shlwapi: Check for NULL string in UrlIs.

dlls/shlwapi/tests/url.c

@@ -1048,6 +1048,15 @@ static void test_UrlCreateFromPath(void)
 
 /* ########################### */
 
+static void test_UrlIs_null(DWORD flag)
+{
+    BOOL ret;
+    ret = pUrlIsA(NULL, flag);
+    ok(ret == FALSE, "pUrlIsA(NULL, %d) failed\n", flag);
+    ret = pUrlIsW(NULL, flag);
+    ok(ret == FALSE, "pUrlIsW(NULL, %d) failed\n", flag);
+}
+
 static void test_UrlIs(void)
 {
     BOOL ret;
@@ -1059,6 +1068,14 @@ static void test_UrlIs(void)
         return;
     }
 
+    test_UrlIs_null(URLIS_APPLIABLE);
+    test_UrlIs_null(URLIS_DIRECTORY);
+    test_UrlIs_null(URLIS_FILEURL);
+    test_UrlIs_null(URLIS_HASQUERY);
+    test_UrlIs_null(URLIS_NOHISTORY);
+    test_UrlIs_null(URLIS_OPAQUE);
+    test_UrlIs_null(URLIS_URL);
+
     for(i = 0; i < sizeof(TEST_PATH_IS_URL) / sizeof(TEST_PATH_IS_URL[0]); i++) {
 	MultiByteToWideChar(CP_ACP, 0, TEST_PATH_IS_URL[i].path, -1, wurl, 80);
 

dlls/shlwapi/url.c

@@ -1719,6 +1719,9 @@ BOOL WINAPI UrlIsA(LPCSTR pszUrl, URLIS Urlis)
 
     TRACE("(%s %d)\n", debugstr_a(pszUrl), Urlis);
 
+    if(!pszUrl)
+        return FALSE;
+
     switch (Urlis) {
 
     case URLIS_OPAQUE:
@@ -1769,6 +1772,9 @@ BOOL WINAPI UrlIsW(LPCWSTR pszUrl, URLIS Urlis)
 
     TRACE("(%s %d)\n", debugstr_w(pszUrl), Urlis);
 
+    if(!pszUrl)
+        return FALSE;
+
     switch (Urlis) {
 
     case URLIS_OPAQUE: