+validate_monkeysphere() {
+ local hostKey
+
+ # specify keyserver checking. the behavior of this proxy command
+ # is intentionally different than that of running monkeyesphere
+ # normally, and keyserver checking is intentionally done under
+ # certain circumstances. This can be overridden by setting the
+ # MONKEYSPHERE_CHECK_KEYSERVER environment variable, or by setting
+ # the CHECK_KEYSERVER variable in the monkeysphere.conf file.
+
+ # if the host is in the gpg keyring...
+ if gpg_user --list-key ="${URI}" &>/dev/null ; then
+ # do not check the keyserver
+ CHECK_KEYSERVER=${CHECK_KEYSERVER:="false"}
+
+ # if the host is NOT in the keyring...
+ else
+ # FIXME: what about system-wide known_hosts file (/etc/ssh/known_hosts)?
+
+ if [ -r "$KNOWN_HOSTS" ]; then
+ # look up the host key is found in the known_hosts file...
+ if (type ssh-keygen &>/dev/null) ; then
+ hostKey=$(ssh-keygen -F "$HOST" -f "$KNOWN_HOSTS" 2>/dev/null)
+ else
+ # FIXME: we're not dealing with digested known_hosts
+ # if we don't have ssh-keygen
+
+ # But we could do this without needing ssh-keygen.
+ # hashed known_hosts looks like: |1|X|Y where 1 means
+ # SHA1 (nothing else is defined in openssh sources), X
+ # is the salt (same length as the digest output),
+ # base64-encoded, and Y is the digested hostname (also
+ # base64-encoded).
+
+ # see hostfile.{c,h} in openssh sources.
+
+ hostKey=$(cut -f1 -d\ < .ssh/known_hosts | tr ',' '\n' | grep -Fx -e "$HOST" || :)
+ fi
+ fi
+
+ if [ "$hostKey" ] ; then
+ # do not check the keyserver
+ # FIXME: more nuanced checking should be done here to properly
+ # take into consideration hosts that join monkeysphere by
+ # converting an existing and known ssh key
+ CHECK_KEYSERVER=${CHECK_KEYSERVER:="false"}
+
+ # if the host key is not found in the known_hosts file...
+ else
+ # check the keyserver
+ CHECK_KEYSERVER=${CHECK_KEYSERVER:="true"}
+ fi
+ fi
+
+ # finally look in the MONKEYSPHERE_ environment variable for a
+ # CHECK_KEYSERVER setting to override all else
+ CHECK_KEYSERVER=${MONKEYSPHERE_CHECK_KEYSERVER:=$CHECK_KEYSERVER}
+
+ declare -i KEYS_PROCESSED=0
+ declare -i KEYS_VALID=0
+
+ # update the known_hosts file for the host
+ source "${MSHAREDIR}/update_known_hosts"
+ update_known_hosts "$HOSTP"
+
+ if ((KEYS_PROCESSED > 0)) && ((KEYS_VALID == 0)) ; then
+ log debug "output ssh marginal ui..."
+ output_no_valid_key
+ fi
+
+ # FIXME: what about the case where monkeysphere successfully finds
+ # a valid key for the host and adds it to the known_hosts file,
+ # but a different non-monkeysphere key for the host already exists
+ # in the known_hosts, and it is this non-ms key that is offered by
+ # the host? monkeysphere will succeed, and the ssh connection
+ # will succeed, and the user will be left with the impression that
+ # they are dealing with a OpenPGP/PKI host key when in fact they
+ # are not. should we use ssh-keyscan to compare the keys first?
+}
+