Files
tinyaes/fuzz/fuzz_ctr.cpp
Brandon Lehmann b4df5d078a Fix ARM CE byte ordering, expand C/C++ API, and harden build
ARM backends: fix round key byte-swap on little-endian (vrev32q_u8),
rewrite decrypt to pre-process middle keys with InvMixColumns, fix
GHASH PMULL reflect and reduction ordering.

API: add nonce/IV-generating convenience overloads for CTR, CBC, and
GCM (library generates and prepends nonce, appends tag). Add C API
for IV/nonce generation. Rename error codes (TINYAES_OK, Result::Ok,
Result::AuthenticationFailed, etc.).

Build: add MinGW GCC AVX-512 debug alignment fix, harden bench/fuzz
CMake targets (warnings-as-errors, linker hardening), align with
tinysha CMake conventions. Add README.

Tests: expand coverage for nonce-generating API overloads, add NIST
GCM test vectors, improve fuzz target differential testing.
2026-02-24 21:59:23 -05:00

71 lines
2.2 KiB
C++

// Copyright (c) 2025-2026, Brandon Lehmann
// BSD 3-Clause License (see LICENSE)
#include "tinyaes/ctr.h"
#include "internal/aes_impl.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <cstring>
// Differential: run CTR pipeline via portable vs dispatched and compare
static void diff_ctr_pipeline(const uint8_t *key, size_t key_len, const uint8_t *data, size_t data_len,
const uint8_t iv[16])
{
int rounds = tinyaes::internal::aes_rounds(key_len);
if (rounds == 0)
return;
size_t blocks = data_len / 16;
if (blocks == 0)
return;
uint32_t rk[tinyaes::internal::AES_MAX_RK_WORDS];
tinyaes::internal::aes_key_expand_portable(key, key_len, rk);
std::vector<uint8_t> out_portable(blocks * 16);
std::vector<uint8_t> out_dispatch(blocks * 16);
uint8_t ctr_p[16], ctr_d[16];
std::memcpy(ctr_p, iv, 16);
std::memcpy(ctr_d, iv, 16);
tinyaes::internal::aes_ctr_pipeline_portable(rk, rounds, data, out_portable.data(), blocks, ctr_p);
tinyaes::internal::get_ctr_pipeline()(rk, rounds, data, out_dispatch.data(), blocks, ctr_d);
assert(out_portable == out_dispatch);
assert(std::memcmp(ctr_p, ctr_d, 16) == 0);
}
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
{
if (size < 2)
return 0;
// First byte selects key size: 16, 24, or 32
static const size_t key_sizes[] = {16, 24, 32};
size_t key_len = key_sizes[data[0] % 3];
data++;
size--;
if (size < key_len + 16 + 1)
return 0;
std::vector<uint8_t> key(data, data + key_len);
std::vector<uint8_t> iv(data + key_len, data + key_len + 16);
std::vector<uint8_t> plaintext(data + key_len + 16, data + size);
std::vector<uint8_t> ct, pt;
auto result = tinyaes::ctr_crypt(key, iv, plaintext, ct);
if (result != tinyaes::Result::Ok)
return 0;
result = tinyaes::ctr_crypt(key, iv, ct, pt);
assert(result == tinyaes::Result::Ok);
assert(pt == plaintext);
// Differential: portable vs dispatched CTR pipeline
diff_ctr_pipeline(data, key_len, data + key_len + 16, size - key_len - 16, data + key_len);
return 0;
}