[Qemu-devel] [PATCH v1 2/2] crypto: fix cipher function signature mismatch with nettle & xts

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

For versions of nettle < 3.0.0, the cipher functions took a
'void *ctx' and 'unsigned len' instad of 'const void *ctx'
and 'size_t len'. The xts functions though are builtin to
QEMU and always expect the latter signatures. Define a
second set of wrappers to use with the correct signatures
needed by XTS mode.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 crypto/cipher-nettle.c | 141 +++++++++++++++++++++++++++++++++++++------------
 1 file changed, 107 insertions(+), 34 deletions(-)

diff --git a/crypto/cipher-nettle.c b/crypto/cipher-nettle.c
index bec4f1c..f89adc0 100644
--- a/crypto/cipher-nettle.c
+++ b/crypto/cipher-nettle.c
@@ -29,85 +29,146 @@
 #include <nettle/serpent.h>
 #include <nettle/twofish.h>
 
+typedef void (*QCryptoCipherNettleFuncWrapper)(const void *ctx, size_t length,
+                                               uint8_t *dst, const uint8_t *src);
+
 #if CONFIG_NETTLE_VERSION_MAJOR < 3
-typedef nettle_crypt_func nettle_cipher_func;
+typedef nettle_crypt_func *QCryptoCipherNettleFuncNative;
 
 typedef void *       cipher_ctx_t;
 typedef unsigned     cipher_length_t;
 
 #define cast5_set_key cast128_set_key
 #else
+typedef nettle_cipher_func *QCryptoCipherNettleFuncNative;
 typedef const void * cipher_ctx_t;
 typedef size_t       cipher_length_t;
 #endif
 
-static nettle_cipher_func aes_encrypt_wrapper;
-static nettle_cipher_func aes_decrypt_wrapper;
-static nettle_cipher_func des_encrypt_wrapper;
-static nettle_cipher_func des_decrypt_wrapper;
-
 typedef struct QCryptoNettleAES {
     struct aes_ctx enc;
     struct aes_ctx dec;
 } QCryptoNettleAES;
 
-static void aes_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void aes_encrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                               uint8_t *dst, const uint8_t *src)
+{
+    const QCryptoNettleAES *aesctx = ctx;
+    aes_encrypt(&aesctx->enc, length, dst, src);
+}
+
+static void aes_decrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                               uint8_t *dst, const uint8_t *src)
+{
+    const QCryptoNettleAES *aesctx = ctx;
+    aes_decrypt(&aesctx->dec, length, dst, src);
+}
+
+static void des_encrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                               uint8_t *dst, const uint8_t *src)
+{
+    des_encrypt(ctx, length, dst, src);
+}
+
+static void des_decrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                               uint8_t *dst, const uint8_t *src)
+{
+    des_decrypt(ctx, length, dst, src);
+}
+
+static void cast128_encrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                                   uint8_t *dst, const uint8_t *src)
+{
+    cast128_encrypt(ctx, length, dst, src);
+}
+
+static void cast128_decrypt_native(cipher_ctx_t ctx, cipher_length_t length,
+                                   uint8_t *dst, const uint8_t *src)
+{
+    cast128_decrypt(ctx, length, dst, src);
+}
+
+static void serpent_encrypt_native(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_native(cipher_ctx_t ctx, cipher_length_t length,
+                                   uint8_t *dst, const uint8_t *src)
+{
+    serpent_decrypt(ctx, length, dst, src);
+}
+
+static void twofish_encrypt_native(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_native(cipher_ctx_t ctx, cipher_length_t length,
+                                   uint8_t *dst, const uint8_t *src)
+{
+    twofish_decrypt(ctx, length, dst, src);
+}
+
+static void aes_encrypt_wrapper(const void *ctx, size_t length,
                                 uint8_t *dst, const uint8_t *src)
 {
     const QCryptoNettleAES *aesctx = ctx;
     aes_encrypt(&aesctx->enc, length, dst, src);
 }
 
-static void aes_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void aes_decrypt_wrapper(const void *ctx, size_t length,
                                 uint8_t *dst, const uint8_t *src)
 {
     const QCryptoNettleAES *aesctx = ctx;
     aes_decrypt(&aesctx->dec, length, dst, src);
 }
 
-static void des_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void des_encrypt_wrapper(const void *ctx, size_t length,
                                 uint8_t *dst, const uint8_t *src)
 {
     des_encrypt(ctx, length, dst, src);
 }
 
-static void des_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void des_decrypt_wrapper(const void *ctx, size_t length,
                                 uint8_t *dst, const uint8_t *src)
 {
     des_decrypt(ctx, length, dst, src);
 }
 
-static void cast128_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void cast128_encrypt_wrapper(const void *ctx, size_t length,
                                     uint8_t *dst, const uint8_t *src)
 {
     cast128_encrypt(ctx, length, dst, src);
 }
 
-static void cast128_decrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void cast128_decrypt_wrapper(const void *ctx, size_t length,
                                     uint8_t *dst, const uint8_t *src)
 {
     cast128_decrypt(ctx, length, dst, src);
 }
 
-static void serpent_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void serpent_encrypt_wrapper(const void *ctx, size_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,
+static void serpent_decrypt_wrapper(const void *ctx, size_t length,
                                     uint8_t *dst, const uint8_t *src)
 {
     serpent_decrypt(ctx, length, dst, src);
 }
 
-static void twofish_encrypt_wrapper(cipher_ctx_t ctx, cipher_length_t length,
+static void twofish_encrypt_wrapper(const void *ctx, size_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,
+static void twofish_decrypt_wrapper(const void *ctx, size_t length,
                                     uint8_t *dst, const uint8_t *src)
 {
     twofish_decrypt(ctx, length, dst, src);
@@ -120,8 +181,10 @@ struct QCryptoCipherNettle {
     /* Second cipher context for XTS mode only */
     void *ctx_tweak;
     /* Cipher callbacks for both contexts */
-    nettle_cipher_func *alg_encrypt;
-    nettle_cipher_func *alg_decrypt;
+    QCryptoCipherNettleFuncNative alg_encrypt_native;
+    QCryptoCipherNettleFuncNative alg_decrypt_native;
+    QCryptoCipherNettleFuncWrapper alg_encrypt_wrapper;
+    QCryptoCipherNettleFuncWrapper alg_decrypt_wrapper;
 
     uint8_t *iv;
     size_t blocksize;
@@ -184,8 +247,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
         des_set_key(ctx->ctx, rfbkey);
         g_free(rfbkey);
 
-        ctx->alg_encrypt = des_encrypt_wrapper;
-        ctx->alg_decrypt = des_decrypt_wrapper;
+        ctx->alg_encrypt_native = des_encrypt_native;
+        ctx->alg_decrypt_native = des_decrypt_native;
+        ctx->alg_encrypt_wrapper = des_encrypt_wrapper;
+        ctx->alg_decrypt_wrapper = des_decrypt_wrapper;
 
         ctx->blocksize = DES_BLOCK_SIZE;
         break;
@@ -215,8 +280,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
                                 nkey, key);
         }
 
-        ctx->alg_encrypt = aes_encrypt_wrapper;
-        ctx->alg_decrypt = aes_decrypt_wrapper;
+        ctx->alg_encrypt_native = aes_encrypt_native;
+        ctx->alg_decrypt_native = aes_decrypt_native;
+        ctx->alg_encrypt_wrapper = aes_encrypt_wrapper;
+        ctx->alg_decrypt_wrapper = aes_decrypt_wrapper;
 
         ctx->blocksize = AES_BLOCK_SIZE;
         break;
@@ -234,8 +301,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
             cast5_set_key(ctx->ctx, nkey, key);
         }
 
-        ctx->alg_encrypt = cast128_encrypt_wrapper;
-        ctx->alg_decrypt = cast128_decrypt_wrapper;
+        ctx->alg_encrypt_native = cast128_encrypt_native;
+        ctx->alg_decrypt_native = cast128_decrypt_native;
+        ctx->alg_encrypt_wrapper = cast128_encrypt_wrapper;
+        ctx->alg_decrypt_wrapper = cast128_decrypt_wrapper;
 
         ctx->blocksize = CAST128_BLOCK_SIZE;
         break;
@@ -255,8 +324,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
             serpent_set_key(ctx->ctx, nkey, key);
         }
 
-        ctx->alg_encrypt = serpent_encrypt_wrapper;
-        ctx->alg_decrypt = serpent_decrypt_wrapper;
+        ctx->alg_encrypt_native = serpent_encrypt_native;
+        ctx->alg_decrypt_native = serpent_decrypt_native;
+        ctx->alg_encrypt_wrapper = serpent_encrypt_wrapper;
+        ctx->alg_decrypt_wrapper = serpent_decrypt_wrapper;
 
         ctx->blocksize = SERPENT_BLOCK_SIZE;
         break;
@@ -276,8 +347,10 @@ QCryptoCipher *qcrypto_cipher_new(QCryptoCipherAlgorithm alg,
             twofish_set_key(ctx->ctx, nkey, key);
         }
 
-        ctx->alg_encrypt = twofish_encrypt_wrapper;
-        ctx->alg_decrypt = twofish_decrypt_wrapper;
+        ctx->alg_encrypt_native = twofish_encrypt_native;
+        ctx->alg_decrypt_native = twofish_decrypt_native;
+        ctx->alg_encrypt_wrapper = twofish_encrypt_wrapper;
+        ctx->alg_decrypt_wrapper = twofish_decrypt_wrapper;
 
         ctx->blocksize = TWOFISH_BLOCK_SIZE;
         break;
@@ -332,18 +405,18 @@ int qcrypto_cipher_encrypt(QCryptoCipher *cipher,
 
     switch (cipher->mode) {
     case QCRYPTO_CIPHER_MODE_ECB:
-        ctx->alg_encrypt(ctx->ctx, len, out, in);
+        ctx->alg_encrypt_wrapper(ctx->ctx, len, out, in);
         break;
 
     case QCRYPTO_CIPHER_MODE_CBC:
-        cbc_encrypt(ctx->ctx, ctx->alg_encrypt,
+        cbc_encrypt(ctx->ctx, ctx->alg_encrypt_native,
                     ctx->blocksize, ctx->iv,
                     len, out, in);
         break;
 
     case QCRYPTO_CIPHER_MODE_XTS:
         xts_encrypt(ctx->ctx, ctx->ctx_tweak,
-                    ctx->alg_encrypt, ctx->alg_encrypt,
+                    ctx->alg_encrypt_wrapper, ctx->alg_encrypt_wrapper,
                     ctx->iv, len, out, in);
         break;
 
@@ -372,11 +445,11 @@ int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
 
     switch (cipher->mode) {
     case QCRYPTO_CIPHER_MODE_ECB:
-        ctx->alg_decrypt(ctx->ctx, len, out, in);
+        ctx->alg_decrypt_wrapper(ctx->ctx, len, out, in);
         break;
 
     case QCRYPTO_CIPHER_MODE_CBC:
-        cbc_decrypt(ctx->ctx, ctx->alg_decrypt,
+        cbc_decrypt(ctx->ctx, ctx->alg_decrypt_native,
                     ctx->blocksize, ctx->iv,
                     len, out, in);
         break;
@@ -388,7 +461,7 @@ int qcrypto_cipher_decrypt(QCryptoCipher *cipher,
             return -1;
         }
         xts_decrypt(ctx->ctx, ctx->ctx_tweak,
-                    ctx->alg_encrypt, ctx->alg_decrypt,
+                    ctx->alg_encrypt_wrapper, ctx->alg_decrypt_wrapper,
                     ctx->iv, len, out, in);
         break;
 
-- 
2.5.0