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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C478AC43334 for ; Wed, 22 Jun 2022 16:04:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1376500AbiFVQEO (ORCPT ); Wed, 22 Jun 2022 12:04:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39284 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376436AbiFVQEJ (ORCPT ); Wed, 22 Jun 2022 12:04:09 -0400 Received: from mail-pg1-x549.google.com (mail-pg1-x549.google.com [IPv6:2607:f8b0:4864:20::549]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F10B626AD3 for ; Wed, 22 Jun 2022 09:03:59 -0700 (PDT) Received: by mail-pg1-x549.google.com with SMTP id 15-20020a63040f000000b0040c9f7f2978so5387552pge.12 for ; Wed, 22 Jun 2022 09:03:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=pp6HkjLeA9NZbHZxyUE2iiB8Biyi+3A9z58GXZU/nnw=; b=PxXd17R+mhgYh/TAbDnbUgqP3WS4a1ly1EdhXuiPaV6/2vmal6zuK/vQ/U0ATFozqN 3OmuYvfT/beOBrb8Tz3QFmm3fcQt/M0dohkUwDZKQG2cq1+Pj52Vryz+YJpnP2oH7RId ruA/MZyBA3Slpb244g3Md4xHsryrLUUt4uqB6OeXalB77qCOQySGbgJwiaKoNoRGF+iA 0jk53FRN+F41ScyWR6cUBtKKWaMdpsCV0fxyZr8rB6bGV8HjoF/0Ip2snWYgM+4N4zu0 8WhnVqP42NZhV+PJgWiHSBy7/QBlYUwv84dOCZiDph5tKCmGdlr9lcXUyYbZU4dWW3cP Wyfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=pp6HkjLeA9NZbHZxyUE2iiB8Biyi+3A9z58GXZU/nnw=; b=o7x/O9fSAb55yn1duS3e8Tzd769nEqgp2eHLa7A6Pq7clnDqx2Lnz+aV30K3HPn0sw Be9TM2119jqfi6XJ5RpM721rSzrEGhZWwklQpDQmY7mVQbNas93i762abrLnh7uH/kmT IDYkDJcu50PgwVYU+Km8mWzR1Jv6+joAvrAUHOqSjXPHGfUHWyDfm+pJhLKNTOmxDrzf VLcNNBGNX/YJ+CUZQbjs2Ldn7Ko2Ldx0YsZxtgfRrxgMawVJKLCAD1jUEAgMkl10TEgs lHVmNSm0LPYcSO8PBmjGKr+VaNPiZy3z6yxvP9ENfgNHYxjhUAmjhhnr7n8qmw3nCfBo GApw== X-Gm-Message-State: AJIora8lFK2skAGvMW+yep4/FZadsuYu6J7ynygVUn67jIaVIk5bwij1 z5nKG3mgOFAUlusRL9Sid0LeJZE7n2nZ8pd289Ew0+9TFFL7kyxgjFM3GRwzJQHW34ss7rdmSnp rCK8LPuwCHF7ZNeXZmaWEg8D7MAmxh2ZyIuSpvL8jcm6/4Mi62LqZcg== X-Google-Smtp-Source: AGRyM1un/wjrLrnz0KrTUSFeit7ncXkja4gFYaXaE+mpx2OgHi2/D0QmlUMzH9g9C0Q3BvixQYM2AoU= X-Received: from sdf.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5935]) (user=sdf job=sendgmr) by 2002:a63:ea09:0:b0:3fd:3c6a:47c2 with SMTP id c9-20020a63ea09000000b003fd3c6a47c2mr3484937pgi.242.1655913839536; Wed, 22 Jun 2022 09:03:59 -0700 (PDT) Date: Wed, 22 Jun 2022 09:03:41 -0700 In-Reply-To: <20220622160346.967594-1-sdf@google.com> Message-Id: <20220622160346.967594-7-sdf@google.com> Mime-Version: 1.0 References: <20220622160346.967594-1-sdf@google.com> X-Mailer: git-send-email 2.37.0.rc0.104.g0611611a94-goog Subject: [PATCH bpf-next v10 06/11] bpf: expose bpf_{g,s}etsockopt to lsm cgroup From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, Stanislav Fomichev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org I don't see how to make it nice without introducing btf id lists for the hooks where these helpers are allowed. Some LSM hooks work on the locked sockets, some are triggering early and don't grab any locks, so have two lists for now: 1. LSM hooks which trigger under socket lock - minority of the hooks, but ideal case for us, we can expose existing BTF-based helpers 2. LSM hooks which trigger without socket lock, but they trigger early in the socket creation path where it should be safe to do setsockopt without any locks 3. The rest are prohibited. I'm thinking that this use-case might be a good gateway to sleeping lsm cgroup hooks in the future. We can either expose lock/unlock operations (and add tracking to the verifier) or have another set of bpf_setsockopt wrapper that grab the locks and might sleep. Signed-off-by: Stanislav Fomichev --- include/linux/bpf.h | 2 ++ kernel/bpf/bpf_lsm.c | 38 ++++++++++++++++++++++++++++ net/core/filter.c | 60 ++++++++++++++++++++++++++++++++++++++------ 3 files changed, 93 insertions(+), 7 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 5d2afa55c7c3..2b21f2a3452f 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -2386,6 +2386,8 @@ extern const struct bpf_func_proto bpf_for_each_map_elem_proto; extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto; extern const struct bpf_func_proto bpf_sk_setsockopt_proto; extern const struct bpf_func_proto bpf_sk_getsockopt_proto; +extern const struct bpf_func_proto bpf_unlocked_sk_setsockopt_proto; +extern const struct bpf_func_proto bpf_unlocked_sk_getsockopt_proto; extern const struct bpf_func_proto bpf_find_vma_proto; extern const struct bpf_func_proto bpf_loop_proto; extern const struct bpf_func_proto bpf_copy_from_user_task_proto; diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 83aa431dd52e..d469b7f3deef 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -45,6 +45,24 @@ BTF_ID(func, bpf_lsm_sk_alloc_security) BTF_ID(func, bpf_lsm_sk_free_security) BTF_SET_END(bpf_lsm_current_hooks) +/* List of LSM hooks that trigger while the socket is properly locked. + */ +BTF_SET_START(bpf_lsm_locked_sockopt_hooks) +BTF_ID(func, bpf_lsm_socket_sock_rcv_skb) +BTF_ID(func, bpf_lsm_sock_graft) +BTF_ID(func, bpf_lsm_inet_csk_clone) +BTF_ID(func, bpf_lsm_inet_conn_established) +BTF_SET_END(bpf_lsm_locked_sockopt_hooks) + +/* List of LSM hooks that trigger while the socket is _not_ locked, + * but it's ok to call bpf_{g,s}etsockopt because the socket is still + * in the early init phase. + */ +BTF_SET_START(bpf_lsm_unlocked_sockopt_hooks) +BTF_ID(func, bpf_lsm_socket_post_create) +BTF_ID(func, bpf_lsm_socket_socketpair) +BTF_SET_END(bpf_lsm_unlocked_sockopt_hooks) + void bpf_lsm_find_cgroup_shim(const struct bpf_prog *prog, bpf_func_t *bpf_func) { @@ -201,6 +219,26 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_get_retval: return prog->expected_attach_type == BPF_LSM_CGROUP ? &bpf_get_retval_proto : NULL; + case BPF_FUNC_setsockopt: + if (prog->expected_attach_type != BPF_LSM_CGROUP) + return NULL; + if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, + prog->aux->attach_btf_id)) + return &bpf_sk_setsockopt_proto; + if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, + prog->aux->attach_btf_id)) + return &bpf_unlocked_sk_setsockopt_proto; + return NULL; + case BPF_FUNC_getsockopt: + if (prog->expected_attach_type != BPF_LSM_CGROUP) + return NULL; + if (btf_id_set_contains(&bpf_lsm_locked_sockopt_hooks, + prog->aux->attach_btf_id)) + return &bpf_sk_getsockopt_proto; + if (btf_id_set_contains(&bpf_lsm_unlocked_sockopt_hooks, + prog->aux->attach_btf_id)) + return &bpf_unlocked_sk_getsockopt_proto; + return NULL; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/net/core/filter.c b/net/core/filter.c index 151aa4756bd6..c6941ab0eb52 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5012,8 +5012,8 @@ static const struct bpf_func_proto bpf_get_socket_uid_proto = { .arg1_type = ARG_PTR_TO_CTX, }; -static int _bpf_setsockopt(struct sock *sk, int level, int optname, - char *optval, int optlen) +static int __bpf_setsockopt(struct sock *sk, int level, int optname, + char *optval, int optlen) { char devname[IFNAMSIZ]; int val, valbool; @@ -5024,8 +5024,6 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, if (!sk_fullsock(sk)) return -EINVAL; - sock_owned_by_me(sk); - if (level == SOL_SOCKET) { if (optlen != sizeof(int) && optname != SO_BINDTODEVICE) return -EINVAL; @@ -5258,14 +5256,20 @@ static int _bpf_setsockopt(struct sock *sk, int level, int optname, return ret; } -static int _bpf_getsockopt(struct sock *sk, int level, int optname, +static int _bpf_setsockopt(struct sock *sk, int level, int optname, char *optval, int optlen) +{ + if (sk_fullsock(sk)) + sock_owned_by_me(sk); + return __bpf_setsockopt(sk, level, optname, optval, optlen); +} + +static int __bpf_getsockopt(struct sock *sk, int level, int optname, + char *optval, int optlen) { if (!sk_fullsock(sk)) goto err_clear; - sock_owned_by_me(sk); - if (level == SOL_SOCKET) { if (optlen != sizeof(int)) goto err_clear; @@ -5360,6 +5364,14 @@ static int _bpf_getsockopt(struct sock *sk, int level, int optname, return -EINVAL; } +static int _bpf_getsockopt(struct sock *sk, int level, int optname, + char *optval, int optlen) +{ + if (sk_fullsock(sk)) + sock_owned_by_me(sk); + return __bpf_getsockopt(sk, level, optname, optval, optlen); +} + BPF_CALL_5(bpf_sk_setsockopt, struct sock *, sk, int, level, int, optname, char *, optval, int, optlen) { @@ -5400,6 +5412,40 @@ const struct bpf_func_proto bpf_sk_getsockopt_proto = { .arg5_type = ARG_CONST_SIZE, }; +BPF_CALL_5(bpf_unlocked_sk_setsockopt, struct sock *, sk, int, level, + int, optname, char *, optval, int, optlen) +{ + return __bpf_setsockopt(sk, level, optname, optval, optlen); +} + +const struct bpf_func_proto bpf_unlocked_sk_setsockopt_proto = { + .func = bpf_unlocked_sk_setsockopt, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_MEM | MEM_RDONLY, + .arg5_type = ARG_CONST_SIZE, +}; + +BPF_CALL_5(bpf_unlocked_sk_getsockopt, struct sock *, sk, int, level, + int, optname, char *, optval, int, optlen) +{ + return __bpf_getsockopt(sk, level, optname, optval, optlen); +} + +const struct bpf_func_proto bpf_unlocked_sk_getsockopt_proto = { + .func = bpf_unlocked_sk_getsockopt, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, + .arg2_type = ARG_ANYTHING, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_PTR_TO_UNINIT_MEM, + .arg5_type = ARG_CONST_SIZE, +}; + BPF_CALL_5(bpf_sock_addr_setsockopt, struct bpf_sock_addr_kern *, ctx, int, level, int, optname, char *, optval, int, optlen) { -- 2.37.0.rc0.104.g0611611a94-goog