Re: "tla build-config" question and suggestion

Ludovic Courtès wrote:
> Hi,
>
> Thomas Lord <[email protected]> writes:
>
>   
>>> Now, it seems that `is_non_upwards_relative_path ()' would also reject
>>> paths like `chbouib/../foo' which theoretically it should accept.  But
>>> well, arguably, that shouldn't be too much of a problem.  ;-)
>>>
>>>       
>> The simpler rule is easy to explain and handling that generality properly
>> would be pretty tricky.
>>     
>
> Well, there are `realpath(3)' (which is specified by SuSv2 [0]) and
> `canonicalize_file_name(3)' (an equivalent GNU extension).  These
> functions handle symlinks as well.
>
> Thus, the "right thing" might be to pass paths through them and then
> check for a common prefix with the (canonicalized) tree root path,
> rather than use `is_non_upwards_relative_path ()'.
>
> This way, Arch would be resistant against maliciously-broken-config
> attacks.  ;-)
>   

Ok, yr just f'ing around now, right? 

I mean, you do understand that the paths in question *don't exist* at the
point in time where canonicalization is desired, right?  And therefore
the functions you mention can not possibly do a Right Thing.  

Yr just baiting me, right?  And, ha!  -- called you out on it.

(Or are you just being sloppy?)

Regards,
-t

> Thanks,
> Ludovic.
>
> [0] http://www.opengroup.org/onlinepubs/007908799/xsh/realpath.html
>
>
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