diff options
| -rw-r--r-- | security/integrity/ima/Kconfig | 6 | ||||
| -rw-r--r-- | security/integrity/ima/Makefile | 1 | ||||
| -rw-r--r-- | security/integrity/ima/ima.h | 24 | ||||
| -rw-r--r-- | security/integrity/ima/ima_asymmetric_keys.c | 8 | ||||
| -rw-r--r-- | security/integrity/ima/ima_init.c | 8 | ||||
| -rw-r--r-- | security/integrity/ima/ima_policy.c | 3 | ||||
| -rw-r--r-- | security/integrity/ima/ima_queue_keys.c | 171 |
7 files changed, 220 insertions, 1 deletions
diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index 355754a6b6ca..711ff10fa36e 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -316,3 +316,9 @@ config IMA_MEASURE_ASYMMETRIC_KEYS depends on IMA depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE=y default y + +config IMA_QUEUE_EARLY_BOOT_KEYS + bool + depends on IMA_MEASURE_ASYMMETRIC_KEYS + depends on SYSTEM_TRUSTED_KEYRING + default y diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile index 3e9d0ad68c7b..064a256f8725 100644 --- a/security/integrity/ima/Makefile +++ b/security/integrity/ima/Makefile @@ -13,3 +13,4 @@ ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o obj-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o +obj-$(CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS) += ima_queue_keys.o diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h index f06238e41a7c..64317d95363e 100644 --- a/security/integrity/ima/ima.h +++ b/security/integrity/ima/ima.h @@ -205,6 +205,30 @@ extern const char *const func_tokens[]; struct modsig; +#ifdef CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS +/* + * To track keys that need to be measured. + */ +struct ima_key_entry { + struct list_head list; + void *payload; + size_t payload_len; + char *keyring_name; +}; +void ima_init_key_queue(void); +bool ima_should_queue_key(void); +bool ima_queue_key(struct key *keyring, const void *payload, + size_t payload_len); +void ima_process_queued_keys(void); +#else +static inline void ima_init_key_queue(void) {} +static inline bool ima_should_queue_key(void) { return false; } +static inline bool ima_queue_key(struct key *keyring, + const void *payload, + size_t payload_len) { return false; } +static inline void ima_process_queued_keys(void) {} +#endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */ + /* LIM API function definitions */ int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid, int mask, enum ima_hooks func, int *pcr, diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c index fea2e7dd3b09..7678f0e3e84d 100644 --- a/security/integrity/ima/ima_asymmetric_keys.c +++ b/security/integrity/ima/ima_asymmetric_keys.c @@ -30,6 +30,8 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, const void *payload, size_t payload_len, unsigned long flags, bool create) { + bool queued = false; + /* Only asymmetric keys are handled by this hook. */ if (key->type != &key_type_asymmetric) return; @@ -37,6 +39,12 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, if (!payload || (payload_len == 0)) return; + if (ima_should_queue_key()) + queued = ima_queue_key(keyring, payload, payload_len); + + if (queued) + return; + /* * keyring->description points to the name of the keyring * (such as ".builtin_trusted_keys", ".ima", etc.) to diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c index 5d55ade5f3b9..195cb4079b2b 100644 --- a/security/integrity/ima/ima_init.c +++ b/security/integrity/ima/ima_init.c @@ -131,5 +131,11 @@ int __init ima_init(void) ima_init_policy(); - return ima_fs_init(); + rc = ima_fs_init(); + if (rc != 0) + return rc; + + ima_init_key_queue(); + + return rc; } diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index b560a3ffeabb..f45ae380e966 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -809,6 +809,9 @@ void ima_update_policy(void) kfree(arch_policy_entry); } ima_update_policy_flag(); + + /* Custom IMA policy has been loaded */ + ima_process_queued_keys(); } /* Keep the enumeration in sync with the policy_tokens! */ diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c new file mode 100644 index 000000000000..c87c72299191 --- /dev/null +++ b/security/integrity/ima/ima_queue_keys.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Copyright (C) 2019 Microsoft Corporation + * + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) + * + * File: ima_queue_keys.c + * Enables deferred processing of keys + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/workqueue.h> +#include <keys/asymmetric-type.h> +#include "ima.h" + +/* + * Flag to indicate whether a key can be processed + * right away or should be queued for processing later. + */ +static bool ima_process_keys; + +/* + * To synchronize access to the list of keys that need to be measured + */ +static DEFINE_MUTEX(ima_keys_lock); +static LIST_HEAD(ima_keys); + +/* + * If custom IMA policy is not loaded then keys queued up + * for measurement should be freed. This worker is used + * for handling this scenario. + */ +static long ima_key_queue_timeout = 300000; /* 5 Minutes */ +static void ima_keys_handler(struct work_struct *work); +static DECLARE_DELAYED_WORK(ima_keys_delayed_work, ima_keys_handler); +static bool timer_expired; + +/* + * This worker function frees keys that may still be + * queued up in case custom IMA policy was not loaded. + */ +static void ima_keys_handler(struct work_struct *work) +{ + timer_expired = true; + ima_process_queued_keys(); +} + +/* + * This function sets up a worker to free queued keys in case + * custom IMA policy was never loaded. + */ +void ima_init_key_queue(void) +{ + schedule_delayed_work(&ima_keys_delayed_work, + msecs_to_jiffies(ima_key_queue_timeout)); +} + +static void ima_free_key_entry(struct ima_key_entry *entry) +{ + if (entry) { + kfree(entry->payload); + kfree(entry->keyring_name); + kfree(entry); + } +} + +static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring, + const void *payload, + size_t payload_len) +{ + int rc = 0; + struct ima_key_entry *entry; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (entry) { + entry->payload = kmemdup(payload, payload_len, GFP_KERNEL); + entry->keyring_name = kstrdup(keyring->description, + GFP_KERNEL); + entry->payload_len = payload_len; + } + + if ((entry == NULL) || (entry->payload == NULL) || + (entry->keyring_name == NULL)) { + rc = -ENOMEM; + goto out; + } + + INIT_LIST_HEAD(&entry->list); + +out: + if (rc) { + ima_free_key_entry(entry); + entry = NULL; + } + + return entry; +} + +bool ima_queue_key(struct key *keyring, const void *payload, + size_t payload_len) +{ + bool queued = false; + struct ima_key_entry *entry; + + entry = ima_alloc_key_entry(keyring, payload, payload_len); + if (!entry) + return false; + + mutex_lock(&ima_keys_lock); + if (!ima_process_keys) { + list_add_tail(&entry->list, &ima_keys); + queued = true; + } + mutex_unlock(&ima_keys_lock); + + if (!queued) + ima_free_key_entry(entry); + + return queued; +} + +/* + * ima_process_queued_keys() - process keys queued for measurement + * + * This function sets ima_process_keys to true and processes queued keys. + * From here on keys will be processed right away (not queued). + */ +void ima_process_queued_keys(void) +{ + struct ima_key_entry *entry, *tmp; + bool process = false; + + if (ima_process_keys) + return; + + /* + * Since ima_process_keys is set to true, any new key will be + * processed immediately and not be queued to ima_keys list. + * First one setting the ima_process_keys flag to true will + * process the queued keys. + */ + mutex_lock(&ima_keys_lock); + if (!ima_process_keys) { + ima_process_keys = true; + process = true; + } + mutex_unlock(&ima_keys_lock); + + if (!process) + return; + + if (!timer_expired) + cancel_delayed_work_sync(&ima_keys_delayed_work); + + list_for_each_entry_safe(entry, tmp, &ima_keys, list) { + if (!timer_expired) + process_buffer_measurement(entry->payload, + entry->payload_len, + entry->keyring_name, + KEY_CHECK, 0, + entry->keyring_name); + list_del(&entry->list); + ima_free_key_entry(entry); + } +} + +inline bool ima_should_queue_key(void) +{ + return !ima_process_keys; +} |