RSA: verify only build fixes

configuration: --disable-ecc --disable-dh --disable-aes --disable-aesgcm
--disable-sha512 --disable-sha384 --disable-sha --disable-poly1305
--disable-chacha --disable-md5 --disable-sha3 --enable-cryptonly
--disable-inline --enable-rsavfy --disable-asn --disable-oaep
--disable-rng --disable-filesystem --enable-sp=rsa2048 --enable-sp-math
Fixes to make code build again.

wolfcrypt/src/coding.c

@@ -100,7 +100,7 @@ static WC_INLINE byte Base64_Char2Val(byte c)
     byte mask;
 
     c -= BASE64_MIN;
-    mask = ctMaskLTE(c, 0x3f);
+    mask = (((byte)(0x3f - c)) >> 7) - 1;
     /* Load a value from the first cache line and use when mask set. */
     v  = base64Decode[ c & 0x3f        ] &   mask ;
     /* Load a value from the second cache line and use when mask not set. */

wolfcrypt/src/sp_int.c

@@ -2152,7 +2152,6 @@ int sp_grow(sp_int* a, int l)
 }
 #endif /* !WOLFSSL_RSA_VERIFY_ONLY || !NO_DH || HAVE_ECC */
 
-#if !defined(WOLFSSL_RSA_VERIFY_ONLY) || defined(WOLFSSL_KEY_GEN)
 /* Set the multi-precision number to zero.
  *
  * Assumes a is not NULL.
@@ -2167,7 +2166,6 @@ static void _sp_zero(sp_int* a)
     a->sign = MP_ZPOS;
 #endif
 }
-#endif /* !WOLFSSL_RSA_VERIFY_ONLY || WOLFSSL_KEY_GEN */
 
 #if !defined(WOLFSSL_RSA_VERIFY_ONLY)
 /* Set the multi-precision number to zero.
@@ -2222,8 +2220,7 @@ void sp_forcezero(sp_int* a)
 #endif /* !WOLFSSL_RSA_VERIFY_ONLY || !NO_DH || HAVE_ECC */
 
 #if defined(WOLSSL_SP_MATH_ALL) || !defined(NO_DH) || defined(HAVE_ECC) || \
-    (!defined(NO_RSA) && !defined(WOLFSSL_RSA_VERIFY_ONLY)) || \
+    !defined(NO_RSA)
-    defined(SQR_MUL_ASM)
 /* Copy value of multi-precision number a into r.
  *
  * @param  [in]   a  SP integer - source.
@@ -7684,6 +7681,7 @@ int sp_mul(sp_int* a, sp_int* b, sp_int* r)
 }
 /* END SP_MUL implementations. */
 
+#if !defined(WOLFSSL_RSA_VERIFY_ONLY)
 /* Multiply a by b mod m and store in r: r = (a * b) mod m
  *
  * @param  [in]   a  SP integer to multiply.
@@ -7738,6 +7736,7 @@ int sp_mulmod(sp_int* a, sp_int* b, sp_int* m, sp_int* r)
 #endif
     return err;
 }
+#endif /* !WOLFSSL_RSA_VERIFY_ONLY */
 
 #if defined(HAVE_ECC) || !defined(NO_DSA) || defined(OPENSSL_EXTRA) || \
     (!defined(NO_RSA) && !defined(WOLFSSL_RSA_VERIFY_ONLY))

wolfcrypt/test/test.c

@@ -13236,7 +13236,9 @@ static int rsa_even_mod_test(WC_RNG* rng, RsaKey* key)
     size_t bytes;
     int    ret;
     word32 inLen   = 0;
+#ifndef NO_ASN
     word32 idx     = 0;
+#endif
     word32 outSz   = RSA_TEST_BYTES;
     word32 plainSz = RSA_TEST_BYTES;
 #if !defined(USE_CERT_BUFFERS_2048) && !defined(USE_CERT_BUFFERS_3072) && \
@@ -13289,10 +13291,28 @@ static int rsa_even_mod_test(WC_RNG* rng, RsaKey* key)
     ERROR_OUT(-7802, exit_rsa_even_mod);
 #endif /* USE_CERT_BUFFERS */
 
+#ifndef NO_ASN
     ret = wc_RsaPrivateKeyDecode(tmp, &idx, key, (word32)bytes);
     if (ret != 0) {
         ERROR_OUT(-7804, exit_rsa_even_mod);
     }
+#else
+    #ifdef USE_CERT_BUFFERS_2048
+        ret = mp_read_unsigned_bin(&key->n, &tmp[12], 256);
+        if (ret != 0) {
+            ERROR_OUT(-7804, exit_rsa_even_mod);
+        }
+        ret = mp_set_int(&key->e, WC_RSA_EXPONENT);
+        if (ret != 0) {
+            ERROR_OUT(-7804, exit_rsa_even_mod);
+        }
+#ifndef NO_SIG_WRAPPER
+        modLen = 2048;
+#endif
+    #else
+        #error Not supported yet!
+    #endif
+#endif
 
     key->n.dp[0] &= (mp_digit)-2;
     if (ret != 0) {
@@ -13346,6 +13366,13 @@ exit_rsa_even_mod:
     FREE_VAR(out, HEAP_HINT);
     FREE_VAR(plain, HEAP_HINT);
 
+    (void)out;
+    (void)outSz;
+    (void)plain;
+    (void)plainSz;
+    (void)inLen;
+    (void)rng;
+
     return ret;
 }
 #endif /* WOLFSSL_HAVE_SP_RSA */