[aes/model] Extend crypto with support for CBC and CTR modes
Signed-off-by: Pirmin Vogel <vogelpi@lowrisc.org>
diff --git a/hw/ip/aes/dv/aes_model_dpi/aes_model_dpi.c b/hw/ip/aes/dv/aes_model_dpi/aes_model_dpi.c
index 67cbafc..1ae6b33 100644
--- a/hw/ip/aes/dv/aes_model_dpi/aes_model_dpi.c
+++ b/hw/ip/aes/dv/aes_model_dpi/aes_model_dpi.c
@@ -46,9 +46,9 @@
unsigned char iv[16];
memset(iv, 0, 16);
if (!op_i) {
- crypto_encrypt(ref_out, iv, ref_in, 16, key, key_len);
+ crypto_encrypt(ref_out, iv, ref_in, 16, key, key_len, kCryptoAesEcb);
} else {
- crypto_decrypt(ref_out, iv, ref_in, 16, key, key_len);
+ crypto_decrypt(ref_out, iv, ref_in, 16, key, key_len, kCryptoAesEcb);
}
}
diff --git a/hw/ip/aes/model/aes_example.c b/hw/ip/aes/model/aes_example.c
index f0ffcec..20a7ce0 100644
--- a/hw/ip/aes/model/aes_example.c
+++ b/hw/ip/aes/model/aes_example.c
@@ -213,8 +213,8 @@
}
// check state vs BoringSSL/OpenSSL
- cipher_text_len =
- crypto_encrypt(cipher_text, iv, plain_text, 16, key, key_len);
+ cipher_text_len = crypto_encrypt(cipher_text, iv, plain_text, 16, key,
+ key_len, kCryptoAesEcb);
if (!check_block(state, cipher_text, 0)) {
printf("SUCCESS: state matches %s cipher text\n", crypto_lib);
} else {
@@ -333,8 +333,8 @@
}
// check state vs BoringSSL/OpenSSL
- crypto_decrypt(decrypted_text, iv, cipher_text, cipher_text_len, key,
- key_len);
+ crypto_decrypt(decrypted_text, iv, cipher_text, cipher_text_len, key, key_len,
+ kCryptoAesEcb);
if (!check_block(state, decrypted_text, 0)) {
printf("SUCCESS: state matches %s decrypted text\n", crypto_lib);
} else {
diff --git a/hw/ip/aes/model/crypto.c b/hw/ip/aes/model/crypto.c
index 56c3ff2..6bbaab8 100644
--- a/hw/ip/aes/model/crypto.c
+++ b/hw/ip/aes/model/crypto.c
@@ -5,9 +5,52 @@
#include <openssl/conf.h>
#include <openssl/evp.h>
+#include "crypto.h"
+
+/**
+ * Get EVP_CIPHER type pointer defined by key_len and mode.
+ * If the selected cipher is not supported, the AES-128 ECB type is returned.
+ *
+ * @param key_len Encryption key length in bytes (16, 24, 32)
+ * @param mode AES cipher mode @see crypto_mode.
+ * @return Pointer to EVP_CIPHER type
+ */
+static const EVP_CIPHER *crypto_get_EVP_cipher(int key_len,
+ crypto_mode_t mode) {
+ const EVP_CIPHER *cipher;
+
+ if (mode == kCryptoAesCbc) {
+ if (key_len == 32) {
+ cipher = EVP_aes_256_cbc();
+ } else if (key_len == 24) {
+ cipher = EVP_aes_192_cbc();
+ } else { // key_len = 16
+ cipher = EVP_aes_128_cbc();
+ }
+ } else if (mode == kCryptoAesCtr) {
+ if (key_len == 32) {
+ cipher = EVP_aes_256_ctr();
+ } else if (key_len == 24) {
+ cipher = EVP_aes_192_ctr();
+ } else { // key_len = 16
+ cipher = EVP_aes_128_ctr();
+ }
+ } else { // kCryptoAesEcb
+ if (key_len == 32) {
+ cipher = EVP_aes_256_ecb();
+ } else if (key_len == 24) {
+ cipher = EVP_aes_192_ecb();
+ } else { // key_len = 16
+ cipher = EVP_aes_128_ecb();
+ }
+ }
+
+ return cipher;
+}
+
int crypto_encrypt(unsigned char *output, const unsigned char *iv,
- const unsigned char *input, const int input_len,
- const unsigned char *key, const int key_len) {
+ const unsigned char *input, int input_len,
+ const unsigned char *key, int key_len, crypto_mode_t mode) {
EVP_CIPHER_CTX *ctx;
int ret;
int len, output_len;
@@ -19,14 +62,12 @@
return -1;
}
+ // Get cipher
+ const EVP_CIPHER *cipher = crypto_get_EVP_cipher(key_len, mode);
+
// Init encryption context
- if (key_len == 16) {
- ret = EVP_EncryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, key, iv);
- } else if (key_len == 24) {
- ret = EVP_EncryptInit_ex(ctx, EVP_aes_192_ecb(), NULL, key, iv);
- } else { // key_len = 32
- ret = EVP_EncryptInit_ex(ctx, EVP_aes_256_ecb(), NULL, key, iv);
- }
+ ret = EVP_EncryptInit_ex(ctx, cipher, NULL, key, iv);
+
if (ret != 1) {
printf("ERROR: Initialization of encryption context failed\n");
return -1;
@@ -58,8 +99,8 @@
}
int crypto_decrypt(unsigned char *output, const unsigned char *iv,
- const unsigned char *input, const int input_len,
- const unsigned char *key, const int key_len) {
+ const unsigned char *input, int input_len,
+ const unsigned char *key, int key_len, crypto_mode_t mode) {
EVP_CIPHER_CTX *ctx;
int ret;
int len, output_len;
@@ -71,14 +112,11 @@
return -1;
}
+ // Get cipher
+ const EVP_CIPHER *cipher = crypto_get_EVP_cipher(key_len, mode);
+
// Init decryption context
- if (key_len == 16) {
- ret = EVP_DecryptInit_ex(ctx, EVP_aes_128_ecb(), NULL, key, iv);
- } else if (key_len == 24) {
- ret = EVP_DecryptInit_ex(ctx, EVP_aes_192_ecb(), NULL, key, iv);
- } else { // key_len == 32
- ret = EVP_DecryptInit_ex(ctx, EVP_aes_256_ecb(), NULL, key, iv);
- }
+ ret = EVP_DecryptInit_ex(ctx, cipher, NULL, key, iv);
if (ret != 1) {
printf("ERROR: Initialization of decryption context failed\n");
return -1;
diff --git a/hw/ip/aes/model/crypto.h b/hw/ip/aes/model/crypto.h
index 1f92abb..ba22e5e 100644
--- a/hw/ip/aes/model/crypto.h
+++ b/hw/ip/aes/model/crypto.h
@@ -6,6 +6,15 @@
#define CRYPTO_H_
/**
+ * AES cipher mode
+ */
+typedef enum crypto_mode {
+ kCryptoAesEcb = 1 << 0,
+ kCryptoAesCbc = 1 << 1,
+ kCryptoAesCtr = 1 << 2
+} crypto_mode_t;
+
+/**
* Encrypt using BoringSSL/OpenSSL
*
* @param output Output cipher text, must be a multiple of 16 bytes
@@ -15,11 +24,12 @@
* of 16
* @param key Encryption key
* @param key_len Encryption key length in bytes (16, 24, 32)
+ * @param mode AES cipher mode @see crypto_mode.
* @return Length of the output cipher text in bytes, -1 in case of error
*/
int crypto_encrypt(unsigned char *output, const unsigned char *iv,
- const unsigned char *input, const int input_len,
- const unsigned char *key, const int key_len);
+ const unsigned char *input, int input_len,
+ const unsigned char *key, int key_len, crypto_mode_t mode);
/**
* Decrypt using BoringSSL/OpenSSL
@@ -31,10 +41,11 @@
* multiple of 16
* @param key Encryption key, decryption key is derived internally
* @param key_len Encryption key length in bytes (16, 24, 32)
+ * @param mode AES cipher mode @see crypto_mode.
* @return Length of the output plain text in bytes, -1 in case of error
*/
int crypto_decrypt(unsigned char *output, const unsigned char *iv,
- const unsigned char *input, const int input_len,
- const unsigned char *key, const int key_len);
+ const unsigned char *input, int input_len,
+ const unsigned char *key, int key_len, crypto_mode_t mode);
#endif // CRYPTO_H_
