5 files changed, 100 insertions, 18 deletions

diff --git a/security/integrity/evm/Kconfig b/security/integrity/evm/Kconfig
index bf19723cf..e825e0ae7 100644
--- a/security/integrity/evm/Kconfig
+++ b/security/integrity/evm/Kconfig
@@ -42,3 +42,20 @@ config EVM_EXTRA_SMACK_XATTRS
 	  additional info to the calculation, requires existing EVM
 	  labeled file systems to be relabeled.
 
+config EVM_LOAD_X509
+	bool "Load an X509 certificate onto the '.evm' trusted keyring"
+	depends on EVM && INTEGRITY_TRUSTED_KEYRING
+	default n
+	help
+	   Load an X509 certificate onto the '.evm' trusted keyring.
+
+	   This option enables X509 certificate loading from the kernel
+	   onto the '.evm' trusted keyring.  A public key can be used to
+	   verify EVM integrity starting from the 'init' process.
+
+config EVM_X509_PATH
+	string "EVM X509 certificate path"
+	depends on EVM_LOAD_X509
+	default "/etc/keys/x509_evm.der"
+	help
+	   This option defines X509 certificate path.
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 88bfe77ef..f5f127277 100644
--- a/security/integrity/evm/evm.h
+++ b/security/integrity/evm/evm.h
@@ -21,6 +21,9 @@
 
 #include "../integrity.h"
 
+#define EVM_INIT_HMAC	0x0001
+#define EVM_INIT_X509	0x0002
+
 extern int evm_initialized;
 extern char *evm_hmac;
 extern char *evm_hash;
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 461f8d891..30b6b7d04 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -18,6 +18,7 @@
 #include <linux/module.h>
 #include <linux/crypto.h>
 #include <linux/xattr.h>
+#include <linux/evm.h>
 #include <keys/encrypted-type.h>
 #include <crypto/hash.h>
 #include "evm.h"
@@ -32,6 +33,44 @@ struct crypto_shash *hash_tfm;
 
 static DEFINE_MUTEX(mutex);
 
+#define EVM_SET_KEY_BUSY 0
+
+static unsigned long evm_set_key_flags;
+
+/**
+ * evm_set_key() - set EVM HMAC key from the kernel
+ * @key: pointer to a buffer with the key data
+ * @size: length of the key data
+ *
+ * This function allows setting the EVM HMAC key from the kernel
+ * without using the "encrypted" key subsystem keys. It can be used
+ * by the crypto HW kernel module which has its own way of managing
+ * keys.
+ *
+ * key length should be between 32 and 128 bytes long
+ */
+int evm_set_key(void *key, size_t keylen)
+{
+	int rc;
+
+	rc = -EBUSY;
+	if (test_and_set_bit(EVM_SET_KEY_BUSY, &evm_set_key_flags))
+		goto busy;
+	rc = -EINVAL;
+	if (keylen > MAX_KEY_SIZE)
+		goto inval;
+	memcpy(evmkey, key, keylen);
+	evm_initialized |= EVM_INIT_HMAC;
+	pr_info("key initialized\n");
+	return 0;
+inval:
+	clear_bit(EVM_SET_KEY_BUSY, &evm_set_key_flags);
+busy:
+	pr_err("key initialization failed\n");
+	return rc;
+}
+EXPORT_SYMBOL_GPL(evm_set_key);
+
 static struct shash_desc *init_desc(char type)
 {
 	long rc;
@@ -40,6 +79,10 @@ static struct shash_desc *init_desc(char type)
 	struct shash_desc *desc;
 
 	if (type == EVM_XATTR_HMAC) {
+		if (!(evm_initialized & EVM_INIT_HMAC)) {
+			pr_err("HMAC key is not set\n");
+			return ERR_PTR(-ENOKEY);
+		}
 		tfm = &hmac_tfm;
 		algo = evm_hmac;
 	} else {
@@ -240,7 +283,7 @@ int evm_init_key(void)
 {
 	struct key *evm_key;
 	struct encrypted_key_payload *ekp;
-	int rc = 0;
+	int rc;
 
 	evm_key = request_key(&key_type_encrypted, EVMKEY, NULL);
 	if (IS_ERR(evm_key))
@@ -248,12 +291,9 @@ int evm_init_key(void)
 
 	down_read(&evm_key->sem);
 	ekp = evm_key->payload.data[0];
-	if (ekp->decrypted_datalen > MAX_KEY_SIZE) {
-		rc = -EINVAL;
-		goto out;
-	}
-	memcpy(evmkey, ekp->decrypted_data, ekp->decrypted_datalen);
-out:
+
+	rc = evm_set_key(ekp->decrypted_data, ekp->decrypted_datalen);
+
 	/* burn the original key contents */
 	memset(ekp->decrypted_data, 0, ekp->decrypted_datalen);
 	up_read(&evm_key->sem);
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 3d145a3ff..e6ea9d4b1 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -359,6 +359,15 @@ int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name)
 	return evm_protect_xattr(dentry, xattr_name, NULL, 0);
 }
 
+static void evm_reset_status(struct inode *inode)
+{
+	struct integrity_iint_cache *iint;
+
+	iint = integrity_iint_find(inode);
+	if (iint)
+		iint->evm_status = INTEGRITY_UNKNOWN;
+}
+
 /**
  * evm_inode_post_setxattr - update 'security.evm' to reflect the changes
  * @dentry: pointer to the affected dentry
@@ -379,6 +388,8 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name,
 				 && !posix_xattr_acl(xattr_name)))
 		return;
 
+	evm_reset_status(dentry->d_inode);
+
 	evm_update_evmxattr(dentry, xattr_name, xattr_value, xattr_value_len);
 }
 
@@ -397,6 +408,8 @@ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name)
 	if (!evm_initialized || !evm_protected_xattr(xattr_name))
 		return;
 
+	evm_reset_status(dentry->d_inode);
+
 	evm_update_evmxattr(dentry, xattr_name, NULL, 0);
 }
 
@@ -473,21 +486,34 @@ out:
 }
 EXPORT_SYMBOL_GPL(evm_inode_init_security);
 
+#ifdef CONFIG_EVM_LOAD_X509
+void __init evm_load_x509(void)
+{
+	int rc;
+
+	rc = integrity_load_x509(INTEGRITY_KEYRING_EVM, CONFIG_EVM_X509_PATH);
+	if (!rc)
+		evm_initialized |= EVM_INIT_X509;
+}
+#endif
+
 static int __init init_evm(void)
 {
 	int error;
 
 	evm_init_config();
 
+	error = integrity_init_keyring(INTEGRITY_KEYRING_EVM);
+	if (error)
+		return error;
+
 	error = evm_init_secfs();
 	if (error < 0) {
 		pr_info("Error registering secfs\n");
-		goto err;
+		return error;
 	}
 
 	return 0;
-err:
-	return error;
 }
 
 /*
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index cf12a0471..c8dccd54d 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -62,9 +62,9 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
 			     size_t count, loff_t *ppos)
 {
 	char temp[80];
-	int i, error;
+	int i;
 
-	if (!capable(CAP_SYS_ADMIN) || evm_initialized)
+	if (!capable(CAP_SYS_ADMIN) || (evm_initialized & EVM_INIT_HMAC))
 		return -EPERM;
 
 	if (count >= sizeof(temp) || count == 0)
@@ -78,12 +78,8 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
 	if ((sscanf(temp, "%d", &i) != 1) || (i != 1))
 		return -EINVAL;
 
-	error = evm_init_key();
-	if (!error) {
-		evm_initialized = 1;
-		pr_info("initialized\n");
-	} else
-		pr_err("initialization failed\n");
+	evm_init_key();
+
 	return count;
 }