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 B50F9EB64D9 for ; Mon, 26 Jun 2023 18:57:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229821AbjFZS5S (ORCPT ); Mon, 26 Jun 2023 14:57:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229626AbjFZS5R (ORCPT ); Mon, 26 Jun 2023 14:57:17 -0400 Received: from smtp-8fa9.mail.infomaniak.ch (smtp-8fa9.mail.infomaniak.ch [83.166.143.169]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 28FDFF2 for ; Mon, 26 Jun 2023 11:57:15 -0700 (PDT) Received: from smtp-3-0001.mail.infomaniak.ch (unknown [10.4.36.108]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4QqcXT2gZtzMpnq3; Mon, 26 Jun 2023 18:57:13 +0000 (UTC) Received: from unknown by smtp-3-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 4QqcXS3nDqzMpvTt; Mon, 26 Jun 2023 20:57:12 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1687805833; bh=i82AV8gAS5naCAVaAT5nSKqFj/O0yC+fa0yOcPb/vLo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bvzCKTOsg4bfFKVhUzs52KZeYPsOt66VCe7PtS9Rxttzf/b1DeKsuO+MwEYmFA6zf 1YICBTyBUAQsOLf7SMSM9Msmr6zO2BLGjLuHTGPaUNDOcVZNleQA/tuVEMSo+5s3TG 7l1gc0xwP4O+hQj53youxM4eGm/VlC/pPW62HNc0= Message-ID: Date: Mon, 26 Jun 2023 20:57:11 +0200 MIME-Version: 1.0 User-Agent: Subject: Re: [PATCH v11 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: <20230515161339.631577-1-konstantin.meskhidze@huawei.com> <20230515161339.631577-9-konstantin.meskhidze@huawei.com> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= In-Reply-To: <20230515161339.631577-9-konstantin.meskhidze@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Infomaniak-Routing: alpha Precedence: bulk List-ID: Complementary review: On 15/05/2023 18:13, 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 enables to restrict TCP socket binding and connection > to specific ports. > > Co-developed-by: Mickaël Salaün > Signed-off-by: Konstantin Meskhidze > --- > > Changes since v10: > * Removes "packed" attribute. > * Applies Mickaёl's patch with some refactoring. > * Deletes get_port() and check_addrlen() helpers. > * Refactors check_socket_access() by squashing get_port() and > check_addrlen() helpers into it. > * Fixes commit message. > > Changes since v9: > * Changes UAPI port field to __u64. > * Moves shared code into check_socket_access(). > * Adds get_raw_handled_net_accesses() and > get_current_net_domain() helpers. > * Minor fixes. > > 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. > > --- > include/uapi/linux/landlock.h | 48 +++++ > security/landlock/Kconfig | 1 + > security/landlock/Makefile | 2 + > security/landlock/limits.h | 6 +- > security/landlock/net.c | 174 +++++++++++++++++++ > security/landlock/net.h | 26 +++ > security/landlock/ruleset.c | 52 +++++- > security/landlock/ruleset.h | 63 +++++-- > security/landlock/setup.c | 2 + > security/landlock/syscalls.c | 72 +++++++- > tools/testing/selftests/landlock/base_test.c | 2 +- > 11 files changed, 425 insertions(+), 23 deletions(-) > create mode 100644 security/landlock/net.c > create mode 100644 security/landlock/net.h > > diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h > index 81d09ef9aa50..93794759dad4 100644 > --- a/include/uapi/linux/landlock.h > +++ b/include/uapi/linux/landlock.h > @@ -31,6 +31,13 @@ struct landlock_ruleset_attr { > * this access right. > */ > __u64 handled_access_fs; > + Please remove this empty line. > + /** > + * @handled_access_net: Bitmask of actions (cf. `Network flags`_) > + * that is handled by this ruleset and should then be forbidden if no > + * rule explicitly allow them. > + */ > + __u64 handled_access_net; > }; > > /* > @@ -54,6 +61,11 @@ enum landlock_rule_type { > * landlock_path_beneath_attr . > */ > LANDLOCK_RULE_PATH_BENEATH = 1, > + /** > + * @LANDLOCK_RULE_NET_SERVICE: Type of a &struct > + * landlock_net_service_attr . > + */ > + LANDLOCK_RULE_NET_SERVICE = 2, > }; > > /** > @@ -79,6 +91,23 @@ struct landlock_path_beneath_attr { > */ > } __attribute__((packed)); > > +/** > + * struct landlock_net_service_attr - TCP subnet definition s/TCP subnet definition/Network service definition/ > + * > + * Argument of sys_landlock_add_rule(). > + */ > +struct landlock_net_service_attr { > + /** > + * @allowed_access: Bitmask of allowed access network for services > + * (cf. `Network flags`_). > + */ > + __u64 allowed_access; > + /** > + * @port: Network port. > + */ > + __u64 port; > +}; > + > /** > * DOC: fs_access > * > @@ -189,4 +218,23 @@ struct landlock_path_beneath_attr { > #define LANDLOCK_ACCESS_FS_TRUNCATE (1ULL << 14) > /* clang-format on */ > > +/** > + * DOC: net_access > + * > + * Network flags > + * ~~~~~~~~~~~~~~~~ > + * > + * These flags enable to restrict a sandboxed process to a set of network > + * actions. > + * > + * TCP sockets with allowed actions: > + * > + * - %LANDLOCK_ACCESS_NET_BIND_TCP: Bind a TCP socket to a local port. > + * - %LANDLOCK_ACCESS_NET_CONNECT_TCP: Connect an active TCP socket to > + * a remote port. > + */ > +/* clang-format off */ > +#define LANDLOCK_ACCESS_NET_BIND_TCP (1ULL << 0) > +#define LANDLOCK_ACCESS_NET_CONNECT_TCP (1ULL << 1) > +/* clang-format on */ > #endif /* _UAPI_LINUX_LANDLOCK_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/limits.h b/security/landlock/limits.h > index bafb3b8dc677..8a1a6463c64e 100644 > --- a/security/landlock/limits.h > +++ b/security/landlock/limits.h > @@ -23,6 +23,10 @@ > #define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS) > #define LANDLOCK_SHIFT_ACCESS_FS 0 > > -/* clang-format on */ > +#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP > +#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1) > +#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET) > +#define LANDLOCK_SHIFT_ACCESS_NET LANDLOCK_NUM_ACCESS_FS > > +/* clang-format on */ Please the empty line to make this patch clean. > #endif /* _SECURITY_LANDLOCK_LIMITS_H */ > diff --git a/security/landlock/net.c b/security/landlock/net.c > new file mode 100644 > index 000000000000..f8d2be53ac0d > --- /dev/null > +++ b/security/landlock/net.c > @@ -0,0 +1,174 @@ > +// 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 = (__force uintptr_t)htons(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 access_mask_t > +get_raw_handled_net_accesses(const struct landlock_ruleset *const domain) > +{ > + access_mask_t access_dom = 0; > + size_t layer_level; > + > + for (layer_level = 0; layer_level < domain->num_layers; layer_level++) > + access_dom |= landlock_get_net_access_mask(domain, layer_level); > + return access_dom; > +} > + > +static const struct landlock_ruleset *get_current_net_domain(void) > +{ > + const struct landlock_ruleset *const dom = > + landlock_get_current_domain(); > + > + if (!dom || !get_raw_handled_net_accesses(dom)) > + return NULL; > + > + return dom; > +} > + > +static int check_socket_access(struct socket *const sock, > + struct sockaddr *const address, > + const int addrlen, > + const access_mask_t access_request) > +{ > + __be16 port; > + layer_mask_t layer_masks[LANDLOCK_NUM_ACCESS_NET] = {}; > + const struct landlock_rule *rule; > + access_mask_t handled_access; > + struct landlock_id id = { > + .type = LANDLOCK_KEY_NET_PORT, > + }; > + const struct landlock_ruleset *const domain = get_current_net_domain(); > + > + if (WARN_ON_ONCE(!domain)) The WARN_ON_ONCE() needs to be removed for processes not sandboxed. This should be printed when running the tests. > + return 0; > + if (WARN_ON_ONCE(domain->num_layers < 1)) > + return -EACCES; > + > + /* Checks if it's a TCP socket. */ > + if (sock->type != SOCK_STREAM) > + return 0; > + > + /* Checks for minimal header length. */ > + if (addrlen < offsetofend(struct sockaddr, sa_family)) You can use "typeof(*address)" instead of struct sockaddr, this makes it easier to review. > + return -EINVAL; > + [...]