PuTTY wish pageant-rsa-sha2

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summary: Pageant support for SHA-256/512 RSA signatures, used by e.g. OpenSSH client
class: wish: This is a request for an enhancement.
present-in: 0.70
fixed-in: 13b29008b40249ded5af594b8c93ffb99d79b316 (0.71)

The traditional SSH agent protocol has recently been extended, as documented in draft-miller-ssh-agent, to allow signatures with SHA-256 and SHA-512 ("SHA2") hashes as well as the traditional but weak SHA-1. The client signals this with a 'flags' word that previously didn't exist in the protocol.

Previously, Pageant has ignored this. OpenSSH has apparently been requesting these hashes since 7.2; 7.7 started warning when it didn't get what it asked for from the agent (bz#2799):

agent key RSA SHA256:XXXXXXXXXXXXXXX returned incorrect signature type

This warning could show up for instance in agent forwarding scenarios.

Now Pageant looks at the flag word, returns SHA-256 or SHA-512 signatures if requested, and complains if any of the other flag bits are set.


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Audit trail for this wish.
(last revision of this bug record was at 2019-03-19 00:43:48 +0000)