Support multi-prime RSA (RFC 8017)

* Introduce RSA_generate_multi_prime_key to generate multi-prime
  RSA private key. As well as the following functions:
    RSA_get_multi_prime_extra_count
    RSA_get0_multi_prime_factors
    RSA_get0_multi_prime_crt_params
    RSA_set0_multi_prime_params
    RSA_get_version
* Support EVP operations for multi-prime RSA
* Support ASN.1 operations for multi-prime RSA
* Support multi-prime check in RSA_check_key_ex
* Support multi-prime RSA in apps/genrsa and apps/speed
* Support multi-prime RSA manipulation functions
* Test cases and documentation are added
* CHANGES is updated

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
(Merged from https://github.com/openssl/openssl/pull/4241)

1 files changed, 12 insertions, 5 deletions

diff --git a/apps/genrsa.c b/apps/genrsa.c
index b4a986cb58..f147852902 100644
--- a/apps/genrsa.c
+++ b/apps/genrsa.c
@@ -27,13 +27,14 @@ NON_EMPTY_TRANSLATION_UNIT
 # include <openssl/rand.h>
 
 # define DEFBITS 2048
+# define DEFPRIMES 2
 
 static int genrsa_cb(int p, int n, BN_GENCB *cb);
 
 typedef enum OPTION_choice {
     OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
     OPT_3, OPT_F4, OPT_ENGINE,
-    OPT_OUT, OPT_PASSOUT, OPT_CIPHER,
+    OPT_OUT, OPT_PASSOUT, OPT_CIPHER, OPT_PRIMES,
     OPT_R_ENUM
 } OPTION_CHOICE;
 
@@ -49,6 +50,7 @@ const OPTIONS genrsa_options[] = {
 # ifndef OPENSSL_NO_ENGINE
     {"engine", OPT_ENGINE, 's', "Use engine, possibly a hardware device"},
 # endif
+    {"primes", OPT_PRIMES, 'p', "Specify number of primes"},
     {NULL}
 };
 
@@ -62,7 +64,7 @@ int genrsa_main(int argc, char **argv)
     const BIGNUM *e;
     RSA *rsa = NULL;
     const EVP_CIPHER *enc = NULL;
-    int ret = 1, num = DEFBITS, private = 0;
+    int ret = 1, num = DEFBITS, private = 0, primes = DEFPRIMES;
     unsigned long f4 = RSA_F4;
     char *outfile = NULL, *passoutarg = NULL, *passout = NULL;
     char *prog, *hexe, *dece;
@@ -108,6 +110,10 @@ opthelp:
             if (!opt_cipher(opt_unknown(), &enc))
                 goto end;
             break;
+        case OPT_PRIMES:
+            if (!opt_int(opt_arg(), &primes))
+                goto end;
+            break;
         }
     }
     argc = opt_num_rest();
@@ -131,13 +137,14 @@ opthelp:
     if (out == NULL)
         goto end;
 
-    BIO_printf(bio_err, "Generating RSA private key, %d bit long modulus\n",
-               num);
+    BIO_printf(bio_err, "Generating RSA private key, %d bit long modulus (%d primes)\n",
+               num, primes);
     rsa = eng ? RSA_new_method(eng) : RSA_new();
     if (rsa == NULL)
         goto end;
 
-    if (!BN_set_word(bn, f4) || !RSA_generate_key_ex(rsa, num, bn, cb))
+    if (!BN_set_word(bn, f4)
+        || !RSA_generate_multi_prime_key(rsa, num, primes, bn, cb))
         goto end;
 
     RSA_get0_key(rsa, NULL, &e, NULL);