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Subject[PATCH v6 1/3] IMA: Add KEY_CHECK func to measure keys
Date
Measure keys loaded onto any keyring.

This patch defines a new IMA policy func namely KEY_CHECK to
measure keys. Updated ima_match_rules() to check for KEY_CHECK
and ima_parse_rule() to handle KEY_CHECK.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
Documentation/ABI/testing/ima_policy | 6 +++++-
security/integrity/ima/ima.h | 1 +
security/integrity/ima/ima_main.c | 7 +++++++
security/integrity/ima/ima_policy.c | 4 +++-
4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
index 29aaedf33246..066d32797500 100644
--- a/Documentation/ABI/testing/ima_policy
+++ b/Documentation/ABI/testing/ima_policy
@@ -29,7 +29,7 @@ Description:
base: func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
[FIRMWARE_CHECK]
[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
- [KEXEC_CMDLINE]
+ [KEXEC_CMDLINE] [KEY_CHECK]
mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
[[^]MAY_EXEC]
fsmagic:= hex value
@@ -113,3 +113,7 @@ Description:
Example of appraise rule allowing modsig appended signatures:

appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig
+
+ Example of measure rule using KEY_CHECK to measure all keys:
+
+ measure func=KEY_CHECK
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index df4ca482fb53..fe6c698617bd 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -193,6 +193,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
hook(KEXEC_INITRAMFS_CHECK) \
hook(POLICY_CHECK) \
hook(KEXEC_CMDLINE) \
+ hook(KEY_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 d7e987baf127..12684e8d7124 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -655,6 +655,13 @@ void process_buffer_measurement(const void *buf, int size,
int action = 0;
u32 secid;

+ /*
+ * If IMA is not yet initialized or IMA policy is empty
+ * then there is no need to measure.
+ */
+ if (!ima_policy_flag)
+ return;
+
/*
* Both LSM hooks and auxilary based buffer measurements are
* based on policy. To avoid code duplication, differentiate
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index f19a895ad7cd..1525a28fd705 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -373,7 +373,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
{
int i;

- if (func == KEXEC_CMDLINE) {
+ if ((func == KEXEC_CMDLINE) || (func == KEY_CHECK)) {
if ((rule->flags & IMA_FUNC) && (rule->func == func))
return true;
return false;
@@ -997,6 +997,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
entry->func = POLICY_CHECK;
else if (strcmp(args[0].from, "KEXEC_CMDLINE") == 0)
entry->func = KEXEC_CMDLINE;
+ else if (strcmp(args[0].from, "KEY_CHECK") == 0)
+ entry->func = KEY_CHECK;
else
result = -EINVAL;
if (!result)
--
2.17.1
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