GSSAPI key exchange support

This patch has been rejected upstream: "None of the OpenSSH developers are
in favour of adding this, and this situation has not changed for several
years.  This is not a slight on Simon's patch, which is of fine quality, but
just that a) we don't trust GSSAPI implementations that much and b) we don't
like adding new KEX since they are pre-auth attack surface.  This one is
particularly scary, since it requires hooks out to typically root-owned
system resources."

However, quite a lot of people rely on this in Debian, and it's better to
have it merged into the main openssh package rather than having separate
-krb5 packages (as we used to have).  It seems to have a generally good
security history.

Author: Simon Wilkinson <simon@sxw.org.uk>
Author: Colin Watson <cjwatson@debian.org>
Author: Jakub Jelen <jjelen@redhat.com>
Origin: other, https://github.com/openssh-gsskex/openssh-gsskex/commits/debian/master
Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1242
Last-Updated: 2020-06-07

Patch-Name: gssapi.patch

1 files changed, 3 insertions, 0 deletions

diff --git a/servconf.h b/servconf.h
index a420f398d..253cad97e 100644
--- a/servconf.h
+++ b/servconf.h
@@ -137,8 +137,11 @@ typedef struct {
         int     kerberos_get_afs_token;         /* If true, try to get AFS token if
                                                  * authenticated with Kerberos. */
         int     gss_authentication;     /* If true, permit GSSAPI authentication */
+        int     gss_keyex;              /* If true, permit GSSAPI key exchange */
         int     gss_cleanup_creds;      /* If true, destroy cred cache on logout */
         int     gss_strict_acceptor;    /* If true, restrict the GSSAPI acceptor name */
+        int     gss_store_rekey;
+        char   *gss_kex_algorithms;     /* GSSAPI kex methods to be offered by client. */
         int     password_authentication;        /* If true, permit password
                                                  * authentication. */
         int     kbd_interactive_authentication; /* If true, permit */