[Qemu-devel] [PULL v3 08/13] crypto: add support for the twofish cipher algorithm

["Daniel P. Berrange" <berrange@redhat.com>]

New cipher algorithms 'twofish-128', 'twofish-192' and
'twofish-256' are defined for the Twofish algorithm.
The gcrypt backend does not support 'twofish-192'.

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>
---
 crypto/cipher-gcrypt.c     | 12 ++++++++++++
 crypto/cipher-nettle.c     | 30 ++++++++++++++++++++++++++++++
 crypto/cipher.c            |  6 ++++++
 qapi/crypto.json           |  6 +++++-
 tests/test-crypto-cipher.c | 29 +++++++++++++++++++++++++++++
 5 files changed, 82 insertions(+), 1 deletion(-)

diff --git a/crypto/cipher-gcrypt.c b/crypto/cipher-gcrypt.c
index a667d59..ce26456 100644
--- a/crypto/cipher-gcrypt.c
+++ b/crypto/cipher-gcrypt.c
@@ -33,6 +33,8 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
     case QCRYPTO_CIPHER_ALG_SERPENT_128:
     case QCRYPTO_CIPHER_ALG_SERPENT_192:
     case QCRYPTO_CIPHER_ALG_SERPENT_256:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
         return true;
     default:
         return false;
@@ -104,6 +106,14 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         gcryalg = GCRY_CIPHER_SERPENT256;
         break;
 
+    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
+        gcryalg = GCRY_CIPHER_TWOFISH128;
+        break;
+
+    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
+        gcryalg = GCRY_CIPHER_TWOFISH;
+        break;
+
     default:
         error_setg(errp, "Unsupported cipher algorithm %d", alg);
         return NULL;
@@ -140,6 +150,8 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         case QCRYPTO_CIPHER_ALG_SERPENT_128:
         case QCRYPTO_CIPHER_ALG_SERPENT_192:
         case QCRYPTO_CIPHER_ALG_SERPENT_256:
+        case QCRYPTO_CIPHER_ALG_TWOFISH_128:
+        case QCRYPTO_CIPHER_ALG_TWOFISH_256:
             ctx->blocksize = 16;
             break;
         case QCRYPTO_CIPHER_ALG_CAST5_128:
diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index 74b55ab..9b057fd 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -25,6 +25,7 @@
 #include <nettle/cbc.h>
 #include <nettle/cast128.h>
 #include <nettle/serpent.h>
+#include <nettle/twofish.h>
 
 #if CONFIG_NETTLE_VERSION_MAJOR < 3
 typedef nettle_crypt_func nettle_cipher_func;
@@ -89,6 +90,18 @@ static void serpent_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
     serpent_decrypt(ctx, length, dst, src);
 }
 
+static void twofish_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+                                    uint8_t *dst, const uint8_t *src)
+{
+    twofish_encrypt(ctx, length, dst, src);
+}
+
+static void twofish_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+                                    uint8_t *dst, const uint8_t *src)
+{
+    twofish_decrypt(ctx, length, dst, src);
+}
+
 typedef struct QCryptoCipherNettle QCryptoCipherNettle;
 struct QCryptoCipherNettle {
     void *ctx_encrypt;
@@ -110,6 +123,9 @@ bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
     case QCRYPTO_CIPHER_ALG_SERPENT_128:
     case QCRYPTO_CIPHER_ALG_SERPENT_192:
     case QCRYPTO_CIPHER_ALG_SERPENT_256:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_192:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
         return true;
     default:
         return false;
@@ -200,6 +216,20 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         ctx->blocksize = SERPENT_BLOCK_SIZE;
         break;
 
+    case QCRYPTO_CIPHER_ALG_TWOFISH_128:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_192:
+    case QCRYPTO_CIPHER_ALG_TWOFISH_256:
+        ctx->ctx_encrypt = g_new0(struct twofish_ctx, 1);
+        ctx->ctx_decrypt = NULL; /* 1 ctx can do both */
+
+        twofish_set_key(ctx->ctx_encrypt, nkey, key);
+
+        ctx->alg_encrypt = twofish_encrypt_wrapper;
+        ctx->alg_decrypt = twofish_decrypt_wrapper;
+
+        ctx->blocksize = TWOFISH_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 0f6fe98..89fa5a2 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -31,6 +31,9 @@ static size_t alg_key_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 24,
     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 32,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 24,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 32,
 };
 
 static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
@@ -42,6 +45,9 @@ static size_t alg_block_len[QCRYPTO_CIPHER_ALG__MAX] = {
     [QCRYPTO_CIPHER_ALG_SERPENT_128] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_192] = 16,
     [QCRYPTO_CIPHER_ALG_SERPENT_256] = 16,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_128] = 16,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_192] = 16,
+    [QCRYPTO_CIPHER_ALG_TWOFISH_256] = 16,
 };
 
 static bool mode_need_iv[QCRYPTO_CIPHER_MODE__MAX] = {
diff --git a/qapi/crypto.json b/qapi/crypto.json
index 6738b95..63c001a 100644
--- a/qapi/crypto.json
+++ b/qapi/crypto.json
@@ -63,6 +63,9 @@
 # @serpent-128: Serpent with 128 bit / 16 byte keys
 # @serpent-192: Serpent with 192 bit / 24 byte keys
 # @serpent-256: Serpent with 256 bit / 32 byte keys
+# @twofish-128: Twofish with 128 bit / 16 byte keys
+# @twofish-192: Twofish with 192 bit / 24 byte keys
+# @twofish-256: Twofish with 256 bit / 32 byte keys
 # Since: 2.6
 ##
 { 'enum': 'QCryptoCipherAlgorithm',
@@ -70,7 +73,8 @@
   'data': ['aes-128', 'aes-192', 'aes-256',
            'des-rfb',
            'cast5-128',
-           'serpent-128', 'serpent-192', 'serpent-256']}
+           'serpent-128', 'serpent-192', 'serpent-256',
+           'twofish-128', 'twofish-192', 'twofish-256']}
 
 
 ##
diff --git a/tests/test-crypto-cipher.c b/tests/test-crypto-cipher.c
index 5268723..f18bcaa 100644
--- a/tests/test-crypto-cipher.c
+++ b/tests/test-crypto-cipher.c
@@ -213,6 +213,35 @@ static QCryptoCipherTestData test_data[] = {
         .plaintext = "00000000010000000200000003000000",
         .ciphertext = "2061a42782bd52ec691ec383b03ba77c",
     },
+    {
+        /* Twofish paper "Known Answer Test" */
+        .path = "/crypto/cipher/twofish-128",
+        .alg = QCRYPTO_CIPHER_ALG_TWOFISH_128,
+        .mode = QCRYPTO_CIPHER_MODE_ECB,
+        .key = "d491db16e7b1c39e86cb086b789f5419",
+        .plaintext = "019f9809de1711858faac3a3ba20fbc3",
+        .ciphertext = "6363977de839486297e661c6c9d668eb",
+    },
+    {
+        /* Twofish paper "Known Answer Test", I=3 */
+        .path = "/crypto/cipher/twofish-192",
+        .alg = QCRYPTO_CIPHER_ALG_TWOFISH_192,
+        .mode = QCRYPTO_CIPHER_MODE_ECB,
+        .key = "88b2b2706b105e36b446bb6d731a1e88"
+               "efa71f788965bd44",
+        .plaintext = "39da69d6ba4997d585b6dc073ca341b2",
+        .ciphertext = "182b02d81497ea45f9daacdc29193a65",
+    },
+    {
+        /* Twofish paper "Known Answer Test", I=4 */
+        .path = "/crypto/cipher/twofish-256",
+        .alg = QCRYPTO_CIPHER_ALG_TWOFISH_256,
+        .mode = QCRYPTO_CIPHER_MODE_ECB,
+        .key = "d43bb7556ea32e46f2a282b7d45b4e0d"
+               "57ff739d4dc92c1bd7fc01700cc8216f",
+        .plaintext = "90afe91bb288544f2c32dc239b2635e6",
+        .ciphertext = "6cb4561c40bf0a9705931cb6d408e7fa",
+    },
 };
 
 
-- 
2.5.0