[PATCH v4 1/1] kernelbase: Check if locale is NULL before using it in Internal_EnumDateFormats().

[Zhiyi Zhang]

From: Zhiyi Zhang

Initialize the calendars variable after checking if locale is NULL before using it to avoid NULL
pointer references. Fix a Excel 2016 crash when formatting dates with the custom format 'ddd'.
It calls EnumDateFormatsExEx() with the 'yi-Hebr' locale, which is added in Win10.

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=55099
---
 dlls/kernel32/tests/locale.c | 33 +++++++++++++++++++++++++++++++++
 dlls/kernelbase/locale.c     |  4 +++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/dlls/kernel32/tests/locale.c b/dlls/kernel32/tests/locale.c
index 5c99e644f15..bebd857dfa4 100644
--- a/dlls/kernel32/tests/locale.c
+++ b/dlls/kernel32/tests/locale.c
@@ -8402,6 +8402,36 @@ static void dump_sortkeys( char *argv[] )
     fclose( f );
 }

+static BOOL CALLBACK EnumDateFormatsExEx_proc(LPWSTR date_format_string, CALID calendar_id, LPARAM lp)
+{
+    return TRUE;
+}
+
+static void test_EnumDateFormatsExEx(void)
+{
+    DWORD error;
+    BOOL ret;
+
+    /* Invalid locale name */
+    ret = EnumDateFormatsExEx(EnumDateFormatsExEx_proc, L"deadbeef", DATE_SHORTDATE, 0);
+    error = GetLastError();
+    ok(!ret, "EnumDateFormatsExEx succeeded.\n");
+    ok(error == ERROR_INVALID_PARAMETER, "Got unexpected error %#lx.\n", error);
+
+    /* yi-Hebr is missing on versions < Win10 */
+    /* Running the following tests will cause other tests that use LOCALE_CUSTOM_UNSPECIFIED to
+     * report yi-Hebr instead the default locale on Windows 10. So run them at the end */
+    ret = EnumDateFormatsExEx(EnumDateFormatsExEx_proc, L"yi-Hebr", DATE_SHORTDATE, 0);
+    error = GetLastError();
+    ok(ret || (!ret && error == ERROR_INVALID_PARAMETER), /* < Win10 */
+       "EnumDateFormatsExEx failed, error %#lx.\n", error);
+
+    ret = EnumDateFormatsExEx(EnumDateFormatsExEx_proc, L"yi-Hebr", DATE_LONGDATE, 0);
+    error = GetLastError();
+    ok(ret || (!ret && error == ERROR_INVALID_PARAMETER), /* < Win10 */
+       "EnumDateFormatsExEx failed, error %#lx.\n", error);
+}
+
 START_TEST(locale)
 {
   char **argv;
@@ -8473,4 +8503,7 @@ START_TEST(locale)
   test_EnumCalendarInfoW();
   test_EnumCalendarInfoExA();
   test_EnumCalendarInfoExW();
+
+  /* Run this test at the end */
+  test_EnumDateFormatsExEx();
 }
diff --git a/dlls/kernelbase/locale.c b/dlls/kernelbase/locale.c
index 45180f4bb8a..e8060fe9205 100644
--- a/dlls/kernelbase/locale.c
+++ b/dlls/kernelbase/locale.c
@@ -4390,7 +4390,7 @@ BOOL WINAPI DECLSPEC_HOTPATCH Internal_EnumDateFormats( DATEFMT_ENUMPROCW proc,
     INT i, j, ret;
     DWORD pos;
     const struct calendar *cal;
-    const USHORT *calendars = locale_strings + locale->scalendartype;
+    const USHORT *calendars;
     const DWORD *array;

if (!proc || !locale)
@@ -4399,6 +4399,8 @@ BOOL WINAPI DECLSPEC_HOTPATCH Internal_EnumDateFormats( DATEFMT_ENUMPROCW proc,
         return FALSE;
     }

+    calendars = locale_strings + locale->scalendartype;
+
     switch (flags & ~LOCALE_USE_CP_ACP)
     {
     case 0: