openssh diff stable/14 10.1p1 vs stable/15 10.1p1

[emaste]

Summary

We have some changes in stable/14's ssh that have been removed upstream. To validate the MFC this is a diff of my proposed update against stable/15 at 687a0d4a6b2391cd045951e4e431dd585d131575 ("OpenSSH: Update to 10.1p1")

[emaste]

Note that DSA support was disabled in 0b707d5fe8b6b1920eb29c6375a6be92b7e44758 in early 2025 (prior to 15.x).
This MFC would remove the code in 14.x. We need to decide between:

• merging 0b707d5fe8b6b1920eb29c6375a6be92b7e44758 and related changes to disable DSA support in 14.x
• leaving the DSA support in place as a local patch set for the duration of 14.x

[emaste]

The removal in openssh-portable is:

commit a32d28d792567253bb601362f36391f155f8f772
Author: [e-mail] <[e-mail]>
Date:   Tue May 6 05:40:56 2025 +0000

    upstream: finally remove DSA signature support from OpenSSH.
    
    feedback/ok tb@, ok deraadt@
    
    OpenBSD-Commit-ID: bfe6ee73c1b676c81a2901030c791f8ec888228f

Conflicts trying to apply this:

both modified:   crypto/openssh/PROTOCOL
both modified:   crypto/openssh/authfd.c
both modified:   crypto/openssh/authfile.c
both modified:   crypto/openssh/dns.c
both modified:   crypto/openssh/pathnames.h
both modified:   crypto/openssh/readconf.c
both modified:   crypto/openssh/ssh-add.c
both modified:   crypto/openssh/ssh-keygen.c
both modified:   crypto/openssh/ssh-keyscan.c
both modified:   crypto/openssh/ssh-keysign.c
both modified:   crypto/openssh/ssh.c
both modified:   crypto/openssh/sshconnect.c
both modified:   crypto/openssh/sshd-auth.c
both modified:   crypto/openssh/sshd-session.c
both modified:   crypto/openssh/sshd.c
both modified:   crypto/openssh/sshkey.c
both modified:   crypto/openssh/sshkey.h