randombit/botan | Build 5230455705 | source/src/lib/modes/aead/ocb/ocb.cpp | Coveralls

20

      explicit L_computer(const BlockCipher& cipher) :

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21

            m_BS(cipher.block_size()), m_max_blocks(cipher.parallel_bytes() / m_BS) {

486✔

22

         m_L_star.resize(m_BS);

243✔

23

         cipher.encrypt(m_L_star);

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24

         m_L_dollar = poly_double(star());

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25

         m_L.push_back(poly_double(dollar()));

243✔

27

         while(m_L.size() < 8) {

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28

            m_L.push_back(poly_double(m_L.back()));

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31

         m_offset_buf.resize(m_BS * m_max_blocks);

243✔

32

243✔

34

      void init(const secure_vector<uint8_t>& offset) { m_offset = offset; }

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36

      bool initialized() const { return m_offset.empty() == false; }

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38

      const secure_vector<uint8_t>& star() const { return m_L_star; }

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40

      const secure_vector<uint8_t>& dollar() const { return m_L_dollar; }

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42

      const secure_vector<uint8_t>& offset() const { return m_offset; }

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44

      const secure_vector<uint8_t>& get(size_t i) const {

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45

         while(m_L.size() <= i) {

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46

            m_L.push_back(poly_double(m_L.back()));

69✔

49

         return m_L[i];

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52

      const uint8_t* compute_offsets(size_t block_index, size_t blocks) {

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53

         BOTAN_ASSERT(blocks <= m_max_blocks, "OCB offsets");

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55

         uint8_t* offsets = m_offset_buf.data();

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57

         if(block_index % 4 == 0) {

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58

            const secure_vector<uint8_t>& L0 = get(0);

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59

            const secure_vector<uint8_t>& L1 = get(1);

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61

            while(blocks >= 4) {

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65

               block_index += 4;

3,411✔

66

               const size_t ntz4 = var_ctz32(static_cast<uint32_t>(block_index));

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68

               xor_buf(offsets, m_offset.data(), L0.data(), m_BS);

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69

               offsets += m_BS;

3,411✔

71

               xor_buf(offsets, offsets - m_BS, L1.data(), m_BS);

3,411✔

72

               offsets += m_BS;

3,411✔

74

               xor_buf(m_offset.data(), L1.data(), m_BS);

3,411✔

75

               copy_mem(offsets, m_offset.data(), m_BS);

3,411✔

76

               offsets += m_BS;

3,411✔

78

               xor_buf(m_offset.data(), get(ntz4).data(), m_BS);

3,411✔

79

               copy_mem(offsets, m_offset.data(), m_BS);

3,411✔

80

               offsets += m_BS;

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82

               blocks -= 4;

3,411✔

86

         for(size_t i = 0; i != blocks; ++i) {  // could be done in parallel

15,901✔

87

            const size_t ntz = var_ctz32(static_cast<uint32_t>(block_index + i + 1));

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88

            xor_buf(m_offset.data(), get(ntz).data(), m_BS);

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89

            copy_mem(offsets, m_offset.data(), m_BS);

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90

            offsets += m_BS;

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93

         return m_offset_buf.data();

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97

      static secure_vector<uint8_t> poly_double(const secure_vector<uint8_t>& in) {

2,256✔

98

         secure_vector<uint8_t> out(in.size());

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99

         poly_double_n(out.data(), in.data(), out.size());

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100

         return out;

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115

secure_vector<uint8_t> ocb_hash(const L_computer& L, const BlockCipher& cipher, const uint8_t ad[], size_t ad_len) {

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116

   const size_t BS = cipher.block_size();

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117

   secure_vector<uint8_t> sum(BS);

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118

   secure_vector<uint8_t> offset(BS);

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120

   secure_vector<uint8_t> buf(BS);

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122

   const size_t ad_blocks = (ad_len / BS);

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123

   const size_t ad_remainder = (ad_len % BS);

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125

   for(size_t i = 0; i != ad_blocks; ++i) {

56,522✔

127

      offset ^= L.get(var_ctz32(static_cast<uint32_t>(i + 1)));

94,054✔

128

      buf = offset;

47,027✔

129

      xor_buf(buf.data(), &ad[BS * i], BS);

47,027✔

130

      cipher.encrypt(buf);

47,027✔

131

      sum ^= buf;

47,027✔

134

   if(ad_remainder) {

9,495✔

135

      offset ^= L.star();

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136

      buf = offset;

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137

      xor_buf(buf.data(), &ad[BS * ad_blocks], ad_remainder);

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138

      buf[ad_remainder] ^= 0x80;

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139

      cipher.encrypt(buf);

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140

      sum ^= buf;

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143

   return sum;

9,495✔

144

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148

OCB_Mode::OCB_Mode(std::unique_ptr<BlockCipher> cipher, size_t tag_size) :

335✔

149

      m_cipher(std::move(cipher)),

335✔

150

      m_checksum(m_cipher->parallel_bytes()),

670✔

151

      m_ad_hash(m_cipher->block_size()),

335✔

152

      m_tag_size(tag_size),

335✔

153

      m_block_size(m_cipher->block_size()),

335✔

154

      m_par_blocks(m_cipher->parallel_bytes() / m_block_size) {

1,005✔

155

   const size_t BS = block_size();

335✔

162

   BOTAN_ARG_CHECK(BS == 16 || BS == 24 || BS == 32 || BS == 64, "Invalid block size for OCB");

335✔

164

   BOTAN_ARG_CHECK(m_tag_size % 4 == 0 && m_tag_size >= 8 && m_tag_size <= BS && m_tag_size <= 32,

335✔

166

335✔

168

OCB_Mode::~OCB_Mode() = default;

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170

void OCB_Mode::clear() {

92✔

171

   m_cipher->clear();

92✔

172

   m_L.reset();  // add clear here?

92✔

173

   reset();

92✔

174

92✔

176

void OCB_Mode::reset() {

410✔

177

   m_block_index = 0;

410✔

178

   zeroise(m_ad_hash);

410✔

179

   zeroise(m_checksum);

410✔

180

   m_last_nonce.clear();

410✔

181

   m_stretch.clear();

410✔

182

410✔

184

bool OCB_Mode::valid_nonce_length(size_t length) const {

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185

   if(length == 0) {

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188

   if(block_size() == 16) {

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189

      return length < 16;

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191

      return length < (block_size() - 1);

1,602✔

195

std::string OCB_Mode::name() const {

506✔

196

   return m_cipher->name() + "/OCB";  // include tag size?

1,012✔

199

size_t OCB_Mode::update_granularity() const {

1,254✔

200

   return block_size();

1,254✔

203

size_t OCB_Mode::ideal_granularity() const {

276✔

204

   return (m_par_blocks * block_size());

276✔

207

Key_Length_Specification OCB_Mode::key_spec() const {

243✔

208

   return m_cipher->key_spec();

243✔

211

bool OCB_Mode::has_keying_material() const {

36,236✔

212

   return m_cipher->has_keying_material();

36,236✔

215

void OCB_Mode::key_schedule(const uint8_t key[], size_t length) {

243✔

216

   m_cipher->set_key(key, length);

243✔

217

   m_L = std::make_unique<L_computer>(*m_cipher);

243✔

218

243✔

220

void OCB_Mode::set_associated_data_n(size_t idx, std::span<const uint8_t> ad) {

9,679✔

221

   BOTAN_ARG_CHECK(idx == 0, "OCB: cannot handle non-zero index in set_associated_data_n");

9,679✔

222

   assert_key_material_set();

9,679✔

223

   m_ad_hash = ocb_hash(*m_L, *m_cipher, ad.data(), ad.size());

9,495✔

224

9,495✔

226

const secure_vector<uint8_t>& OCB_Mode::update_nonce(const uint8_t nonce[], size_t nonce_len) {

9,445✔

227

   const size_t BS = block_size();

9,445✔

229

   BOTAN_ASSERT(BS == 16 || BS == 24 || BS == 32 || BS == 64, "OCB block size is supported");

9,445✔

231

   const size_t MASKLEN = (BS == 16 ? 6 : ((BS == 24) ? 7 : 8));

9,445✔

233

   const uint8_t BOTTOM_MASK = static_cast<uint8_t>((static_cast<uint16_t>(1) << MASKLEN) - 1);

9,445✔

235

   m_nonce_buf.resize(BS);

9,445✔

236

   clear_mem(&m_nonce_buf[0], m_nonce_buf.size());

9,445✔

238

   copy_mem(&m_nonce_buf[BS - nonce_len], nonce, nonce_len);

9,445✔

239

   m_nonce_buf[0] = static_cast<uint8_t>(((tag_size() * 8) % (BS * 8)) << (BS <= 16 ? 1 : 0));

11,043✔

241

   m_nonce_buf[BS - nonce_len - 1] ^= 1;

9,445✔

243

   const uint8_t bottom = m_nonce_buf[BS - 1] & BOTTOM_MASK;

9,445✔

244

   m_nonce_buf[BS - 1] &= ~BOTTOM_MASK;

9,445✔

246

   const bool need_new_stretch = (m_last_nonce != m_nonce_buf);

9,445✔

248

   if(need_new_stretch) {

9,445✔

249

      m_last_nonce = m_nonce_buf;

681✔

251

      m_cipher->encrypt(m_nonce_buf);

681✔

273

      if(BS == 16) {

681✔

274

         for(size_t i = 0; i != BS / 2; ++i) {

5,517✔

275

            m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 1]);

4,904✔

277

      } else if(BS == 24) {

68✔

278

         for(size_t i = 0; i != 16; ++i) {

408✔

279

            m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 5]);

384✔

281

      } else if(BS == 32) {

44✔

282

         for(size_t i = 0; i != BS; ++i) {

1,089✔

283

            m_nonce_buf.push_back(m_nonce_buf[i] ^ (m_nonce_buf[i] << 1) ^ (m_nonce_buf[i + 1] >> 7));

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286

         for(size_t i = 0; i != BS / 2; ++i) {

363✔

287

            m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 22]);

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291

      m_stretch = m_nonce_buf;

681✔

295

   const size_t shift_bytes = bottom / 8;

9,445✔

296

   const size_t shift_bits = bottom % 8;

9,445✔

298

   BOTAN_ASSERT(m_stretch.size() >= BS + shift_bytes + 1, "Size ok");

9,445✔

300

   m_offset.resize(BS);

9,445✔

301

   for(size_t i = 0; i != BS; ++i) {

195,501✔

302

      m_offset[i] = (m_stretch[i + shift_bytes] << shift_bits);

186,056✔

303

      m_offset[i] |= (m_stretch[i + shift_bytes + 1] >> (8 - shift_bits));

186,056✔

306

   return m_offset;

9,445✔

309

void OCB_Mode::start_msg(const uint8_t nonce[], size_t nonce_len) {

9,445✔

310

   if(!valid_nonce_length(nonce_len)) {

9,445✔

314

   assert_key_material_set();

9,445✔

316

   m_L->init(update_nonce(nonce, nonce_len));

9,445✔

317

   zeroise(m_checksum);

9,445✔

318

   m_block_index = 0;

9,445✔

319

9,445✔

321

void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks) {

4,161✔

322

   assert_key_material_set();

4,161✔

323

   BOTAN_STATE_CHECK(m_L->initialized());

4,115✔

325

   const size_t BS = block_size();

4,069✔

327

   while(blocks) {

7,674✔

328

      const size_t proc_blocks = std::min(blocks, par_blocks());

3,605✔

329

      const size_t proc_bytes = proc_blocks * BS;

3,605✔

331

      const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);

3,605✔

333

      xor_buf(m_checksum.data(), buffer, proc_bytes);

3,605✔

335

      m_cipher->encrypt_n_xex(buffer, offsets, proc_blocks);

3,605✔

337

      buffer += proc_bytes;

3,605✔

338

      blocks -= proc_blocks;

3,605✔

339

      m_block_index += proc_blocks;

3,605✔

341

4,069✔

343

size_t OCB_Encryption::process_msg(uint8_t buf[], size_t sz) {

467✔

344

   BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");

467✔

345

   encrypt(buf, sz / block_size());

467✔

346

   return sz;

375✔

349

void OCB_Encryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {

5,702✔

350

   assert_key_material_set();

5,702✔

351

   BOTAN_STATE_CHECK(m_L->initialized());

5,610✔

353

   const size_t BS = block_size();

5,564✔

355

   BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");

5,564✔

356

   const size_t sz = buffer.size() - offset;

5,564✔

357

   uint8_t* buf = buffer.data() + offset;

5,564✔

359

   secure_vector<uint8_t> mac(BS);

5,564✔

361

   if(sz) {

5,564✔

362

      const size_t final_full_blocks = sz / BS;

3,694✔

363

      const size_t remainder_bytes = sz - (final_full_blocks * BS);

3,694✔

365

      encrypt(buf, final_full_blocks);

3,694✔

366

      mac = m_L->offset();

3,694✔

368

      if(remainder_bytes) {

3,694✔

369

         BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");

3,492✔

370

         uint8_t* remainder = &buf[sz - remainder_bytes];

3,492✔

372

         xor_buf(m_checksum.data(), remainder, remainder_bytes);

3,492✔

373

         m_checksum[remainder_bytes] ^= 0x80;

3,492✔

376

         mac ^= m_L->star();

3,492✔

378

         secure_vector<uint8_t> pad(BS);

3,492✔

379

         m_cipher->encrypt(mac, pad);

3,492✔

380

         xor_buf(remainder, pad.data(), remainder_bytes);

3,492✔

381

3,492✔

383

      mac = m_L->offset();

1,870✔

389

   for(size_t i = 0; i != m_checksum.size(); i += BS) {

82,220✔

390

      xor_buf(mac.data(), m_checksum.data() + i, BS);

76,656✔

393

   xor_buf(mac.data(), m_L->dollar().data(), BS);

5,564✔

394

   m_cipher->encrypt(mac);

5,564✔

395

   xor_buf(mac.data(), m_ad_hash.data(), BS);

5,564✔

397

   buffer += std::make_pair(mac.data(), tag_size());

5,564✔

399

   zeroise(m_checksum);

5,564✔

400

   m_block_index = 0;

5,564✔

401

5,564✔

403

void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks) {

3,000✔

404

   assert_key_material_set();

3,000✔

405

   BOTAN_STATE_CHECK(m_L->initialized());

2,954✔

407

   const size_t BS = block_size();

2,908✔

409

   while(blocks) {

5,586✔

410

      const size_t proc_blocks = std::min(blocks, par_blocks());

2,678✔

411

      const size_t proc_bytes = proc_blocks * BS;

2,678✔

413

      const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);

2,678✔

415

      m_cipher->decrypt_n_xex(buffer, offsets, proc_blocks);

2,678✔

417

      xor_buf(m_checksum.data(), buffer, proc_bytes);

2,678✔

419

      buffer += proc_bytes;

2,678✔

420

      blocks -= proc_blocks;

2,678✔

421

      m_block_index += proc_blocks;

2,678✔

423

2,908✔

425

size_t OCB_Decryption::process_msg(uint8_t buf[], size_t sz) {

479✔

426

   BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");

479✔

427

   decrypt(buf, sz / block_size());

479✔

428

   return sz;

387✔

431

void OCB_Decryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {

3,927✔

432

   assert_key_material_set();

3,927✔

433

   BOTAN_STATE_CHECK(m_L->initialized());

3,835✔

435

   const size_t BS = block_size();

3,789✔

437

   BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");

3,789✔

438

   const size_t sz = buffer.size() - offset;

3,789✔

439

   uint8_t* buf = buffer.data() + offset;

3,789✔

441

   BOTAN_ARG_CHECK(sz >= tag_size(), "input did not include the tag");

3,789✔

443

   const size_t remaining = sz - tag_size();

3,789✔

445

   secure_vector<uint8_t> mac(BS);

3,789✔

447

   if(remaining) {

3,789✔

448

      const size_t final_full_blocks = remaining / BS;

2,521✔

449

      const size_t final_bytes = remaining - (final_full_blocks * BS);

2,521✔

451

      decrypt(buf, final_full_blocks);

2,521✔

452

      mac ^= m_L->offset();

2,521✔

454

      if(final_bytes) {

2,521✔

455

         BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");

2,328✔

457

         uint8_t* remainder = &buf[remaining - final_bytes];

2,328✔

459

         mac ^= m_L->star();

2,328✔

460

         secure_vector<uint8_t> pad(BS);

2,466✔

461

         m_cipher->encrypt(mac, pad);  // P_*

2,328✔

462

         xor_buf(remainder, pad.data(), final_bytes);

2,328✔

464

         xor_buf(m_checksum.data(), remainder, final_bytes);

2,328✔

465

         m_checksum[final_bytes] ^= 0x80;

2,328✔

466

2,328✔

468

      mac = m_L->offset();

1,268✔

474

   for(size_t i = 0; i != m_checksum.size(); i += BS) {

64,505✔

475

      xor_buf(mac.data(), m_checksum.data() + i, BS);

60,716✔

478

   mac ^= m_L->dollar();

3,789✔

479

   m_cipher->encrypt(mac);

3,789✔

480

   mac ^= m_ad_hash;

3,789✔

483

   zeroise(m_checksum);

3,789✔

484

   m_block_index = 0;

3,789✔

487

   const uint8_t* included_tag = &buf[remaining];

3,789✔

489

   if(!constant_time_compare(mac.data(), included_tag, tag_size())) {

3,789✔

490

      throw Invalid_Authentication_Tag("OCB tag check failed");

138✔

494

   buffer.resize(remaining + offset);

3,651✔

495

3,651✔

randombit / botan / 5230455705

Source File
Press 'n' to go to next uncovered line, 'b' for previous

1	/*
2	* OCB Mode
3	* (C) 2013,2017 Jack Lloyd
4	* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
5	*
6	* Botan is released under the Simplified BSD License (see license.txt)
7	*/
8
9	#include <botan/internal/ocb.h>
10
11	#include <botan/block_cipher.h>
12	#include <botan/internal/bit_ops.h>
13	#include <botan/internal/poly_dbl.h>
14
15	namespace Botan {
16
17	// Has to be in Botan namespace so unique_ptr can reference it
18	class L_computer final {
19	public:
20	explicit L_computer(const BlockCipher& cipher) :	243✔
21	m_BS(cipher.block_size()), m_max_blocks(cipher.parallel_bytes() / m_BS) {	486✔
22	m_L_star.resize(m_BS);	243✔
23	cipher.encrypt(m_L_star);	243✔
24	m_L_dollar = poly_double(star());	243✔
25	m_L.push_back(poly_double(dollar()));	243✔
26
27	while(m_L.size() < 8) {	1,944✔
28	m_L.push_back(poly_double(m_L.back()));	3,402✔
29	}
30
31	m_offset_buf.resize(m_BS * m_max_blocks);	243✔
32	}	243✔
33
34	void init(const secure_vector<uint8_t>& offset) { m_offset = offset; }	9,445✔
35
36	bool initialized() const { return m_offset.empty() == false; }	16,514✔
37
38	const secure_vector<uint8_t>& star() const { return m_L_star; }	6,063✔
39
40	const secure_vector<uint8_t>& dollar() const { return m_L_dollar; }	9,596✔
41
42	const secure_vector<uint8_t>& offset() const { return m_offset; }	9,353✔
43
44	const secure_vector<uint8_t>& get(size_t i) const {	71,714✔
45	while(m_L.size() <= i) {	71,783✔
46	m_L.push_back(poly_double(m_L.back()));	69✔
47	}
48
49	return m_L[i];	71,714✔
50	}
51
52	const uint8_t* compute_offsets(size_t block_index, size_t blocks) {	6,283✔
53	BOTAN_ASSERT(blocks <= m_max_blocks, "OCB offsets");	6,283✔
54
55	uint8_t* offsets = m_offset_buf.data();	6,283✔
56
57	if(block_index % 4 == 0) {	6,283✔
58	const secure_vector<uint8_t>& L0 = get(0);	5,829✔
59	const secure_vector<uint8_t>& L1 = get(1);	5,829✔
60
61	while(blocks >= 4) {	15,069✔
62	// ntz(4*i+1) == 0
63	// ntz(4*i+2) == 1
64	// ntz(4*i+3) == 0
65	block_index += 4;	3,411✔
66	const size_t ntz4 = var_ctz32(static_cast<uint32_t>(block_index));	3,411✔
67
68	xor_buf(offsets, m_offset.data(), L0.data(), m_BS);	3,411✔
69	offsets += m_BS;	3,411✔
70
71	xor_buf(offsets, offsets - m_BS, L1.data(), m_BS);	3,411✔
72	offsets += m_BS;	3,411✔
73
74	xor_buf(m_offset.data(), L1.data(), m_BS);	3,411✔
75	copy_mem(offsets, m_offset.data(), m_BS);	3,411✔
76	offsets += m_BS;	3,411✔
77
78	xor_buf(m_offset.data(), get(ntz4).data(), m_BS);	3,411✔
79	copy_mem(offsets, m_offset.data(), m_BS);	3,411✔
80	offsets += m_BS;	3,411✔
81
82	blocks -= 4;	3,411✔
83	}
84	}
85
86	for(size_t i = 0; i != blocks; ++i) { // could be done in parallel	15,901✔
87	const size_t ntz = var_ctz32(static_cast<uint32_t>(block_index + i + 1));	9,618✔
88	xor_buf(m_offset.data(), get(ntz).data(), m_BS);	9,618✔
89	copy_mem(offsets, m_offset.data(), m_BS);	9,618✔
90	offsets += m_BS;	9,618✔
91	}
92
93	return m_offset_buf.data();	6,283✔
94	}
95
96	private:
97	static secure_vector<uint8_t> poly_double(const secure_vector<uint8_t>& in) {	2,256✔
98	secure_vector<uint8_t> out(in.size());	2,256✔
99	poly_double_n(out.data(), in.data(), out.size());	2,256✔
100	return out;	2,256✔
101	}	×
102
103	const size_t m_BS, m_max_blocks;
104	secure_vector<uint8_t> m_L_dollar, m_L_star;
105	secure_vector<uint8_t> m_offset;
106	mutable std::vector<secure_vector<uint8_t>> m_L;
107	secure_vector<uint8_t> m_offset_buf;
108	};
109
110	namespace {
111
112	/*
113	* OCB's HASH
114	*/
115	secure_vector<uint8_t> ocb_hash(const L_computer& L, const BlockCipher& cipher, const uint8_t ad[], size_t ad_len) {	9,495✔
116	const size_t BS = cipher.block_size();	9,495✔
117	secure_vector<uint8_t> sum(BS);	9,495✔
118	secure_vector<uint8_t> offset(BS);	9,495✔
119
120	secure_vector<uint8_t> buf(BS);	9,495✔
121
122	const size_t ad_blocks = (ad_len / BS);	9,495✔
123	const size_t ad_remainder = (ad_len % BS);	9,495✔
124
125	for(size_t i = 0; i != ad_blocks; ++i) {	56,522✔
126	// this loop could run in parallel
127	offset ^= L.get(var_ctz32(static_cast<uint32_t>(i + 1)));	94,054✔
128	buf = offset;	47,027✔
129	xor_buf(buf.data(), &ad[BS * i], BS);	47,027✔
130	cipher.encrypt(buf);	47,027✔
131	sum ^= buf;	47,027✔
132	}
133
134	if(ad_remainder) {	9,495✔
135	offset ^= L.star();	5,865✔
136	buf = offset;	5,865✔
137	xor_buf(buf.data(), &ad[BS * ad_blocks], ad_remainder);	5,865✔
138	buf[ad_remainder] ^= 0x80;	5,865✔
139	cipher.encrypt(buf);	5,865✔
140	sum ^= buf;	5,865✔
141	}
142
143	return sum;	9,495✔
144	}	18,990✔
145
146	} // namespace
147
148	OCB_Mode::OCB_Mode(std::unique_ptr<BlockCipher> cipher, size_t tag_size) :	335✔
149	m_cipher(std::move(cipher)),	335✔
150	m_checksum(m_cipher->parallel_bytes()),	670✔
151	m_ad_hash(m_cipher->block_size()),	335✔
152	m_tag_size(tag_size),	335✔
153	m_block_size(m_cipher->block_size()),	335✔
154	m_par_blocks(m_cipher->parallel_bytes() / m_block_size) {	1,005✔
155	const size_t BS = block_size();	335✔
156
157	/*
158	* draft-krovetz-ocb-wide-d1 specifies OCB for several other block
159	* sizes but only 128, 192, 256 and 512 bit are currently supported
160	* by this implementation.
161	*/
162	BOTAN_ARG_CHECK(BS == 16 \|\| BS == 24 \|\| BS == 32 \|\| BS == 64, "Invalid block size for OCB");	335✔
163
164	BOTAN_ARG_CHECK(m_tag_size % 4 == 0 && m_tag_size >= 8 && m_tag_size <= BS && m_tag_size <= 32,	335✔
165	"Invalid OCB tag length");
166	}	335✔
167
168	OCB_Mode::~OCB_Mode() = default;	1,977✔
169
170	void OCB_Mode::clear() {	92✔
171	m_cipher->clear();	92✔
172	m_L.reset(); // add clear here?	92✔
173	reset();	92✔
174	}	92✔
175
176	void OCB_Mode::reset() {	410✔
177	m_block_index = 0;	410✔
178	zeroise(m_ad_hash);	410✔
179	zeroise(m_checksum);	410✔
180	m_last_nonce.clear();	410✔
181	m_stretch.clear();	410✔
182	}	410✔
183
184	bool OCB_Mode::valid_nonce_length(size_t length) const {	9,491✔
185	if(length == 0) {	9,491✔
186	return false;
187	}
188	if(block_size() == 16) {	9,491✔
189	return length < 16;	7,889✔
190	} else {
191	return length < (block_size() - 1);	1,602✔
192	}
193	}
194
195	std::string OCB_Mode::name() const {	506✔
196	return m_cipher->name() + "/OCB"; // include tag size?	1,012✔
197	}
198
199	size_t OCB_Mode::update_granularity() const {	1,254✔
200	return block_size();	1,254✔
201	}
202
203	size_t OCB_Mode::ideal_granularity() const {	276✔
204	return (m_par_blocks * block_size());	276✔
205	}
206
207	Key_Length_Specification OCB_Mode::key_spec() const {	243✔
208	return m_cipher->key_spec();	243✔
209	}
210
211	bool OCB_Mode::has_keying_material() const {	36,236✔
212	return m_cipher->has_keying_material();	36,236✔
213	}
214
215	void OCB_Mode::key_schedule(const uint8_t key[], size_t length) {	243✔
216	m_cipher->set_key(key, length);	243✔
217	m_L = std::make_unique<L_computer>(*m_cipher);	243✔
218	}	243✔
219
220	void OCB_Mode::set_associated_data_n(size_t idx, std::span<const uint8_t> ad) {	9,679✔
221	BOTAN_ARG_CHECK(idx == 0, "OCB: cannot handle non-zero index in set_associated_data_n");	9,679✔
222	assert_key_material_set();	9,679✔
223	m_ad_hash = ocb_hash(m_L, m_cipher, ad.data(), ad.size());	9,495✔
224	}	9,495✔
225
226	const secure_vector<uint8_t>& OCB_Mode::update_nonce(const uint8_t nonce[], size_t nonce_len) {	9,445✔
227	const size_t BS = block_size();	9,445✔
228
229	BOTAN_ASSERT(BS == 16 \|\| BS == 24 \|\| BS == 32 \|\| BS == 64, "OCB block size is supported");	9,445✔
230
231	const size_t MASKLEN = (BS == 16 ? 6 : ((BS == 24) ? 7 : 8));	9,445✔
232
233	const uint8_t BOTTOM_MASK = static_cast<uint8_t>((static_cast<uint16_t>(1) << MASKLEN) - 1);	9,445✔
234
235	m_nonce_buf.resize(BS);	9,445✔
236	clear_mem(&m_nonce_buf[0], m_nonce_buf.size());	9,445✔
237
238	copy_mem(&m_nonce_buf[BS - nonce_len], nonce, nonce_len);	9,445✔
239	m_nonce_buf[0] = static_cast<uint8_t>(((tag_size() * 8) % (BS * 8)) << (BS <= 16 ? 1 : 0));	11,043✔
240
241	m_nonce_buf[BS - nonce_len - 1] ^= 1;	9,445✔
242
243	const uint8_t bottom = m_nonce_buf[BS - 1] & BOTTOM_MASK;	9,445✔
244	m_nonce_buf[BS - 1] &= ~BOTTOM_MASK;	9,445✔
245
246	const bool need_new_stretch = (m_last_nonce != m_nonce_buf);	9,445✔
247
248	if(need_new_stretch) {	9,445✔
249	m_last_nonce = m_nonce_buf;	681✔
250
251	m_cipher->encrypt(m_nonce_buf);	681✔
252
253	/*
254	The loop bounds (BS vs BS/2) are derived from the relation
255	between the block size and the MASKLEN. Using the terminology
256	of draft-krovetz-ocb-wide, we have to derive enough bits in
257	ShiftedKtop to read up to BLOCKLEN+bottom bits from Stretch.
258
259	+----------+---------+-------+---------+
260	\| BLOCKLEN \| RESIDUE \| SHIFT \| MASKLEN \|
261	+----------+---------+-------+---------+
262	\| 32 \| 141 \| 17 \| 4 \|
263	\| 64 \| 27 \| 25 \| 5 \|
264	\| 96 \| 1601 \| 33 \| 6 \|
265	\| 128 \| 135 \| 8 \| 6 \|
266	\| 192 \| 135 \| 40 \| 7 \|
267	\| 256 \| 1061 \| 1 \| 8 \|
268	\| 384 \| 4109 \| 80 \| 8 \|
269	\| 512 \| 293 \| 176 \| 8 \|
270	\| 1024 \| 524355 \| 352 \| 9 \|
271	+----------+---------+-------+---------+
272	*/
273	if(BS == 16) {	681✔
274	for(size_t i = 0; i != BS / 2; ++i) {	5,517✔
275	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 1]);	4,904✔
276	}
277	} else if(BS == 24) {	68✔
278	for(size_t i = 0; i != 16; ++i) {	408✔
279	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 5]);	384✔
280	}
281	} else if(BS == 32) {	44✔
282	for(size_t i = 0; i != BS; ++i) {	1,089✔
283	m_nonce_buf.push_back(m_nonce_buf[i] ^ (m_nonce_buf[i] << 1) ^ (m_nonce_buf[i + 1] >> 7));	1,056✔
284	}
285	} else if(BS == 64) {
286	for(size_t i = 0; i != BS / 2; ++i) {	363✔
287	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 22]);	352✔
288	}
289	}
290
291	m_stretch = m_nonce_buf;	681✔
292	}
293
294	// now set the offset from stretch and bottom
295	const size_t shift_bytes = bottom / 8;	9,445✔
296	const size_t shift_bits = bottom % 8;	9,445✔
297
298	BOTAN_ASSERT(m_stretch.size() >= BS + shift_bytes + 1, "Size ok");	9,445✔
299
300	m_offset.resize(BS);	9,445✔
301	for(size_t i = 0; i != BS; ++i) {	195,501✔
302	m_offset[i] = (m_stretch[i + shift_bytes] << shift_bits);	186,056✔
303	m_offset[i] \|= (m_stretch[i + shift_bytes + 1] >> (8 - shift_bits));	186,056✔
304	}
305
306	return m_offset;	9,445✔
307	}
308
309	void OCB_Mode::start_msg(const uint8_t nonce[], size_t nonce_len) {	9,445✔
310	if(!valid_nonce_length(nonce_len)) {	9,445✔
311	throw Invalid_IV_Length(name(), nonce_len);	×
312	}
313
314	assert_key_material_set();	9,445✔
315
316	m_L->init(update_nonce(nonce, nonce_len));	9,445✔
317	zeroise(m_checksum);	9,445✔
318	m_block_index = 0;	9,445✔
319	}	9,445✔
320
321	void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks) {	4,161✔
322	assert_key_material_set();	4,161✔
323	BOTAN_STATE_CHECK(m_L->initialized());	4,115✔
324
325	const size_t BS = block_size();	4,069✔
326
327	while(blocks) {	7,674✔
328	const size_t proc_blocks = std::min(blocks, par_blocks());	3,605✔
329	const size_t proc_bytes = proc_blocks * BS;	3,605✔
330
331	const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);	3,605✔
332
333	xor_buf(m_checksum.data(), buffer, proc_bytes);	3,605✔
334
335	m_cipher->encrypt_n_xex(buffer, offsets, proc_blocks);	3,605✔
336
337	buffer += proc_bytes;	3,605✔
338	blocks -= proc_blocks;	3,605✔
339	m_block_index += proc_blocks;	3,605✔
340	}
341	}	4,069✔
342
343	size_t OCB_Encryption::process_msg(uint8_t buf[], size_t sz) {	467✔
344	BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");	467✔
345	encrypt(buf, sz / block_size());	467✔
346	return sz;	375✔
347	}
348
349	void OCB_Encryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {	5,702✔
350	assert_key_material_set();	5,702✔
351	BOTAN_STATE_CHECK(m_L->initialized());	5,610✔
352
353	const size_t BS = block_size();	5,564✔
354
355	BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");	5,564✔
356	const size_t sz = buffer.size() - offset;	5,564✔
357	uint8_t* buf = buffer.data() + offset;	5,564✔
358
359	secure_vector<uint8_t> mac(BS);	5,564✔
360
361	if(sz) {	5,564✔
362	const size_t final_full_blocks = sz / BS;	3,694✔
363	const size_t remainder_bytes = sz - (final_full_blocks * BS);	3,694✔
364
365	encrypt(buf, final_full_blocks);	3,694✔
366	mac = m_L->offset();	3,694✔
367
368	if(remainder_bytes) {	3,694✔
369	BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");	3,492✔
370	uint8_t* remainder = &buf[sz - remainder_bytes];	3,492✔
371
372	xor_buf(m_checksum.data(), remainder, remainder_bytes);	3,492✔
373	m_checksum[remainder_bytes] ^= 0x80;	3,492✔
374
375	// Offset_*
376	mac ^= m_L->star();	3,492✔
377
378	secure_vector<uint8_t> pad(BS);	3,492✔
379	m_cipher->encrypt(mac, pad);	3,492✔
380	xor_buf(remainder, pad.data(), remainder_bytes);	3,492✔
381	}	3,492✔
382	} else {
383	mac = m_L->offset();	1,870✔
384	}
385
386	// now compute the tag
387
388	// fold checksum
389	for(size_t i = 0; i != m_checksum.size(); i += BS) {	82,220✔
390	xor_buf(mac.data(), m_checksum.data() + i, BS);	76,656✔
391	}
392
393	xor_buf(mac.data(), m_L->dollar().data(), BS);	5,564✔
394	m_cipher->encrypt(mac);	5,564✔
395	xor_buf(mac.data(), m_ad_hash.data(), BS);	5,564✔
396
397	buffer += std::make_pair(mac.data(), tag_size());	5,564✔
398
399	zeroise(m_checksum);	5,564✔
400	m_block_index = 0;	5,564✔
401	}	5,564✔
402
403	void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks) {	3,000✔
404	assert_key_material_set();	3,000✔
405	BOTAN_STATE_CHECK(m_L->initialized());	2,954✔
406
407	const size_t BS = block_size();	2,908✔
408
409	while(blocks) {	5,586✔
410	const size_t proc_blocks = std::min(blocks, par_blocks());	2,678✔
411	const size_t proc_bytes = proc_blocks * BS;	2,678✔
412
413	const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);	2,678✔
414
415	m_cipher->decrypt_n_xex(buffer, offsets, proc_blocks);	2,678✔
416
417	xor_buf(m_checksum.data(), buffer, proc_bytes);	2,678✔
418
419	buffer += proc_bytes;	2,678✔
420	blocks -= proc_blocks;	2,678✔
421	m_block_index += proc_blocks;	2,678✔
422	}
423	}	2,908✔
424
425	size_t OCB_Decryption::process_msg(uint8_t buf[], size_t sz) {	479✔
426	BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");	479✔
427	decrypt(buf, sz / block_size());	479✔
428	return sz;	387✔
429	}
430
431	void OCB_Decryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {	3,927✔
432	assert_key_material_set();	3,927✔
433	BOTAN_STATE_CHECK(m_L->initialized());	3,835✔
434
435	const size_t BS = block_size();	3,789✔
436
437	BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");	3,789✔
438	const size_t sz = buffer.size() - offset;	3,789✔
439	uint8_t* buf = buffer.data() + offset;	3,789✔
440
441	BOTAN_ARG_CHECK(sz >= tag_size(), "input did not include the tag");	3,789✔
442
443	const size_t remaining = sz - tag_size();	3,789✔
444
445	secure_vector<uint8_t> mac(BS);	3,789✔
446
447	if(remaining) {	3,789✔
448	const size_t final_full_blocks = remaining / BS;	2,521✔
449	const size_t final_bytes = remaining - (final_full_blocks * BS);	2,521✔
450
451	decrypt(buf, final_full_blocks);	2,521✔
452	mac ^= m_L->offset();	2,521✔
453
454	if(final_bytes) {	2,521✔
455	BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");	2,328✔
456
457	uint8_t* remainder = &buf[remaining - final_bytes];	2,328✔
458
459	mac ^= m_L->star();	2,328✔
460	secure_vector<uint8_t> pad(BS);	2,466✔
461	m_cipher->encrypt(mac, pad); // P_*	2,328✔
462	xor_buf(remainder, pad.data(), final_bytes);	2,328✔
463
464	xor_buf(m_checksum.data(), remainder, final_bytes);	2,328✔
465	m_checksum[final_bytes] ^= 0x80;	2,328✔
466	}	2,328✔
467	} else {
468	mac = m_L->offset();	1,268✔
469	}
470
471	// compute the mac
472
473	// fold checksum
474	for(size_t i = 0; i != m_checksum.size(); i += BS) {	64,505✔
475	xor_buf(mac.data(), m_checksum.data() + i, BS);	60,716✔
476	}
477
478	mac ^= m_L->dollar();	3,789✔
479	m_cipher->encrypt(mac);	3,789✔
480	mac ^= m_ad_hash;	3,789✔
481
482	// reset state
483	zeroise(m_checksum);	3,789✔
484	m_block_index = 0;	3,789✔
485
486	// compare mac
487	const uint8_t* included_tag = &buf[remaining];	3,789✔
488
489	if(!constant_time_compare(mac.data(), included_tag, tag_size())) {	3,789✔
490	throw Invalid_Authentication_Tag("OCB tag check failed");	138✔
491	}
492
493	// remove tag from end of message
494	buffer.resize(remaining + offset);	3,651✔
495	}	3,651✔
496
497	} // namespace Botan

randombit / botan / 5230455705

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