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/*
* (C) 2018 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include "fuzzers.h"
#include <botan/mode_pad.h>
#include <botan/internal/tls_cbc.h>
namespace {
size_t ref_pkcs7_unpad(const uint8_t in[], size_t len)
{
if(len <= 2)
return len;
const size_t padding_length = in[len-1];
if(padding_length == 0 || padding_length > len)
return len;
const size_t padding_start = len - padding_length;
for(size_t i = padding_start; i != len; ++i)
{
if(in[i] != padding_length)
return len;
}
return len - padding_length;
}
size_t ref_x923_unpad(const uint8_t in[], size_t len)
{
if(len <= 2)
return len;
const size_t padding_length = in[len-1];
if(padding_length == 0 || padding_length > len)
return len;
const size_t padding_start = len - padding_length;
for(size_t i = padding_start; i != len - 1; ++i)
{
if(in[i] != 0)
{
return len;
}
}
return len - padding_length;
}
size_t ref_oneandzero_unpad(const uint8_t in[], size_t len)
{
if(len <= 2)
return len;
size_t idx = len - 1;
for(;;)
{
if(in[idx] == 0)
{
if(idx == 0)
return len;
idx -= 1;
continue;
}
else if(in[idx] == 0x80)
{
return idx;
}
else
return len;
}
return len;
}
size_t ref_esp_unpad(const uint8_t in[], size_t len)
{
if(len <= 2)
return len;
const size_t padding_bytes = in[len - 1];
if(padding_bytes == 0 || padding_bytes > len)
{
return len;
}
const size_t padding_start = len - padding_bytes;
for(size_t i = padding_start; i != len; ++i)
{
if(in[i] != (i - padding_start + 1))
{
return len;
}
}
return len - padding_bytes;
}
uint16_t ref_tls_cbc_unpad(const uint8_t in[], size_t len)
{
if(len == 0)
return 0;
const size_t padding_length = in[(len-1)];
if(padding_length >= len)
return 0;
/*
* TLS v1.0 and up require all the padding bytes be the same value
* and allows up to 255 bytes.
*/
for(size_t i = 0; i != 1 + padding_length; ++i)
{
if(in[(len-i-1)] != padding_length)
return 0;
}
return padding_length + 1;
}
}
void fuzz(const uint8_t in[], size_t len)
{
static Botan::PKCS7_Padding pkcs7;
static Botan::ANSI_X923_Padding x923;
static Botan::OneAndZeros_Padding oneandzero;
static Botan::ESP_Padding esp;
if(pkcs7.valid_blocksize(len))
{
const size_t ct_pkcs7 = pkcs7.unpad(in, len);
const size_t ref_pkcs7 = ref_pkcs7_unpad(in, len);
FUZZER_ASSERT_EQUAL(ct_pkcs7, ref_pkcs7);
}
if(x923.valid_blocksize(len))
{
const size_t ct_x923 = x923.unpad(in, len);
const size_t ref_x923 = ref_x923_unpad(in, len);
FUZZER_ASSERT_EQUAL(ct_x923, ref_x923);
}
if(oneandzero.valid_blocksize(len))
{
const size_t ct_oneandzero = oneandzero.unpad(in, len);
const size_t ref_oneandzero = ref_oneandzero_unpad(in, len);
FUZZER_ASSERT_EQUAL(ct_oneandzero, ref_oneandzero);
}
if(esp.valid_blocksize(len))
{
const size_t ct_esp = esp.unpad(in, len);
const size_t ref_esp = ref_esp_unpad(in, len);
FUZZER_ASSERT_EQUAL(ct_esp, ref_esp);
}
const uint16_t ct_cbc = Botan::TLS::check_tls_cbc_padding(in, len);
const uint16_t ref_cbc = ref_tls_cbc_unpad(in, len);
FUZZER_ASSERT_EQUAL(ct_cbc, ref_cbc);
}
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