/* Copyright (c) 2015, Google Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */

#include <stdio.h>

#include <algorithm>

#include <gtest/gtest.h>

#include <openssl/cipher.h>
#include <openssl/cmac.h>
#include <openssl/mem.h>

#include "../test/test_util.h"


static void test(const char *name, const uint8_t *key, size_t key_len,
                 const uint8_t *msg, size_t msg_len, const uint8_t *expected) {
  SCOPED_TRACE(name);

  // Test the single-shot API.
  uint8_t out[16];
  ASSERT_TRUE(AES_CMAC(out, key, key_len, msg, msg_len));
  EXPECT_EQ(Bytes(expected, sizeof(out)), Bytes(out));

  bssl::UniquePtr<CMAC_CTX> ctx(CMAC_CTX_new());
  ASSERT_TRUE(ctx);
  ASSERT_TRUE(CMAC_Init(ctx.get(), key, key_len, EVP_aes_128_cbc(), NULL));

  for (unsigned chunk_size = 1; chunk_size <= msg_len; chunk_size++) {
    SCOPED_TRACE(chunk_size);

    ASSERT_TRUE(CMAC_Reset(ctx.get()));

    size_t done = 0;
    while (done < msg_len) {
      size_t todo = std::min(msg_len - done, static_cast<size_t>(chunk_size));
      ASSERT_TRUE(CMAC_Update(ctx.get(), msg + done, todo));
      done += todo;
    }

    size_t out_len;
    ASSERT_TRUE(CMAC_Final(ctx.get(), out, &out_len));
    EXPECT_EQ(Bytes(expected, sizeof(out)), Bytes(out, out_len));
  }

  // Test that |CMAC_CTX_copy| works.
  ASSERT_TRUE(CMAC_Reset(ctx.get()));
  size_t chunk = msg_len / 2;
  ASSERT_TRUE(CMAC_Update(ctx.get(), msg, chunk));
  bssl::UniquePtr<CMAC_CTX> ctx2(CMAC_CTX_new());
  ASSERT_TRUE(ctx2);
  ASSERT_TRUE(CMAC_CTX_copy(ctx2.get(), ctx.get()));
  ASSERT_TRUE(CMAC_Update(ctx2.get(), msg + chunk, msg_len - chunk));
  size_t out_len;
  ASSERT_TRUE(CMAC_Final(ctx2.get(), out, &out_len));
  EXPECT_EQ(Bytes(expected, sizeof(out)), Bytes(out, out_len));
}

TEST(CMACTest, RFC4493TestVectors) {
  static const uint8_t kKey[16] = {
      0x2b, 0x7e, 0x15, 0x16, 0x28, 0xae, 0xd2, 0xa6,
      0xab, 0xf7, 0x15, 0x88, 0x09, 0xcf, 0x4f, 0x3c,
  };
  static const uint8_t kOut1[16] = {
      0xbb, 0x1d, 0x69, 0x29, 0xe9, 0x59, 0x37, 0x28,
      0x7f, 0xa3, 0x7d, 0x12, 0x9b, 0x75, 0x67, 0x46,
  };
  static const uint8_t kMsg2[] = {
      0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
      0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
  };
  static const uint8_t kOut2[16] = {
      0x07, 0x0a, 0x16, 0xb4, 0x6b, 0x4d, 0x41, 0x44,
      0xf7, 0x9b, 0xdd, 0x9d, 0xd0, 0x4a, 0x28, 0x7c,
  };
  static const uint8_t kMsg3[] = {
      0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
      0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
      0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
      0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
      0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
  };
  static const uint8_t kOut3[16] = {
      0xdf, 0xa6, 0x67, 0x47, 0xde, 0x9a, 0xe6, 0x30,
      0x30, 0xca, 0x32, 0x61, 0x14, 0x97, 0xc8, 0x27,
  };
  static const uint8_t kMsg4[] = {
      0x6b, 0xc1, 0xbe, 0xe2, 0x2e, 0x40, 0x9f, 0x96,
      0xe9, 0x3d, 0x7e, 0x11, 0x73, 0x93, 0x17, 0x2a,
      0xae, 0x2d, 0x8a, 0x57, 0x1e, 0x03, 0xac, 0x9c,
      0x9e, 0xb7, 0x6f, 0xac, 0x45, 0xaf, 0x8e, 0x51,
      0x30, 0xc8, 0x1c, 0x46, 0xa3, 0x5c, 0xe4, 0x11,
      0xe5, 0xfb, 0xc1, 0x19, 0x1a, 0x0a, 0x52, 0xef,
      0xf6, 0x9f, 0x24, 0x45, 0xdf, 0x4f, 0x9b, 0x17,
      0xad, 0x2b, 0x41, 0x7b, 0xe6, 0x6c, 0x37, 0x10,
  };
  static const uint8_t kOut4[16] = {
      0x51, 0xf0, 0xbe, 0xbf, 0x7e, 0x3b, 0x9d, 0x92,
      0xfc, 0x49, 0x74, 0x17, 0x79, 0x36, 0x3c, 0xfe,
  };

  test("RFC 4493 #1", kKey, sizeof(kKey), NULL, 0, kOut1);
  test("RFC 4493 #2", kKey, sizeof(kKey), kMsg2, sizeof(kMsg2), kOut2);
  test("RFC 4493 #3", kKey, sizeof(kKey), kMsg3, sizeof(kMsg3), kOut3);
  test("RFC 4493 #4", kKey, sizeof(kKey), kMsg4, sizeof(kMsg4), kOut4);
}