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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>
This commit is contained in:
Dmitry Kasatkin 2015-10-22 21:26:26 +03:00 committed by Mimi Zohar
parent 2ce523eb89
commit 26ddabfe96
4 changed files with 14 additions and 3 deletions
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3
security/integrity/evm/evm.h
View File

@ -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;

4
security/integrity/evm/evm_crypto.c
View File

@ -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 {

6
security/integrity/evm/evm_main.c
View File

@ -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

4
security/integrity/evm/evm_secfs.c
View File

@ -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");