crypto: introduce generic cipher API & built-in implementation

Introduce a generic cipher API and an implementation of it that
supports only the built-in AES and DES-RFB algorithms.

The test suite checks the supported algorithms + modes to
validate that every backend implementation is actually correctly
complying with the specs.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1435770638-25715-5-git-send-email-berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 398 insertions, 0 deletions

diff --git a/crypto/cipher-builtin.c b/crypto/cipher-builtin.c
new file mode 100644
index 0000000000..c625cb40f7
--- /dev/null
+++ b/crypto/cipher-builtin.c
@@ -0,0 +1,398 @@
+/*
+ * QEMU Crypto cipher built-in algorithms
+ *
+ * Copyright (c) 2015 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "crypto/aes.h"
+#include "crypto/desrfb.h"
+
+typedef struct QCryptoCipherBuiltinAES QCryptoCipherBuiltinAES;
+struct QCryptoCipherBuiltinAES {
+    AES_KEY encrypt_key;
+    AES_KEY decrypt_key;
+    uint8_t *iv;
+    size_t niv;
+};
+typedef struct QCryptoCipherBuiltinDESRFB QCryptoCipherBuiltinDESRFB;
+struct QCryptoCipherBuiltinDESRFB {
+    uint8_t *key;
+    size_t nkey;
+};
+
+typedef struct QCryptoCipherBuiltin QCryptoCipherBuiltin;
+struct QCryptoCipherBuiltin {
+    union {
+        QCryptoCipherBuiltinAES aes;
+        QCryptoCipherBuiltinDESRFB desrfb;
+    } state;
+    void (*free)(QCryptoCipher *cipher);
+    int (*setiv)(QCryptoCipher *cipher,
+                 const uint8_t *iv, size_t niv,
+                 Error **errp);
+    int (*encrypt)(QCryptoCipher *cipher,
+                   const void *in,
+                   void *out,
+                   size_t len,
+                   Error **errp);
+    int (*decrypt)(QCryptoCipher *cipher,
+                   const void *in,
+                   void *out,
+                   size_t len,
+                   Error **errp);
+};
+
+
+static void qcrypto_cipher_free_aes(QCryptoCipher *cipher)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    g_free(ctxt->state.aes.iv);
+    g_free(ctxt);
+    cipher->opaque = NULL;
+}
+
+
+static int qcrypto_cipher_encrypt_aes(QCryptoCipher *cipher,
+                                      const void *in,
+                                      void *out,
+                                      size_t len,
+                                      Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    if (cipher->mode == QCRYPTO_CIPHER_MODE_ECB) {
+        const uint8_t *inptr = in;
+        uint8_t *outptr = out;
+        while (len) {
+            if (len > AES_BLOCK_SIZE) {
+                AES_encrypt(inptr, outptr, &ctxt->state.aes.encrypt_key);
+                inptr += AES_BLOCK_SIZE;
+                outptr += AES_BLOCK_SIZE;
+                len -= AES_BLOCK_SIZE;
+            } else {
+                uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
+                memcpy(tmp1, inptr, len);
+                /* Fill with 0 to avoid valgrind uninitialized reads */
+                memset(tmp1 + len, 0, sizeof(tmp1) - len);
+                AES_encrypt(tmp1, tmp2, &ctxt->state.aes.encrypt_key);
+                memcpy(outptr, tmp2, len);
+                len = 0;
+            }
+        }
+    } else {
+        AES_cbc_encrypt(in, out, len,
+                        &ctxt->state.aes.encrypt_key,
+                        ctxt->state.aes.iv, 1);
+    }
+
+    return 0;
+}
+
+
+static int qcrypto_cipher_decrypt_aes(QCryptoCipher *cipher,
+                                      const void *in,
+                                      void *out,
+                                      size_t len,
+                                      Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    if (cipher->mode == QCRYPTO_CIPHER_MODE_ECB) {
+        const uint8_t *inptr = in;
+        uint8_t *outptr = out;
+        while (len) {
+            if (len > AES_BLOCK_SIZE) {
+                AES_decrypt(inptr, outptr, &ctxt->state.aes.encrypt_key);
+                inptr += AES_BLOCK_SIZE;
+                outptr += AES_BLOCK_SIZE;
+                len -= AES_BLOCK_SIZE;
+            } else {
+                uint8_t tmp1[AES_BLOCK_SIZE], tmp2[AES_BLOCK_SIZE];
+                memcpy(tmp1, inptr, len);
+                /* Fill with 0 to avoid valgrind uninitialized reads */
+                memset(tmp1 + len, 0, sizeof(tmp1) - len);
+                AES_decrypt(tmp1, tmp2, &ctxt->state.aes.encrypt_key);
+                memcpy(outptr, tmp2, len);
+                len = 0;
+            }
+        }
+    } else {
+        AES_cbc_encrypt(in, out, len,
+                        &ctxt->state.aes.encrypt_key,
+                        ctxt->state.aes.iv, 1);
+    }
+
+    return 0;
+}
+
+static int qcrypto_cipher_setiv_aes(QCryptoCipher *cipher,
+                                     const uint8_t *iv, size_t niv,
+                                     Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+    if (niv != 16) {
+        error_setg(errp, "IV must be 16 bytes not %zu", niv);
+        return -1;
+    }
+
+    g_free(ctxt->state.aes.iv);
+    ctxt->state.aes.iv = g_new0(uint8_t, niv);
+    memcpy(ctxt->state.aes.iv, iv, niv);
+    ctxt->state.aes.niv = niv;
+
+    return 0;
+}
+
+
+
+
+static int qcrypto_cipher_init_aes(QCryptoCipher *cipher,
+                                   const uint8_t *key, size_t nkey,
+                                   Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt;
+
+    if (cipher->mode != QCRYPTO_CIPHER_MODE_CBC &&
+        cipher->mode != QCRYPTO_CIPHER_MODE_ECB) {
+        error_setg(errp, "Unsupported cipher mode %d", cipher->mode);
+        return -1;
+    }
+
+    ctxt = g_new0(QCryptoCipherBuiltin, 1);
+
+    if (AES_set_encrypt_key(key, nkey * 8, &ctxt->state.aes.encrypt_key) != 0) {
+        error_setg(errp, "Failed to set encryption key");
+        goto error;
+    }
+
+    if (AES_set_decrypt_key(key, nkey * 8, &ctxt->state.aes.decrypt_key) != 0) {
+        error_setg(errp, "Failed to set decryption key");
+        goto error;
+    }
+
+    ctxt->free = qcrypto_cipher_free_aes;
+    ctxt->setiv = qcrypto_cipher_setiv_aes;
+    ctxt->encrypt = qcrypto_cipher_encrypt_aes;
+    ctxt->decrypt = qcrypto_cipher_decrypt_aes;
+
+    cipher->opaque = ctxt;
+
+    return 0;
+
+ error:
+    g_free(ctxt);
+    return -1;
+}
+
+
+static void qcrypto_cipher_free_des_rfb(QCryptoCipher *cipher)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    g_free(ctxt->state.desrfb.key);
+    g_free(ctxt);
+    cipher->opaque = NULL;
+}
+
+
+static int qcrypto_cipher_encrypt_des_rfb(QCryptoCipher *cipher,
+                                          const void *in,
+                                          void *out,
+                                          size_t len,
+                                          Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+    size_t i;
+
+    if (len % 8) {
+        error_setg(errp, "Buffer size must be multiple of 8 not %zu",
+                   len);
+        return -1;
+    }
+
+    deskey(ctxt->state.desrfb.key, EN0);
+
+    for (i = 0; i < len; i += 8) {
+        des((void *)in + i, out + i);
+    }
+
+    return 0;
+}
+
+
+static int qcrypto_cipher_decrypt_des_rfb(QCryptoCipher *cipher,
+                                          const void *in,
+                                          void *out,
+                                          size_t len,
+                                          Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+    size_t i;
+
+    if (len % 8) {
+        error_setg(errp, "Buffer size must be multiple of 8 not %zu",
+                   len);
+        return -1;
+    }
+
+    deskey(ctxt->state.desrfb.key, DE1);
+
+    for (i = 0; i < len; i += 8) {
+        des((void *)in + i, out + i);
+    }
+
+    return 0;
+}
+
+
+static int qcrypto_cipher_setiv_des_rfb(QCryptoCipher *cipher,
+                                        const uint8_t *iv, size_t niv,
+                                        Error **errp)
+{
+    error_setg(errp, "Setting IV is not supported");
+    return -1;
+}
+
+
+static int qcrypto_cipher_init_des_rfb(QCryptoCipher *cipher,
+                                       const uint8_t *key, size_t nkey,
+                                       Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt;
+
+    if (cipher->mode != QCRYPTO_CIPHER_MODE_ECB) {
+        error_setg(errp, "Unsupported cipher mode %d", cipher->mode);
+        return -1;
+    }
+
+    ctxt = g_new0(QCryptoCipherBuiltin, 1);
+
+    ctxt->state.desrfb.key = g_new0(uint8_t, nkey);
+    memcpy(ctxt->state.desrfb.key, key, nkey);
+    ctxt->state.desrfb.nkey = nkey;
+
+    ctxt->free = qcrypto_cipher_free_des_rfb;
+    ctxt->setiv = qcrypto_cipher_setiv_des_rfb;
+    ctxt->encrypt = qcrypto_cipher_encrypt_des_rfb;
+    ctxt->decrypt = qcrypto_cipher_decrypt_des_rfb;
+
+    cipher->opaque = ctxt;
+
+    return 0;
+}
+
+
+bool qcrypto_cipher_supports(QCryptoCipherAlgorithm alg)
+{
+    switch (alg) {
+    case QCRYPTO_CIPHER_ALG_DES_RFB:
+    case QCRYPTO_CIPHER_ALG_AES_128:
+    case QCRYPTO_CIPHER_ALG_AES_192:
+    case QCRYPTO_CIPHER_ALG_AES_256:
+        return true;
+    default:
+        return false;
+    }
+}
+
+
+QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
+                                  QCryptoCipherMode mode,
+                                  const uint8_t *key, size_t nkey,
+                                  Error **errp)
+{
+    QCryptoCipher *cipher;
+
+    cipher = g_new0(QCryptoCipher, 1);
+    cipher->alg = alg;
+    cipher->mode = mode;
+
+    if (!qcrypto_cipher_validate_key_length(alg, nkey, errp)) {
+        goto error;
+    }
+
+    switch (cipher->alg) {
+    case QCRYPTO_CIPHER_ALG_DES_RFB:
+        if (qcrypto_cipher_init_des_rfb(cipher, key, nkey, errp) < 0) {
+            goto error;
+        }
+        break;
+    case QCRYPTO_CIPHER_ALG_AES_128:
+    case QCRYPTO_CIPHER_ALG_AES_192:
+    case QCRYPTO_CIPHER_ALG_AES_256:
+        if (qcrypto_cipher_init_aes(cipher, key, nkey, errp) < 0) {
+            goto error;
+        }
+        break;
+    default:
+        error_setg(errp,
+                   "Unsupported cipher algorithm %d", cipher->alg);
+        goto error;
+    }
+
+    return cipher;
+
+ error:
+    g_free(cipher);
+    return NULL;
+}
+
+void qcrypto_cipher_free(QCryptoCipher *cipher)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+    if (!cipher) {
+        return;
+    }
+
+    ctxt->free(cipher);
+    g_free(cipher);
+}
+
+
+int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
+                           const void *in,
+                           void *out,
+                           size_t len,
+                           Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    return ctxt->encrypt(cipher, in, out, len, errp);
+}
+
+
+int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
+                           const void *in,
+                           void *out,
+                           size_t len,
+                           Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    return ctxt->decrypt(cipher, in, out, len, errp);
+}
+
+
+int qcrypto_cipher_setiv(QCryptoCipher *cipher,
+                         const uint8_t *iv, size_t niv,
+                         Error **errp)
+{
+    QCryptoCipherBuiltin *ctxt = cipher->opaque;
+
+    return ctxt->setiv(cipher, iv, niv, errp);
+}