mirror of
https://github.com/Huntereb/Awoo-Installer
synced 2024-11-29 15:10:17 +00:00
89 lines
No EOL
2.9 KiB
C++
Executable file
89 lines
No EOL
2.9 KiB
C++
Executable file
#include "util/crypto.hpp"
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#include <string.h>
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#include <mbedtls/bignum.h>
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#include <stdexcept>
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void Crypto::calculateMGF1andXOR(unsigned char* data, size_t data_size, const void* source, size_t source_size) {
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unsigned char h_buf[RSA_2048_BYTES] = {0};
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memcpy(h_buf, source, source_size);
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unsigned char mgf1_buf[0x20];
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size_t ofs = 0;
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unsigned int seed = 0;
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while (ofs < data_size) {
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for (unsigned int i = 0; i < sizeof(seed); i++) {
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h_buf[source_size + 3 - i] = (seed >> (8 * i)) & 0xFF;
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}
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sha256CalculateHash(mgf1_buf, h_buf, source_size + 4);
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for (unsigned int i = ofs; i < data_size && i < ofs + 0x20; i++) {
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data[i] ^= mgf1_buf[i - ofs];
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}
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seed++;
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ofs += 0x20;
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}
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}
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bool Crypto::rsa2048PssVerify(const void *data, size_t len, const unsigned char *signature, const unsigned char *modulus) {
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mbedtls_mpi signature_mpi;
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mbedtls_mpi modulus_mpi;
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mbedtls_mpi e_mpi;
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mbedtls_mpi message_mpi;
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mbedtls_mpi_init(&signature_mpi);
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mbedtls_mpi_init(&modulus_mpi);
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mbedtls_mpi_init(&e_mpi);
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mbedtls_mpi_init(&message_mpi);
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mbedtls_mpi_lset(&message_mpi, RSA_2048_BITS);
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unsigned char m_buf[RSA_2048_BYTES];
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unsigned char h_buf[0x24];
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const unsigned char E[3] = {1, 0, 1};
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mbedtls_mpi_read_binary(&e_mpi, E, 3);
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mbedtls_mpi_read_binary(&signature_mpi, signature, RSA_2048_BYTES);
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mbedtls_mpi_read_binary(&modulus_mpi, modulus, RSA_2048_BYTES);
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mbedtls_mpi_exp_mod(&message_mpi, &signature_mpi, &e_mpi, &modulus_mpi, NULL);
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if (mbedtls_mpi_write_binary(&message_mpi, m_buf, RSA_2048_BYTES) != 0) {
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throw std::runtime_error("Failed to export exponentiated RSA message!");
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}
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mbedtls_mpi_free(&signature_mpi);
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mbedtls_mpi_free(&modulus_mpi);
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mbedtls_mpi_free(&e_mpi);
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mbedtls_mpi_free(&message_mpi);
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/* There's no automated PSS verification as far as I can tell. */
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if (m_buf[RSA_2048_BYTES-1] != 0xBC) {
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return false;
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}
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memset(h_buf, 0, 0x24);
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memcpy(h_buf, m_buf + RSA_2048_BYTES - 0x20 - 0x1, 0x20);
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/* Decrypt maskedDB. */
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calculateMGF1andXOR(m_buf, RSA_2048_BYTES - 0x20 - 1, h_buf, 0x20);
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m_buf[0] &= 0x7F; /* Constant lmask for rsa-2048-pss. */
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/* Validate DB. */
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for (unsigned int i = 0; i < RSA_2048_BYTES - 0x20 - 0x20 - 1 - 1; i++) {
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if (m_buf[i] != 0) {
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return false;
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}
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}
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if (m_buf[RSA_2048_BYTES - 0x20 - 0x20 - 1 - 1] != 1) {
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return false;
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}
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/* Check hash correctness. */
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unsigned char validate_buf[8 + 0x20 + 0x20];
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unsigned char validate_hash[0x20];
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memset(validate_buf, 0, 0x48);
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sha256CalculateHash(&validate_buf[8], data, len);
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memcpy(&validate_buf[0x28], &m_buf[RSA_2048_BYTES - 0x20 - 0x20 - 1], 0x20);
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sha256CalculateHash(validate_hash, validate_buf, 0x48);
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return memcmp(h_buf, validate_hash, 0x20) == 0;
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} |