[PATCH 19/20] evm: try enable EVM from the kernel

[Dmitry Kasatkin]

EVM key might be initialzed in the kernel by kernel module
using HW specific way. For example such method would suite
devices with ARM Trust Zone technology.

This patch tries enable EVM by checking if evm-key already
exists in the kernel keyring.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@xxxxxxxxxxx>
---
 security/integrity/evm/evm_crypto.c |  5 +++++
 security/integrity/evm/evm_main.c   |  2 ++
 security/integrity/evm/evm_secfs.c  | 10 +++-------
 3 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 5396769..f79ebf5 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -258,5 +258,10 @@ out:
 	memset(ekp->decrypted_data, 0, ekp->decrypted_datalen);
 	up_read(&evm_key->sem);
 	key_put(evm_key);
+	if (!rc) {
+		evm_initialized = 1;
+		pr_info("initialized\n");
+	} else
+		pr_err("initialization failed\n");
 	return rc;
 }
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index ad5e641..d2c06d3 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -463,6 +463,8 @@ static int __init init_evm(void)
 		goto err;
 	}
 
+	evm_init_key();
+
 	return 0;
 err:
 	return error;
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index 4c81ef6..d7b5d11 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -62,7 +62,7 @@ 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 ||
 		    evm_mode == EVM_MODE_OFF)
@@ -79,12 +79,8 @@ 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;
 }
 
-- 
1.8.3.2

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