ShellPkg: Add checking for memory allocation and pointer returns from functions.

signed-off-by: jcarsey
reviewed-by: geekboy15a

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12540 6f19259b-4bc3-4df7-8a09-765794883524

ShellPkg/Library/UefiShellLevel2CommandsLib/TimeDate.c

@@ -642,10 +642,15 @@ CheckAndSetTimeZone (
   }
 
   Status = gRT->GetTime(&TheTime, NULL);
-  ASSERT_EFI_ERROR(Status);
+  if (EFI_ERROR(Status)) {
+    return (SHELL_DEVICE_ERROR);
+  }
 
   TimeZoneCopy = NULL;
   TimeZoneCopy = StrnCatGrow(&TimeZoneCopy, NULL, TimeZoneString, 0);
+  if (TimeZoneCopy == NULL) {
+    return (SHELL_OUT_OF_RESOURCES);
+  }
   Walker = TimeZoneCopy;
   Walker2 = StrStr(Walker, L":");
   if (Walker2 != NULL && *Walker2 == L':') {