randombit / botan / 14607601421

coverage: 91.387% (+0.07%) from 91.316%
14607601421

Pull #4835

github

web-flow 
Merge 3d72c5cab into 4c413a8ac
Pull Request #4835: New Barrett Reduction implementation

95773 of 104799 relevant lines covered (91.39%)

12982398.04 hits per line

Source File
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93.33
/src/fuzzer/ressol.cpp
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/*
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* (C) 2015,2016 Jack Lloyd
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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 "fuzzers.h"










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#include <botan/numthry.h>










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#include <botan/internal/barrett.h>










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void fuzz(std::span<const uint8_t> in) {




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   // Ressol is mostly used for ECC point decompression so best to test smaller sizes










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   static const size_t p_bits = 256;




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   // Use p == 1 mod 4 since sqrt modulo p == 3 mod 4 is a fast case










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   static const Botan::BigInt p = random_prime(fuzzer_rng(), p_bits, 0, 1, 4);




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   static auto mod_p = Botan::Barrett_Reduction::for_public_modulus(p);




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   if(in.size() > p_bits / 8) {




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      return;










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   }










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   try {




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      const Botan::BigInt a = Botan::BigInt::from_bytes(in);




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      Botan::BigInt a_sqrt = Botan::sqrt_modulo_prime(a, p);




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      if(a_sqrt > 0) {




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         const Botan::BigInt a_redc = mod_p.reduce(a);




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         const Botan::BigInt z = mod_p.square(a_sqrt);




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         if(z != a_redc) {




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            FUZZER_WRITE_AND_CRASH("A = " << a.to_hex_string() << "\n"




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                                          << "P = " << p.to_hex_string() << "\n"










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                                          << "R = " << a_sqrt.to_hex_string() << "\n"










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                                          << "Z = " << z.to_hex_string() << "\n");










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         }










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      }




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   } catch(Botan::Exception& e) {}




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}
























    

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