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=-7.1 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, UNWANTED_LANGUAGE_BODY,USER_AGENT_GIT 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 252A7C2D0DB for ; Wed, 22 Jan 2020 13:06:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF56B24683 for ; Wed, 22 Jan 2020 13:06:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=cloudflare.com header.i=@cloudflare.com header.b="V4wQrNgv" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729158AbgAVNGE (ORCPT ); Wed, 22 Jan 2020 08:06:04 -0500 Received: from mail-lj1-f196.google.com ([209.85.208.196]:45163 "EHLO mail-lj1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729137AbgAVNGE (ORCPT ); Wed, 22 Jan 2020 08:06:04 -0500 Received: by mail-lj1-f196.google.com with SMTP id j26so6666959ljc.12 for ; Wed, 22 Jan 2020 05:06:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cloudflare.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=WDO2nKU1fG1HYrmFQY9JEu5IKkozhVaPgoSVYJJKkMI=; b=V4wQrNgvRxPPH5lCCP8EnDGbaVYaDdy/hxai5VL5n1Q1L23749AhnMb/6STX2ELlI8 Y6XIahqQOiz4QE/oFc9stVAAfRpu6c19Xl3sCN8v0c9xuJHyIal/Os63u2PfKFxZZXSy YkDOS6p1nYxXqPv5iIRvftR78ghX0yxeNZMMw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=WDO2nKU1fG1HYrmFQY9JEu5IKkozhVaPgoSVYJJKkMI=; b=K5EQaYQWuYrM4XyHltW74cIZ1tvr9ytaiV4AoDruvp1pnBVJOdjuBKEMZHD3Av6KBX YWQOyHYMmlflzmnoRv65uP1jNIEuZ+/1PagYSw46K+ZTECRtPE+NtQjUPRVQWCFfuCJi gcuAWLJHybgsRdVbuNJUvemXTqWxCJNNF0Inq6ESC+fO8CjpB5bk/NnRTnZRfhqX98wq /FA4MZSQHvgKyPkeeN8ViSW8kWAzCMb5W9J4CgXWQiBAku9lMMThmHzAjEpAe56ZvuYh UCHbZVRZE4dKchyVhkN+NvLVOfFbkFH7x0xjNL895gejIApr0efXUObZrNym5JV1VZTC FxqQ== X-Gm-Message-State: APjAAAVMyBxKDWwvRe0SH1KQnK7d3tG73z6/Gwnq+uTQ3BNryRq+HGhr 0uVmdI9SiVwQNUrvHtea4FiWuM7TGvJ6Rg== X-Google-Smtp-Source: APXvYqzBx66ktUhe3bGrmjmUCTeJGlUkEDWVtDztQ01dKIAxptJxribVaCAh0jxNbtnxboNvZkDq7w== X-Received: by 2002:a2e:b4cb:: with SMTP id r11mr19168856ljm.68.1579698361831; Wed, 22 Jan 2020 05:06:01 -0800 (PST) Received: from cloudflare.com ([2a02:a310:c262:aa00:b35e:8938:2c2a:ba8b]) by smtp.gmail.com with ESMTPSA id t13sm20242233ljk.78.2020.01.22.05.06.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2020 05:06:01 -0800 (PST) From: Jakub Sitnicki To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, kernel-team@cloudflare.com, Alexei Starovoitov , Daniel Borkmann , John Fastabend , Lorenz Bauer , Martin Lau Subject: [PATCH bpf-next v3 07/12] bpf, sockmap: Return socket cookie on lookup from syscall Date: Wed, 22 Jan 2020 14:05:44 +0100 Message-Id: <20200122130549.832236-8-jakub@cloudflare.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200122130549.832236-1-jakub@cloudflare.com> References: <20200122130549.832236-1-jakub@cloudflare.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Tooling that populates the SOCKMAP with sockets from user-space needs a way to inspect its contents. Returning the struct sock * that SOCKMAP holds to user-space is neither safe nor useful. An approach established by REUSEPORT_SOCKARRAY is to return a socket cookie (a unique identifier) instead. Since socket cookies are u64 values, SOCKMAP needs to support such a value size for lookup to be possible. This requires special handling on update, though. Attempts to do a lookup on SOCKMAP holding u32 values will be met with ENOSPC error. Acked-by: John Fastabend Acked-by: Martin KaFai Lau Signed-off-by: Jakub Sitnicki --- net/core/sock_map.c | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) diff --git a/net/core/sock_map.c b/net/core/sock_map.c index 439f1e0b995e..cabe85892ba3 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -10,6 +10,7 @@ #include #include #include +#include struct bpf_stab { struct bpf_map map; @@ -31,7 +32,8 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) return ERR_PTR(-EPERM); if (attr->max_entries == 0 || attr->key_size != 4 || - attr->value_size != 4 || + (attr->value_size != sizeof(u32) && + attr->value_size != sizeof(u64)) || attr->map_flags & ~SOCK_CREATE_FLAG_MASK) return ERR_PTR(-EINVAL); @@ -298,6 +300,21 @@ static void *sock_map_lookup(struct bpf_map *map, void *key) return ERR_PTR(-EOPNOTSUPP); } +static void *sock_map_lookup_sys(struct bpf_map *map, void *key) +{ + struct sock *sk; + + if (map->value_size != sizeof(u64)) + return ERR_PTR(-ENOSPC); + + sk = __sock_map_lookup_elem(map, *(u32 *)key); + if (!sk) + return ERR_PTR(-ENOENT); + + sock_gen_cookie(sk); + return &sk->sk_cookie; +} + static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test, struct sock **psk) { @@ -460,12 +477,19 @@ static bool sock_map_redirect_okay(const struct sock *sk) static int sock_map_update_elem(struct bpf_map *map, void *key, void *value, u64 flags) { - u32 ufd = *(u32 *)value; u32 idx = *(u32 *)key; struct socket *sock; struct sock *sk; + u64 ufd; int ret; + if (map->value_size == sizeof(u64)) + ufd = *(u64 *)value; + else + ufd = *(u32 *)value; + if (ufd > S32_MAX) + return -EINVAL; + sock = sockfd_lookup(ufd, &ret); if (!sock) return ret; @@ -569,6 +593,7 @@ const struct bpf_map_ops sock_map_ops = { .map_alloc = sock_map_alloc, .map_free = sock_map_free, .map_get_next_key = sock_map_get_next_key, + .map_lookup_elem_sys_only = sock_map_lookup_sys, .map_update_elem = sock_map_update_elem, .map_delete_elem = sock_map_delete_elem, .map_lookup_elem = sock_map_lookup, -- 2.24.1