Re: [PATCH] GNU canonicalize_file_name can return a NULL pointer

[Frank Terbeck <ft@bewatermyfriend.org>]

Timothy Redaelli wrote:
> In Src/hist.c on line 1668 there is a NULL pointer dereference because
> GNU canonicalize_file_name returns NULL on some errors.
>
> In attachment you will find a small patch that fixes that bug.

Thanks!

I've looked at the code and it bails out for a couple of errors in
`errno'. I've looked at how canonicalize_file_name() is implemented by
glibc, and it's just a short hand for "realpath(foo, NULL)". So at least
on GNU systems the errors from realpath(3) apply to
canonicalize_file_name(), too. Here's the current standard:

<http://pubs.opengroup.org/onlinepubs/9699919799/functions/realpath.html>

I don't know if it's worth checking all those or just go with bailing
out if `real' is NULL.

Both HAVE_REALPATH and HAVE_CANONICALIZE_FILE_NAME use a `real' pointer,
so I think the "if (!null)" test should be in there unconditionally,
without the `#ifdef'.

Comments?

Regards, Frank