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Diffstat (limited to 'security/integrity/evm/evm_crypto.c')
-rw-r--r--security/integrity/evm/evm_crypto.c54
1 files changed, 47 insertions, 7 deletions
diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c
index 461f8d891579..30b6b7d0429f 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);