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make it easier for the chrono fuzzer to explore
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using a fixed size makes the cases cross pollinate
each other better.

the execution speed is much higher as well
@pauldreik
pauldreik committed May 30, 2019

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Learn about vigilant mode
1 parent f0d7ccc commit 1c274cf
Showing 1 changed file with 110 additions and 67 deletions.
177 changes: 110 additions & 67 deletions fuzzing/chrono_duration.cpp
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Original file line number Diff line number Diff line change
@@ -3,41 +3,50 @@

#include <fmt/core.h>
#include <cstdint>
#include <limits>
#include <stdexcept>
#include <type_traits>
#include <vector>
#include <limits>

#include <fmt/chrono.h>

template <typename Item, typename Ratio>
void doit_impl(const char* formatstring, const Item item) {
const std::chrono::duration<Item, Ratio> value(item);
try {
std::string message = fmt::format(formatstring, value);
std::string message = fmt::format(formatstring, value);
} catch (std::exception& e) {
}
}

// Item is the underlying type for duration (int, long etc)
template <typename Item> void doit(const uint8_t* Data, std::size_t Size) {
template <typename Item>
void doit(const uint8_t* Data, std::size_t Size, const int scaling) {
//always use a fixed location of the data, so different cases will
//cooperate better. the same bit pattern, interpreted as another type,
//is likely interesting.
const auto Nfixed=std::max(sizeof(long double),sizeof(std::intmax_t));
const auto N = sizeof(Item);
if (Size <= N) {
static_assert(N<=Nfixed,"fixed size is too small");
if (Size <= Nfixed + 1) {
return;
}
Item item{};
std::memcpy(&item, Data, N);
Data += N;
Size -= N;

//fast forward
Data += Nfixed;
Size -= Nfixed;

// see https://github.com/fmtlib/fmt/issues/1178
const bool github_1178_is_solved=true;
if(!github_1178_is_solved) {
if(std::is_floating_point<Item>::value || std::numeric_limits<Item>::is_signed) {
if(item<0) {
return;
}
const bool github_1178_is_solved = true;
if (!github_1178_is_solved) {
if (std::is_floating_point<Item>::value ||
std::numeric_limits<Item>::is_signed) {
if (item < 0) {
return;
}
}
}

// allocates as tight as possible, making it easier to catch buffer overruns
@@ -46,74 +55,108 @@ template <typename Item> void doit(const uint8_t* Data, std::size_t Size) {
std::memcpy(buf.data(), Data, Size);
// doit_impl<Item,std::yocto>(buf.data(),item);
// doit_impl<Item,std::zepto>(buf.data(),item);
doit_impl<Item, std::atto>(buf.data(), item);
doit_impl<Item, std::femto>(buf.data(), item);
doit_impl<Item, std::pico>(buf.data(), item);
doit_impl<Item, std::nano>(buf.data(), item);
doit_impl<Item, std::micro>(buf.data(), item);
doit_impl<Item, std::milli>(buf.data(), item);
doit_impl<Item, std::centi>(buf.data(), item);
doit_impl<Item, std::deci>(buf.data(), item);
doit_impl<Item, std::deca>(buf.data(), item);
doit_impl<Item, std::kilo>(buf.data(), item);
doit_impl<Item, std::mega>(buf.data(), item);
doit_impl<Item, std::giga>(buf.data(), item);
doit_impl<Item, std::tera>(buf.data(), item);
doit_impl<Item, std::peta>(buf.data(), item);
doit_impl<Item, std::exa>(buf.data(), item);
// doit_impl<Item,std::zeta>(buf.data(),item);
// doit_impl<Item,std::yotta>(buf.data(),item);
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
if (Size <= 3) {
return 0;
}

const auto first = Data[0];
Data++;
Size--;

switch (first) {
case 1:
doit<char>(Data, Size);
switch (scaling) {
case 1:
doit_impl<Item, std::atto>(buf.data(), item);
break;
case 21:
doit<unsigned char>(Data, Size);
case 2:
doit_impl<Item, std::femto>(buf.data(), item);
break;
case 31:
doit<signed char>(Data, Size);
case 3:
doit_impl<Item, std::pico>(buf.data(), item);
break;
case 2:
doit<short>(Data, Size);
case 4:
doit_impl<Item, std::nano>(buf.data(), item);
break;
case 22:
doit<unsigned short>(Data, Size);
case 5:
doit_impl<Item, std::micro>(buf.data(), item);
break;
case 3:
doit<int>(Data, Size);
case 6:
doit_impl<Item, std::milli>(buf.data(), item);
break;
case 23:
doit<unsigned int>(Data, Size);
case 7:
doit_impl<Item, std::centi>(buf.data(), item);
break;
case 4:
doit<long>(Data, Size);
case 8:
doit_impl<Item, std::deci>(buf.data(), item);
break;
case 24:
doit<unsigned long>(Data, Size);
case 9:
doit_impl<Item, std::deca>(buf.data(), item);
break;
case 5:
doit<float>(Data, Size);
case 10:
doit_impl<Item, std::kilo>(buf.data(), item);
break;
case 6:
doit<double>(Data, Size);
case 11:
doit_impl<Item, std::mega>(buf.data(), item);
break;
case 7:
doit<long double>(Data, Size);
case 12:
doit_impl<Item, std::giga>(buf.data(), item);
break;
case 13:
doit_impl<Item, std::tera>(buf.data(), item);
break;
default:
case 14:
doit_impl<Item, std::peta>(buf.data(), item);
break;
}
case 15:
doit_impl<Item, std::exa>(buf.data(), item);
}
// doit_impl<Item,std::zeta>(buf.data(),item);
// doit_impl<Item,std::yotta>(buf.data(),item);
}

extern "C" int LLVMFuzzerTestOneInput(const uint8_t* Data, std::size_t Size) {
if (Size <= 4) {
return 0;
}

const auto first = Data[0];
Data++;
Size--;
const auto second = Data[0];
Data++;
Size--;

switch (first) {
case 1:
doit<char>(Data, Size, second);
break;
case 21:
doit<unsigned char>(Data, Size, second);
break;
case 31:
doit<signed char>(Data, Size, second);
break;
case 2:
doit<short>(Data, Size, second);
break;
case 22:
doit<unsigned short>(Data, Size, second);
break;
case 3:
doit<int>(Data, Size, second);
break;
case 23:
doit<unsigned int>(Data, Size, second);
break;
case 4:
doit<long>(Data, Size, second);
break;
case 24:
doit<unsigned long>(Data, Size, second);
break;
case 5:
doit<float>(Data, Size, second);
break;
case 6:
doit<double>(Data, Size, second);
break;
case 7:
doit<long double>(Data, Size, second);
break;
default:
break;
}

return 0;
}

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