crypto: add support for the serpent cipher algorithm

New cipher algorithms 'serpent-128', 'serpent-192' and
'serpent-256' are defined for the Serpent algorithm.

The nettle and gcrypt cipher backends are updated to
support the new cipher and a test vector added to the
cipher test suite. The new algorithm is enabled in the
LUKS block encryption driver.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

3 files changed, 55 insertions, 0 deletions

diff --git a/crypto/cipher-gcrypt.c b/crypto/cipher-gcrypt.c
index aa1d8c5889..a667d592b6 100644
--- a/crypto/cipher-gcrypt.c
+++ b/crypto/cipher-gcrypt.c
@@ -30,6 +30,9 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
     case QCRYPTO_CIPHER_ALG_AES_192:
     case QCRYPTO_CIPHER_ALG_AES_256:
     case QCRYPTO_CIPHER_ALG_CAST5_128:
+    case QCRYPTO_CIPHER_ALG_SERPENT_128:
+    case QCRYPTO_CIPHER_ALG_SERPENT_192:
+    case QCRYPTO_CIPHER_ALG_SERPENT_256:
         return true;
     default:
         return false;
@@ -89,6 +92,18 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         gcryalg = GCRY_CIPHER_CAST5;
         break;
 
+    case QCRYPTO_CIPHER_ALG_SERPENT_128:
+        gcryalg = GCRY_CIPHER_SERPENT128;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_SERPENT_192:
+        gcryalg = GCRY_CIPHER_SERPENT192;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_SERPENT_256:
+        gcryalg = GCRY_CIPHER_SERPENT256;
+        break;
+
     default:
         error_setg(errp, "Unsupported cipher algorithm %d", alg);
         return NULL;
@@ -122,6 +137,9 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         case QCRYPTO_CIPHER_ALG_AES_128:
         case QCRYPTO_CIPHER_ALG_AES_192:
         case QCRYPTO_CIPHER_ALG_AES_256:
+        case QCRYPTO_CIPHER_ALG_SERPENT_128:
+        case QCRYPTO_CIPHER_ALG_SERPENT_192:
+        case QCRYPTO_CIPHER_ALG_SERPENT_256:
             ctx->blocksize = 16;
             break;
         case QCRYPTO_CIPHER_ALG_CAST5_128:
diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index cfa69cc5d7..74b55abee0 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -24,6 +24,7 @@
 #include <nettle/des.h>
 #include <nettle/cbc.h>
 #include <nettle/cast128.h>
+#include <nettle/serpent.h>
 
 #if CONFIG_NETTLE_VERSION_MAJOR < 3
 typedef nettle_crypt_func nettle_cipher_func;
@@ -76,6 +77,18 @@ static void cast128_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
     cast128_decrypt(ctx, length, dst, src);
 }
 
+static void serpent_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+                                    uint8_t *dst, const uint8_t *src)
+{
+    serpent_encrypt(ctx, length, dst, src);
+}
+
+static void serpent_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+                                    uint8_t *dst, const uint8_t *src)
+{
+    serpent_decrypt(ctx, length, dst, src);
+}
+
 typedef struct QCryptoCipherNettle QCryptoCipherNettle;
 struct QCryptoCipherNettle {
     void *ctx_encrypt;
@@ -94,6 +107,9 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
     case QCRYPTO_CIPHER_ALG_AES_192:
     case QCRYPTO_CIPHER_ALG_AES_256:
     case QCRYPTO_CIPHER_ALG_CAST5_128:
+    case QCRYPTO_CIPHER_ALG_SERPENT_128:
+    case QCRYPTO_CIPHER_ALG_SERPENT_192:
+    case QCRYPTO_CIPHER_ALG_SERPENT_256:
         return true;
     default:
         return false;
@@ -169,6 +185,21 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
 
         ctx->blocksize = CAST128_BLOCK_SIZE;
         break;
+
+    case QCRYPTO_CIPHER_ALG_SERPENT_128:
+    case QCRYPTO_CIPHER_ALG_SERPENT_192:
+    case QCRYPTO_CIPHER_ALG_SERPENT_256:
+        ctx->ctx_encrypt = g_new0(struct serpent_ctx, 1);
+        ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+
+        serpent_set_key(ctx->ctx_encrypt, nkey, key);
+
+        ctx->alg_encrypt = serpent_encrypt_wrapper;
+        ctx->alg_decrypt = serpent_decrypt_wrapper;
+
+        ctx->blocksize = SERPENT_BLOCK_SIZE;
+        break;
+
     default:
         error_setg(errp, "Unsupported cipher algorithm %d", alg);
         goto error;
diff --git a/crypto/cipher.c b/crypto/cipher.c
index 9e0a226d3c..0f6fe98a1f 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -28,6 +28,9 @@ static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_AES_256] = 32,
     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
     [QCRYPTO_CIPHER_ALG_CAST5_128] = 16,
+    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
+    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
+    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
 };
 
 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
@@ -36,6 +39,9 @@ static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_AES_256] = 16,
     [QCRYPTO_CIPHER_ALG_DES_RFB] = 8,
     [QCRYPTO_CIPHER_ALG_CAST5_128] = 8,
+    [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
+    [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
+    [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
 };
 
 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {