shlexec: Fixes for buffer overrun problems

[Alexandre Julliard]

Andrew de Quincey <adq_dvb at lidskialf.net> writes:

> Hi, this is a cleanup of shell32/shlexec.c to remove potential buffer 
> overruns. I've also tried to make parts of the code a little easier to 
> follow, without affecting the functionality.

It's a very inefficient mechanism, you are reallocating the same
string over and over to append sometimes only a single char. The right
way to avoid overflows is to compute the length of the full string
first and then allocate all the needed space at once.

-- 
Alexandre Julliard
julliard at winehq.com