Enhancement / cleanup of the "wc_ecc_make_key_ex" API so it can be used with "keysize" or "dp" and allows compatibility with existing "wc_ecc_make_key". Note: "wc_ecc_make_key_ex" was not previously public, so changing it at this point is okay.

wolfcrypt/src/ecc.c

@@ -1624,9 +1624,10 @@ int wc_ecc_point_is_at_infinity(ecc_point* p)
 }
 
 
-int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp)
+int wc_ecc_make_key_ex(WC_RNG* rng, int keysize, ecc_key* key,
+                       const ecc_set_type* dp)
 {
-   int            err;
+    int            err, x;
     ecc_point*     base = NULL;
     mp_int         prime;
     mp_int         a;
@@ -1636,10 +1637,29 @@ int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp)
 #else
     byte           buf[ECC_MAXSIZE_GEN];
 #endif
-   int            keysize;
 
-   if (key == NULL || rng == NULL || dp == NULL)
+    if (key == NULL || rng == NULL || (keysize <= 0 && dp == NULL)) {
-       return ECC_BAD_ARG_E;
+        return BAD_FUNC_ARG;
+    }
+
+    /* determine curve type/index */
+    if (dp == NULL) {
+        /* find key size */
+        for (x = 0; (keysize > ecc_sets[x].size) && 
+            (ecc_sets[x].size != 0); x++);
+        keysize = ecc_sets[x].size;
+
+        if (keysize > ECC_MAXSIZE || ecc_sets[x].size == 0) {
+            return BAD_FUNC_ARG;
+        }
+        dp = &ecc_sets[x];
+    }
+    else {
+        x = ECC_CUSTOM_IDX;
+    }
+
+    key->idx = x;
+    key->dp  = dp;
 
 #ifdef WOLFSSL_SMALL_STACK
     buf = (byte*)XMALLOC(ECC_MAXSIZE_GEN, NULL, DYNAMIC_TYPE_TMP_BUFFER);
@@ -1647,9 +1667,6 @@ int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp)
         return MEMORY_E;
 #endif
 
-   key->idx = ECC_CUSTOM_IDX;
-   key->dp  = dp;
-
     /*generate 8 extra bytes to mitigate bias from the modulo operation below*/
     /*see section A.1.2 in 'Suite B Implementor's Guide to FIPS 186-3 (ECDSA)'*/
     keysize  = dp->size + 8;
@@ -1712,6 +1729,7 @@ int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp)
         if (mp_cmp(&key->k, &order) != MP_LT)
             err = mp_mod(&key->k, &order, &key->k);
     }
+
     /* make the public key */
     if (err == MP_OKAY)
         err = wc_ecc_mulmod_ex(&key->k, base, &key->pubkey, &a, &prime, 1,
@@ -1757,23 +1775,7 @@ int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp)
  */
 int wc_ecc_make_key(WC_RNG* rng, int keysize, ecc_key* key)
 {
-    int x, err;
+    return wc_ecc_make_key_ex(rng, keysize, key, NULL);
-
-    if (key == NULL || rng == NULL)
-        return ECC_BAD_ARG_E;
-
-    /* find key size */
-    for (x = 0; (keysize > ecc_sets[x].size) && (ecc_sets[x].size != 0); x++)
-        ;
-    keysize = ecc_sets[x].size;
-
-    if (keysize > ECC_MAXSIZE || ecc_sets[x].size == 0) {
-        return BAD_FUNC_ARG;
-    }
-    err = wc_ecc_make_key_ex(rng, key, &ecc_sets[x]);
-    key->idx = x;
-
-    return err;
 }
 
 /* Setup dynamic pointers is using normal math for proper freeing */
@@ -1928,7 +1930,7 @@ int wc_ecc_sign_hash_ex(const byte* in, word32 inlen, WC_RNG* rng,
                     err = RNG_FAILURE_E;
                     break;
                }
-               err = wc_ecc_make_key_ex(rng, &pubkey, key->dp);
+               err = wc_ecc_make_key_ex(rng, 0, &pubkey, key->dp);
                if (err != MP_OKAY) break;
 
                /* find r = x1 mod n */

wolfcrypt/test/test.c

@@ -6703,12 +6703,7 @@ static int ecc_test_curve_size(WC_RNG* rng, int keySize, int testVerifyCount,
     wc_ecc_init(&userB);
     wc_ecc_init(&pubKey);
 
-    if (dp) {
+    ret = wc_ecc_make_key_ex(rng, keySize, &userA, dp);
-        ret = wc_ecc_make_key_ex(rng, &userA, dp);
-    }
-    else {
-        ret = wc_ecc_make_key(rng, keySize, &userA);
-    }
     if (ret != 0)
         ERROR_OUT(-1014, done);
 
@@ -6716,12 +6711,7 @@ static int ecc_test_curve_size(WC_RNG* rng, int keySize, int testVerifyCount,
     if (ret != 0)
         ERROR_OUT(-1023, done);
 
-    if (dp) {
+    ret = wc_ecc_make_key_ex(rng, keySize, &userB, dp);
-        ret = wc_ecc_make_key_ex(rng, &userB, dp);
-    }
-    else {
-        ret = wc_ecc_make_key(rng, keySize, &userB);
-    }
     if (ret != 0)
         ERROR_OUT(-1002, done);
 

wolfssl/wolfcrypt/ecc.h

@@ -179,7 +179,8 @@ extern const ecc_set_type ecc_sets[];
 WOLFSSL_API
 int wc_ecc_make_key(WC_RNG* rng, int keysize, ecc_key* key);
 WOLFSSL_API
-int wc_ecc_make_key_ex(WC_RNG* rng, ecc_key* key, const ecc_set_type* dp);
+int wc_ecc_make_key_ex(WC_RNG* rng, int keysize, ecc_key* key,
+    const ecc_set_type* dp);
 WOLFSSL_API
 int wc_ecc_check_key(ecc_key* key);