add BN_mod_mul

src/ssl.c

@@ -18497,6 +18497,31 @@ int wolfSSL_BN_mod_exp(WOLFSSL_BIGNUM *r, const WOLFSSL_BIGNUM *a,
     return WOLFSSL_FAILURE;
 }
 
+/* r = (a * p) % m */
+int wolfSSL_BN_mod_mul(WOLFSSL_BIGNUM *r, const WOLFSSL_BIGNUM *a,
+        const WOLFSSL_BIGNUM *p, const WOLFSSL_BIGNUM *m, WOLFSSL_BN_CTX *ctx)
+{
+    int ret;
+
+    WOLFSSL_ENTER("wolfSSL_BN_mod_mul");
+
+    (void) ctx;
+    if (r == NULL || a == NULL || p == NULL || m == NULL) {
+        WOLFSSL_MSG("Bad Argument");
+        return SSL_FAILURE;
+    }
+
+    if ((ret = mp_mulmod((mp_int*)a->internal,(mp_int*)p->internal,
+               (mp_int*)m->internal, (mp_int*)r->internal)) == MP_OKAY) {
+        return SSL_SUCCESS;
+    }
+
+    WOLFSSL_LEAVE("wolfSSL_BN_mod_mul", ret);
+    (void)ret;
+
+    return SSL_FAILURE;
+}
+
 const WOLFSSL_BIGNUM* wolfSSL_BN_value_one(void)
 {
     static WOLFSSL_BIGNUM* bn_one = NULL;

tests/api.c

@@ -10293,7 +10293,17 @@ static void test_wolfSSL_BN(void)
     /* check result  3^2 mod 5 */
     value[0] = 0;
     AssertIntEQ(BN_bn2bin(d, value), WOLFSSL_SUCCESS);
-    AssertIntEQ((int)(value[0] & 0x04), 4);
+    AssertIntEQ(BN_bn2bin(d, value), SSL_SUCCESS);
+    AssertIntEQ((int)(value[0]), 4);
+
+    /* a*b mod c = */
+    AssertIntEQ(BN_mod_mul(d, NULL, b, c, NULL), SSL_FAILURE);
+    AssertIntEQ(BN_mod_mul(d, a, b, c, NULL), SSL_SUCCESS);
+
+    /* check result  3*2 mod 5 */
+    value[0] = 0;
+    AssertIntEQ(BN_bn2bin(d, value), SSL_SUCCESS);
+    AssertIntEQ((int)(value[0]), 1);
 
     /* BN_mod_inverse test */
     value[0] = 0;

wolfssl/openssl/bn.h

@@ -37,6 +37,8 @@ WOLFSSL_API int wolfSSL_BN_mod(WOLFSSL_BIGNUM*, const WOLFSSL_BIGNUM*,
                              const WOLFSSL_BIGNUM*, const WOLFSSL_BN_CTX*);
 WOLFSSL_API int wolfSSL_BN_mod_exp(WOLFSSL_BIGNUM *r, const WOLFSSL_BIGNUM *a,
         const WOLFSSL_BIGNUM *p, const WOLFSSL_BIGNUM *m, WOLFSSL_BN_CTX *ctx);
+WOLFSSL_API int wolfSSL_BN_mod_mul(WOLFSSL_BIGNUM *r, const WOLFSSL_BIGNUM *a,
+        const WOLFSSL_BIGNUM *b, const WOLFSSL_BIGNUM *m, WOLFSSL_BN_CTX *ctx);
 WOLFSSL_API const WOLFSSL_BIGNUM* wolfSSL_BN_value_one(void);
 
 
@@ -112,6 +114,7 @@ typedef WOLFSSL_BN_GENCB BN_GENCB;
 
 #define BN_mod       wolfSSL_BN_mod
 #define BN_mod_exp   wolfSSL_BN_mod_exp
+#define BN_mod_mul   wolfSSL_BN_mod_mul
 #define BN_sub       wolfSSL_BN_sub
 #define BN_value_one wolfSSL_BN_value_one