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-rw-r--r--comm/third_party/botan/src/lib/modes/aead/ocb/ocb.cpp533
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diff --git a/comm/third_party/botan/src/lib/modes/aead/ocb/ocb.cpp b/comm/third_party/botan/src/lib/modes/aead/ocb/ocb.cpp
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+++ b/comm/third_party/botan/src/lib/modes/aead/ocb/ocb.cpp
@@ -0,0 +1,533 @@
+/*
+* OCB Mode
+* (C) 2013,2017 Jack Lloyd
+* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/ocb.h>
+#include <botan/block_cipher.h>
+#include <botan/internal/poly_dbl.h>
+#include <botan/internal/bit_ops.h>
+
+namespace Botan {
+
+// Has to be in Botan namespace so unique_ptr can reference it
+class L_computer final
+ {
+ public:
+ explicit L_computer(const BlockCipher& cipher) :
+ m_BS(cipher.block_size()),
+ m_max_blocks(cipher.parallel_bytes() / m_BS)
+ {
+ m_L_star.resize(m_BS);
+ cipher.encrypt(m_L_star);
+ m_L_dollar = poly_double(star());
+ m_L.push_back(poly_double(dollar()));
+
+ while(m_L.size() < 8)
+ m_L.push_back(poly_double(m_L.back()));
+
+ m_offset_buf.resize(m_BS * m_max_blocks);
+ }
+
+ void init(const secure_vector<uint8_t>& offset)
+ {
+ m_offset = offset;
+ }
+
+ bool initialized() const { return m_offset.empty() == false; }
+
+ const secure_vector<uint8_t>& star() const { return m_L_star; }
+ const secure_vector<uint8_t>& dollar() const { return m_L_dollar; }
+ const secure_vector<uint8_t>& offset() const { return m_offset; }
+
+ const secure_vector<uint8_t>& get(size_t i) const
+ {
+ while(m_L.size() <= i)
+ m_L.push_back(poly_double(m_L.back()));
+
+ return m_L[i];
+ }
+
+ const uint8_t*
+ compute_offsets(size_t block_index, size_t blocks)
+ {
+ BOTAN_ASSERT(blocks <= m_max_blocks, "OCB offsets");
+
+ uint8_t* offsets = m_offset_buf.data();
+
+ if(block_index % 4 == 0)
+ {
+ const secure_vector<uint8_t>& L0 = get(0);
+ const secure_vector<uint8_t>& L1 = get(1);
+
+ while(blocks >= 4)
+ {
+ // ntz(4*i+1) == 0
+ // ntz(4*i+2) == 1
+ // ntz(4*i+3) == 0
+ block_index += 4;
+ const size_t ntz4 = var_ctz32(static_cast<uint32_t>(block_index));
+
+ xor_buf(offsets, m_offset.data(), L0.data(), m_BS);
+ offsets += m_BS;
+
+ xor_buf(offsets, offsets - m_BS, L1.data(), m_BS);
+ offsets += m_BS;
+
+ xor_buf(m_offset.data(), L1.data(), m_BS);
+ copy_mem(offsets, m_offset.data(), m_BS);
+ offsets += m_BS;
+
+ xor_buf(m_offset.data(), get(ntz4).data(), m_BS);
+ copy_mem(offsets, m_offset.data(), m_BS);
+ offsets += m_BS;
+
+ blocks -= 4;
+ }
+ }
+
+ for(size_t i = 0; i != blocks; ++i)
+ { // could be done in parallel
+ const size_t ntz = var_ctz32(static_cast<uint32_t>(block_index + i + 1));
+ xor_buf(m_offset.data(), get(ntz).data(), m_BS);
+ copy_mem(offsets, m_offset.data(), m_BS);
+ offsets += m_BS;
+ }
+
+ return m_offset_buf.data();
+ }
+
+ private:
+ secure_vector<uint8_t> poly_double(const secure_vector<uint8_t>& in) const
+ {
+ secure_vector<uint8_t> out(in.size());
+ poly_double_n(out.data(), in.data(), out.size());
+ return out;
+ }
+
+ const size_t m_BS, m_max_blocks;
+ secure_vector<uint8_t> m_L_dollar, m_L_star;
+ secure_vector<uint8_t> m_offset;
+ mutable std::vector<secure_vector<uint8_t>> m_L;
+ secure_vector<uint8_t> m_offset_buf;
+ };
+
+namespace {
+
+/*
+* OCB's HASH
+*/
+secure_vector<uint8_t> ocb_hash(const L_computer& L,
+ const BlockCipher& cipher,
+ const uint8_t ad[], size_t ad_len)
+ {
+ const size_t BS = cipher.block_size();
+ secure_vector<uint8_t> sum(BS);
+ secure_vector<uint8_t> offset(BS);
+
+ secure_vector<uint8_t> buf(BS);
+
+ const size_t ad_blocks = (ad_len / BS);
+ const size_t ad_remainder = (ad_len % BS);
+
+ for(size_t i = 0; i != ad_blocks; ++i)
+ {
+ // this loop could run in parallel
+ offset ^= L.get(var_ctz32(static_cast<uint32_t>(i+1)));
+ buf = offset;
+ xor_buf(buf.data(), &ad[BS*i], BS);
+ cipher.encrypt(buf);
+ sum ^= buf;
+ }
+
+ if(ad_remainder)
+ {
+ offset ^= L.star();
+ buf = offset;
+ xor_buf(buf.data(), &ad[BS*ad_blocks], ad_remainder);
+ buf[ad_remainder] ^= 0x80;
+ cipher.encrypt(buf);
+ sum ^= buf;
+ }
+
+ return sum;
+ }
+
+}
+
+OCB_Mode::OCB_Mode(BlockCipher* cipher, size_t tag_size) :
+ m_cipher(cipher),
+ m_checksum(m_cipher->parallel_bytes()),
+ m_ad_hash(m_cipher->block_size()),
+ m_tag_size(tag_size),
+ m_block_size(m_cipher->block_size()),
+ m_par_blocks(m_cipher->parallel_bytes() / m_block_size)
+ {
+ const size_t BS = block_size();
+
+ /*
+ * draft-krovetz-ocb-wide-d1 specifies OCB for several other block
+ * sizes but only 128, 192, 256 and 512 bit are currently supported
+ * by this implementation.
+ */
+ BOTAN_ARG_CHECK(BS == 16 || BS == 24 || BS == 32 || BS == 64,
+ "Invalid block size for OCB");
+
+ BOTAN_ARG_CHECK(m_tag_size % 4 == 0 &&
+ m_tag_size >= 8 && m_tag_size <= BS &&
+ m_tag_size <= 32,
+ "Invalid OCB tag length");
+ }
+
+OCB_Mode::~OCB_Mode() { /* for unique_ptr destructor */ }
+
+void OCB_Mode::clear()
+ {
+ m_cipher->clear();
+ m_L.reset(); // add clear here?
+ reset();
+ }
+
+void OCB_Mode::reset()
+ {
+ m_block_index = 0;
+ zeroise(m_ad_hash);
+ zeroise(m_checksum);
+ m_last_nonce.clear();
+ m_stretch.clear();
+ }
+
+bool OCB_Mode::valid_nonce_length(size_t length) const
+ {
+ if(length == 0)
+ return false;
+ if(block_size() == 16)
+ return length < 16;
+ else
+ return length < (block_size() - 1);
+ }
+
+std::string OCB_Mode::name() const
+ {
+ return m_cipher->name() + "/OCB"; // include tag size?
+ }
+
+size_t OCB_Mode::update_granularity() const
+ {
+ return (m_par_blocks * block_size());
+ }
+
+Key_Length_Specification OCB_Mode::key_spec() const
+ {
+ return m_cipher->key_spec();
+ }
+
+void OCB_Mode::key_schedule(const uint8_t key[], size_t length)
+ {
+ m_cipher->set_key(key, length);
+ m_L.reset(new L_computer(*m_cipher));
+ }
+
+void OCB_Mode::set_associated_data(const uint8_t ad[], size_t ad_len)
+ {
+ verify_key_set(m_L != nullptr);
+ m_ad_hash = ocb_hash(*m_L, *m_cipher, ad, ad_len);
+ }
+
+const secure_vector<uint8_t>&
+OCB_Mode::update_nonce(const uint8_t nonce[], size_t nonce_len)
+ {
+ const size_t BS = block_size();
+
+ BOTAN_ASSERT(BS == 16 || BS == 24 || BS == 32 || BS == 64,
+ "OCB block size is supported");
+
+ const size_t MASKLEN = (BS == 16 ? 6 : ((BS == 24) ? 7 : 8));
+
+ const uint8_t BOTTOM_MASK =
+ static_cast<uint8_t>((static_cast<uint16_t>(1) << MASKLEN) - 1);
+
+ m_nonce_buf.resize(BS);
+ clear_mem(&m_nonce_buf[0], m_nonce_buf.size());
+
+ copy_mem(&m_nonce_buf[BS - nonce_len], nonce, nonce_len);
+ m_nonce_buf[0] = static_cast<uint8_t>(((tag_size()*8) % (BS*8)) << (BS <= 16 ? 1 : 0));
+
+ m_nonce_buf[BS - nonce_len - 1] ^= 1;
+
+ const uint8_t bottom = m_nonce_buf[BS-1] & BOTTOM_MASK;
+ m_nonce_buf[BS-1] &= ~BOTTOM_MASK;
+
+ const bool need_new_stretch = (m_last_nonce != m_nonce_buf);
+
+ if(need_new_stretch)
+ {
+ m_last_nonce = m_nonce_buf;
+
+ m_cipher->encrypt(m_nonce_buf);
+
+ /*
+ The loop bounds (BS vs BS/2) are derived from the relation
+ between the block size and the MASKLEN. Using the terminology
+ of draft-krovetz-ocb-wide, we have to derive enough bits in
+ ShiftedKtop to read up to BLOCKLEN+bottom bits from Stretch.
+
+ +----------+---------+-------+---------+
+ | BLOCKLEN | RESIDUE | SHIFT | MASKLEN |
+ +----------+---------+-------+---------+
+ | 32 | 141 | 17 | 4 |
+ | 64 | 27 | 25 | 5 |
+ | 96 | 1601 | 33 | 6 |
+ | 128 | 135 | 8 | 6 |
+ | 192 | 135 | 40 | 7 |
+ | 256 | 1061 | 1 | 8 |
+ | 384 | 4109 | 80 | 8 |
+ | 512 | 293 | 176 | 8 |
+ | 1024 | 524355 | 352 | 9 |
+ +----------+---------+-------+---------+
+ */
+ if(BS == 16)
+ {
+ for(size_t i = 0; i != BS / 2; ++i)
+ m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i+1]);
+ }
+ else if(BS == 24)
+ {
+ for(size_t i = 0; i != 16; ++i)
+ m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i+5]);
+ }
+ else if(BS == 32)
+ {
+ for(size_t i = 0; i != BS; ++i)
+ m_nonce_buf.push_back(m_nonce_buf[i] ^ (m_nonce_buf[i] << 1) ^ (m_nonce_buf[i+1] >> 7));
+ }
+ else if(BS == 64)
+ {
+ for(size_t i = 0; i != BS / 2; ++i)
+ m_nonce_buf.push_back(m_nonce_buf[i] ^ m_nonce_buf[i+22]);
+ }
+
+ m_stretch = m_nonce_buf;
+ }
+
+ // now set the offset from stretch and bottom
+ const size_t shift_bytes = bottom / 8;
+ const size_t shift_bits = bottom % 8;
+
+ BOTAN_ASSERT(m_stretch.size() >= BS + shift_bytes + 1, "Size ok");
+
+ m_offset.resize(BS);
+ for(size_t i = 0; i != BS; ++i)
+ {
+ m_offset[i] = (m_stretch[i+shift_bytes] << shift_bits);
+ m_offset[i] |= (m_stretch[i+shift_bytes+1] >> (8-shift_bits));
+ }
+
+ return m_offset;
+ }
+
+void OCB_Mode::start_msg(const uint8_t nonce[], size_t nonce_len)
+ {
+ if(!valid_nonce_length(nonce_len))
+ throw Invalid_IV_Length(name(), nonce_len);
+
+ verify_key_set(m_L != nullptr);
+
+ m_L->init(update_nonce(nonce, nonce_len));
+ zeroise(m_checksum);
+ m_block_index = 0;
+ }
+
+void OCB_Encryption::encrypt(uint8_t buffer[], size_t blocks)
+ {
+ verify_key_set(m_L != nullptr);
+ BOTAN_STATE_CHECK(m_L->initialized());
+
+ const size_t BS = block_size();
+
+ while(blocks)
+ {
+ const size_t proc_blocks = std::min(blocks, par_blocks());
+ const size_t proc_bytes = proc_blocks * BS;
+
+ const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);
+
+ xor_buf(m_checksum.data(), buffer, proc_bytes);
+
+ m_cipher->encrypt_n_xex(buffer, offsets, proc_blocks);
+
+ buffer += proc_bytes;
+ blocks -= proc_blocks;
+ m_block_index += proc_blocks;
+ }
+ }
+
+size_t OCB_Encryption::process(uint8_t buf[], size_t sz)
+ {
+ BOTAN_ASSERT(sz % update_granularity() == 0, "Invalid OCB input size");
+ encrypt(buf, sz / block_size());
+ return sz;
+ }
+
+void OCB_Encryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
+ {
+ verify_key_set(m_L != nullptr);
+
+ const size_t BS = block_size();
+
+ BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+ const size_t sz = buffer.size() - offset;
+ uint8_t* buf = buffer.data() + offset;
+
+ secure_vector<uint8_t> mac(BS);
+
+ if(sz)
+ {
+ const size_t final_full_blocks = sz / BS;
+ const size_t remainder_bytes = sz - (final_full_blocks * BS);
+
+ encrypt(buf, final_full_blocks);
+ mac = m_L->offset();
+
+ if(remainder_bytes)
+ {
+ BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");
+ uint8_t* remainder = &buf[sz - remainder_bytes];
+
+ xor_buf(m_checksum.data(), remainder, remainder_bytes);
+ m_checksum[remainder_bytes] ^= 0x80;
+
+ // Offset_*
+ mac ^= m_L->star();
+
+ secure_vector<uint8_t> pad(BS);
+ m_cipher->encrypt(mac, pad);
+ xor_buf(remainder, pad.data(), remainder_bytes);
+ }
+ }
+ else
+ {
+ mac = m_L->offset();
+ }
+
+ // now compute the tag
+
+ // fold checksum
+ for(size_t i = 0; i != m_checksum.size(); i += BS)
+ {
+ xor_buf(mac.data(), m_checksum.data() + i, BS);
+ }
+
+ xor_buf(mac.data(), m_L->dollar().data(), BS);
+ m_cipher->encrypt(mac);
+ xor_buf(mac.data(), m_ad_hash.data(), BS);
+
+ buffer += std::make_pair(mac.data(), tag_size());
+
+ zeroise(m_checksum);
+ m_block_index = 0;
+ }
+
+void OCB_Decryption::decrypt(uint8_t buffer[], size_t blocks)
+ {
+ verify_key_set(m_L != nullptr);
+ BOTAN_STATE_CHECK(m_L->initialized());
+
+ const size_t BS = block_size();
+
+ while(blocks)
+ {
+ const size_t proc_blocks = std::min(blocks, par_blocks());
+ const size_t proc_bytes = proc_blocks * BS;
+
+ const uint8_t* offsets = m_L->compute_offsets(m_block_index, proc_blocks);
+
+ m_cipher->decrypt_n_xex(buffer, offsets, proc_blocks);
+
+ xor_buf(m_checksum.data(), buffer, proc_bytes);
+
+ buffer += proc_bytes;
+ blocks -= proc_blocks;
+ m_block_index += proc_blocks;
+ }
+ }
+
+size_t OCB_Decryption::process(uint8_t buf[], size_t sz)
+ {
+ BOTAN_ASSERT(sz % update_granularity() == 0, "Invalid OCB input size");
+ decrypt(buf, sz / block_size());
+ return sz;
+ }
+
+void OCB_Decryption::finish(secure_vector<uint8_t>& buffer, size_t offset)
+ {
+ verify_key_set(m_L != nullptr);
+
+ const size_t BS = block_size();
+
+ BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
+ const size_t sz = buffer.size() - offset;
+ uint8_t* buf = buffer.data() + offset;
+
+ BOTAN_ASSERT(sz >= tag_size(), "We have the tag");
+
+ const size_t remaining = sz - tag_size();
+
+ secure_vector<uint8_t> mac(BS);
+
+ if(remaining)
+ {
+ const size_t final_full_blocks = remaining / BS;
+ const size_t final_bytes = remaining - (final_full_blocks * BS);
+
+ decrypt(buf, final_full_blocks);
+ mac ^= m_L->offset();
+
+ if(final_bytes)
+ {
+ BOTAN_ASSERT(final_bytes < BS, "Only a partial block left");
+
+ uint8_t* remainder = &buf[remaining - final_bytes];
+
+ mac ^= m_L->star();
+ secure_vector<uint8_t> pad(BS);
+ m_cipher->encrypt(mac, pad); // P_*
+ xor_buf(remainder, pad.data(), final_bytes);
+
+ xor_buf(m_checksum.data(), remainder, final_bytes);
+ m_checksum[final_bytes] ^= 0x80;
+ }
+ }
+ else
+ mac = m_L->offset();
+
+ // compute the mac
+
+ // fold checksum
+ for(size_t i = 0; i != m_checksum.size(); i += BS)
+ {
+ xor_buf(mac.data(), m_checksum.data() + i, BS);
+ }
+
+ mac ^= m_L->dollar();
+ m_cipher->encrypt(mac);
+ mac ^= m_ad_hash;
+
+ // reset state
+ zeroise(m_checksum);
+ m_block_index = 0;
+
+ // compare mac
+ const uint8_t* included_tag = &buf[remaining];
+
+ if(!constant_time_compare(mac.data(), included_tag, tag_size()))
+ throw Invalid_Authentication_Tag("OCB tag check failed");
+
+ // remove tag from end of message
+ buffer.resize(remaining + offset);
+ }
+
+}
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