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/*
* RSA/SHA-256 signature verification program
*
* Copyright The Mbed TLS Contributors
* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
*/
#include "mbedtls/build_info.h"
#include "mbedtls/platform.h"
/* md.h is included this early since MD_CAN_XXX macros are defined there. */
#include "mbedtls/md.h"
#if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_RSA_C) || \
!defined(MBEDTLS_MD_CAN_SHA256) || !defined(MBEDTLS_MD_C) || \
!defined(MBEDTLS_FS_IO)
int main(void)
{
mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_RSA_C and/or "
"MBEDTLS_MD_C and/or "
"MBEDTLS_MD_CAN_SHA256 and/or MBEDTLS_FS_IO not defined.\n");
mbedtls_exit(0);
}
#else
#include "mbedtls/rsa.h"
#include <stdio.h>
#include <string.h>
int main(int argc, char *argv[])
{
FILE *f;
int ret = 1;
unsigned c;
int exit_code = MBEDTLS_EXIT_FAILURE;
size_t i;
mbedtls_rsa_context rsa;
mbedtls_mpi N, E;
unsigned char hash[32];
unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
char filename[512];
mbedtls_rsa_init(&rsa);
mbedtls_mpi_init(&N);
mbedtls_mpi_init(&E);
if (argc != 2) {
mbedtls_printf("usage: rsa_verify <filename>\n");
#if defined(_WIN32)
mbedtls_printf("\n");
#endif
goto exit;
}
mbedtls_printf("\n . Reading public key from rsa_pub.txt");
fflush(stdout);
if ((f = fopen("rsa_pub.txt", "rb")) == NULL) {
mbedtls_printf(" failed\n ! Could not open rsa_pub.txt\n" \
" ! Please run rsa_genkey first\n\n");
goto exit;
}
if ((ret = mbedtls_mpi_read_file(&N, 16, f)) != 0 ||
(ret = mbedtls_mpi_read_file(&E, 16, f)) != 0 ||
(ret = mbedtls_rsa_import(&rsa, &N, NULL, NULL, NULL, &E) != 0)) {
mbedtls_printf(" failed\n ! mbedtls_mpi_read_file returned %d\n\n", ret);
fclose(f);
goto exit;
}
fclose(f);
/*
* Extract the RSA signature from the text file
*/
mbedtls_snprintf(filename, sizeof(filename), "%s.sig", argv[1]);
if ((f = fopen(filename, "rb")) == NULL) {
mbedtls_printf("\n ! Could not open %s\n\n", filename);
goto exit;
}
i = 0;
while (fscanf(f, "%02X", (unsigned int *) &c) > 0 &&
i < (int) sizeof(buf)) {
buf[i++] = (unsigned char) c;
}
fclose(f);
if (i != mbedtls_rsa_get_len(&rsa)) {
mbedtls_printf("\n ! Invalid RSA signature format\n\n");
goto exit;
}
/*
* Compute the SHA-256 hash of the input file and
* verify the signature
*/
mbedtls_printf("\n . Verifying the RSA/SHA-256 signature");
fflush(stdout);
if ((ret = mbedtls_md_file(
mbedtls_md_info_from_type(MBEDTLS_MD_SHA256),
argv[1], hash)) != 0) {
mbedtls_printf(" failed\n ! Could not open or read %s\n\n", argv[1]);
goto exit;
}
if ((ret = mbedtls_rsa_pkcs1_verify(&rsa, MBEDTLS_MD_SHA256,
32, hash, buf)) != 0) {
mbedtls_printf(" failed\n ! mbedtls_rsa_pkcs1_verify returned -0x%0x\n\n",
(unsigned int) -ret);
goto exit;
}
mbedtls_printf("\n . OK (the signature is valid)\n\n");
exit_code = MBEDTLS_EXIT_SUCCESS;
exit:
mbedtls_rsa_free(&rsa);
mbedtls_mpi_free(&N);
mbedtls_mpi_free(&E);
mbedtls_exit(exit_code);
}
#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_RSA_C && MBEDTLS_MD_CAN_SHA256 &&
MBEDTLS_FS_IO */
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