libc/fuzzing/stdlib/strtointeger_fuzz.cpp

   1 //===-- strtointeger_fuzz.cpp ---------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 ///
   9 /// Fuzzing test for llvm-libc atof implementation.
  10 ///
  11 //===----------------------------------------------------------------------===//
  12 #include "src/stdlib/atoi.h"
  13 #include "src/stdlib/atol.h"
  14 #include "src/stdlib/atoll.h"
  15 #include "src/stdlib/strtol.h"
  16 #include "src/stdlib/strtoll.h"
  17 #include "src/stdlib/strtoul.h"
  18 #include "src/stdlib/strtoull.h"
  19 #include <stddef.h>
  20 #include <stdint.h>
  21
  22 // This takes the randomized bytes in data and interprets the first byte as the
  23 // base for the string to integer conversion and the rest of them as a string to
  24 // be passed to the string to integer conversion.
  25 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
  26   size_t container_size = 0;
  27   if (size == 0) {
  28     container_size = 1;
  29   } else {
  30     container_size = size;
  31   }
  32   uint8_t *container = new uint8_t[container_size];
  33   if (!container)
  34     __builtin_trap();
  35
  36   int base = 0;
  37   if (size > 0) {
  38     base = data[0] % 36;
  39     base = base + ((base == 0) ? 0 : 1);
  40   }
  41   for (size_t i = 1; i < size; ++i) {
  42     container[i - 1] = data[i];
  43   }
  44
  45   container[container_size - 1] = '\0'; // Add null terminator to container.
  46
  47   const char *str_ptr = reinterpret_cast<const char *>(container);
  48
  49   char *out_ptr = nullptr;
  50
  51   auto volatile atoi_output = __llvm_libc::atoi(str_ptr);
  52   auto volatile atol_output = __llvm_libc::atol(str_ptr);
  53   auto volatile atoll_output = __llvm_libc::atoll(str_ptr);
  54   auto volatile strtol_output = __llvm_libc::strtol(str_ptr, &out_ptr, base);
  55   if (str_ptr + container_size - 1 < out_ptr)
  56     __builtin_trap();
  57   auto volatile strtoll_output = __llvm_libc::strtoll(str_ptr, &out_ptr, base);
  58   if (str_ptr + container_size - 1 < out_ptr)
  59     __builtin_trap();
  60   auto volatile strtoul_output = __llvm_libc::strtoul(str_ptr, &out_ptr, base);
  61   if (str_ptr + container_size - 1 < out_ptr)
  62     __builtin_trap();
  63   auto volatile strtoull_output =
  64       __llvm_libc::strtoull(str_ptr, &out_ptr, base);
  65   if (str_ptr + container_size - 1 < out_ptr)
  66     __builtin_trap();
  67
  68   // If atoi is non-zero and the base is at least 10
  69   if (atoi_output != 0 && base >= 10) {
  70     // Then all of the other functions should output non-zero values as well.
  71     // This is a trivial check meant to silence the "unused variable" warnings.
  72     if (atol_output == 0 || atoll_output == 0 || strtol_output == 0 ||
  73         strtoll_output == 0 || strtoul_output == 0 || strtoull_output == 0) {
  74       __builtin_trap();
  75     }
  76   }
  77
  78   delete[] container;
  79   return 0;
  80 }