msi: Fix NULL dereference in MsiQueryComponentStateW (coverity)

[Nikolay Sivov]

Changelog:
    - Fix NULL dereference in MsiQueryComponentStateW, test added

>From 417ffa5fcc23f3806fe1082e339c94bc5f482513 Mon Sep 17 00:00:00 2001
From: Nikolay Sivov <bunglehead at gmail.com>
Date: Sat, 24 Jan 2009 16:56:49 +0300
Subject:   Fix NULL dereference in MsiQueryComponentStateW

---
 dlls/msi/msi.c       |    2 +-
 dlls/msi/tests/msi.c |    6 ++++++
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/dlls/msi/msi.c b/dlls/msi/msi.c
index 86713fd..9503cf9 100644
--- a/dlls/msi/msi.c
+++ b/dlls/msi/msi.c
@@ -1553,7 +1553,7 @@ UINT WINAPI MsiQueryComponentStateW(LPCWSTR szProductCode,
     TRACE("(%s, %s, %d, %s, %p)\n", debugstr_w(szProductCode),
           debugstr_w(szUserSid), dwContext, debugstr_w(szComponent), pdwState);
 
-    if (!pdwState)
+    if (!pdwState || !szComponent)
         return ERROR_INVALID_PARAMETER;
 
     if (!szProductCode || !*szProductCode || lstrlenW(szProductCode) != GUID_SIZE - 1)
diff --git a/dlls/msi/tests/msi.c b/dlls/msi/tests/msi.c
index 3ce1a0d..5fb4395 100644
--- a/dlls/msi/tests/msi.c
+++ b/dlls/msi/tests/msi.c
@@ -1278,6 +1278,12 @@ static void test_MsiQueryComponentState(void)
     ok(state == INSTALLSTATE_NOTUSED || state == INSTALLSTATE_LOCAL,
        "Expected INSTALLSTATE_NOTUSED or INSTALLSTATE_LOCAL, got %d\n", state);
 
+    /* NULL component, product exists */
+    state = MAGIC_ERROR;
+    r = pMsiQueryComponentStateA(prodcode, NULL, MSIINSTALLCONTEXT_MACHINE, NULL, &state);
+    ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_SUCCESS, got %d\n", r);
+    ok(state == MAGIC_ERROR, "Expected state not changed, got %d\n", state);
+
     res = RegSetValueExA(compkey, prod_squashed, 0, REG_SZ, (const BYTE *)"hi", 2);
     ok(res == ERROR_SUCCESS, "Expected ERROR_SUCCESS, got %d\n", res);
 
-- 
1.5.6.5