Add RSA key generation example

.gitignore

@@ -220,6 +220,7 @@ pk/ed25519_gen/gen_key_files
 pk/ed25519_gen/sign_and_verify
 pk/ecdh_generate_secret/ecdh_gen_secret
 pk/rsa-kg/rsa-kg-sv
+pk/rsa-kg/rsa-kg
 pk/dh-pg/dh-pg-ka
 pk/test_cert_and_private_keypair/test-cert-privkey-pair
 pk/srp/srp_gen

pk/rsa-kg/Makefile

@@ -2,15 +2,21 @@ CC=gcc
 CFLAGS=-Wall
 LIBS= -lwolfssl -lm
 
-all: rsa-kg-sv
+all: rsa-kg-sv rsa-kg
 
 rsa-kg-sv.o: rsa-kg-sv.c rsa-key.h
 	$(CC) -c -o $@ $< $(CFLAGS)
 
 rsa-kg-sv: rsa-kg-sv.o
-	$(CC) -o $@ $^ $(CFLAGS) $(LIBS) 
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
+
+rsa-kg.o: rsa-kg.c
+	$(CC) -c -o $@ $< $(CFLAGS)
+
+rsa-kg: rsa-kg.o
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
 
 .PHONY: clean
 
 clean:
-	rm -f *.o rsa-kg-sv
+	rm -f *.o rsa-kg-sv rsa-kg

pk/rsa-kg/README.md

@@ -13,6 +13,21 @@ How to use rsa-kg-sv.c
         NOTE: on error, the key and digest will be displayed so that they can be
         copied into rsa-key.h replacing the existing values.
 
-4)  Running 'make clean' will delete the executable and object files.
+3)  Running 'make clean' will delete the executable and object files.
 
 
+How to use rsa-kg.c
+
+1) a. Compile wolfSSL with  ./configure --enable-keygen, run
+      'make', and then install by typing 'sudo make install'.
+   b. In the pk/rsa-kg directory run the Makefile by typing 'make'.
+2)  run the executable, for help run with -help. Basic command is as follows:
+
+        ./rsa-kg <options>
+
+        Key sizes supported, in bits: 1024-4096.
+
+        Specify the name of the output files with -priv and -pub.
+
+3)  Running 'make clean' will delete the executable and object files.
+

pk/rsa-kg/rsa-kg.c

@@ -0,0 +1,243 @@
+/* rsa-kg.c
+ *
+ * Copyright (C) 2006-2020 wolfSSL Inc.
+ *
+ * This file is part of wolfSSL.
+ *
+ * wolfSSL is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * wolfSSL is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
+ */
+
+/*
+* An implementation of RSA key generation using wolfSSL
+* Usage:
+./rsa-kg -priv <private key filename> -pub <public key filename>
+*/
+
+#include <stdio.h>
+#include <string.h>
+
+#include <wolfssl/options.h>
+#include <wolfssl/wolfcrypt/settings.h>
+#include <wolfssl/ssl.h>
+#include <wolfssl/wolfcrypt/rsa.h>
+#include <wolfssl/wolfcrypt/error-crypt.h>
+
+#define MAX_DER_SIZE        2500
+#define MIN_RSA_KEY_SIZE    1024
+#define MAX_RSA_KEY_SIZE    4096
+#define DEF_RSA_KEY_SIZE    2048
+
+static const char* kRsaPubKey = "./rsa-public.der";
+static const char* kRsaPrivKey = "./rsa-private.der";
+
+/* Shows usage information */
+void usage()
+{
+    fprintf(stderr, "rsa_kg <options>:\n");
+    fprintf(stderr, "  -bits <num>       Size in bits of RSA keys generated\n");
+    fprintf(stderr, "                    Range: 1024-4096\n");
+    fprintf(stderr, "  -priv <filename>  Private key filename\n");
+    fprintf(stderr, "  -pub <filename>   Public key filename\n");
+    fprintf(stderr, "\n");
+}
+
+int main(int argc, char** argv)
+{
+/* These examples require RSA and Key Gen */
+#if !defined(NO_RSA) && defined(WOLFSSL_KEY_GEN)
+    RsaKey* pRsaKey = NULL;
+    WC_RNG rng;
+    int ret = 0;
+    int bits = DEF_RSA_KEY_SIZE;
+    int sz;
+    unsigned char derBuf[MAX_DER_SIZE];
+    FILE* f;
+    const char* pubKey = kRsaPubKey;
+    const char* privKey = kRsaPrivKey;
+
+    argc--;
+    argv++;
+    while (argc > 0) {
+        /* Number of bits in RSA key to generate */
+        if (XSTRNCMP(*argv, "-bits", 6) == 0) {
+            ++argv;
+            if (--argc == 0) {
+                fprintf(stderr, "Missing bits value\n");
+                usage();
+                return 1;
+            }
+            bits = atoi(*argv);
+        }
+        else if (XSTRNCMP(*argv, "-priv", 6) == 0) {
+            ++argv;
+            if (--argc == 0) {
+                fprintf(stderr, "Missing private key filename\n");
+                usage();
+                return 1;
+            }
+            privKey = *argv;
+        }
+        else if (XSTRNCMP(*argv, "-pub", 6) == 0) {
+            ++argv;
+            if (--argc == 0) {
+                fprintf(stderr, "Missing public key filename\n");
+                usage();
+                return 1;
+            }
+            pubKey = *argv;
+        }
+        else if (XSTRNCMP(*argv, "-help", 6) == 0) {
+            usage();
+            return 0;
+        }
+        else {
+            fprintf(stderr, "Unrecognized option: %s\n", *argv);
+            usage();
+            return 1;
+        }
+
+        argc--;
+        argv++;
+    }
+
+    /* Check bit count if generating keys */
+    if ((bits < MIN_RSA_KEY_SIZE || bits > MAX_RSA_KEY_SIZE)) {
+        fprintf(stderr, "Bits out of range (%d-%d): %d\n", MIN_RSA_KEY_SIZE,
+                MAX_RSA_KEY_SIZE, bits);
+        usage();
+        return 1;
+    }
+#ifdef WOLFSSL_SP_MATH
+    if (0) {
+    }
+#ifndef WOLFSSL_SP_NO_2048
+    else if (bits == 2048) {
+    }
+#endif
+#ifndef WOLFSSL_SP_NO_3072
+    else if (bits == 3072) {
+    }
+#endif
+#ifdef WOLFSSL_SP_4096
+    else if (bits == 4096) {
+    }
+#endif
+    else {
+        fprintf(stderr, "Bit size not supported with SP_MATH: %d\n", bits);
+        fprintf(stderr, " wolfSSL compiled to support, in bits:");
+#ifndef WOLFSSL_SP_NO_2048
+        fprintf(stderr, " 2048");
+#endif
+#ifndef WOLFSSL_SP_NO_3072
+        fprintf(stderr, " 3072");
+#endif
+#ifdef WOLFSSL_SP_4096
+        fprintf(stderr, " 4096");
+#endif
+        fprintf(stderr, "\n");
+        return 1;
+    }
+#endif
+
+    wolfSSL_Debugging_ON();
+
+    wolfSSL_Init();
+
+    /* Allocate space for RSA key object. */
+    pRsaKey = malloc(sizeof(RsaKey));
+    if (!pRsaKey) {
+        printf("RSA_generate_key failed with error\n");
+        return MEMORY_E;
+    }
+
+    /* Create a random number generator for key generation. */
+    ret = wc_InitRng(&rng);
+    if (ret != 0) {
+        printf("Init RNG failed %d\n", ret);
+        free(pRsaKey);
+        return ret;
+    }
+
+    /* Initialize RSA key object. */
+    ret = wc_InitRsaKey(pRsaKey, NULL);
+    if (ret != 0) {
+        printf("Init RSA key failed %d\n", ret);
+        wc_FreeRng(&rng);
+        free(pRsaKey);
+        return ret;
+    }
+
+    printf("Generating RSA key\n");
+
+    /* Generate an RSA key pair. */
+    if (wc_MakeRsaKey(pRsaKey, bits, WC_RSA_EXPONENT, &rng) != 0) {
+        printf("failed to create rsa key\n");
+    }
+    else {
+        /* Open public key file. */
+        f = fopen(pubKey, "wb");
+        printf("writing public key to %s\n", pubKey);
+        if (f == NULL) {
+            printf("unable to write out public key\n");
+        }
+        else {
+            /* Encode public key to DER. */
+            sz = wc_RsaKeyToPublicDer(pRsaKey, derBuf, sizeof(derBuf));
+            if (sz <= 0) {
+                printf("error with rsa to public der %d\n", sz);
+            }
+            else {
+                /* Write DER encoded public key to file. */
+                fwrite(derBuf, 1, sz, f);
+            }
+            fclose(f);
+        }
+
+        /* Open private key file. */
+        f = fopen(privKey, "wb");
+        printf("writing public key to %s\n", privKey);
+        if (f == NULL) {
+            printf("unable to write out public key\n");
+        }
+        else {
+            /* Encode private key to DER. */
+            sz = wc_RsaKeyToDer(pRsaKey, derBuf, sizeof(derBuf));
+            if (sz <= 0) {
+                printf("error with rsa to public der %d\n", sz);
+            }
+            else {
+                /* Write DER encoded private key to file. */
+                fwrite(derBuf, 1, sz, f);
+            }
+            fclose(f);
+        }
+    }
+
+    /* Dispose of allocated memory. */
+    wc_FreeRsaKey(pRsaKey);
+    wc_FreeRng(&rng);
+    free(pRsaKey);
+    wolfSSL_Cleanup();
+
+    return 0;
+#else
+    (void)kRsaPubKey;
+    (void)kRsaPrivKey;
+
+    printf("wolfSSL missing build features.\n");
+    printf("Please build using `./configure --enable-keygen`\n");
+    return 1;
+#endif
+}