ssh: agent support is incompatible with OpenSSH >= 8.9 (ssh: parse error in message type 27)

[AkihiroSuda]

As of BuildKit v0.10.5, buildctl build --ssh default=$SSH_AUTH_SOCK seems incompatible with OpenSSH 8.9 (https://www.openssh.com/agent-restrict.html).

Any ssh-enabled command such as RUN --mount=type=ssh ssh [email protected] fails with ssh: parse error in message type 27 in the --debug log.

Tried to bump up x/crypto to v0.2.0, but no success; The ssh: parse error in message type 27 error disappears after bumping up x/crypto, but the ssh command still fails with [email protected]: Permission denied (publickey). (EDIT: just forgot to run ssh-add)

Initially reported by several people in golang/go#51689 (comment)

This issue does not affect the non-agent mode (--ssh default=$HOME/.ssh/id_rsa)

[tonistiigi]

What's in v0.10.5 that breaks this?

[AkihiroSuda]

What's in v0.10.5 that breaks this?

Not a regression in v0.10.5.

x/crypto/ssh was incompatible with OpenSSH 8.9, and fixed in golang/crypto@bd7e27e

[AkihiroSuda]

Noticed that my English usage of "as of" was wrong 🙇
https://en.wiktionary.org/wiki/as_of

I meant I just tested v0.10.5