X-Git-Url: https://gitweb.ps.run/matrix_esp_thesis/blobdiff_plain/21c6e8484b0bd05c27e5a91f2884d431926adc61..da776f86b42946715c27edd64f7558b9d5080df1:/ext/olm/src/crypto.cpp

diff --git a/ext/olm/src/crypto.cpp b/ext/olm/src/crypto.cpp
new file mode 100644
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+++ b/ext/olm/src/crypto.cpp
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+/* Copyright 2015 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "olm/crypto.h"
+#include "olm/memory.hh"
+
+#include <cstring>
+
+extern "C" {
+
+#include "crypto-algorithms/aes.h"
+#include "crypto-algorithms/sha256.h"
+
+}
+
+#include "ed25519/src/ed25519.h"
+#include "curve25519-donna.h"
+
+namespace {
+
+static const std::uint8_t CURVE25519_BASEPOINT[32] = {9};
+static const std::size_t AES_KEY_SCHEDULE_LENGTH = 60;
+static const std::size_t AES_KEY_BITS = 8 * AES256_KEY_LENGTH;
+static const std::size_t AES_BLOCK_LENGTH = 16;
+static const std::size_t SHA256_BLOCK_LENGTH = 64;
+static const std::uint8_t HKDF_DEFAULT_SALT[32] = {};
+
+
+template<std::size_t block_size>
+inline static void xor_block(
+    std::uint8_t * block,
+    std::uint8_t const * input
+) {
+    for (std::size_t i = 0; i < block_size; ++i) {
+        block[i] ^= input[i];
+    }
+}
+
+
+inline static void hmac_sha256_key(
+    std::uint8_t const * input_key, std::size_t input_key_length,
+    std::uint8_t * hmac_key
+) {
+    std::memset(hmac_key, 0, SHA256_BLOCK_LENGTH);
+    if (input_key_length > SHA256_BLOCK_LENGTH) {
+        ::SHA256_CTX context;
+        ::sha256_init(&context);
+        ::sha256_update(&context, input_key, input_key_length);
+        ::sha256_final(&context, hmac_key);
+    } else {
+        std::memcpy(hmac_key, input_key, input_key_length);
+    }
+}
+
+
+inline static void hmac_sha256_init(
+    ::SHA256_CTX * context,
+    std::uint8_t const * hmac_key
+) {
+    std::uint8_t i_pad[SHA256_BLOCK_LENGTH];
+    std::memcpy(i_pad, hmac_key, SHA256_BLOCK_LENGTH);
+    for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
+        i_pad[i] ^= 0x36;
+    }
+    ::sha256_init(context);
+    ::sha256_update(context, i_pad, SHA256_BLOCK_LENGTH);
+    olm::unset(i_pad);
+}
+
+
+inline static void hmac_sha256_final(
+    ::SHA256_CTX * context,
+    std::uint8_t const * hmac_key,
+    std::uint8_t * output
+) {
+    std::uint8_t o_pad[SHA256_BLOCK_LENGTH + SHA256_OUTPUT_LENGTH];
+    std::memcpy(o_pad, hmac_key, SHA256_BLOCK_LENGTH);
+    for (std::size_t i = 0; i < SHA256_BLOCK_LENGTH; ++i) {
+        o_pad[i] ^= 0x5C;
+    }
+    ::sha256_final(context, o_pad + SHA256_BLOCK_LENGTH);
+    ::SHA256_CTX final_context;
+    ::sha256_init(&final_context);
+    ::sha256_update(&final_context, o_pad, sizeof(o_pad));
+    ::sha256_final(&final_context, output);
+    olm::unset(final_context);
+    olm::unset(o_pad);
+}
+
+} // namespace
+
+void _olm_crypto_curve25519_generate_key(
+    uint8_t const * random_32_bytes,
+    struct _olm_curve25519_key_pair *key_pair
+) {
+    std::memcpy(
+        key_pair->private_key.private_key, random_32_bytes,
+        CURVE25519_KEY_LENGTH
+    );
+    ::curve25519_donna(
+        key_pair->public_key.public_key,
+        key_pair->private_key.private_key,
+        CURVE25519_BASEPOINT
+    );
+}
+
+
+void _olm_crypto_curve25519_shared_secret(
+    const struct _olm_curve25519_key_pair *our_key,
+    const struct _olm_curve25519_public_key * their_key,
+    std::uint8_t * output
+) {
+    ::curve25519_donna(output, our_key->private_key.private_key, their_key->public_key);
+}
+
+
+void _olm_crypto_ed25519_generate_key(
+    std::uint8_t const * random_32_bytes,
+    struct _olm_ed25519_key_pair *key_pair
+) {
+    ::ed25519_create_keypair(
+        key_pair->public_key.public_key, key_pair->private_key.private_key,
+        random_32_bytes
+    );
+}
+
+
+void _olm_crypto_ed25519_sign(
+    const struct _olm_ed25519_key_pair *our_key,
+    std::uint8_t const * message, std::size_t message_length,
+    std::uint8_t * output
+) {
+    ::ed25519_sign(
+        output,
+        message, message_length,
+        our_key->public_key.public_key,
+        our_key->private_key.private_key
+    );
+}
+
+
+int _olm_crypto_ed25519_verify(
+    const struct _olm_ed25519_public_key *their_key,
+    std::uint8_t const * message, std::size_t message_length,
+    std::uint8_t const * signature
+) {
+    return 0 != ::ed25519_verify(
+        signature,
+        message, message_length,
+        their_key->public_key
+    );
+}
+
+
+std::size_t _olm_crypto_aes_encrypt_cbc_length(
+    std::size_t input_length
+) {
+    return input_length + AES_BLOCK_LENGTH - input_length % AES_BLOCK_LENGTH;
+}
+
+
+void _olm_crypto_aes_encrypt_cbc(
+    _olm_aes256_key const *key,
+    _olm_aes256_iv const *iv,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+) {
+    std::uint32_t key_schedule[AES_KEY_SCHEDULE_LENGTH];
+    ::_olm_aes_key_setup(key->key, key_schedule, AES_KEY_BITS);
+    std::uint8_t input_block[AES_BLOCK_LENGTH];
+    std::memcpy(input_block, iv->iv, AES_BLOCK_LENGTH);
+    while (input_length >= AES_BLOCK_LENGTH) {
+        xor_block<AES_BLOCK_LENGTH>(input_block, input);
+        ::_olm_aes_encrypt(input_block, output, key_schedule, AES_KEY_BITS);
+        std::memcpy(input_block, output, AES_BLOCK_LENGTH);
+        input += AES_BLOCK_LENGTH;
+        output += AES_BLOCK_LENGTH;
+        input_length -= AES_BLOCK_LENGTH;
+    }
+    std::size_t i = 0;
+    for (; i < input_length; ++i) {
+        input_block[i] ^= input[i];
+    }
+    for (; i < AES_BLOCK_LENGTH; ++i) {
+        input_block[i] ^= AES_BLOCK_LENGTH - input_length;
+    }
+    ::_olm_aes_encrypt(input_block, output, key_schedule, AES_KEY_BITS);
+    olm::unset(key_schedule);
+    olm::unset(input_block);
+}
+
+
+std::size_t _olm_crypto_aes_decrypt_cbc(
+    _olm_aes256_key const *key,
+    _olm_aes256_iv const *iv,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+) {
+    std::uint32_t key_schedule[AES_KEY_SCHEDULE_LENGTH];
+    ::_olm_aes_key_setup(key->key, key_schedule, AES_KEY_BITS);
+    std::uint8_t block1[AES_BLOCK_LENGTH];
+    std::uint8_t block2[AES_BLOCK_LENGTH];
+    std::memcpy(block1, iv->iv, AES_BLOCK_LENGTH);
+    for (std::size_t i = 0; i < input_length; i += AES_BLOCK_LENGTH) {
+        std::memcpy(block2, &input[i], AES_BLOCK_LENGTH);
+        ::_olm_aes_decrypt(&input[i], &output[i], key_schedule, AES_KEY_BITS);
+        xor_block<AES_BLOCK_LENGTH>(&output[i], block1);
+        std::memcpy(block1, block2, AES_BLOCK_LENGTH);
+    }
+    olm::unset(key_schedule);
+    olm::unset(block1);
+    olm::unset(block2);
+    std::size_t padding = output[input_length - 1];
+    return (padding > input_length) ? std::size_t(-1) : (input_length - padding);
+}
+
+
+void _olm_crypto_sha256(
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+) {
+    ::SHA256_CTX context;
+    ::sha256_init(&context);
+    ::sha256_update(&context, input, input_length);
+    ::sha256_final(&context, output);
+    olm::unset(context);
+}
+
+
+void _olm_crypto_hmac_sha256(
+    std::uint8_t const * key, std::size_t key_length,
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t * output
+) {
+    std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
+    ::SHA256_CTX context;
+    hmac_sha256_key(key, key_length, hmac_key);
+    hmac_sha256_init(&context, hmac_key);
+    ::sha256_update(&context, input, input_length);
+    hmac_sha256_final(&context, hmac_key, output);
+    olm::unset(hmac_key);
+    olm::unset(context);
+}
+
+
+void _olm_crypto_hkdf_sha256(
+    std::uint8_t const * input, std::size_t input_length,
+    std::uint8_t const * salt, std::size_t salt_length,
+    std::uint8_t const * info, std::size_t info_length,
+    std::uint8_t * output, std::size_t output_length
+) {
+    ::SHA256_CTX context;
+    std::uint8_t hmac_key[SHA256_BLOCK_LENGTH];
+    std::uint8_t step_result[SHA256_OUTPUT_LENGTH];
+    std::size_t bytes_remaining = output_length;
+    std::uint8_t iteration = 1;
+    if (!salt) {
+        salt = HKDF_DEFAULT_SALT;
+        salt_length = sizeof(HKDF_DEFAULT_SALT);
+    }
+    /* Extract */
+    hmac_sha256_key(salt, salt_length, hmac_key);
+    hmac_sha256_init(&context, hmac_key);
+    ::sha256_update(&context, input, input_length);
+    hmac_sha256_final(&context, hmac_key, step_result);
+    hmac_sha256_key(step_result, SHA256_OUTPUT_LENGTH, hmac_key);
+
+    /* Expand */
+    hmac_sha256_init(&context, hmac_key);
+    ::sha256_update(&context, info, info_length);
+    ::sha256_update(&context, &iteration, 1);
+    hmac_sha256_final(&context, hmac_key, step_result);
+    while (bytes_remaining > SHA256_OUTPUT_LENGTH) {
+        std::memcpy(output, step_result, SHA256_OUTPUT_LENGTH);
+        output += SHA256_OUTPUT_LENGTH;
+        bytes_remaining -= SHA256_OUTPUT_LENGTH;
+        iteration ++;
+        hmac_sha256_init(&context, hmac_key);
+        ::sha256_update(&context, step_result, SHA256_OUTPUT_LENGTH);
+        ::sha256_update(&context, info, info_length);
+        ::sha256_update(&context, &iteration, 1);
+        hmac_sha256_final(&context, hmac_key, step_result);
+    }
+    std::memcpy(output, step_result, bytes_remaining);
+    olm::unset(context);
+    olm::unset(hmac_key);
+    olm::unset(step_result);
+}