Re: [PATCH 7/9] fsck: consider gpgsig headers expected in tags

From: brian m. carlson <sandals@crustytoothpaste.net>
Date: Sep 22, 2025, 21:38 UTC
Message-ID: <aNHB4V7figj9lmfk@fruit.crustytoothpaste.net>
In-Reply-To: <xmqqecs2yq83.fsf@gitster.g>

On 2025-09-19 at 23:31:08, Junio C Hamano wrote:

Show 5 quoted lines

> Could you wrap this overly long line?
> 
> 	if (buffer < buffer_end && 
> 	    (skip_prefix(buffer, "gpgsig ", &buffer) ||
> 	     skip_prefix(buffer, "gpgsig-sha256 ", &buffer))) {

Will fix in v2.

Show 9 quoted lines

> Do we allow a tag object with both "gpgsig" and "gpgsig-sha256" or
> detect as an error?  I think the most natural way to extend this
> system in the future with a third hash function would be to still
> have the primary hash in the payload and signatures created with
> other compatibility hash functions on the header, so if we were to
> detect, the rule may be "gpgsig* in the headers ought to be unique
> and should not include the primary hash algorithm" plus "if you have
> gpgsig* in the header, the body must also have inline signature, and
> if you don't, the body must not", perhaps?

In v2, I'll make it such that `gpgsig` is allowed only when we're not using SHA-1 and `gpgsig-sha256` is allowed only when we're not using SHA-256. It may be that we don't have a trailing signature, though, since we might turn a SHA-1 tag (signed only with SHA-1) into a SHA-256 tag (which would have only a `gpgsig` header and no trailing SHA-256 signature).

-- 
brian m. carlson (they/them)
Toronto, Ontario, CA