wininet: Avoid crash in InternetCreateUrl with scheme unknown.

dlls/wininet/internet.c

@@ -4405,6 +4405,12 @@ static BOOL calc_url_length(LPURL_COMPONENTSW lpUrlComponents,
     {
         LPCWSTR scheme;
 
+        if (lpUrlComponents->nScheme == INTERNET_SCHEME_UNKNOWN)
+        {
+            INTERNET_SetLastError(ERROR_INVALID_PARAMETER);
+            return FALSE;
+        }
+
         nScheme = lpUrlComponents->nScheme;
 
         if (nScheme == INTERNET_SCHEME_DEFAULT)

dlls/wininet/tests/url.c

@@ -1231,6 +1231,21 @@ static void InternetCreateUrlA_test(void)
     ok(!strcmp(szUrl, CREATE_URL13), "Expected \"%s\", got \"%s\"\n", CREATE_URL13, szUrl);
 
     HeapFree(GetProcessHeap(), 0, szUrl);
+
+    memset(&urlComp, 0, sizeof(urlComp));
+    fill_url_components(&urlComp);
+    urlComp.lpszScheme = NULL;
+    urlComp.dwSchemeLength = 0;
+    urlComp.nScheme = INTERNET_SCHEME_UNKNOWN;
+    len = 256;
+    szUrl = HeapAlloc(GetProcessHeap(), 0, len);
+    SetLastError(0xdeadbeef);
+    ret = InternetCreateUrlA(&urlComp, 0, szUrl, &len);
+    ok(!ret, "Expected failure\n");
+    ok(GetLastError() == ERROR_INVALID_PARAMETER,
+            "Expected ERROR_INVALID_PARAMETER, got %ld\n", GetLastError());
+
+    HeapFree(GetProcessHeap(), 0, szUrl);
 }
 
 static void InternetCanonicalizeUrl_test(void)