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 BC116C54EBD for ; Mon, 9 Jan 2023 08:07:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233833AbjAIIHz (ORCPT ); Mon, 9 Jan 2023 03:07:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236440AbjAIIHY (ORCPT ); Mon, 9 Jan 2023 03:07:24 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 776D76359; Mon, 9 Jan 2023 00:07:15 -0800 (PST) Received: from lhrpeml500004.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Nr5y95jnWz6HJVg; Mon, 9 Jan 2023 16:02:09 +0800 (CST) Received: from [10.123.123.126] (10.123.123.126) by lhrpeml500004.china.huawei.com (7.191.163.9) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Mon, 9 Jan 2023 08:07:05 +0000 Message-ID: <38f4e2ac-0cd4-e205-bff1-a859e0855731@huawei.com> Date: Mon, 9 Jan 2023 11:07:04 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.4.1 Subject: Re: [PATCH v8 08/12] landlock: Implement TCP network hooks Content-Language: ru To: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= , , , "Alejandro Colomar (man-pages)" CC: , , , , References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> <20221021152644.155136-9-konstantin.meskhidze@huawei.com> <3452964b-04d3-b297-92a1-1220e087323e@digikod.net> <258ba4aa-6b12-abda-75b9-ffa196fba683@huawei.com> From: "Konstantin Meskhidze (A)" In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.123.123.126] X-ClientProxiedBy: lhrpeml100005.china.huawei.com (7.191.160.25) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 1/6/2023 10:30 PM, Mickaël Salaün пишет: > > On 05/01/2023 09:57, Konstantin Meskhidze (A) wrote: >> >> >> 11/17/2022 9:43 PM, Mickaël Salaün пишет: >>> >>> On 21/10/2022 17:26, Konstantin Meskhidze wrote: >>>> This patch adds support of socket_bind() and socket_connect() hooks. >>>> It's possible to restrict binding and connecting of TCP sockets to >>>> particular ports. >>> >>> 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 v7: >>>> * Minor fixes. >>>> * Refactors commit message. >>>> >>>> Changes since v6: >>>> * Updates copyright. >>>> * Refactors landlock_append_net_rule() and check_socket_access() >>>> functions with landlock_id type. >>>> >>>> Changes since v5: >>>> * Fixes some logic errors. >>>> * Formats code with clang-format-14. >>>> >>>> Changes since v4: >>>> * Factors out CONFIG_INET into make file. >>>> * Refactors check_socket_access(). >>>> * Adds helper get_port(). >>>> * Adds CONFIG_IPV6 in get_port(), hook_socket_bind/connect >>>> functions to support AF_INET6 family. >>>> * Adds AF_UNSPEC family support in hook_socket_bind/connect >>>> functions. >>>> * Refactors add_rule_net_service() and landlock_add_rule >>>> syscall to support network rule inserting. >>>> * Refactors init_layer_masks() to support network rules. >>>> >>>> Changes since v3: >>>> * Splits commit. >>>> * Adds SECURITY_NETWORK in config. >>>> * Adds IS_ENABLED(CONFIG_INET) if a kernel has no INET configuration. >>>> * Adds hook_socket_bind and hook_socket_connect hooks. >>>> >>>> --- >>>> security/landlock/Kconfig | 1 + >>>> security/landlock/Makefile | 2 + >>>> security/landlock/net.c | 164 +++++++++++++++++++++++++++++++++++ >>>> security/landlock/net.h | 26 ++++++ >>>> security/landlock/setup.c | 2 + >>>> security/landlock/syscalls.c | 59 ++++++++++++- >>>> 6 files changed, 251 insertions(+), 3 deletions(-) >>>> create mode 100644 security/landlock/net.c >>>> create mode 100644 security/landlock/net.h >>>> >>>> diff --git a/security/landlock/Kconfig b/security/landlock/Kconfig >>>> index 8e33c4e8ffb8..10c099097533 100644 >>>> --- a/security/landlock/Kconfig >>>> +++ b/security/landlock/Kconfig >>>> @@ -3,6 +3,7 @@ >>>> config SECURITY_LANDLOCK >>>> bool "Landlock support" >>>> depends on SECURITY && !ARCH_EPHEMERAL_INODES >>>> + select SECURITY_NETWORK >>>> select SECURITY_PATH >>>> help >>>> Landlock is a sandboxing mechanism that enables processes to restrict >>>> diff --git a/security/landlock/Makefile b/security/landlock/Makefile >>>> index 7bbd2f413b3e..53d3c92ae22e 100644 >>>> --- a/security/landlock/Makefile >>>> +++ b/security/landlock/Makefile >>>> @@ -2,3 +2,5 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o >>>> >>>> landlock-y := setup.o syscalls.o object.o ruleset.o \ >>>> cred.o ptrace.o fs.o >>>> + >>>> +landlock-$(CONFIG_INET) += net.o >>>> \ No newline at end of file >>>> diff --git a/security/landlock/net.c b/security/landlock/net.c >>>> new file mode 100644 >>>> index 000000000000..39e8a156a1f4 >>>> --- /dev/null >>>> +++ b/security/landlock/net.c >>>> @@ -0,0 +1,164 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only >>>> +/* >>>> + * Landlock LSM - Network management and hooks >>>> + * >>>> + * Copyright © 2022 Huawei Tech. Co., Ltd. >>>> + * Copyright © 2022 Microsoft Corporation >>>> + */ >>>> + >>>> +#include >>>> +#include >>>> +#include >>>> +#include >>>> + >>>> +#include "common.h" >>>> +#include "cred.h" >>>> +#include "limits.h" >>>> +#include "net.h" >>>> +#include "ruleset.h" >>>> + >>>> +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, >>>> + const u16 port, access_mask_t access_rights) >>>> +{ >>>> + int err; >>>> + const struct landlock_id id = { >>>> + .key.data = port, >>>> + .type = LANDLOCK_KEY_NET_PORT, >>>> + }; >>>> + BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data)); >>>> + >>>> + /* Transforms relative access rights to absolute ones. */ >>>> + access_rights |= LANDLOCK_MASK_ACCESS_NET & >>>> + ~landlock_get_net_access_mask(ruleset, 0); >>>> + >>>> + mutex_lock(&ruleset->lock); >>>> + err = landlock_insert_rule(ruleset, id, access_rights); >>>> + mutex_unlock(&ruleset->lock); >>>> + >>>> + return err; >>>> +} >>>> + >>>> +static int check_socket_access(const struct landlock_ruleset *const domain, >>>> + u16 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; >>>> + >>>> + rule = landlock_find_rule(domain, id); >>>> + handled_access = init_layer_masks(domain, access_request, &layer_masks, >>>> + LANDLOCK_KEY_NET_PORT); >>>> + allowed = unmask_layers(rule, handled_access, &layer_masks, >>>> + ARRAY_SIZE(layer_masks)); >>>> + >>>> + return allowed ? 0 : -EACCES; >>>> +} >>>> + >>>> +static u16 get_port(const struct sockaddr *const address) >>> >>> get_port() should return a __be16 type. This enables to avoid converting >>> port when checking a rule. >> >> In this case a user must do a coverting port into __be16: >> >> struct landlock_net_service_attr net_service = { >> .allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP, >> >> .port = htons(sock_port), >> }; >> I think that a user should not think about this conversion cause it >> makes UAPI more complex to use. Lets do this under kernel's hood and let >> it as it is now -> u16 port. >> >> What do you think? > > BE and LE conversions may be error prone without strong typing, but the > current Linux network UAPI uses this convention (see related syscalls), > so developers already use htons() in their applications. I think it is > less hazardous to use the same convention. It would be nice to have the > point of view of network and API folks though. Ok. Thanks. Let ports be in BE format like in network packets. What should a selftest with port conversion be like? 1. Set a port with a Landlock rule with no conversion. get an error wit bind/connect actions. 2. Convert a port with htons(sock_port). get no error. What do you think? > .