randombit/botan | Build 5111374265 | source/src/lib/modes/aead/ocb/ocb.cpp | Coveralls

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✔

27

         while(m_L.size() < 8)

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28

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

3,402✔

30

         m_offset_buf.resize(m_BS * m_max_blocks);

243✔

31

243✔

33

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

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35

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

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37

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

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39

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

9,600✔

41

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

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43

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

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44

         while(m_L.size() <= i)

72,372✔

45

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

69✔

47

         return m_L[i];

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50

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

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51

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

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53

         uint8_t* offsets = m_offset_buf.data();

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55

         if(block_index % 4 == 0) {

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56

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

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57

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

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59

            while(blocks >= 4) {

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63

               block_index += 4;

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64

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

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66

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

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67

               offsets += m_BS;

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69

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

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70

               offsets += m_BS;

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72

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

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73

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

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74

               offsets += m_BS;

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76

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

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77

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

3,795✔

78

               offsets += m_BS;

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80

               blocks -= 4;

3,795✔

84

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

16,008✔

85

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

9,627✔

86

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

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87

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

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88

            offsets += m_BS;

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91

         return m_offset_buf.data();

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95

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

2,256✔

96

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

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97

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

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98

         return out;

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113

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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114

   const size_t BS = cipher.block_size();

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115

   secure_vector<uint8_t> sum(BS);

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116

   secure_vector<uint8_t> offset(BS);

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118

   secure_vector<uint8_t> buf(BS);

9,499✔

120

   const size_t ad_blocks = (ad_len / BS);

9,499✔

121

   const size_t ad_remainder = (ad_len % BS);

9,499✔

123

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

56,526✔

125

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

94,054✔

126

      buf = offset;

47,027✔

127

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

47,027✔

128

      cipher.encrypt(buf);

47,027✔

129

      sum ^= buf;

47,027✔

132

   if(ad_remainder) {

9,499✔

133

      offset ^= L.star();

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134

      buf = offset;

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135

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

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136

      buf[ad_remainder] ^= 0x80;

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137

      cipher.encrypt(buf);

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138

      sum ^= buf;

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141

   return sum;

9,499✔

142

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146

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

335✔

147

      m_cipher(std::move(cipher)),

335✔

148

      m_checksum(m_cipher->parallel_bytes()),

670✔

149

      m_ad_hash(m_cipher->block_size()),

335✔

150

      m_tag_size(tag_size),

335✔

151

      m_block_size(m_cipher->block_size()),

335✔

152

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

1,005✔

153

   const size_t BS = block_size();

335✔

160

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

335✔

162

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

335✔

164

335✔

166

OCB_Mode::~OCB_Mode() = default;

1,977✔

168

void OCB_Mode::clear() {

92✔

169

   m_cipher->clear();

92✔

170

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

92✔

171

   reset();

92✔

172

92✔

174

void OCB_Mode::reset() {

410✔

175

   m_block_index = 0;

410✔

176

   zeroise(m_ad_hash);

410✔

177

   zeroise(m_checksum);

410✔

178

   m_last_nonce.clear();

410✔

179

   m_stretch.clear();

410✔

180

410✔

182

bool OCB_Mode::valid_nonce_length(size_t length) const {

9,495✔

183

   if(length == 0)

9,495✔

185

   if(block_size() == 16)

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186

      return length < 16;

7,893✔

188

      return length < (block_size() - 1);

1,602✔

191

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

506✔

192

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

1,012✔

195

size_t OCB_Mode::update_granularity() const { return block_size(); }

1,254✔

197

size_t OCB_Mode::ideal_granularity() const { return (m_par_blocks * block_size()); }

276✔

199

Key_Length_Specification OCB_Mode::key_spec() const { return m_cipher->key_spec(); }

243✔

201

bool OCB_Mode::has_keying_material() const { return m_cipher->has_keying_material(); }

36,252✔

203

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

243✔

204

   m_cipher->set_key(key, length);

243✔

205

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

243✔

206

243✔

208

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

9,683✔

209

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

9,683✔

210

   assert_key_material_set();

9,683✔

211

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

9,499✔

212

9,499✔

214

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

9,449✔

215

   const size_t BS = block_size();

9,449✔

217

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

9,449✔

219

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

9,449✔

221

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

9,449✔

223

   m_nonce_buf.resize(BS);

9,449✔

224

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

9,449✔

226

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

9,449✔

227

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

11,047✔

229

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

9,449✔

231

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

9,449✔

232

   m_nonce_buf[BS - 1] &= ~BOTTOM_MASK;

9,449✔

234

   const bool need_new_stretch = (m_last_nonce != m_nonce_buf);

9,449✔

236

   if(need_new_stretch) {

9,449✔

237

      m_last_nonce = m_nonce_buf;

681✔

239

      m_cipher->encrypt(m_nonce_buf);

681✔

261

      if(BS == 16) {

681✔

262

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

5,517✔

263

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

4,904✔

264

      } else if(BS == 24) {

68✔

265

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

408✔

266

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

384✔

267

      } else if(BS == 32) {

44✔

268

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

1,089✔

269

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

1,056✔

271

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

363✔

272

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

352✔

275

      m_stretch = m_nonce_buf;

681✔

279

   const size_t shift_bytes = bottom / 8;

9,449✔

280

   const size_t shift_bits = bottom % 8;

9,449✔

282

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

9,449✔

284

   m_offset.resize(BS);

9,449✔

285

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

195,569✔

286

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

186,120✔

287

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

186,120✔

290

   return m_offset;

9,449✔

293

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

9,449✔

294

   if(!valid_nonce_length(nonce_len))

9,449✔

297

   assert_key_material_set();

9,449✔

299

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

9,449✔

300

   zeroise(m_checksum);

9,449✔

301

   m_block_index = 0;

9,449✔

302

9,449✔

304

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

4,163✔

305

   assert_key_material_set();

4,163✔

306

   BOTAN_STATE_CHECK(m_L->initialized());

4,117✔

308

   const size_t BS = block_size();

4,071✔

310

   while(blocks) {

7,725✔

311

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

3,654✔

312

      const size_t proc_bytes = proc_blocks * BS;

3,654✔

314

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

3,654✔

316

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

3,654✔

318

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

3,654✔

320

      buffer += proc_bytes;

3,654✔

321

      blocks -= proc_blocks;

3,654✔

322

      m_block_index += proc_blocks;

3,654✔

324

4,071✔

326

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

467✔

327

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

467✔

328

   encrypt(buf, sz / block_size());

467✔

329

   return sz;

375✔

332

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

5,704✔

333

   assert_key_material_set();

5,704✔

334

   BOTAN_STATE_CHECK(m_L->initialized());

5,612✔

336

   const size_t BS = block_size();

5,566✔

338

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

5,566✔

339

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

5,566✔

340

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

5,566✔

342

   secure_vector<uint8_t> mac(BS);

5,566✔

344

   if(sz) {

5,566✔

345

      const size_t final_full_blocks = sz / BS;

3,696✔

346

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

3,696✔

348

      encrypt(buf, final_full_blocks);

3,696✔

349

      mac = m_L->offset();

3,696✔

351

      if(remainder_bytes) {

3,696✔

352

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

3,493✔

353

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

3,493✔

355

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

3,493✔

356

         m_checksum[remainder_bytes] ^= 0x80;

3,493✔

359

         mac ^= m_L->star();

3,493✔

361

         secure_vector<uint8_t> pad(BS);

3,493✔

362

         m_cipher->encrypt(mac, pad);

3,493✔

363

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

3,493✔

364

3,493✔

366

      mac = m_L->offset();

1,870✔

372

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

82,254✔

373

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

76,688✔

376

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

5,566✔

377

   m_cipher->encrypt(mac);

5,566✔

378

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

5,566✔

380

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

5,566✔

382

   zeroise(m_checksum);

5,566✔

383

   m_block_index = 0;

5,566✔

384

5,566✔

386

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

3,002✔

387

   assert_key_material_set();

3,002✔

388

   BOTAN_STATE_CHECK(m_L->initialized());

2,956✔

390

   const size_t BS = block_size();

2,910✔

392

   while(blocks) {

5,637✔

393

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

2,727✔

394

      const size_t proc_bytes = proc_blocks * BS;

2,727✔

396

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

2,727✔

398

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

2,727✔

400

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

2,727✔

402

      buffer += proc_bytes;

2,727✔

403

      blocks -= proc_blocks;

2,727✔

404

      m_block_index += proc_blocks;

2,727✔

406

2,910✔

408

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

479✔

409

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

479✔

410

   decrypt(buf, sz / block_size());

479✔

411

   return sz;

387✔

414

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

3,929✔

415

   assert_key_material_set();

3,929✔

416

   BOTAN_STATE_CHECK(m_L->initialized());

3,837✔

418

   const size_t BS = block_size();

3,791✔

420

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

3,791✔

421

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

3,791✔

422

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

3,791✔

424

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

3,791✔

426

   const size_t remaining = sz - tag_size();

3,791✔

428

   secure_vector<uint8_t> mac(BS);

3,791✔

430

   if(remaining) {

3,791✔

431

      const size_t final_full_blocks = remaining / BS;

2,523✔

432

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

2,523✔

434

      decrypt(buf, final_full_blocks);

2,523✔

435

      mac ^= m_L->offset();

2,523✔

437

      if(final_bytes) {

2,523✔

438

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

2,328✔

440

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

2,328✔

442

         mac ^= m_L->star();

2,328✔

443

         secure_vector<uint8_t> pad(BS);

2,466✔

444

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

2,328✔

445

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

2,328✔

447

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

2,328✔

448

         m_checksum[final_bytes] ^= 0x80;

2,328✔

449

2,328✔

451

      mac = m_L->offset();

1,268✔

456

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

64,539✔

457

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

60,748✔

460

   mac ^= m_L->dollar();

3,791✔

461

   m_cipher->encrypt(mac);

3,791✔

462

   mac ^= m_ad_hash;

3,791✔

465

   zeroise(m_checksum);

3,791✔

466

   m_block_index = 0;

3,791✔

469

   const uint8_t* included_tag = &buf[remaining];

3,791✔

471

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

3,791✔

472

      throw Invalid_Authentication_Tag("OCB tag check failed");

138✔

475

   buffer.resize(remaining + offset);

3,653✔

476

3,653✔

randombit / botan / 5111374265

Source File
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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	m_offset_buf.resize(m_BS * m_max_blocks);	243✔
31	}	243✔
32
33	void init(const secure_vector<uint8_t>& offset) { m_offset = offset; }	9,449✔
34
35	bool initialized() const { return m_offset.empty() == false; }	16,522✔
36
37	const secure_vector<uint8_t>& star() const { return m_L_star; }	6,064✔
38
39	const secure_vector<uint8_t>& dollar() const { return m_L_dollar; }	9,600✔
40
41	const secure_vector<uint8_t>& offset() const { return m_offset; }	9,357✔
42
43	const secure_vector<uint8_t>& get(size_t i) const {	72,303✔
44	while(m_L.size() <= i)	72,372✔
45	m_L.push_back(poly_double(m_L.back()));	69✔
46
47	return m_L[i];	72,303✔
48	}
49
50	const uint8_t* compute_offsets(size_t block_index, size_t blocks) {	6,381✔
51	BOTAN_ASSERT(blocks <= m_max_blocks, "OCB offsets");	6,381✔
52
53	uint8_t* offsets = m_offset_buf.data();	6,381✔
54
55	if(block_index % 4 == 0) {	6,381✔
56	const secure_vector<uint8_t>& L0 = get(0);	5,927✔
57	const secure_vector<uint8_t>& L1 = get(1);	5,927✔
58
59	while(blocks >= 4) {	15,649✔
60	// ntz(4*i+1) == 0
61	// ntz(4*i+2) == 1
62	// ntz(4*i+3) == 0
63	block_index += 4;	3,795✔
64	const size_t ntz4 = var_ctz32(static_cast<uint32_t>(block_index));	3,795✔
65
66	xor_buf(offsets, m_offset.data(), L0.data(), m_BS);	3,795✔
67	offsets += m_BS;	3,795✔
68
69	xor_buf(offsets, offsets - m_BS, L1.data(), m_BS);	3,795✔
70	offsets += m_BS;	3,795✔
71
72	xor_buf(m_offset.data(), L1.data(), m_BS);	3,795✔
73	copy_mem(offsets, m_offset.data(), m_BS);	3,795✔
74	offsets += m_BS;	3,795✔
75
76	xor_buf(m_offset.data(), get(ntz4).data(), m_BS);	3,795✔
77	copy_mem(offsets, m_offset.data(), m_BS);	3,795✔
78	offsets += m_BS;	3,795✔
79
80	blocks -= 4;	3,795✔
81	}
82	}
83
84	for(size_t i = 0; i != blocks; ++i) { // could be done in parallel	16,008✔
85	const size_t ntz = var_ctz32(static_cast<uint32_t>(block_index + i + 1));	9,627✔
86	xor_buf(m_offset.data(), get(ntz).data(), m_BS);	9,627✔
87	copy_mem(offsets, m_offset.data(), m_BS);	9,627✔
88	offsets += m_BS;	9,627✔
89	}
90
91	return m_offset_buf.data();	6,381✔
92	}
93
94	private:
95	static secure_vector<uint8_t> poly_double(const secure_vector<uint8_t>& in) {	2,256✔
96	secure_vector<uint8_t> out(in.size());	2,256✔
97	poly_double_n(out.data(), in.data(), out.size());	2,256✔
98	return out;	2,256✔
99	}	×
100
101	const size_t m_BS, m_max_blocks;
102	secure_vector<uint8_t> m_L_dollar, m_L_star;
103	secure_vector<uint8_t> m_offset;
104	mutable std::vector<secure_vector<uint8_t>> m_L;
105	secure_vector<uint8_t> m_offset_buf;
106	};
107
108	namespace {
109
110	/*
111	* OCB's HASH
112	*/
113	secure_vector<uint8_t> ocb_hash(const L_computer& L, const BlockCipher& cipher, const uint8_t ad[], size_t ad_len) {	9,499✔
114	const size_t BS = cipher.block_size();	9,499✔
115	secure_vector<uint8_t> sum(BS);	9,499✔
116	secure_vector<uint8_t> offset(BS);	9,499✔
117
118	secure_vector<uint8_t> buf(BS);	9,499✔
119
120	const size_t ad_blocks = (ad_len / BS);	9,499✔
121	const size_t ad_remainder = (ad_len % BS);	9,499✔
122
123	for(size_t i = 0; i != ad_blocks; ++i) {	56,526✔
124	// this loop could run in parallel
125	offset ^= L.get(var_ctz32(static_cast<uint32_t>(i + 1)));	94,054✔
126	buf = offset;	47,027✔
127	xor_buf(buf.data(), &ad[BS * i], BS);	47,027✔
128	cipher.encrypt(buf);	47,027✔
129	sum ^= buf;	47,027✔
130	}
131
132	if(ad_remainder) {	9,499✔
133	offset ^= L.star();	5,869✔
134	buf = offset;	5,869✔
135	xor_buf(buf.data(), &ad[BS * ad_blocks], ad_remainder);	5,869✔
136	buf[ad_remainder] ^= 0x80;	5,869✔
137	cipher.encrypt(buf);	5,869✔
138	sum ^= buf;	5,869✔
139	}
140
141	return sum;	9,499✔
142	}	18,998✔
143
144	} // namespace
145
146	OCB_Mode::OCB_Mode(std::unique_ptr<BlockCipher> cipher, size_t tag_size) :	335✔
147	m_cipher(std::move(cipher)),	335✔
148	m_checksum(m_cipher->parallel_bytes()),	670✔
149	m_ad_hash(m_cipher->block_size()),	335✔
150	m_tag_size(tag_size),	335✔
151	m_block_size(m_cipher->block_size()),	335✔
152	m_par_blocks(m_cipher->parallel_bytes() / m_block_size) {	1,005✔
153	const size_t BS = block_size();	335✔
154
155	/*
156	* draft-krovetz-ocb-wide-d1 specifies OCB for several other block
157	* sizes but only 128, 192, 256 and 512 bit are currently supported
158	* by this implementation.
159	*/
160	BOTAN_ARG_CHECK(BS == 16 \|\| BS == 24 \|\| BS == 32 \|\| BS == 64, "Invalid block size for OCB");	335✔
161
162	BOTAN_ARG_CHECK(m_tag_size % 4 == 0 && m_tag_size >= 8 && m_tag_size <= BS && m_tag_size <= 32,	335✔
163	"Invalid OCB tag length");
164	}	335✔
165
166	OCB_Mode::~OCB_Mode() = default;	1,977✔
167
168	void OCB_Mode::clear() {	92✔
169	m_cipher->clear();	92✔
170	m_L.reset(); // add clear here?	92✔
171	reset();	92✔
172	}	92✔
173
174	void OCB_Mode::reset() {	410✔
175	m_block_index = 0;	410✔
176	zeroise(m_ad_hash);	410✔
177	zeroise(m_checksum);	410✔
178	m_last_nonce.clear();	410✔
179	m_stretch.clear();	410✔
180	}	410✔
181
182	bool OCB_Mode::valid_nonce_length(size_t length) const {	9,495✔
183	if(length == 0)	9,495✔
184	return false;
185	if(block_size() == 16)	9,495✔
186	return length < 16;	7,893✔
187	else
188	return length < (block_size() - 1);	1,602✔
189	}
190
191	std::string OCB_Mode::name() const {	506✔
192	return m_cipher->name() + "/OCB"; // include tag size?	1,012✔
193	}
194
195	size_t OCB_Mode::update_granularity() const { return block_size(); }	1,254✔
196
197	size_t OCB_Mode::ideal_granularity() const { return (m_par_blocks * block_size()); }	276✔
198
199	Key_Length_Specification OCB_Mode::key_spec() const { return m_cipher->key_spec(); }	243✔
200
201	bool OCB_Mode::has_keying_material() const { return m_cipher->has_keying_material(); }	36,252✔
202
203	void OCB_Mode::key_schedule(const uint8_t key[], size_t length) {	243✔
204	m_cipher->set_key(key, length);	243✔
205	m_L = std::make_unique<L_computer>(*m_cipher);	243✔
206	}	243✔
207
208	void OCB_Mode::set_associated_data_n(size_t idx, std::span<const uint8_t> ad) {	9,683✔
209	BOTAN_ARG_CHECK(idx == 0, "OCB: cannot handle non-zero index in set_associated_data_n");	9,683✔
210	assert_key_material_set();	9,683✔
211	m_ad_hash = ocb_hash(m_L, m_cipher, ad.data(), ad.size());	9,499✔
212	}	9,499✔
213
214	const secure_vector<uint8_t>& OCB_Mode::update_nonce(const uint8_t nonce[], size_t nonce_len) {	9,449✔
215	const size_t BS = block_size();	9,449✔
216
217	BOTAN_ASSERT(BS == 16 \|\| BS == 24 \|\| BS == 32 \|\| BS == 64, "OCB block size is supported");	9,449✔
218
219	const size_t MASKLEN = (BS == 16 ? 6 : ((BS == 24) ? 7 : 8));	9,449✔
220
221	const uint8_t BOTTOM_MASK = static_cast<uint8_t>((static_cast<uint16_t>(1) << MASKLEN) - 1);	9,449✔
222
223	m_nonce_buf.resize(BS);	9,449✔
224	clear_mem(&m_nonce_buf[0], m_nonce_buf.size());	9,449✔
225
226	copy_mem(&m_nonce_buf[BS - nonce_len], nonce, nonce_len);	9,449✔
227	m_nonce_buf[0] = static_cast<uint8_t>(((tag_size() * 8) % (BS * 8)) << (BS <= 16 ? 1 : 0));	11,047✔
228
229	m_nonce_buf[BS - nonce_len - 1] ^= 1;	9,449✔
230
231	const uint8_t bottom = m_nonce_buf[BS - 1] & BOTTOM_MASK;	9,449✔
232	m_nonce_buf[BS - 1] &= ~BOTTOM_MASK;	9,449✔
233
234	const bool need_new_stretch = (m_last_nonce != m_nonce_buf);	9,449✔
235
236	if(need_new_stretch) {	9,449✔
237	m_last_nonce = m_nonce_buf;	681✔
238
239	m_cipher->encrypt(m_nonce_buf);	681✔
240
241	/*
242	The loop bounds (BS vs BS/2) are derived from the relation
243	between the block size and the MASKLEN. Using the terminology
244	of draft-krovetz-ocb-wide, we have to derive enough bits in
245	ShiftedKtop to read up to BLOCKLEN+bottom bits from Stretch.
246
247	+----------+---------+-------+---------+
248	\| BLOCKLEN \| RESIDUE \| SHIFT \| MASKLEN \|
249	+----------+---------+-------+---------+
250	\| 32 \| 141 \| 17 \| 4 \|
251	\| 64 \| 27 \| 25 \| 5 \|
252	\| 96 \| 1601 \| 33 \| 6 \|
253	\| 128 \| 135 \| 8 \| 6 \|
254	\| 192 \| 135 \| 40 \| 7 \|
255	\| 256 \| 1061 \| 1 \| 8 \|
256	\| 384 \| 4109 \| 80 \| 8 \|
257	\| 512 \| 293 \| 176 \| 8 \|
258	\| 1024 \| 524355 \| 352 \| 9 \|
259	+----------+---------+-------+---------+
260	*/
261	if(BS == 16) {	681✔
262	for(size_t i = 0; i != BS / 2; ++i)	5,517✔
263	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 1]);	4,904✔
264	} else if(BS == 24) {	68✔
265	for(size_t i = 0; i != 16; ++i)	408✔
266	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 5]);	384✔
267	} else if(BS == 32) {	44✔
268	for(size_t i = 0; i != BS; ++i)	1,089✔
269	m_nonce_buf.push_back(m_nonce_buf[i] ^ (m_nonce_buf[i] << 1) ^ (m_nonce_buf[i + 1] >> 7));	1,056✔
270	} else if(BS == 64) {
271	for(size_t i = 0; i != BS / 2; ++i)	363✔
272	m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i + 22]);	352✔
273	}
274
275	m_stretch = m_nonce_buf;	681✔
276	}
277
278	// now set the offset from stretch and bottom
279	const size_t shift_bytes = bottom / 8;	9,449✔
280	const size_t shift_bits = bottom % 8;	9,449✔
281
282	BOTAN_ASSERT(m_stretch.size() >= BS + shift_bytes + 1, "Size ok");	9,449✔
283
284	m_offset.resize(BS);	9,449✔
285	for(size_t i = 0; i != BS; ++i) {	195,569✔
286	m_offset[i] = (m_stretch[i + shift_bytes] << shift_bits);	186,120✔
287	m_offset[i] \|= (m_stretch[i + shift_bytes + 1] >> (8 - shift_bits));	186,120✔
288	}
289
290	return m_offset;	9,449✔
291	}
292
293	void OCB_Mode::start_msg(const uint8_t nonce[], size_t nonce_len) {	9,449✔
294	if(!valid_nonce_length(nonce_len))	9,449✔
295	throw Invalid_IV_Length(name(), nonce_len);	×
296
297	assert_key_material_set();	9,449✔
298
299	m_L->init(update_nonce(nonce, nonce_len));	9,449✔
300	zeroise(m_checksum);	9,449✔
301	m_block_index = 0;	9,449✔
302	}	9,449✔
303
304	void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks) {	4,163✔
305	assert_key_material_set();	4,163✔
306	BOTAN_STATE_CHECK(m_L->initialized());	4,117✔
307
308	const size_t BS = block_size();	4,071✔
309
310	while(blocks) {	7,725✔
311	const size_t proc_blocks = std::min(blocks, par_blocks());	3,654✔
312	const size_t proc_bytes = proc_blocks * BS;	3,654✔
313
314	const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);	3,654✔
315
316	xor_buf(m_checksum.data(), buffer, proc_bytes);	3,654✔
317
318	m_cipher->encrypt_n_xex(buffer, offsets, proc_blocks);	3,654✔
319
320	buffer += proc_bytes;	3,654✔
321	blocks -= proc_blocks;	3,654✔
322	m_block_index += proc_blocks;	3,654✔
323	}
324	}	4,071✔
325
326	size_t OCB_Encryption::process_msg(uint8_t buf[], size_t sz) {	467✔
327	BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");	467✔
328	encrypt(buf, sz / block_size());	467✔
329	return sz;	375✔
330	}
331
332	void OCB_Encryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {	5,704✔
333	assert_key_material_set();	5,704✔
334	BOTAN_STATE_CHECK(m_L->initialized());	5,612✔
335
336	const size_t BS = block_size();	5,566✔
337
338	BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");	5,566✔
339	const size_t sz = buffer.size() - offset;	5,566✔
340	uint8_t* buf = buffer.data() + offset;	5,566✔
341
342	secure_vector<uint8_t> mac(BS);	5,566✔
343
344	if(sz) {	5,566✔
345	const size_t final_full_blocks = sz / BS;	3,696✔
346	const size_t remainder_bytes = sz - (final_full_blocks * BS);	3,696✔
347
348	encrypt(buf, final_full_blocks);	3,696✔
349	mac = m_L->offset();	3,696✔
350
351	if(remainder_bytes) {	3,696✔
352	BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");	3,493✔
353	uint8_t* remainder = &buf[sz - remainder_bytes];	3,493✔
354
355	xor_buf(m_checksum.data(), remainder, remainder_bytes);	3,493✔
356	m_checksum[remainder_bytes] ^= 0x80;	3,493✔
357
358	// Offset_*
359	mac ^= m_L->star();	3,493✔
360
361	secure_vector<uint8_t> pad(BS);	3,493✔
362	m_cipher->encrypt(mac, pad);	3,493✔
363	xor_buf(remainder, pad.data(), remainder_bytes);	3,493✔
364	}	3,493✔
365	} else {
366	mac = m_L->offset();	1,870✔
367	}
368
369	// now compute the tag
370
371	// fold checksum
372	for(size_t i = 0; i != m_checksum.size(); i += BS) {	82,254✔
373	xor_buf(mac.data(), m_checksum.data() + i, BS);	76,688✔
374	}
375
376	xor_buf(mac.data(), m_L->dollar().data(), BS);	5,566✔
377	m_cipher->encrypt(mac);	5,566✔
378	xor_buf(mac.data(), m_ad_hash.data(), BS);	5,566✔
379
380	buffer += std::make_pair(mac.data(), tag_size());	5,566✔
381
382	zeroise(m_checksum);	5,566✔
383	m_block_index = 0;	5,566✔
384	}	5,566✔
385
386	void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks) {	3,002✔
387	assert_key_material_set();	3,002✔
388	BOTAN_STATE_CHECK(m_L->initialized());	2,956✔
389
390	const size_t BS = block_size();	2,910✔
391
392	while(blocks) {	5,637✔
393	const size_t proc_blocks = std::min(blocks, par_blocks());	2,727✔
394	const size_t proc_bytes = proc_blocks * BS;	2,727✔
395
396	const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);	2,727✔
397
398	m_cipher->decrypt_n_xex(buffer, offsets, proc_blocks);	2,727✔
399
400	xor_buf(m_checksum.data(), buffer, proc_bytes);	2,727✔
401
402	buffer += proc_bytes;	2,727✔
403	blocks -= proc_blocks;	2,727✔
404	m_block_index += proc_blocks;	2,727✔
405	}
406	}	2,910✔
407
408	size_t OCB_Decryption::process_msg(uint8_t buf[], size_t sz) {	479✔
409	BOTAN_ARG_CHECK(sz % update_granularity() == 0, "Invalid OCB input size");	479✔
410	decrypt(buf, sz / block_size());	479✔
411	return sz;	387✔
412	}
413
414	void OCB_Decryption::finish_msg(secure_vector<uint8_t>& buffer, size_t offset) {	3,929✔
415	assert_key_material_set();	3,929✔
416	BOTAN_STATE_CHECK(m_L->initialized());	3,837✔
417
418	const size_t BS = block_size();	3,791✔
419
420	BOTAN_ARG_CHECK(buffer.size() >= offset, "Offset is out of range");	3,791✔
421	const size_t sz = buffer.size() - offset;	3,791✔
422	uint8_t* buf = buffer.data() + offset;	3,791✔
423
424	BOTAN_ARG_CHECK(sz >= tag_size(), "input did not include the tag");	3,791✔
425
426	const size_t remaining = sz - tag_size();	3,791✔
427
428	secure_vector<uint8_t> mac(BS);	3,791✔
429
430	if(remaining) {	3,791✔
431	const size_t final_full_blocks = remaining / BS;	2,523✔
432	const size_t final_bytes = remaining - (final_full_blocks * BS);	2,523✔
433
434	decrypt(buf, final_full_blocks);	2,523✔
435	mac ^= m_L->offset();	2,523✔
436
437	if(final_bytes) {	2,523✔
438	BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");	2,328✔
439
440	uint8_t* remainder = &buf[remaining - final_bytes];	2,328✔
441
442	mac ^= m_L->star();	2,328✔
443	secure_vector<uint8_t> pad(BS);	2,466✔
444	m_cipher->encrypt(mac, pad); // P_*	2,328✔
445	xor_buf(remainder, pad.data(), final_bytes);	2,328✔
446
447	xor_buf(m_checksum.data(), remainder, final_bytes);	2,328✔
448	m_checksum[final_bytes] ^= 0x80;	2,328✔
449	}	2,328✔
450	} else
451	mac = m_L->offset();	1,268✔
452
453	// compute the mac
454
455	// fold checksum
456	for(size_t i = 0; i != m_checksum.size(); i += BS) {	64,539✔
457	xor_buf(mac.data(), m_checksum.data() + i, BS);	60,748✔
458	}
459
460	mac ^= m_L->dollar();	3,791✔
461	m_cipher->encrypt(mac);	3,791✔
462	mac ^= m_ad_hash;	3,791✔
463
464	// reset state
465	zeroise(m_checksum);	3,791✔
466	m_block_index = 0;	3,791✔
467
468	// compare mac
469	const uint8_t* included_tag = &buf[remaining];	3,791✔
470
471	if(!constant_time_compare(mac.data(), included_tag, tag_size()))	3,791✔
472	throw Invalid_Authentication_Tag("OCB tag check failed");	138✔
473
474	// remove tag from end of message
475	buffer.resize(remaining + offset);	3,653✔
476	}	3,653✔
477
478	} // namespace Botan

randombit / botan / 5111374265

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