diff options
Diffstat (limited to 'security/keys/request_key.c')
| -rw-r--r-- | security/keys/request_key.c | 212 |
1 files changed, 139 insertions, 73 deletions
diff --git a/security/keys/request_key.c b/security/keys/request_key.c index 75d87f9e0f49..957b9e3e1492 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -1,13 +1,9 @@ +// SPDX-License-Identifier: GPL-2.0-or-later /* Request a key from userspace * * Copyright (C) 2004-2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - * * See Documentation/security/keys/request-key.rst */ @@ -17,14 +13,40 @@ #include <linux/err.h> #include <linux/keyctl.h> #include <linux/slab.h> +#include <net/net_namespace.h> #include "internal.h" #include <keys/request_key_auth-type.h> #define key_negative_timeout 60 /* default timeout on a negative key's existence */ +static struct key *check_cached_key(struct keyring_search_context *ctx) +{ +#ifdef CONFIG_KEYS_REQUEST_CACHE + struct key *key = current->cached_requested_key; + + if (key && + ctx->match_data.cmp(key, &ctx->match_data) && + !(key->flags & ((1 << KEY_FLAG_INVALIDATED) | + (1 << KEY_FLAG_REVOKED)))) + return key_get(key); +#endif + return NULL; +} + +static void cache_requested_key(struct key *key) +{ +#ifdef CONFIG_KEYS_REQUEST_CACHE + struct task_struct *t = current; + + key_put(t->cached_requested_key); + t->cached_requested_key = key_get(key); + set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); +#endif +} + /** * complete_request_key - Complete the construction of a key. - * @auth_key: The authorisation key. + * @authkey: The authorisation key. * @error: The success or failute of the construction. * * Complete the attempt to construct a key. The key will be negated @@ -96,7 +118,7 @@ static int call_sbin_request_key(struct key *authkey, void *aux) struct request_key_auth *rka = get_request_key_auth(authkey); const struct cred *cred = current_cred(); key_serial_t prkey, sskey; - struct key *key = rka->target_key, *keyring, *session; + struct key *key = rka->target_key, *keyring, *session, *user_session; char *argv[9], *envp[3], uid_str[12], gid_str[12]; char key_str[12], keyring_str[3][12]; char desc[20]; @@ -104,9 +126,9 @@ static int call_sbin_request_key(struct key *authkey, void *aux) kenter("{%d},{%d},%s", key->serial, authkey->serial, rka->op); - ret = install_user_keyrings(); + ret = look_up_user_keyrings(NULL, &user_session); if (ret < 0) - goto error_alloc; + goto error_us; /* allocate a new session keyring */ sprintf(desc, "_req.%u", key->serial); @@ -144,7 +166,7 @@ static int call_sbin_request_key(struct key *authkey, void *aux) session = cred->session_keyring; if (!session) - session = cred->user->session_keyring; + session = user_session; sskey = session->serial; sprintf(keyring_str[2], "%d", sskey); @@ -186,6 +208,8 @@ error_link: key_put(keyring); error_alloc: + key_put(user_session); +error_us: complete_request_key(authkey, ret); kleave(" = %d", ret); return ret; @@ -222,7 +246,7 @@ static int construct_key(struct key *key, const void *callout_info, /* check that the actor called complete_request_key() prior to * returning an error */ WARN_ON(ret < 0 && - !test_bit(KEY_FLAG_REVOKED, &authkey->flags)); + !test_bit(KEY_FLAG_INVALIDATED, &authkey->flags)); key_put(authkey); kleave(" = %d", ret); @@ -292,13 +316,15 @@ static int construct_get_dest_keyring(struct key **_dest_keyring) /* fall through */ case KEY_REQKEY_DEFL_USER_SESSION_KEYRING: - dest_keyring = - key_get(READ_ONCE(cred->user->session_keyring)); + ret = look_up_user_keyrings(NULL, &dest_keyring); + if (ret < 0) + return ret; break; case KEY_REQKEY_DEFL_USER_KEYRING: - dest_keyring = - key_get(READ_ONCE(cred->user->uid_keyring)); + ret = look_up_user_keyrings(&dest_keyring, NULL); + if (ret < 0) + return ret; break; case KEY_REQKEY_DEFL_GROUP_KEYRING: @@ -343,7 +369,7 @@ static int construct_alloc_key(struct keyring_search_context *ctx, struct key_user *user, struct key **_key) { - struct assoc_array_edit *edit; + struct assoc_array_edit *edit = NULL; struct key *key; key_perm_t perm; key_ref_t key_ref; @@ -372,6 +398,9 @@ static int construct_alloc_key(struct keyring_search_context *ctx, set_bit(KEY_FLAG_USER_CONSTRUCT, &key->flags); if (dest_keyring) { + ret = __key_link_lock(dest_keyring, &ctx->index_key); + if (ret < 0) + goto link_lock_failed; ret = __key_link_begin(dest_keyring, &ctx->index_key, &edit); if (ret < 0) goto link_prealloc_failed; @@ -382,7 +411,9 @@ static int construct_alloc_key(struct keyring_search_context *ctx, * waited for locks */ mutex_lock(&key_construction_mutex); - key_ref = search_process_keyrings(ctx); + rcu_read_lock(); + key_ref = search_process_keyrings_rcu(ctx); + rcu_read_unlock(); if (!IS_ERR(key_ref)) goto key_already_present; @@ -423,6 +454,8 @@ link_check_failed: return ret; link_prealloc_failed: + __key_link_end(dest_keyring, &ctx->index_key, edit); +link_lock_failed: mutex_unlock(&user->cons_lock); key_put(key); kleave(" = %d [prelink]", ret); @@ -497,16 +530,18 @@ error: * request_key_and_link - Request a key and cache it in a keyring. * @type: The type of key we want. * @description: The searchable description of the key. + * @domain_tag: The domain in which the key operates. * @callout_info: The data to pass to the instantiation upcall (or NULL). * @callout_len: The length of callout_info. * @aux: Auxiliary data for the upcall. * @dest_keyring: Where to cache the key. * @flags: Flags to key_alloc(). * - * A key matching the specified criteria is searched for in the process's - * keyrings and returned with its usage count incremented if found. Otherwise, - * if callout_info is not NULL, a key will be allocated and some service - * (probably in userspace) will be asked to instantiate it. + * A key matching the specified criteria (type, description, domain_tag) is + * searched for in the process's keyrings and returned with its usage count + * incremented if found. Otherwise, if callout_info is not NULL, a key will be + * allocated and some service (probably in userspace) will be asked to + * instantiate it. * * If successfully found or created, the key will be linked to the destination * keyring if one is provided. @@ -522,6 +557,7 @@ error: */ struct key *request_key_and_link(struct key_type *type, const char *description, + struct key_tag *domain_tag, const void *callout_info, size_t callout_len, void *aux, @@ -530,6 +566,7 @@ struct key *request_key_and_link(struct key_type *type, { struct keyring_search_context ctx = { .index_key.type = type, + .index_key.domain_tag = domain_tag, .index_key.description = description, .index_key.desc_len = strlen(description), .cred = current_cred(), @@ -537,7 +574,8 @@ struct key *request_key_and_link(struct key_type *type, .match_data.raw_data = description, .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, .flags = (KEYRING_SEARCH_DO_STATE_CHECK | - KEYRING_SEARCH_SKIP_EXPIRED), + KEYRING_SEARCH_SKIP_EXPIRED | + KEYRING_SEARCH_RECURSE), }; struct key *key; key_ref_t key_ref; @@ -555,10 +593,26 @@ struct key *request_key_and_link(struct key_type *type, } } + key = check_cached_key(&ctx); + if (key) + goto error_free; + /* search all the process keyrings for a key */ - key_ref = search_process_keyrings(&ctx); + rcu_read_lock(); + key_ref = search_process_keyrings_rcu(&ctx); + rcu_read_unlock(); if (!IS_ERR(key_ref)) { + if (dest_keyring) { + ret = key_task_permission(key_ref, current_cred(), + KEY_NEED_LINK); + if (ret < 0) { + key_ref_put(key_ref); + key = ERR_PTR(ret); + goto error_free; + } + } + key = key_ref_to_ptr(key_ref); if (dest_keyring) { ret = key_link(dest_keyring, key); @@ -568,6 +622,9 @@ struct key *request_key_and_link(struct key_type *type, goto error_free; } } + + /* Only cache the key on immediate success */ + cache_requested_key(key); } else if (PTR_ERR(key_ref) != -EAGAIN) { key = ERR_CAST(key_ref); } else { @@ -616,9 +673,10 @@ int wait_for_key_construction(struct key *key, bool intr) EXPORT_SYMBOL(wait_for_key_construction); /** - * request_key - Request a key and wait for construction + * request_key_tag - Request a key and wait for construction * @type: Type of key. * @description: The searchable description of the key. + * @domain_tag: The domain in which the key operates. * @callout_info: The data to pass to the instantiation upcall (or NULL). * * As for request_key_and_link() except that it does not add the returned key @@ -629,9 +687,10 @@ EXPORT_SYMBOL(wait_for_key_construction); * Furthermore, it then works as wait_for_key_construction() to wait for the * completion of keys undergoing construction with a non-interruptible wait. */ -struct key *request_key(struct key_type *type, - const char *description, - const char *callout_info) +struct key *request_key_tag(struct key_type *type, + const char *description, + struct key_tag *domain_tag, + const char *callout_info) { struct key *key; size_t callout_len = 0; @@ -639,7 +698,8 @@ struct key *request_key(struct key_type *type, if (callout_info) callout_len = strlen(callout_info); - key = request_key_and_link(type, description, callout_info, callout_len, + key = request_key_and_link(type, description, domain_tag, + callout_info, callout_len, NULL, NULL, KEY_ALLOC_IN_QUOTA); if (!IS_ERR(key)) { ret = wait_for_key_construction(key, false); @@ -650,12 +710,13 @@ struct key *request_key(struct key_type *type, } return key; } -EXPORT_SYMBOL(request_key); +EXPORT_SYMBOL(request_key_tag); /** * request_key_with_auxdata - Request a key with auxiliary data for the upcaller * @type: The type of key we want. * @description: The searchable description of the key. + * @domain_tag: The domain in which the key operates. * @callout_info: The data to pass to the instantiation upcall (or NULL). * @callout_len: The length of callout_info. * @aux: Auxiliary data for the upcall. @@ -668,6 +729,7 @@ EXPORT_SYMBOL(request_key); */ struct key *request_key_with_auxdata(struct key_type *type, const char *description, + struct key_tag *domain_tag, const void *callout_info, size_t callout_len, void *aux) @@ -675,7 +737,8 @@ struct key *request_key_with_auxdata(struct key_type *type, struct key *key; int ret; - key = request_key_and_link(type, description, callout_info, callout_len, + key = request_key_and_link(type, description, domain_tag, + callout_info, callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA); if (!IS_ERR(key)) { ret = wait_for_key_construction(key, false); @@ -688,52 +751,55 @@ struct key *request_key_with_auxdata(struct key_type *type, } EXPORT_SYMBOL(request_key_with_auxdata); -/* - * request_key_async - Request a key (allow async construction) - * @type: Type of key. - * @description: The searchable description of the key. - * @callout_info: The data to pass to the instantiation upcall (or NULL). - * @callout_len: The length of callout_info. +/** + * request_key_rcu - Request key from RCU-read-locked context + * @type: The type of key we want. + * @description: The name of the key we want. + * @domain_tag: The domain in which the key operates. * - * As for request_key_and_link() except that it does not add the returned key - * to a keyring if found, new keys are always allocated in the user's quota and - * no auxiliary data can be passed. + * Request a key from a context that we may not sleep in (such as RCU-mode + * pathwalk). Keys under construction are ignored. * - * The caller should call wait_for_key_construction() to wait for the - * completion of the returned key if it is still undergoing construction. + * Return a pointer to the found key if successful, -ENOKEY if we couldn't find + * a key or some other error if the key found was unsuitable or inaccessible. */ -struct key *request_key_async(struct key_type *type, - const char *description, - const void *callout_info, - size_t callout_len) +struct key *request_key_rcu(struct key_type *type, + const char *description, + struct key_tag *domain_tag) { - return request_key_and_link(type, description, callout_info, - callout_len, NULL, NULL, - KEY_ALLOC_IN_QUOTA); -} -EXPORT_SYMBOL(request_key_async); + struct keyring_search_context ctx = { + .index_key.type = type, + .index_key.domain_tag = domain_tag, + .index_key.description = description, + .index_key.desc_len = strlen(description), + .cred = current_cred(), + .match_data.cmp = key_default_cmp, + .match_data.raw_data = description, + .match_data.lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, + .flags = (KEYRING_SEARCH_DO_STATE_CHECK | + KEYRING_SEARCH_SKIP_EXPIRED), + }; + struct key *key; + key_ref_t key_ref; -/* - * request a key with auxiliary data for the upcaller (allow async construction) - * @type: Type of key. - * @description: The searchable description of the key. - * @callout_info: The data to pass to the instantiation upcall (or NULL). - * @callout_len: The length of callout_info. - * @aux: Auxiliary data for the upcall. - * - * As for request_key_and_link() except that it does not add the returned key - * to a keyring if found and new keys are always allocated in the user's quota. - * - * The caller should call wait_for_key_construction() to wait for the - * completion of the returned key if it is still undergoing construction. - */ -struct key *request_key_async_with_auxdata(struct key_type *type, - const char *description, - const void *callout_info, - size_t callout_len, - void *aux) -{ - return request_key_and_link(type, description, callout_info, - callout_len, aux, NULL, KEY_ALLOC_IN_QUOTA); + kenter("%s,%s", type->name, description); + + key = check_cached_key(&ctx); + if (key) + return key; + + /* search all the process keyrings for a key */ + key_ref = search_process_keyrings_rcu(&ctx); + if (IS_ERR(key_ref)) { + key = ERR_CAST(key_ref); + if (PTR_ERR(key_ref) == -EAGAIN) + key = ERR_PTR(-ENOKEY); + } else { + key = key_ref_to_ptr(key_ref); + cache_requested_key(key); + } + + kleave(" = %p", key); + return key; } -EXPORT_SYMBOL(request_key_async_with_auxdata); +EXPORT_SYMBOL(request_key_rcu); |