Re: [PATCH] ssh signing: better error message when key not in agent

From: Adam Szkoda <adaszko@gmail.com>
Date: Jan 18, 2023, 15:28 UTC
Message-ID: <CAEroKagqxC86X0SD8=tK0w+yXL7QecZ+z_7sja-K6ajs0=Z=BQ@mail.gmail.com>
In-Reply-To: <8025d5c7-ab55-c533-1997-05b4c7339d61@dunelm.org.uk>

Hi Phillip,

Good point! My first thought is to try doing a stat() syscall on the path from 'user.signingKey' to see if it exists and if not, treat it as a public key (and pass the -U option). If that sounds reasonable, I can update the patch.

Best — Adam

On Wed, Jan 18, 2023 at 3:34 PM Phillip Wood <phillip.wood123@gmail.com> wrote:

Show 24 quoted lines

>
> On 18/01/2023 11:10, Phillip Wood wrote:
> >> the agent [1].  A fix is scheduled to be released in OpenSSH 9.1. All
> >> that
> >> needs to be done is to pass an additional backward-compatible option
> >> -U to
> >> 'ssh-keygen -Y sign' call.  With '-U', ssh-keygen always interprets
> >> the file
> >> as public key and expects to find the private key in the agent.
> >
> > The documentation for user.signingKey says
> >
> >   If gpg.format is set to ssh this can contain the path to either your
> > private ssh key or the public key when ssh-agent is used.
> >
> > If I've understood correctly passing -U will prevent users from setting
> > this to a private key.
>
> If there is an easy way to tell if the user has given us a public key
> then we could pass "-U" in that case.
>
> Best Wishes
>
> Phillip