Re: [Monotone-devel] Re: bug report ver 0.16, on windows

[Jon Bright]

graydon hoare wrote:
> Jon Bright wrote:
>
> > Where are fork() and wait() being used?  Should I maybe look at adding 
> > a forkandexec() call (which is supported everywhere), since Windows 
> > has no fork() ?  wait() could then be used with the result of that...
>
>
> perhaps. we will need help with this, because it's used to implement the 
> execution of mergers and editors from lua. see "execute" in 
> std_hooks.lua. we used to call system(...), but this of course permitted 
> shell attacks by mangling shell scripts into filenames. joy. so now we 
> use fork+exec. something similar -- so long as it doesn't call shell -- 
> would be fine by me.

My basic idea would be to implement using CreateProcess() on Windows, 
and just call down to fork/exec on Unix-like systems.  I don't *think* 
calling CreateProcess() is abusable (other than maybe by getting a 
trojan before the intended .exe in the PATH, but if the attacker can do 
this, you've got bigger problems).

I haven't worked together the promised patch yet because I've become 
sidetracked with doing a VC++ port (which is going moderately well, but 
will need a bit of discussion here, probably).  I'll try and get to the 
patch tomorrow and I'll then do an implementation of forkandexec() to 
see if it meets with approval.

--
Jon Bright
Silicon Circus Ltd.
http://www.siliconcircus.com