(sa)) != 0) + return 0; + + return 1; +}