ima: load x509 certificate from the kernel

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)
* Expand IMA_LOAD_X509 Kconfig help

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

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 17 insertions, 0 deletions

diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 9164fc8cac84..5e4c29d174ee 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];