1 files changed, 134 insertions, 0 deletions
diff --git a/programs/pkey/rsa_verify.c b/programs/pkey/rsa_verify.c
new file mode 100644
index 00000000000..4a9af77faa4
--- /dev/null
+++ b/programs/pkey/rsa_verify.c
@@ -0,0 +1,134 @@
+/*
+ *  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 */