Use AES-256-GCM for the SPTPS protocol.

[tinc] / src / openssl / cipher.c

diff --git a/src/openssl/cipher.c b/src/openssl/cipher.c
index 5d9bebc..b01f526 100644 (file)
--- a/src/openssl/cipher.c
+++ b/src/openssl/cipher.c
@@ -84,7 +84,7 @@ size_t cipher_keylength(const cipher_t *cipher) {
        if(!cipher || !cipher->cipher)
                return 0;
 
-       return cipher->cipher->key_len + cipher->cipher->block_size;
+       return cipher->cipher->key_len + cipher->cipher->iv_len;
 }
 
 bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
@@ -118,13 +118,12 @@ bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encry
 }
 
 bool cipher_set_counter(cipher_t *cipher, const void *counter, size_t len) {
-       if(len > cipher->cipher->block_size - 4) {
+       if(len > cipher->cipher->iv_len - 4) {
                logger(DEBUG_ALWAYS, LOG_ERR, "Counter too long");
-               abort();
+               return false;
        }
 
-       memcpy(cipher->counter->counter + cipher->cipher->block_size - len, counter, len);
-       memset(cipher->counter->counter, 0, 4);
+       memcpy(cipher->counter->counter, counter, len);
        cipher->counter->n = 0;
 
        return true;
@@ -142,41 +141,96 @@ bool cipher_set_counter_key(cipher_t *cipher, void *key) {
        else
                cipher->counter->n = 0;
 
-       memcpy(cipher->counter->counter, (unsigned char *)key + cipher->cipher->key_len, cipher->cipher->block_size);
+       memcpy(cipher->counter->counter, (unsigned char *)key + cipher->cipher->key_len, cipher->cipher->iv_len);
 
        return true;
 }
 
-bool cipher_counter_xor(cipher_t *cipher, const void *indata, size_t inlen, void *outdata) {
-       if(!cipher->counter) {
-               logger(DEBUG_ALWAYS, LOG_ERR, "Counter not initialized");
+bool cipher_gcm_encrypt_start(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       int len = 0;
+       if(!EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)
+                       || (inlen && !EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
                return false;
        }
+       if(outlen)
+               *outlen = len;
+       return true;
+}
 
-       const unsigned char *in = indata;
-       unsigned char *out = outdata;
-
-       while(inlen--) {
-               // Encrypt the new counter value if we need it
-               if(!cipher->counter->n) {
-                       int len;
-                       if(!EVP_EncryptUpdate(&cipher->ctx, cipher->counter->block, &len, cipher->counter->counter, cipher->cipher->block_size)) {
-                               logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
-                               return false;
-                       }
-
-                       // Increase the counter value
-                       for(int i = 0; i < cipher->cipher->block_size; i++)
-                               if(++cipher->counter->counter[i])
-                                       break;
-               }
+bool cipher_gcm_encrypt_finish(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       int len = 0, pad = 0;
+       if(!(inlen && EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))
+                       || !EVP_EncryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
+       }
+       EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_GET_TAG, 16, (unsigned char *)outdata + len + pad);
+       if(outlen)
+               *outlen = len + pad + 16;
+       return true;
+}
 
-               *out++ = *in++ ^ cipher->counter->block[cipher->counter->n++];
+bool cipher_gcm_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       int len = 0, pad = 0;
+       if(!EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter) ||
+                       !EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen) ||
+                       !EVP_EncryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
+       }
+       EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_GET_TAG, 16, (unsigned char *)outdata + len + pad);
+       if(outlen)
+               *outlen = len + pad + 16;
+       return true;
+}
 
-               if(cipher->counter->n >= cipher->cipher->block_size)
-                       cipher->counter->n = 0;
+bool cipher_gcm_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       if(inlen < 16)
+               return false;
+
+       int len = 0, pad = 0;
+       if(!EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
        }
 
+       EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_SET_TAG, 16, (unsigned char *)indata + inlen - 16);
+
+       if(!EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen - 16) ||
+                       !EVP_DecryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
+       }
+       if(outlen)
+               *outlen = len;
+       return true;
+}
+
+bool cipher_gcm_decrypt_start(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       int len = 0;
+       if(!EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)
+                       || (inlen && !EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
+       }
+       if(outlen)
+               *outlen = len;
+       return true;
+}
+
+bool cipher_gcm_decrypt_finish(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
+       if(inlen < 16)
+               return false;
+
+       EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_SET_TAG, 16, (unsigned char *)indata + inlen - 16);
+
+       int len = 0, pad = 0;
+       if((inlen > 16 && !EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen - 16))
+                       || !EVP_DecryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
+               return false;
+       }
        return true;
 }