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 3D3E8C636CD for ; Fri, 10 Feb 2023 17:40:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233076AbjBJRkH (ORCPT ); Fri, 10 Feb 2023 12:40:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47190 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232949AbjBJRkE (ORCPT ); Fri, 10 Feb 2023 12:40:04 -0500 Received: from smtp-bc0b.mail.infomaniak.ch (smtp-bc0b.mail.infomaniak.ch [IPv6:2001:1600:3:17::bc0b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D8F97BFC0 for ; Fri, 10 Feb 2023 09:39:40 -0800 (PST) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4PD1Fj0BpHzMqFxj; Fri, 10 Feb 2023 18:39:37 +0100 (CET) Received: from unknown by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4PD1Fh2Q0dzMrSlm; Fri, 10 Feb 2023 18:39:36 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1676050776; bh=b+OrqShjRbwmcLjB2X0bdHz51OO6Z5luGmCeegifpCg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=J1stQklVC4k83zoyBbLCh7pdNpuAPLtcj0AsHYMXBqUrynLDfK9VOA4XEyZ5+loKL UBZ+wPfg3J7xYy+p3aPTdjPAk1aJ2zuD+RLq/EhU6JM+xPIpealCAUI37TZvUKiDOm nb0PzXRtJbsQrK69hevx3f/Ful7WE0atM8aUouTA= Message-ID: <5198f456-91f5-5c65-76c2-45b82ccb05eb@digikod.net> Date: Fri, 10 Feb 2023 18:39:35 +0100 MIME-Version: 1.0 User-Agent: Subject: Re: [PATCH v9 08/12] landlock: Add network rules and TCP hooks support Content-Language: en-US To: Konstantin Meskhidze Cc: willemdebruijn.kernel@gmail.com, gnoack3000@gmail.com, linux-security-module@vger.kernel.org, netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, yusongping@huawei.com, artem.kuzin@huawei.com References: <20230116085818.165539-1-konstantin.meskhidze@huawei.com> <20230116085818.165539-9-konstantin.meskhidze@huawei.com> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= In-Reply-To: <20230116085818.165539-9-konstantin.meskhidze@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Infomaniak-Routing: alpha Precedence: bulk List-ID: On 16/01/2023 09:58, Konstantin Meskhidze wrote: > This commit adds network rules support in the ruleset management > helpers and the landlock_create_ruleset syscall. > Refactor user space API to support network actions. Add new network > access flags, network rule and network attributes. Increment Landlock > ABI version. Expand access_masks_t to u32 to be sure network access > rights can be stored. Implement socket_bind() and socket_connect() > LSM hooks, which enable to restrict TCP socket binding and connection > to specific ports. > > Signed-off-by: Konstantin Meskhidze > --- > > Changes since v8: > * Squashes commits. > * Refactors commit message. > * Changes UAPI port field to __be16. > * Changes logic of bind/connect hooks with AF_UNSPEC families. > * Adds address length checking. > * Minor fixes. > > Changes since v7: > * Squashes commits. > * Increments ABI version to 4. > * Refactors commit message. > * Minor fixes. > > Changes since v6: > * Renames landlock_set_net_access_mask() to landlock_add_net_access_mask() > because it OR values. > * Makes landlock_add_net_access_mask() more resilient incorrect values. > * Refactors landlock_get_net_access_mask(). > * Renames LANDLOCK_MASK_SHIFT_NET to LANDLOCK_SHIFT_ACCESS_NET and use > LANDLOCK_NUM_ACCESS_FS as value. > * Updates access_masks_t to u32 to support network access actions. > * Refactors landlock internal functions to support network actions with > landlock_key/key_type/id types. > > Changes since v5: > * Gets rid of partial revert from landlock_add_rule > syscall. > * Formats code with clang-format-14. > > Changes since v4: > * Refactors landlock_create_ruleset() - splits ruleset and > masks checks. > * Refactors landlock_create_ruleset() and landlock mask > setters/getters to support two rule types. > * Refactors landlock_add_rule syscall add_rule_path_beneath > function by factoring out get_ruleset_from_fd() and > landlock_put_ruleset(). > > Changes since v3: > * Splits commit. > * Adds network rule support for internal landlock functions. > * Adds set_mask and get_mask for network. > * Adds rb_root root_net_port. [...] > +static int check_socket_access(const struct landlock_ruleset *const domain, > + struct sockaddr *address, __be16 port, > + access_mask_t access_request) > +{ > + bool allowed = false; > + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; > + const struct landlock_rule *rule; > + access_mask_t handled_access; > + const struct landlock_id id = { > + .key.data = port, > + .type = LANDLOCK_KEY_NET_PORT, > + }; > + > + if (WARN_ON_ONCE(!domain)) > + return 0; > + if (WARN_ON_ONCE(domain->num_layers < 1)) > + return -EACCES; > + > + switch (address->sa_family) { > + case AF_UNSPEC: > + /* > + * Connecting to an address with AF_UNSPEC dissolves the TCP > + * association, which have the same effect as closing the > + * connection while retaining the socket object (i.e., the file > + * descriptor). As for dropping privileges, closing > + * connections is always allowed. > + */ > + if (access_request == LANDLOCK_ACCESS_NET_CONNECT_TCP) > + return 0; > + > + /* > + * For compatibility reason, accept AF_UNSPEC for bind > + * accesses (mapped to AF_INET) only if the address is > + * INADDR_ANY (cf. __inet_bind). Checking the address is > + * required to not wrongfully return -EACCES instead of > + * -EAFNOSUPPORT. > + */ > + if (access_request == LANDLOCK_ACCESS_NET_BIND_TCP) { > + const struct sockaddr_in *const sockaddr = > + (struct sockaddr_in *)address; > + > + if (sockaddr->sin_addr.s_addr != htonl(INADDR_ANY)) > + return -EAFNOSUPPORT; > + } > + > + fallthrough; > + case AF_INET: > +#if IS_ENABLED(CONFIG_IPV6) > + case AF_INET6: > +#endif > + rule = landlock_find_rule(domain, id); > + handled_access = landlock_init_layer_masks( > + domain, access_request, &layer_masks, > + LANDLOCK_KEY_NET_PORT); > + allowed = landlock_unmask_layers(rule, handled_access, > + &layer_masks, > + ARRAY_SIZE(layer_masks)); > + > + fallthrough; You can remove this fallthrough. > + } > + return allowed ? 0 : -EACCES; > +} > + > +static u16 get_port(const struct sockaddr *const address) > +{ > + /* Gets port value in host byte order. */ > + switch (address->sa_family) { > + case AF_UNSPEC: > + case AF_INET: { > + const struct sockaddr_in *const sockaddr = > + (struct sockaddr_in *)address; > + return sockaddr->sin_port; > + } > +#if IS_ENABLED(CONFIG_IPV6) > + case AF_INET6: { > + const struct sockaddr_in6 *const sockaddr_ip6 = > + (struct sockaddr_in6 *)address; > + return sockaddr_ip6->sin6_port; > + } > +#endif > + } > + WARN_ON_ONCE(1); > + return 0; > +} > + > +static int hook_socket_bind(struct socket *sock, struct sockaddr *address, > + int addrlen) > +{ > + int ret; > + const struct landlock_ruleset *const dom = > + landlock_get_current_domain(); landlock_get_current_domain() should only be called by a get_current_net_domain() wrapper that checks if the current domain handles network accesses. See get_current_fs_domain() in patch 2/12. > + > + if (!dom) > + return 0; > + > + /* Check if it's a TCP socket. */ > + if (sock->type != SOCK_STREAM) > + return 0; > + > + ret = check_addrlen(address, addrlen); > + if (ret) > + return ret; > + > + return check_socket_access(dom, address, get_port(address), > + LANDLOCK_ACCESS_NET_BIND_TCP); > +}