[PATCH v2 3/4] KEYS: Added BUILTIN_TRUSTED_KEYS enum to measure keys added to builtin_trusted_keys keyring
From: Lakshmi Ramasubramanian <hidden>
Date: 2019-10-23 23:40:06
Also in:
keyrings, linux-integrity, lkml
Subsystem:
certificate handling, extended verification module (evm), integrity measurement architecture (ima), keys/keyrings, security subsystem, the rest · Maintainers:
David Howells, David Woodhouse, Mimi Zohar, Roberto Sassu, Dmitry Kasatkin, Jarkko Sakkinen, Paul Moore, James Morris, "Serge E. Hallyn", Linus Torvalds
Added an ima policy hook BUILTIN_TRUSTED_KEYS to measure keys added to builtin_trusted_keys keyring. Added a helper function to check if the given keyring is the builtin_trusted_keys keyring. Defined a function to map the keyring to ima policy hook function and use it when measuring the key. Signed-off-by: Lakshmi Ramasubramanian <redacted> --- Documentation/ABI/testing/ima_policy | 1 + certs/system_keyring.c | 5 +++++ include/keys/system_keyring.h | 2 ++ security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_api.c | 1 + security/integrity/ima/ima_main.c | 25 +++++++++++++++++++++++-- security/integrity/ima/ima_queue.c | 2 +- 7 files changed, 35 insertions(+), 3 deletions(-)
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index fc376a323908..25566c74e679 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy@@ -29,6 +29,7 @@ Description: [FIRMWARE_CHECK] [KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK] [KEXEC_CMDLINE] + [BUILTIN_TRUSTED_KEYS] mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND] [[^]MAY_EXEC] fsmagic:= hex value
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 1eba08a1af82..5533c7f92fef 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c@@ -283,3 +283,8 @@ void __init set_platform_trusted_keys(struct key *keyring) platform_trusted_keys = keyring; } #endif + +inline bool is_builtin_trusted_keyring(struct key *keyring) +{ + return (keyring == builtin_trusted_keys); +}
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index c1a96fdf598b..2bc0aaa07f05 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h@@ -66,4 +66,6 @@ static inline void set_platform_trusted_keys(struct key *keyring) } #endif +extern bool is_builtin_trusted_keyring(struct key *keyring); + #endif /* _KEYS_SYSTEM_KEYRING_H */
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 38279707632a..92c25a6b4da7 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h@@ -23,6 +23,7 @@ #include <crypto/hash_info.h> #include <crypto/public_key.h> #include <keys/asymmetric-type.h> +#include <keys/system_keyring.h> #include "../integrity.h"
@@ -192,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest) hook(KEXEC_INITRAMFS_CHECK) \ hook(POLICY_CHECK) \ hook(KEXEC_CMDLINE) \ + hook(BUILTIN_TRUSTED_KEYS) \ hook(MAX_CHECK) #define __ima_hook_enumify(ENUM) ENUM,
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index f614e22bf39f..cc04706b7e7a 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c@@ -175,6 +175,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, * subj,obj, and type: are LSM specific. * func: FILE_CHECK | BPRM_CHECK | CREDS_CHECK | MMAP_CHECK | MODULE_CHECK * | KEXEC_CMDLINE + * | BUILTIN_TRUSTED_KEYS * mask: contains the permission mask * fsmagic: hex value *
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index bce430b3386e..986f80eead4d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c@@ -605,6 +605,24 @@ int ima_load_data(enum kernel_load_data_id id) return 0; } +/* + * Maps the given keyring to a IMA Hook. + * @keyring: A keyring to which a key maybe linked to. + * + * This function currently handles only builtin_trusted_keys. + * To handle more keyrings, this function, ima hook and + * ima policy handler need to be updated. + */ +static enum ima_hooks keyring_policy_map(struct key *keyring) +{ + enum ima_hooks func = NONE; + + if (is_builtin_trusted_keyring(keyring)) + func = BUILTIN_TRUSTED_KEYS; + + return func; +} + /* * process_buffer_measurement - Measure the buffer to ima log. * @buf: pointer to the buffer that needs to be added to the log.
@@ -706,19 +724,22 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key, unsigned long flags, bool create) { const struct public_key *pk; + enum ima_hooks func; if (key->type != &key_type_asymmetric) return; + func = keyring_policy_map(keyring); + if (!ima_initialized) { - ima_queue_key_for_measurement(key, NONE); + ima_queue_key_for_measurement(key, func); return; } pk = key->payload.data[asym_crypto]; process_buffer_measurement(pk->key, pk->keylen, key->description, - NONE, 0); + func, 0); } static int __init init_ima(void)
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index d42987022c12..ed77c4dc0520 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c@@ -319,7 +319,7 @@ void ima_measure_queued_keys(void) process_buffer_measurement(entry->public_key, entry->public_key_len, entry->key_description, - NONE, 0); + entry->func, 0); list_del(&entry->list); ima_free_trusted_key_entry(entry); }
--
2.17.1