Re: t7528-signed-commit-ssh.sh fails due to ssh-agent fails to start with ENAMETOOLONG

[Junio C Hamano <gitster@pobox.com>]

Jeff King <peff@peff.net> writes:

> AFAICT, ssh-agent does not quote the path in its output. So for example:
>
>   d='/tmp/has spaces'
>   mkdir "$d"
>   HOME=$d ssh-agent
>
> will produce:
>
>   SSH_AUTH_SOCK=/tmp/has spaces/.ssh/agent/s.IcPuGe26YY.agent.6PtD3uhM4O; export SSH_AUTH_SOCK;
>
> which is nonsense to eval.

So if $d were

    d='/tmp/has rm -rf in it'

would that produce some interesting side effect?

> I expected that would cause ssh-add to fail, since our SSH_AUTH_SOCK
> would point to truncated garbage, and we can't talk to the agent. But it
> doesn't even do that. The extra space turns that line from a variable
> assignment into a one-shot variable attached to a command that fails to
> run. And so we're left with the original SSH_AUTH_SOCK from the
> environment, the one in my real $HOME outside of the trash directory.
> Yikes!
>
> If I unset SSH_AUTH_SOCK in my environment, then the test consistently
> fails. But I'm somewhat amazed that nobody has complained about this
> before. Surely somebody somewhere (especially CI!) is running t7528
> without SSH_AUTH_SOCK set in the environment. Which makes wonder if I'm
> missing something.
>
> -Peff