Re: input validation in receive-pack

On Tue, Jan 01, 2008 at 07:07:25PM -0800, Junio C Hamano wrote:

mkoegler@auto.tuwien.ac.at (Martin Koegler) writes:

quoted

Some lines above:
|        if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
|                error("refusing to create funny ref '%s' remotely", name);
|                return "funny refname";
|        }

Is this code really correct?

Interesting.  Things have been this way forever, I think.  I do
not offhand see any reason not to refuse refs outside refs/, so
you can try 

	if (prefixcmp(name, "refs/") || check_ref_format(name +	5))

and see what happens. 

I tried this and it passed the test suite.

 Some people may however want to push to
HEAD (that is ".git/HEAD" which is outside ".git/refs"), though.

If pushing to HEAD is allowed, it bypasses the fast-forward check.

As minimum,
if (check_ref_format(name))
should be safer, as it rejects totally invalid refnames (especially ../[...]).

Are there more refs outside "refs/", which somebody would want to push to?
If not, the following patch could work:

if (!strcmp(name, "HEAD") && 
   (prefixcmp(name, "refs/") || check_ref_format(name+5))) {
  [..error..]
}

if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
    !is_null_sha1(old_sha1) &&
    (!prefixcmp(name, "refs/heads/")||!strcmp(name, "HEAD")) {
[...]
}

mfg Martin Kögler