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 67494C3DA7D for ; Tue, 3 Jan 2023 12:45:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233119AbjACMol (ORCPT ); Tue, 3 Jan 2023 07:44:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230488AbjACMoi (ORCPT ); Tue, 3 Jan 2023 07:44:38 -0500 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9F5EDF64; Tue, 3 Jan 2023 04:44:36 -0800 (PST) Received: from lhrpeml500004.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4NmXQj0TjLz6J7mG; Tue, 3 Jan 2023 20:41:01 +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; Tue, 3 Jan 2023 12:44:34 +0000 Message-ID: Date: Tue, 3 Jan 2023 15:44:33 +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 07/12] landlock: Add network rules support Content-Language: ru To: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= CC: , , , , , , Linux API , "Alejandro Colomar (man-pages)" References: <20221021152644.155136-1-konstantin.meskhidze@huawei.com> <20221021152644.155136-8-konstantin.meskhidze@huawei.com> <49391484-7401-e7c7-d909-3bd6bd024731@digikod.net> From: "Konstantin Meskhidze (A)" In-Reply-To: <49391484-7401-e7c7-d909-3bd6bd024731@digikod.net> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.123.123.126] X-ClientProxiedBy: lhrpeml500001.china.huawei.com (7.191.163.213) To lhrpeml500004.china.huawei.com (7.191.163.9) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 11/17/2022 9:43 PM, Mickaël Salaün пишет: > > On 21/10/2022 17:26, Konstantin Meskhidze wrote: >> This commit adds network rules support in internal landlock functions >> (presented in ruleset.c) and landlock_create_ruleset syscall. > > …in the ruleset management helpers and the landlock_create_ruleset syscall. > > >> Refactors user space API to support network actions. Adds new network > > Refactor… > >> access flags, network rule and network attributes. Increments Landlock > > Increment… > >> ABI version. >> >> Signed-off-by: Konstantin Meskhidze >> --- >> >> 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/limits.h | 6 +- >> security/landlock/ruleset.c | 55 ++++++++++++++-- >> security/landlock/ruleset.h | 68 ++++++++++++++++---- >> security/landlock/syscalls.c | 13 +++- >> tools/testing/selftests/landlock/base_test.c | 2 +- >> 6 files changed, 170 insertions(+), 23 deletions(-) >> >> diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h >> index f3223f964691..096b683c6ff3 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. >> + */ >> + __u16 port; > > From an UAPI point of view, I think the port field should be __be16, as > for sockaddr_in->port and other network-related APIs. This will require > some kernel changes to please sparse: make C=2 security/landlock/ must > not print any warning. > > Using big-endian values as keys (casted to uintptr_t, not strictly > __be16) in the rb-tree should not be an issue because there is no port > range ordering (for now). > > A dedicated test should check that endianness is correct, e.g. by using > different port encoding. This should include passing and failing tests, > but they should work on all architectures (i.e. big or little endian). > Hi Mickaёl. Could you please give me a piece of advice about these kind of tests? I have not entirely understood this point. > >> + >> +} __attribute__((packed)); >> + >> /** >> * DOC: fs_access >> * >> @@ -173,4 +203,23 @@ 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/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/ruleset.c b/security/landlock/ruleset.c >> index c7cf54ba4f6d..9277c1295114 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 inline 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 inline 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 +171,9 @@ 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) + > > This is correct but because we are dealing with bitmasks I would prefer > to use "|" instead of "+". > > >> + (LANDLOCK_MASK_ACCESS_NET >> + << LANDLOCK_SHIFT_ACCESS_NET)); >> } >> >> /** >> @@ -370,7 +389,12 @@ static int merge_ruleset(struct landlock_ruleset *const dst, >> err = merge_tree(dst, src, LANDLOCK_KEY_INODE); >> if (err) >> goto out_unlock; >> - > > Please keep this newline. > >> +#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); >> @@ -426,7 +450,12 @@ static int inherit_ruleset(struct landlock_ruleset *const parent, >> err = inherit_tree(parent, child, LANDLOCK_KEY_INODE); >> if (err) >> goto out_unlock; >> - > > newline > >> +#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; >> @@ -459,6 +488,11 @@ 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); >> } >> @@ -637,6 +671,9 @@ get_access_mask_t(const struct landlock_ruleset *const ruleset, >> * Populates @layer_masks such that for each access right in @access_request, >> * the bits for all the layers are set where this access right is handled. >> * >> + * @layer_masks must contain LANDLOCK_NUM_ACCESS_FS or LANDLOCK_NUM_ACCESS_NET >> + * elements according to @key_type. > > Please include this sentence in the @layer_masks description below. > >> + * >> * @domain: The domain that defines the current restrictions. >> * @access_request: The requested access rights to check. >> * @layer_masks: The layer masks to populate. > > "It must contain…" > > >> @@ -659,6 +696,12 @@ access_mask_t 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 d9eb79ea9a89..f272d2cd518c 100644 >> --- a/security/landlock/ruleset.h >> +++ b/security/landlock/ruleset.h >> @@ -19,16 +19,20 @@ >> #include "limits.h" >> #include "object.h" >> >> +/* Rule access mask. */ >> 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; > > This type change need to be explained in the commit message. > > >> /* 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. */ >> @@ -82,6 +86,13 @@ 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) */ >> }; >> >> /** >> @@ -156,6 +167,15 @@ 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. >> @@ -166,8 +186,8 @@ struct landlock_ruleset { >> * @work_free: Enables to free a ruleset within a lockless >> * section. This is only used by >> * landlock_put_ruleset_deferred() when @usage reaches zero. >> - * The fields @lock, @usage, @num_rules, @num_layers and >> - * @access_masks are then unused. >> + * The fields @lock, @usage, @num_rules, @num_layers, >> + * @net_access_mask and @access_masks are then unused. > > There is no net_access_mask anymore. > .