[PATCH 03/17] shell32/autocomplete: Handle heap_alloc failure and avoid a potential buffer overflow

[Huw Davies]

On 6 Sep 2018, at 16:05, Gabriel Ivăncescu <gabrielopcode at gmail.com> wrote:
> 
> On Thu, Sep 6, 2018 at 5:51 PM, Huw Davies <huw at codeweavers.com> wrote:
>> 
>> What does Windows do if it's passed %12s for example?
>> 
>> Huw.
> 
> On Windows XP it works fine (Internet Explorer uses it) and shows what
> you'd expect from %12s. It's mostly for user interaction anyway, so I
> think Microsoft have some leeway in changing it in each version.
> 
> That being said, I honestly don't think that copying security
> vulnerabilities from Windows is a good idea, even if it's technically
> "correct". It's not a good idea to crash on such invalid input in my
> opinion, even if an (unpatched?) Windows version does, especially
> since said input is external to the application.

I suggest we do the sprintf ourselves.  All we'd need to do
is replace the first occurrence of '%s' with the appropriate
string.  We can ignore width/precision specifiers for now
unless we find that an app actually depends on them.

Huw.