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 5AC84C7618E for ; Fri, 21 Apr 2023 09:40:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231370AbjDUJjt (ORCPT ); Fri, 21 Apr 2023 05:39:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47236 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232017AbjDUJjU (ORCPT ); Fri, 21 Apr 2023 05:39:20 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF199AD32; Fri, 21 Apr 2023 02:39:06 -0700 (PDT) Received: from lhrpeml500004.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Q2q9P1fsPz6D8WK; Fri, 21 Apr 2023 17:34:17 +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 15.1.2507.23; Fri, 21 Apr 2023 10:39:02 +0100 Message-ID: <07629a06-935c-debf-d490-e02e5ee9f9ec@huawei.com> Date: Fri, 21 Apr 2023 12:39:01 +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 v10 09/13] landlock: Add network rules and TCP hooks support Content-Language: ru To: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= CC: , , , , , , References: <20230323085226.1432550-1-konstantin.meskhidze@huawei.com> <20230323085226.1432550-10-konstantin.meskhidze@huawei.com> <9147b444-dec4-52c3-c724-f19b3f842738@digikod.net> From: "Konstantin Meskhidze (A)" In-Reply-To: <9147b444-dec4-52c3-c724-f19b3f842738@digikod.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.123.123.126] X-ClientProxiedBy: lhrpeml500003.china.huawei.com (7.191.162.67) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: 4/16/2023 7:11 PM, Mickaël Salaün пишет: > > On 23/03/2023 09:52, 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 > > "which enables to" > Got it. > >> to specific ports. >> >> Signed-off-by: Konstantin Meskhidze >> --- >> >> 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 | 49 +++++ >> security/landlock/Kconfig | 1 + >> security/landlock/Makefile | 2 + >> security/landlock/limits.h | 6 +- >> security/landlock/net.c | 198 +++++++++++++++++++ >> 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, 450 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..09b70fb6a9a6 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; >> + >> + /** >> + * @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 +91,24 @@ struct landlock_path_beneath_attr { >> */ >> } __attribute__((packed)); >> >> +/** >> + * struct landlock_net_service_attr - TCP subnet 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; >> + >> +} __attribute__((packed)); > > You can remove the empty line and the packed attribute. > Ok. Thanks. > >> + >> /** >> * DOC: fs_access >> * >> @@ -189,4 +219,23 @@ 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 */ >> #endif /* _SECURITY_LANDLOCK_LIMITS_H */ >> diff --git a/security/landlock/net.c b/security/landlock/net.c >> new file mode 100644 >> index 000000000000..e19c339906e7 >> --- /dev/null >> +++ b/security/landlock/net.c >> @@ -0,0 +1,198 @@ >> +// 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 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_addrlen(const struct sockaddr *const address, int addrlen) >> +{ >> + if (addrlen < offsetofend(struct sockaddr, sa_family)) >> + return -EINVAL; >> + switch (address->sa_family) { >> + case AF_UNSPEC: >> + case AF_INET: >> + if (addrlen < sizeof(struct sockaddr_in)) >> + return -EINVAL; >> + return 0; >> +#if IS_ENABLED(CONFIG_IPV6) >> + case AF_INET6: >> + if (addrlen < SIN6_LEN_RFC2133) >> + return -EINVAL; >> + return 0; >> +#endif >> + } >> + WARN_ON_ONCE(1); >> + return 0; > > With this code, using any non-TCP socket would print a warning. > Yep. Already got this warning printed in tests with unix sockets. I will refactor this part as you suggest below. > All these switch/case make difficult to check consistency across > check_addrlen() and get_port() helpers, they should be inlined into > check_socket_access(), with only one switch statement, but we need to be > careful about the return error orders: first EINVAL and after > EAFNOSUPPORT. Inlining all this also enables to get rid of impossible > cases (that lead to these WARN_ON_ONCE calls). > Got it. Thanks. > > >> +} >> + >> +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 ntohs(sockaddr->sin_port); >> + } >> +#if IS_ENABLED(CONFIG_IPV6) >> + case AF_INET6: { >> + const struct sockaddr_in6 *const sockaddr_ip6 = >> + (struct sockaddr_in6 *)address; >> + return ntohs(sockaddr_ip6->sin6_port); >> + } >> +#endif >> + } >> + WARN_ON_ONCE(1); >> + return 0; >> +} >> + >> +static int check_socket_access(struct socket *sock, struct sockaddr *address, int addrlen, u16 port, >> + access_mask_t access_request) >> +{ >> + int ret; >> + 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, >> + }; >> + const struct landlock_ruleset *const domain = get_current_net_domain(); >> + >> + if (WARN_ON_ONCE(!domain)) >> + return 0; >> + if (WARN_ON_ONCE(domain->num_layers < 1)) >> + return -EACCES; >> + /* Check if it's a TCP socket. */ >> + if (sock->type != SOCK_STREAM) >> + return 0; >> + >> + ret = check_addrlen(address, addrlen); >> + if (ret) >> + return ret; > > As explained above, this should be replaced with: > > if (addrlen < offsetofend(struct sockaddr, sa_family)) > return -EINVAL; > Ok. > >> + >> + switch (address->sa_family) { > > > This below block should be moved after the generic switch statement > (i.e. once port is checked). > Do you mean checking address family after a port has been checked?? > > >> + 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_UNSPEC: > >> + case AF_INET: > > if (addrlen < sizeof(struct sockaddr_in)) > return -EINVAL; > > port = ((struct sockaddr_in *)address)->sin_port; > break; > > >> +#if IS_ENABLED(CONFIG_IPV6) >> + case AF_INET6: > > if (addrlen < SIN6_LEN_RFC2133) > return -EINVAL; > > port = ((struct sockaddr_in6 *)address)->sin6_port; > break; > > >> +#endif > > /* Allows unhandled protocols. */ > default: > return 0; > } > > if (address->sa_family == AF_UNSPEC) { > > // Add here the above AF_UNSPEC checks to be consistent with the > EINVAL/EAFNOSUPPORT return ordering. > > } > > id.key.data = (__force uintprt_t)port; > BUID_BUG_ON(...); > Will be refactored. Thanks. > > >> + 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)); >> + } > > This curly brace can now be removed and the following return line is now OK. > Ok. Got it. > >> + return allowed ? 0 : -EACCES; >> +} >> + >> +static int hook_socket_bind(struct socket *sock, struct sockaddr *address, >> + int addrlen) >> +{ >> + return check_socket_access(sock, address, addrlen, get_port(address), >> + LANDLOCK_ACCESS_NET_BIND_TCP); >> +} >> + >> +static int hook_socket_connect(struct socket *sock, struct sockaddr *address, >> + int addrlen) >> +{ >> + return check_socket_access(sock, address, addrlen, get_port(address), >> + LANDLOCK_ACCESS_NET_CONNECT_TCP); >> +} >> + >> +static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = { >> + LSM_HOOK_INIT(socket_bind, hook_socket_bind), >> + LSM_HOOK_INIT(socket_connect, hook_socket_connect), >> +}; >> + >> +__init void landlock_add_net_hooks(void) >> +{ >> + security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), >> + LANDLOCK_NAME); >> +} >> diff --git a/security/landlock/net.h b/security/landlock/net.h >> new file mode 100644 >> index 000000000000..0da1d9dff5ab >> --- /dev/null >> +++ b/security/landlock/net.h >> @@ -0,0 +1,26 @@ >> +/* SPDX-License-Identifier: GPL-2.0-only */ >> +/* >> + * Landlock LSM - Network management and hooks >> + * >> + * Copyright © 2022 Huawei Tech. Co., Ltd. >> + */ >> + >> +#ifndef _SECURITY_LANDLOCK_NET_H >> +#define _SECURITY_LANDLOCK_NET_H >> + >> +#include "common.h" >> +#include "ruleset.h" >> +#include "setup.h" >> + >> +#if IS_ENABLED(CONFIG_INET) >> +__init void landlock_add_net_hooks(void); >> + >> +int landlock_append_net_rule(struct landlock_ruleset *const ruleset, >> + const u16 port, access_mask_t access_rights); >> +#else /* IS_ENABLED(CONFIG_INET) */ >> +static inline void landlock_add_net_hooks(void) >> +{ >> +} >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> + >> +#endif /* _SECURITY_LANDLOCK_NET_H */ >> diff --git a/security/landlock/ruleset.c b/security/landlock/ruleset.c >> index 14207b666095..53cb62701280 100644 >> --- a/security/landlock/ruleset.c >> +++ b/security/landlock/ruleset.c >> @@ -36,6 +36,9 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) >> refcount_set(&new_ruleset->usage, 1); >> mutex_init(&new_ruleset->lock); >> new_ruleset->root_inode = RB_ROOT; >> +#if IS_ENABLED(CONFIG_INET) >> + new_ruleset->root_net_port = RB_ROOT; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> new_ruleset->num_layers = num_layers; >> /* >> * hierarchy = NULL >> @@ -46,16 +49,21 @@ static struct landlock_ruleset *create_ruleset(const u32 num_layers) >> } >> >> struct landlock_ruleset * >> -landlock_create_ruleset(const access_mask_t fs_access_mask) >> +landlock_create_ruleset(const access_mask_t fs_access_mask, >> + const access_mask_t net_access_mask) >> { >> struct landlock_ruleset *new_ruleset; >> >> /* Informs about useless ruleset. */ >> - if (!fs_access_mask) >> + if (!fs_access_mask && !net_access_mask) >> return ERR_PTR(-ENOMSG); >> new_ruleset = create_ruleset(1); >> - if (!IS_ERR(new_ruleset)) >> + if (IS_ERR(new_ruleset)) >> + return new_ruleset; >> + if (fs_access_mask) >> landlock_add_fs_access_mask(new_ruleset, fs_access_mask, 0); >> + if (net_access_mask) >> + landlock_add_net_access_mask(new_ruleset, net_access_mask, 0); >> return new_ruleset; >> } >> >> @@ -73,6 +81,10 @@ static bool is_object_pointer(const enum landlock_key_type key_type) >> switch (key_type) { >> case LANDLOCK_KEY_INODE: >> return true; >> +#if IS_ENABLED(CONFIG_INET) >> + case LANDLOCK_KEY_NET_PORT: >> + return false; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> } >> WARN_ON_ONCE(1); >> return false; >> @@ -126,6 +138,11 @@ static struct rb_root *get_root(struct landlock_ruleset *const ruleset, >> case LANDLOCK_KEY_INODE: >> root = &ruleset->root_inode; >> break; >> +#if IS_ENABLED(CONFIG_INET) >> + case LANDLOCK_KEY_NET_PORT: >> + root = &ruleset->root_net_port; >> + break; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> } >> if (WARN_ON_ONCE(!root)) >> return ERR_PTR(-EINVAL); >> @@ -154,7 +171,8 @@ static void build_check_ruleset(void) >> BUILD_BUG_ON(ruleset.num_rules < LANDLOCK_MAX_NUM_RULES); >> BUILD_BUG_ON(ruleset.num_layers < LANDLOCK_MAX_NUM_LAYERS); >> BUILD_BUG_ON(access_masks < >> - (LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS)); >> + ((LANDLOCK_MASK_ACCESS_FS << LANDLOCK_SHIFT_ACCESS_FS) | >> + (LANDLOCK_MASK_ACCESS_NET << LANDLOCK_SHIFT_ACCESS_NET))); >> } >> >> /** >> @@ -373,6 +391,12 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> if (err) >> goto out_unlock; >> >> +#if IS_ENABLED(CONFIG_INET) >> + /* Merges the @src network port tree. */ >> + err = merge_tree(dst, src, LANDLOCK_KEY_NET_PORT); >> + if (err) >> + goto out_unlock; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> out_unlock: >> mutex_unlock(&src->lock); >> mutex_unlock(&dst->lock); >> @@ -429,6 +453,12 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, >> if (err) >> goto out_unlock; >> >> +#if IS_ENABLED(CONFIG_INET) >> + /* Copies the @parent network port tree. */ >> + err = inherit_tree(parent, child, LANDLOCK_KEY_NET_PORT); >> + if (err) >> + goto out_unlock; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> if (WARN_ON_ONCE(child->num_layers <= parent->num_layers)) { >> err = -EINVAL; >> goto out_unlock; >> @@ -461,6 +491,11 @@ static void free_ruleset(struct landlock_ruleset *const ruleset) >> rbtree_postorder_for_each_entry_safe(freeme, next, &ruleset->root_inode, >> node) >> free_rule(freeme, LANDLOCK_KEY_INODE); >> +#if IS_ENABLED(CONFIG_INET) >> + rbtree_postorder_for_each_entry_safe(freeme, next, >> + &ruleset->root_net_port, node) >> + free_rule(freeme, LANDLOCK_KEY_NET_PORT); >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> put_hierarchy(ruleset->hierarchy); >> kfree(ruleset); >> } >> @@ -641,7 +676,8 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset, >> * >> * @domain: The domain that defines the current restrictions. >> * @access_request: The requested access rights to check. >> - * @layer_masks: The layer masks to populate. >> + * @layer_masks: It must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET >> + * elements according to @key_type. >> * @key_type: The key type to switch between access masks of different types. >> * >> * Returns: An access mask where each access right bit is set which is handled >> @@ -662,6 +698,12 @@ landlock_init_layer_masks(const struct landlock_ruleset *const domain, >> get_access_mask = landlock_get_fs_access_mask; >> num_access = LANDLOCK_NUM_ACCESS_FS; >> break; >> +#if IS_ENABLED(CONFIG_INET) >> + case LANDLOCK_KEY_NET_PORT: >> + get_access_mask = landlock_get_net_access_mask; >> + num_access = LANDLOCK_NUM_ACCESS_NET; >> + break; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> default: >> WARN_ON_ONCE(1); >> return 0; >> diff --git a/security/landlock/ruleset.h b/security/landlock/ruleset.h >> index 2251e6048ccf..dcf7fbac8367 100644 >> --- a/security/landlock/ruleset.h >> +++ b/security/landlock/ruleset.h >> @@ -33,13 +33,16 @@ >> typedef u16 access_mask_t; >> /* Makes sure all filesystem access rights can be stored. */ >> static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_FS); >> +/* Makes sure all network access rights can be stored. */ >> +static_assert(BITS_PER_TYPE(access_mask_t) >= LANDLOCK_NUM_ACCESS_NET); >> /* Makes sure for_each_set_bit() and for_each_clear_bit() calls are OK. */ >> static_assert(sizeof(unsigned long) >= sizeof(access_mask_t)); >> >> /* Ruleset access masks. */ >> -typedef u16 access_masks_t; >> +typedef u32 access_masks_t; >> /* Makes sure all ruleset access rights can be stored. */ >> -static_assert(BITS_PER_TYPE(access_masks_t) >= LANDLOCK_NUM_ACCESS_FS); >> +static_assert(BITS_PER_TYPE(access_masks_t) >= >> + LANDLOCK_NUM_ACCESS_FS + LANDLOCK_NUM_ACCESS_NET); >> >> typedef u16 layer_mask_t; >> /* Makes sure all layers can be checked. */ >> @@ -84,6 +87,13 @@ enum landlock_key_type { >> * keys. >> */ >> LANDLOCK_KEY_INODE = 1, >> +#if IS_ENABLED(CONFIG_INET) >> + /** >> + * @LANDLOCK_KEY_NET_PORT: Type of &landlock_ruleset.root_net_port's >> + * node keys. >> + */ >> + LANDLOCK_KEY_NET_PORT = 2, >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> }; >> >> /** >> @@ -158,6 +168,15 @@ struct landlock_ruleset { >> * reaches zero. >> */ >> struct rb_root root_inode; >> +#if IS_ENABLED(CONFIG_INET) >> + /** >> + * @root_net_port: Root of a red-black tree containing &struct >> + * landlock_rule nodes with network port. Once a ruleset is tied to a >> + * process (i.e. as a domain), this tree is immutable until @usage >> + * reaches zero. >> + */ >> + struct rb_root root_net_port; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> /** >> * @hierarchy: Enables hierarchy identification even when a parent >> * domain vanishes. This is needed for the ptrace protection. >> @@ -196,13 +215,13 @@ struct landlock_ruleset { >> */ >> u32 num_layers; >> /** >> - * @access_masks: Contains the subset of filesystem >> - * actions that are restricted by a ruleset. A domain >> - * saves all layers of merged rulesets in a stack >> - * (FAM), starting from the first layer to the last >> - * one. These layers are used when merging rulesets, >> - * for user space backward compatibility (i.e. >> - * future-proof), and to properly handle merged >> + * @access_masks: Contains the subset of filesystem and >> + * network actions that are restricted by a ruleset. >> + * A domain saves all layers of merged rulesets in a >> + * stack (FAM), starting from the first layer to the >> + * last one. These layers are used when merging >> + * rulesets, for user space backward compatibility >> + * (i.e. future-proof), and to properly handle merged >> * rulesets without overlapping access rights. These >> * layers are set once and never changed for the >> * lifetime of the ruleset. >> @@ -213,7 +232,8 @@ struct landlock_ruleset { >> }; >> >> struct landlock_ruleset * >> -landlock_create_ruleset(const access_mask_t access_mask); >> +landlock_create_ruleset(const access_mask_t access_mask_fs, >> + const access_mask_t access_mask_net); >> >> void landlock_put_ruleset(struct landlock_ruleset *const ruleset); >> void landlock_put_ruleset_deferred(struct landlock_ruleset *const ruleset); >> @@ -249,6 +269,19 @@ landlock_add_fs_access_mask(struct landlock_ruleset *const ruleset, >> (fs_mask << LANDLOCK_SHIFT_ACCESS_FS); >> } >> >> +static inline void >> +landlock_add_net_access_mask(struct landlock_ruleset *const ruleset, >> + const access_mask_t net_access_mask, >> + const u16 layer_level) >> +{ >> + access_mask_t net_mask = net_access_mask & LANDLOCK_MASK_ACCESS_NET; >> + >> + /* Should already be checked in sys_landlock_create_ruleset(). */ >> + WARN_ON_ONCE(net_access_mask != net_mask); >> + ruleset->access_masks[layer_level] |= >> + (net_mask << LANDLOCK_SHIFT_ACCESS_NET); >> +} >> + >> static inline access_mask_t >> landlock_get_raw_fs_access_mask(const struct landlock_ruleset *const ruleset, >> const u16 layer_level) >> @@ -266,6 +299,16 @@ landlock_get_fs_access_mask(const struct landlock_ruleset *const ruleset, >> return landlock_get_raw_fs_access_mask(ruleset, layer_level) | >> LANDLOCK_ACCESS_FS_INITIALLY_DENIED; >> } >> + >> +static inline access_mask_t >> +landlock_get_net_access_mask(const struct landlock_ruleset *const ruleset, >> + const u16 layer_level) >> +{ >> + return (ruleset->access_masks[layer_level] >> >> + LANDLOCK_SHIFT_ACCESS_NET) & >> + LANDLOCK_MASK_ACCESS_NET; >> +} >> + >> bool landlock_unmask_layers(const struct landlock_rule *const rule, >> const access_mask_t access_request, >> layer_mask_t (*const layer_masks)[], >> diff --git a/security/landlock/setup.c b/security/landlock/setup.c >> index 3f196d2ce4f9..7e4a598177b8 100644 >> --- a/security/landlock/setup.c >> +++ b/security/landlock/setup.c >> @@ -14,6 +14,7 @@ >> #include "fs.h" >> #include "ptrace.h" >> #include "setup.h" >> +#include "net.h" >> >> bool landlock_initialized __lsm_ro_after_init = false; >> >> @@ -29,6 +30,7 @@ static int __init landlock_init(void) >> landlock_add_cred_hooks(); >> landlock_add_ptrace_hooks(); >> landlock_add_fs_hooks(); >> + landlock_add_net_hooks(); >> landlock_initialized = true; >> pr_info("Up and running.\n"); >> return 0; >> diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c >> index 8a54e87dbb17..1f0edd605bc4 100644 >> --- a/security/landlock/syscalls.c >> +++ b/security/landlock/syscalls.c >> @@ -29,6 +29,7 @@ >> #include "cred.h" >> #include "fs.h" >> #include "limits.h" >> +#include "net.h" >> #include "ruleset.h" >> #include "setup.h" >> >> @@ -74,7 +75,8 @@ static void build_check_abi(void) >> { >> struct landlock_ruleset_attr ruleset_attr; >> struct landlock_path_beneath_attr path_beneath_attr; >> - size_t ruleset_size, path_beneath_size; >> + struct landlock_net_service_attr net_service_attr; >> + size_t ruleset_size, path_beneath_size, net_service_size; >> >> /* >> * For each user space ABI structures, first checks that there is no >> @@ -82,13 +84,19 @@ static void build_check_abi(void) >> * struct size. >> */ >> ruleset_size = sizeof(ruleset_attr.handled_access_fs); >> + ruleset_size += sizeof(ruleset_attr.handled_access_net); >> BUILD_BUG_ON(sizeof(ruleset_attr) != ruleset_size); >> - BUILD_BUG_ON(sizeof(ruleset_attr) != 8); >> + BUILD_BUG_ON(sizeof(ruleset_attr) != 16); >> >> path_beneath_size = sizeof(path_beneath_attr.allowed_access); >> path_beneath_size += sizeof(path_beneath_attr.parent_fd); >> BUILD_BUG_ON(sizeof(path_beneath_attr) != path_beneath_size); >> BUILD_BUG_ON(sizeof(path_beneath_attr) != 12); >> + >> + net_service_size = sizeof(net_service_attr.allowed_access); >> + net_service_size += sizeof(net_service_attr.port); >> + BUILD_BUG_ON(sizeof(net_service_attr) != net_service_size); >> + BUILD_BUG_ON(sizeof(net_service_attr) != 16); >> } >> >> /* Ruleset handling */ >> @@ -129,7 +137,7 @@ static const struct file_operations ruleset_fops = { >> .write = fop_dummy_write, >> }; >> >> -#define LANDLOCK_ABI_VERSION 3 >> +#define LANDLOCK_ABI_VERSION 4 >> >> /** >> * sys_landlock_create_ruleset - Create a new ruleset >> @@ -188,8 +196,14 @@ SYSCALL_DEFINE3(landlock_create_ruleset, >> LANDLOCK_MASK_ACCESS_FS) >> return -EINVAL; >> >> + /* Checks network content (and 32-bits cast). */ >> + if ((ruleset_attr.handled_access_net | LANDLOCK_MASK_ACCESS_NET) != >> + LANDLOCK_MASK_ACCESS_NET) >> + return -EINVAL; >> + >> /* Checks arguments and transforms to kernel struct. */ >> - ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs); >> + ruleset = landlock_create_ruleset(ruleset_attr.handled_access_fs, >> + ruleset_attr.handled_access_net); >> if (IS_ERR(ruleset)) >> return PTR_ERR(ruleset); >> >> @@ -315,13 +329,54 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, >> return err; >> } >> >> +static int add_rule_net_service(struct landlock_ruleset *ruleset, >> + const void __user *const rule_attr) >> +{ >> +#if IS_ENABLED(CONFIG_INET) >> + struct landlock_net_service_attr net_service_attr; >> + int res; >> + access_mask_t mask; >> + >> + /* Copies raw user space buffer, only one type for now. */ >> + res = copy_from_user(&net_service_attr, rule_attr, >> + sizeof(net_service_attr)); >> + if (res) >> + return -EFAULT; >> + >> + /* >> + * Informs about useless rule: empty allowed_access (i.e. deny rules) >> + * are ignored by network actions. >> + */ >> + if (!net_service_attr.allowed_access) >> + return -ENOMSG; >> + >> + /* >> + * Checks that allowed_access matches the @ruleset constraints >> + * (ruleset->access_masks[0] is automatically upgraded to 64-bits). >> + */ >> + mask = landlock_get_net_access_mask(ruleset, 0); >> + if ((net_service_attr.allowed_access | mask) != mask) >> + return -EINVAL; >> + >> + /* Denies inserting a rule with port 0 or more than U16_MAX. */ > "Denies inserting a rule with port 0 or higher than 65535." > > A test should check that it works with 65535 but not with 65536. Got it. > > >> + if ((net_service_attr.port == 0) || (net_service_attr.port > U16_MAX)) >> + return -EINVAL; >> + >> + /* Imports the new rule. */ >> + return landlock_append_net_rule(ruleset, net_service_attr.port, >> + net_service_attr.allowed_access); >> +#else /* IS_ENABLED(CONFIG_INET) */ >> + return -EAFNOSUPPORT; >> +#endif /* IS_ENABLED(CONFIG_INET) */ >> +} >> + >> /** >> * sys_landlock_add_rule - Add a new rule to a ruleset >> * >> * @ruleset_fd: File descriptor tied to the ruleset that should be extended >> * with the new rule. >> - * @rule_type: Identify the structure type pointed to by @rule_attr (only >> - * %LANDLOCK_RULE_PATH_BENEATH for now). >> + * @rule_type: Identify the structure type pointed to by @rule_attr: >> + * %LANDLOCK_RULE_PATH_BENEATH or %LANDLOCK_RULE_NET_SERVICE. >> * @rule_attr: Pointer to a rule (only of type &struct >> * landlock_path_beneath_attr for now). >> * @flags: Must be 0. >> @@ -332,6 +387,8 @@ static int add_rule_path_beneath(struct landlock_ruleset *const ruleset, >> * Possible returned errors are: >> * >> * - %EOPNOTSUPP: Landlock is supported by the kernel but disabled at boot time; >> + * - %EAFNOSUPPORT: @rule_type is LANDLOCK_RULE_NET_SERVICE but TCP/IP is not >> + * supported by the running kernel; >> * - %EINVAL: @flags is not 0, or inconsistent access in the rule (i.e. >> * &landlock_path_beneath_attr.allowed_access is not a subset of the >> * ruleset handled accesses); >> @@ -366,6 +423,9 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, >> case LANDLOCK_RULE_PATH_BENEATH: >> err = add_rule_path_beneath(ruleset, rule_attr); >> break; >> + case LANDLOCK_RULE_NET_SERVICE: >> + err = add_rule_net_service(ruleset, rule_attr); >> + break; >> default: >> err = -EINVAL; >> break; >> diff --git a/tools/testing/selftests/landlock/base_test.c b/tools/testing/selftests/landlock/base_test.c >> index 792c3f0a59b4..646f778dfb1e 100644 >> --- a/tools/testing/selftests/landlock/base_test.c >> +++ b/tools/testing/selftests/landlock/base_test.c >> @@ -75,7 +75,7 @@ TEST(abi_version) >> const struct landlock_ruleset_attr ruleset_attr = { >> .handled_access_fs = LANDLOCK_ACCESS_FS_READ_FILE, >> }; >> - ASSERT_EQ(3, landlock_create_ruleset(NULL, 0, >> + ASSERT_EQ(4, landlock_create_ruleset(NULL, 0, >> LANDLOCK_CREATE_RULESET_VERSION)); >> >> ASSERT_EQ(-1, landlock_create_ruleset(&ruleset_attr, 0, >> -- >> 2.25.1 >> > .