282806 - Using _alloca in a loop can overflow stack warning in nsDispatchSupport.cpp

Status: RESOLVED WORKSFORME

(Core :: XPConnect, defect)

Description

[David Gardiner]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.5) Gecko/20041107 Firefox/1.0

PREfast static code analysis warning:

nsdispatchsupport.cpp(78) : warning 263: Using _alloca in a loop. This can
quickly overflow stack.
problem occurs in function 'ClassIsListed'

Line 78 is this:

if(SUCCEEDED(::CLSIDFromString(T2OLE(szCLSID), &clsidToCompare)) && 

I think this is related to the T2OLE macro.

In
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclib/html/_atl_string_conversion_macros.asp
they mention that the ATL 7.0 macros are better behaved. Not sure if we can
require ATL 7.0 though.

-dave

Reproducible: Always

Steps to Reproduce:

Comment 1

[Brendan Eich [:brendan]]

Reporter, please file xpconnect bugs against their component.

/be

Comment 2

[David Bradley]

That conversion should be moved outside of the loop. I'll post a patch 
shortly. It's such an innocent looking macro. What it actually does is 
allocate space on the stack for each invocation and that doesn't get released 
until the function exists.

Comment 3

[David Gardiner]

Sorry about picking the wrong component - I knew the code was in the JS
hierarchy, and even checked Bugzilla's component descriptions (but i only looked
around the Javascript one :-( ). It might be worth updating the Javascript
description to note that XPConnect has a separate component.

-dave

Comment 4

[Andrew McCreight [:mccr8]]

I don't see T2OLE anywhere.