From 26ddabfe96bb7468763c9c92791404d991b16250 Mon Sep 17 00:00:00 2001
From: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Date: Thu, 22 Oct 2015 21:26:26 +0300
Subject: [PATCH] evm: enable EVM when X509 certificate is loaded
In order to enable EVM before starting the 'init' process,
evm_initialized needs to be non-zero. Previously non-zero indicated
that the HMAC key was loaded. When EVM loads the X509 before calling
'init', with this patch it is now possible to enable EVM to start
signature based verification.
This patch defines bits to enable EVM if a key of any type is loaded.
Changes in v3:
* print error message if key is not set
Changes in v2:
* EVM_STATE_KEY_SET replaced by EVM_INIT_HMAC
* EVM_STATE_X509_SET replaced by EVM_INIT_X509
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
security/integrity/evm/evm.h | 3 +++
security/integrity/evm/evm_crypto.c | 4 ++++
security/integrity/evm/evm_main.c | 6 +++++-
security/integrity/evm/evm_secfs.c | 4 ++--
4 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/security/integrity/evm/evm.h b/security/integrity/evm/evm.h
index 88bfe77efa1cf..f5f12727771a0 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 461f8d8915794..2c3591eca9893 100644
--- a/security/integrity/evm/evm_crypto.c
+++ b/security/integrity/evm/evm_crypto.c
@@ -40,6 +40,10 @@ 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 {
diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index 519de0a0ba725..420d94da2793e 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -475,7 +475,11 @@ EXPORT_SYMBOL_GPL(evm_inode_init_security);
#ifdef CONFIG_EVM_LOAD_X509
void __init evm_load_x509(void)
{
- integrity_load_x509(INTEGRITY_KEYRING_EVM, CONFIG_EVM_X509_PATH);
+ int rc;
+
+ rc = integrity_load_x509(INTEGRITY_KEYRING_EVM, CONFIG_EVM_X509_PATH);
+ if (!rc)
+ evm_initialized |= EVM_INIT_X509;
}
#endif
diff --git a/security/integrity/evm/evm_secfs.c b/security/integrity/evm/evm_secfs.c
index cf12a04717d32..3f775dfea8685 100644
--- a/security/integrity/evm/evm_secfs.c
+++ b/security/integrity/evm/evm_secfs.c
@@ -64,7 +64,7 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
char temp[80];
int i, error;
- 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)
@@ -80,7 +80,7 @@ static ssize_t evm_write_key(struct file *file, const char __user *buf,
error = evm_init_key();
if (!error) {
- evm_initialized = 1;
+ evm_initialized |= EVM_INIT_HMAC;
pr_info("initialized\n");
} else
pr_err("initialization failed\n");
--
GitLab