From 6a3eccd344e7ad219d088b321af3a63ca9a3cd1c Mon Sep 17 00:00:00 2001
From: Takashi Kojo <kojo@wolfsssl.com>
Date: Sun, 17 Mar 2019 13:28:04 +0900
Subject: [PATCH] add BN_init, working with tfm, only.

---
 src/ssl.c            | 22 ++++++++++++++++++++++
 tests/api.c          | 45 ++++++++++++++++++++++++++++++++++++++++++++
 wolfssl/openssl/bn.h | 14 +++++++++++---
 3 files changed, 78 insertions(+), 3 deletions(-)

diff --git a/src/ssl.c b/src/ssl.c
index 766f55e5d..be6782080 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -22711,20 +22711,28 @@ WOLFSSL_BIGNUM* wolfSSL_BN_new(void)
 
     WOLFSSL_MSG("wolfSSL_BN_new");
 
+#if !defined(USE_FAST_MATH) || defined(HAVE_WOLF_BIGINT)
     mpi = (mp_int*) XMALLOC(sizeof(mp_int), NULL, DYNAMIC_TYPE_BIGINT);
     if (mpi == NULL) {
         WOLFSSL_MSG("wolfSSL_BN_new malloc mpi failure");
         return NULL;
     }
+#endif
 
     external = (WOLFSSL_BIGNUM*) XMALLOC(sizeof(WOLFSSL_BIGNUM), NULL,
                                         DYNAMIC_TYPE_BIGINT);
     if (external == NULL) {
         WOLFSSL_MSG("wolfSSL_BN_new malloc WOLFSSL_BIGNUM failure");
+#if !defined(USE_FAST_MATH) || defined(HAVE_WOLF_BIGINT)
         XFREE(mpi, NULL, DYNAMIC_TYPE_BIGINT);
+#endif
         return NULL;
     }
 
+#if defined(USE_FAST_MATH) && !defined(HAVE_WOLF_BIGINT)
+    mpi = &external->fp;
+#endif
+
     InitwolfSSL_BigNum(external);
     if (mp_init(mpi) != MP_OKAY) {
         wolfSSL_BN_free(external);
@@ -22735,6 +22743,18 @@ WOLFSSL_BIGNUM* wolfSSL_BN_new(void)
     return external;
 }
 
+#if defined(USE_FAST_MATH) && !defined(HAVE_WOLF_BIGINT)
+/* This function works without BN_free only with TFM */
+void wolfSSL_BN_init(WOLFSSL_BIGNUM* bn)
+{
+    if(bn == NULL)return;
+    WOLFSSL_MSG("wolfSSL_BN_init");
+    InitwolfSSL_BigNum(bn);
+    if (mp_init(&bn->fp) != MP_OKAY)
+        return;
+    bn->internal = (void *)&bn->fp;
+}
+#endif
 
 void wolfSSL_BN_free(WOLFSSL_BIGNUM* bn)
 {
@@ -22744,7 +22764,9 @@ void wolfSSL_BN_free(WOLFSSL_BIGNUM* bn)
             mp_int* bni = (mp_int*)bn->internal;
             mp_forcezero(bni);
             mp_free(bni);
+#if !defined(USE_FAST_MATH) || defined(HAVE_WOLF_BIGINT)
             XFREE(bn->internal, NULL, DYNAMIC_TYPE_BIGINT);
+#endif
             bn->internal = NULL;
         }
         XFREE(bn, NULL, DYNAMIC_TYPE_BIGINT);
diff --git a/tests/api.c b/tests/api.c
index 843bf0bf2..1da87d949 100644
--- a/tests/api.c
+++ b/tests/api.c
@@ -18951,6 +18951,51 @@ static void test_wolfSSL_BN(void)
     BN_free(b);
     BN_free(c);
 
+    #if defined(USE_FAST_MATH) && !defined(HAVE_WOLF_BIGINT)
+    {
+        BIGNUM *ap;
+        BIGNUM bv;
+        BIGNUM cv;
+        BIGNUM dv;
+
+        AssertNotNull(ap = BN_new());
+        BN_init(&bv);
+        BN_init(&cv);
+        BN_init(&dv);
+
+        value[0] = 0x3;
+        AssertNotNull(BN_bin2bn(value, sizeof(value), ap));
+
+        value[0] = 0x02;
+        AssertNotNull(BN_bin2bn(value, sizeof(value), &bv));
+
+        value[0] = 0x05;
+        AssertNotNull(BN_bin2bn(value, sizeof(value), &cv));
+
+        /* a^b mod c = */
+        AssertIntEQ(BN_mod_exp(&dv, NULL, &bv, &cv, NULL), WOLFSSL_FAILURE);
+        AssertIntEQ(BN_mod_exp(&dv, ap, &bv, &cv, NULL), WOLFSSL_SUCCESS);
+
+        /* check result  3^2 mod 5 */
+        value[0] = 0;
+        printf("BN_bn2bin = %d\n", BN_bn2bin(&dv, value));
+        AssertIntEQ(BN_bn2bin(&dv, value), WOLFSSL_SUCCESS);
+        AssertIntEQ(BN_bn2bin(&dv, value), SSL_SUCCESS);
+        AssertIntEQ((int)(value[0]), 4);
+
+        /* a*b mod c = */
+        AssertIntEQ(BN_mod_mul(&dv, NULL, &bv, &cv, NULL), SSL_FAILURE);
+        AssertIntEQ(BN_mod_mul(&dv, ap, &bv, &cv, NULL), SSL_SUCCESS);
+
+        /* check result  3*2 mod 5 */
+        value[0] = 0;
+        AssertIntEQ(BN_bn2bin(&dv, value), SSL_SUCCESS);
+        AssertIntEQ((int)(value[0]), 1);
+
+        BN_free(ap);
+    }
+    #endif
+
     printf(resultFmt, passed);
     #endif /* defined(OPENSSL_EXTRA) && !defined(NO_ASN) */
 }
diff --git a/wolfssl/openssl/bn.h b/wolfssl/openssl/bn.h
index d51450e7b..02297d7d2 100644
--- a/wolfssl/openssl/bn.h
+++ b/wolfssl/openssl/bn.h
@@ -37,9 +37,13 @@
     extern "C" {
 #endif
 
-typedef struct WOLFSSL_BIGNUM {
-    int   neg;              /* openssh deference */
-    void* internal;         /* our big num */
+typedef struct WOLFSSL_BIGNUM
+{
+    int neg;        /* openssh deference */
+    void *internal; /* our big num */
+#if defined(USE_FAST_MATH) && !defined(HAVE_WOLF_BIGINT)
+    fp_int fp;
+#endif
 } WOLFSSL_BIGNUM;
 
 
@@ -53,6 +57,9 @@ WOLFSSL_API void           wolfSSL_BN_CTX_init(WOLFSSL_BN_CTX*);
 WOLFSSL_API void           wolfSSL_BN_CTX_free(WOLFSSL_BN_CTX*);
 
 WOLFSSL_API WOLFSSL_BIGNUM* wolfSSL_BN_new(void);
+#if defined(USE_FAST_MATH) && !defined(HAVE_WOLF_BIGINT)
+WOLFSSL_API void           wolfSSL_BN_init(WOLFSSL_BIGNUM *);
+#endif
 WOLFSSL_API void           wolfSSL_BN_free(WOLFSSL_BIGNUM*);
 WOLFSSL_API void           wolfSSL_BN_clear_free(WOLFSSL_BIGNUM*);
 
@@ -126,6 +133,7 @@ typedef WOLFSSL_BN_GENCB BN_GENCB;
 #define BN_CTX_free       wolfSSL_BN_CTX_free
 
 #define BN_new        wolfSSL_BN_new
+#define BN_init       wolfSSL_BN_init
 #define BN_free       wolfSSL_BN_free
 #define BN_clear_free wolfSSL_BN_clear_free