[PATCH v4 3/6] ima: load x509 certificate from the kernel

[Dmitry Kasatkin]

Define configuration option to load X509 certificate into the
IMA trusted kernel keyring. It implements ima_load_x509() hook
to load X509 certificate into the .ima trusted kernel keyring
from the root filesystem.

Changes in v3:
* use ima_policy_flag in ima_get_action()
  ima_load_x509 temporarily clears ima_policy_flag to disable
  appraisal to load key. Use it to skip appraisal rules.
* Key directory path changed to /etc/keys (Mimi)

Changes in v2:
* added '__init'
* use ima_policy_flag to disable appraisal to load keys

Signed-off-by: Dmitry Kasatkin <d.kasatkin@xxxxxxxxxxx>
---
 security/integrity/ima/Kconfig    | 15 +++++++++++++++
 security/integrity/ima/ima_api.c  |  3 +--
 security/integrity/ima/ima_init.c | 17 +++++++++++++++++
 security/integrity/integrity.h    |  8 ++++++++
 4 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig
index e099875..8288edc 100644
--- a/security/integrity/ima/Kconfig
+++ b/security/integrity/ima/Kconfig
@@ -131,3 +131,18 @@ config IMA_TRUSTED_KEYRING
 	help
 	   This option requires that all keys added to the .ima
 	   keyring be signed by a key on the system trusted keyring.
+
+config IMA_LOAD_X509
+	bool "Load X509 certificate to the '.ima' trusted keyring"
+	depends on IMA_TRUSTED_KEYRING
+	default n
+	help
+	   This option enables X509 certificate loading from the kernel
+	   to the '.ima' trusted keyring.
+
+config IMA_X509_PATH
+	string "IMA X509 certificate path"
+	depends on IMA_LOAD_X509
+	default "/etc/keys/x509_ima.der"
+	help
+	   This option defines IMA X509 certificate path.
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index a99eb6d..b0dc922 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -173,8 +173,7 @@ int ima_get_action(struct inode *inode, int mask, int function)
 {
 	int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE;
 
-	if (!ima_appraise)
-		flags &= ~IMA_APPRAISE;
+	flags &= ima_policy_flag;
 
 	return ima_match_policy(inode, function, mask, flags);
 }
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 9164fc8..5e4c29d 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -24,6 +24,12 @@
 #include <crypto/hash_info.h>
 #include "ima.h"
 
+#ifdef CONFIG_IMA_X509_PATH
+#define IMA_X509_PATH	CONFIG_IMA_X509_PATH
+#else
+#define IMA_X509_PATH	"/etc/keys/x509_ima.der"
+#endif
+
 /* name for boot aggregate entry */
 static const char *boot_aggregate_name = "boot_aggregate";
 int ima_used_chip;
@@ -91,6 +97,17 @@ err_out:
 	return result;
 }
 
+#ifdef CONFIG_IMA_LOAD_X509
+void __init ima_load_x509(void)
+{
+	int unset_flags = ima_policy_flag & IMA_APPRAISE;
+
+	ima_policy_flag &= ~unset_flags;
+	integrity_load_x509(INTEGRITY_KEYRING_IMA, IMA_X509_PATH);
+	ima_policy_flag |= unset_flags;
+}
+#endif
+
 int __init ima_init(void)
 {
 	u8 pcr_i[TPM_DIGEST_SIZE];
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index 1057abb..caa1f6c 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -162,6 +162,14 @@ static inline int asymmetric_verify(struct key *keyring, const char *sig,
 }
 #endif
 
+#ifdef CONFIG_IMA_LOAD_X509
+void __init ima_load_x509(void);
+#else
+static inline void ima_load_x509(void)
+{
+}
+#endif
+
 #ifdef CONFIG_INTEGRITY_AUDIT
 /* declarations */
 void integrity_audit_msg(int audit_msgno, struct inode *inode,
-- 
1.9.1

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