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randombit / botan / 24063525848

06 Apr 2026 10:36PM UTC coverage: 89.448% (-0.007%) from 89.455%
24063525848

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Merge pull request #5521 from randombit/jack/fix-rollup

Rollup of small fixes

105878 of 118368 relevant lines covered (89.45%)

11475460.89 hits per line

Source File
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94.38
/src/lib/utils/ghash/ghash.cpp
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/*
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* GCM GHASH
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* (C) 2013,2015,2017 Jack Lloyd
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* (C) 2016 Daniel Neus, Rohde & Schwarz Cybersecurity
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* (C) 2024 René Meusel, Rohde & Schwarz Cybersecurity
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*
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* Botan is released under the Simplified BSD License (see license.txt)
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*/
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#include <botan/internal/ghash.h>
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#include <botan/exceptn.h>
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#include <botan/internal/ct_utils.h>
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#include <botan/internal/loadstor.h>
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#if defined(BOTAN_HAS_CPUID)
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   #include <botan/internal/cpuid.h>
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#endif
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namespace Botan {
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std::string GHASH::provider() const {
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#if defined(BOTAN_HAS_GHASH_AVX512_CLMUL)
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   if(auto feat = CPUID::check(CPUID::Feature::AVX512_CLMUL)) {
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      return *feat;
×
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   }
×
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#endif
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#if defined(BOTAN_HAS_GHASH_CLMUL_CPU)
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   if(auto feat = CPUID::check(CPUID::Feature::HW_CLMUL)) {
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      return *feat;
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   }
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#endif
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#if defined(BOTAN_HAS_GHASH_CLMUL_VPERM)
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   if(auto feat = CPUID::check(CPUID::Feature::SIMD_4X32)) {
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      return *feat;
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   }
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#endif
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   return "base";
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}
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void GHASH::ghash_multiply(std::span<uint8_t, GCM_BS> x, std::span<const uint8_t> input, size_t blocks) {
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   BOTAN_ASSERT_NOMSG(input.size() % GCM_BS == 0);
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#if defined(BOTAN_HAS_GHASH_AVX512_CLMUL)
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   if(CPUID::has(CPUID::Feature::AVX512_CLMUL)) {
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      BOTAN_ASSERT_NOMSG(!m_H_pow.empty());
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      return ghash_multiply_avx512_clmul(x.data(), m_H_pow.data(), input.data(), blocks);
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   }
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#endif
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#if defined(BOTAN_HAS_GHASH_CLMUL_CPU)
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   if(CPUID::has(CPUID::Feature::HW_CLMUL)) {
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      BOTAN_ASSERT_NOMSG(!m_H_pow.empty());
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      return ghash_multiply_cpu(x.data(), m_H_pow, input.data(), blocks);
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   }
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#endif
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#if defined(BOTAN_HAS_GHASH_CLMUL_VPERM)
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   if(CPUID::has(CPUID::Feature::SIMD_2X64)) {
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      return ghash_multiply_vperm(x.data(), m_HM.data(), input.data(), blocks);
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   }
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#endif
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   auto scope = CT::scoped_poison(x);
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   auto X = load_be<std::array<uint64_t, 2>>(x);
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   BufferSlicer in(input);
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   for(size_t b = 0; b != blocks; ++b) {
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      const auto I = load_be<std::array<uint64_t, 2>>(in.take<GCM_BS>());
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      X[0] ^= I[0];
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      X[1] ^= I[1];
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      std::array<uint64_t, 2> Z{};
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      for(size_t i = 0; i != 64; ++i) {
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         const auto X0MASK = CT::Mask<uint64_t>::expand_top_bit(X[0]);
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         const auto X1MASK = CT::Mask<uint64_t>::expand_top_bit(X[1]);
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         X[0] <<= 1;
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         X[1] <<= 1;
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         Z[0] = X0MASK.select(Z[0] ^ m_HM[4 * i], Z[0]);
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         Z[1] = X0MASK.select(Z[1] ^ m_HM[4 * i + 1], Z[1]);
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         Z[0] = X1MASK.select(Z[0] ^ m_HM[4 * i + 2], Z[0]);
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         Z[1] = X1MASK.select(Z[1] ^ m_HM[4 * i + 3], Z[1]);
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      }
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      X[0] = Z[0];
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      X[1] = Z[1];
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   }
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   store_be(x, X);
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}
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bool GHASH::has_keying_material() const {
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   return !m_HM.empty() || !m_H_pow.empty();
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}
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void GHASH::key_schedule(std::span<const uint8_t> key) {
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   m_H_ad = {0};
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   m_ad_len = 0;
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   m_text_len = 0;
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   BOTAN_ASSERT_NOMSG(key.size() == GCM_BS);
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   auto H = load_be<std::array<uint64_t, 2>>(key.first<GCM_BS>());
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#if defined(BOTAN_HAS_GHASH_AVX512_CLMUL)
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   if(CPUID::has(CPUID::Feature::AVX512_CLMUL)) {
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      zap(m_HM);
×
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      if(m_H_pow.size() != 32) {
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         m_H_pow.resize(32);
×
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      }
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      ghash_precompute_avx512_clmul(key.data(), m_H_pow.data());
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      // m_HM left empty
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      return;
×
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   }
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#endif
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#if defined(BOTAN_HAS_GHASH_CLMUL_CPU)
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   if(CPUID::has(CPUID::Feature::HW_CLMUL)) {
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      zap(m_HM);
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      ghash_precompute_cpu(key.data(), m_H_pow);
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      // m_HM left empty
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      return;
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   }
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#endif
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   const uint64_t R = 0xE100000000000000;
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   if(m_HM.size() != 256) {
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      m_HM.resize(256);
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   }
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   // precompute the multiples of H
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   for(size_t i = 0; i != 2; ++i) {
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      for(size_t j = 0; j != 64; ++j) {
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         /*
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         we interleave H^1, H^65, H^2, H^66, H3, H67, H4, H68
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         to make indexing nicer in the multiplication code
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         */
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         m_HM[4 * j + 2 * i] = H[0];
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         m_HM[4 * j + 2 * i + 1] = H[1];
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         // GCM's bit ops are reversed so we carry out of the bottom
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         const uint64_t carry = CT::Mask<uint64_t>::expand(H[1] & 1).if_set_return(R);
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         H[1] = (H[1] >> 1) | (H[0] << 63);
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         H[0] = (H[0] >> 1) ^ carry;
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      }
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   }
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}
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void GHASH::start(std::span<const uint8_t> nonce) {
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   BOTAN_ARG_CHECK(nonce.size() == 16, "GHASH requires a 128-bit nonce");
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   auto& n = m_nonce.emplace();
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   copy_mem(n, nonce);
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   copy_mem(m_ghash, m_H_ad);
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   m_buffer.clear();
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   m_text_len = 0;
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}
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void GHASH::set_associated_data(std::span<const uint8_t> input) {
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   BOTAN_STATE_CHECK(!m_nonce);
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   assert_key_material_set();
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   m_H_ad = {0};
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   ghash_update(m_H_ad, input);
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   ghash_zeropad(m_H_ad);
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   m_ad_len = input.size();
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}
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void GHASH::reset_associated_data() {
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   // This should only be called in GMAC context
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   BOTAN_STATE_CHECK(m_text_len == 0);
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   assert_key_material_set();
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   m_H_ad = {0};
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   m_ad_len = 0;
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}
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void GHASH::update_associated_data(std::span<const uint8_t> ad) {
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   assert_key_material_set();
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   ghash_update(m_ghash, ad);
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   m_ad_len += ad.size();
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}
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void GHASH::update(std::span<const uint8_t> input) {
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   assert_key_material_set();
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   BOTAN_STATE_CHECK(m_nonce);
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   ghash_update(m_ghash, input);
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   m_text_len += input.size();
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   // NIST SP 800-38D limits plaintext/ciphertext to 2^39 - 256 bits
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   constexpr uint64_t GHASH_MAX_BYTES = (((static_cast<uint64_t>(1) << 39)) - 256) / 8;
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   if(m_text_len > GHASH_MAX_BYTES) {
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      throw Invalid_State("GCM message length limit exceeded");
×
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   }
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}
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void GHASH::final(std::span<uint8_t> mac) {
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   BOTAN_ARG_CHECK(!mac.empty() && mac.size() <= GCM_BS, "GHASH output length");
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   BOTAN_STATE_CHECK(m_nonce);
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   assert_key_material_set();
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   ghash_zeropad(m_ghash);
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   ghash_final_block(m_ghash, m_ad_len, m_text_len);
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   xor_buf(mac, std::span{m_ghash}.first(mac.size()), std::span{*m_nonce}.first(mac.size()));
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   secure_scrub_memory(m_ghash);
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   m_text_len = 0;
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   m_nonce.reset();
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}
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void GHASH::nonce_hash(std::span<uint8_t, GCM_BS> y0, std::span<const uint8_t> nonce) {
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   assert_key_material_set();
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   BOTAN_STATE_CHECK(!m_nonce);
1,256✔
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   ghash_update(y0, nonce);
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   ghash_zeropad(y0);
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   ghash_final_block(y0, 0, nonce.size());
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}
1,256✔
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void GHASH::clear() {
5,559✔
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   zap(m_HM);
5,559✔
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   zap(m_H_pow);
5,559✔
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   this->reset_state();
5,559✔
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}
5,559✔
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void GHASH::reset_state() {
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   m_H_ad = {0};
8,387✔
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   secure_scrub_memory(m_ghash);
8,387✔
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   if(m_nonce) {
8,387✔
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      secure_scrub_memory(m_nonce.value());
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      m_nonce.reset();
1,456✔
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   }
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   m_buffer.clear();
8,387✔
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   m_text_len = 0;
8,387✔
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   m_ad_len = 0;
8,387✔
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}
8,387✔
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void GHASH::ghash_update(std::span<uint8_t, GCM_BS> x, std::span<const uint8_t> input) {
112,778✔
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   BufferSlicer in(input);
112,778✔
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   while(!in.empty()) {
348,690✔
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      if(const auto one_block = m_buffer.handle_unaligned_data(in)) {
123,134✔
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         ghash_multiply(x, one_block.value(), 1);
6,408✔
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      }
251

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      if(m_buffer.in_alignment()) {
123,134✔
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         const auto [aligned_data, full_blocks] = m_buffer.aligned_data_to_process(in);
21,340✔
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         if(full_blocks > 0) {
21,340✔
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            ghash_multiply(x, aligned_data, full_blocks);
15,988✔
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         }
257
      }
258
   }
259
   BOTAN_ASSERT_NOMSG(in.empty());
112,778✔
260
}
112,778✔
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262
void GHASH::ghash_zeropad(std::span<uint8_t, GCM_BS> x) {
22,878✔
263
   if(!m_buffer.in_alignment()) {
22,878✔
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      m_buffer.fill_up_with_zeros();
17,748✔
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      ghash_multiply(x, m_buffer.consume(), 1);
17,748✔
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   }
267
}
22,878✔
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269
void GHASH::ghash_final_block(std::span<uint8_t, GCM_BS> x, uint64_t ad_len, uint64_t text_len) {
14,266✔
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   BOTAN_STATE_CHECK(m_buffer.in_alignment());
14,266✔
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   const auto final_block = store_be(8 * ad_len, 8 * text_len);
14,266✔
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   ghash_multiply(x, final_block, 1);
14,266✔
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}
14,266✔
274

275
}  // namespace Botan
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