An IMA policy to manage measurement of keys is not supported.
A new IMA policy is needed to manage the measurement of keys.
A policy option is also needed to allow measurement of keys
linked to a given set of keyrings only.
This patch defines KEYRING_CHECK and keyrings in IMA policy
for this purpose.
KEYRING_CHECK can be added in the IMA policy to measure keys.
keyrings can be, optionally, set to only measure keys
added or updated to a given set of keyrings. If keyrings is not
specified for KEYRING_CHECK, keys added or updated in
all keyrings are measured.
Signed-off-by: Lakshmi Ramasubramanian <nramas@xxxxxxxxxxxxxxxxxxx>
---
Documentation/ABI/testing/ima_policy | 15 +++++++++++++++
security/integrity/ima/ima.h | 1 +
security/integrity/ima/ima_main.c | 2 +-
security/integrity/ima/ima_policy.c | 2 +-
security/integrity/ima/ima_queue.c | 2 +-
5 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index fc376a323908..757faf1a1a27 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -25,10 +25,12 @@ Description:
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
option: [[appraise_type=]] [template=] [permit_directio]
+ [keyrings=]
base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
[KEXEC_CMDLINE]
+ [KEYRING_CHECK]
mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
[[^]MAY_EXEC]
fsmagic:= hex value
@@ -38,6 +40,9 @@ Description:
fowner:= decimal value
lsm: are LSM specific
option: appraise_type:= [imasig]
+ keyrings: = list of keyrings to measure
+ (eg, .builtin_trusted_keys|.ima). Only valid
+ when action is "measure" and func is KEYRING_CHECK.
template:= name of a defined IMA template type
(eg, ima-ng). Only valid when action is "measure".
pcr:= decimal value
@@ -105,3 +110,13 @@ Description:
measure func=KEXEC_KERNEL_CHECK pcr=4
measure func=KEXEC_INITRAMFS_CHECK pcr=5
+
+ Example of measure rules using KEYRING_CHECK
+ To measure keys added to
+ .builtin_trusted_keys or .ima keyring:
+
+ measure func=KEYRING_CHECK keyrings=.builtin_trusted_keys|.ima
+
+ To measure keys added to all keyrings:
+
+ measure func=KEYRING_CHECK
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index b9600070e415..12e9ec6847b5 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -191,6 +191,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
hook(KEXEC_INITRAMFS_CHECK) \
hook(POLICY_CHECK) \
hook(KEXEC_CMDLINE) \
+ hook(KEYRING_CHECK) \
hook(MAX_CHECK)
#define __ima_hook_enumify(ENUM) ENUM,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 18e1bc105be7..72ae0878ec5d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -718,7 +718,7 @@ void ima_post_key_create_or_update(struct key *keyring, struct key *key,
pk = key->payload.data[asym_crypto];
process_buffer_measurement(pk->key, pk->keylen,
keyring->description,
- NONE, 0);
+ KEYRING_CHECK, 0);
}
static int __init init_ima(void)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 6df7f641ff66..0cc49f2d5233 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -370,7 +370,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
{
int i;
- if (func == KEXEC_CMDLINE) {
+ if ((func == KEXEC_CMDLINE) || (func == KEYRING_CHECK)) {
if ((rule->flags & IMA_FUNC) && (rule->func == func))
return true;
return false;
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index f2503f10abf4..5625381c5a97 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -317,7 +317,7 @@ void ima_measure_queued_keys(void)
process_buffer_measurement(entry->public_key,
entry->public_key_len,
entry->keyring_name,
- NONE, 0);
+ KEYRING_CHECK, 0);
list_del(&entry->list);
ima_free_measure_key_entry(entry);
}
--
2.17.1
