really fix the ssh_host_rsa_key.pub.gpg output.

[monkeysphere.git] / src / monkeysphere-ssh-proxycommand

diff --git a/src/monkeysphere-ssh-proxycommand b/src/monkeysphere-ssh-proxycommand
index 6d6d3c0f65a4ad4dfe8836952d12c7f0d437b4e4..aeea30dcd976dbaef5770e317f41135ef879d7aa 100755 (executable)
--- a/src/monkeysphere-ssh-proxycommand
+++ b/src/monkeysphere-ssh-proxycommand
@@ -1,4 +1,4 @@
-#!/bin/sh -e
+#!/usr/bin/env bash
 
 # monkeysphere-ssh-proxycommand: MonkeySphere ssh ProxyCommand hook
 #
@@ -13,8 +13,19 @@
 # established.  Can be added to ~/.ssh/config as follows:
 #  ProxyCommand monkeysphere-ssh-proxycommand %h %p
 
+########################################################################
+PGRM=$(basename $0)
+
+SYSSHAREDIR=${MONKEYSPHERE_SYSSHAREDIR:-"/usr/share/monkeysphere"}
+export SYSSHAREDIR
+. "${SYSSHAREDIR}/common" || exit 1
+
+########################################################################
+# FUNCTIONS
+########################################################################
+
 usage() {
-cat <<EOF >&2
+    cat <<EOF >&2
 usage: ssh -o ProxyCommand="$(basename $0) %h %p" ...
 EOF
 }
@@ -23,6 +34,72 @@ log() {
     echo "$@" >&2
 }
 
+output_no_valid_key() {
+    local sshKeyOffered
+    local userID
+    local type
+    local validity
+    local keyid
+    local uidfpr
+    local usage
+    local sshKeyGPG
+    local sshFingerprint
+
+    userID="ssh://${HOSTP}"
+
+    log "Monkeysphere found only OpenPGP keys for this host with*out* full validity."
+    log "host:                $userID"
+    log
+
+    # retrieve the actual ssh key
+    sshKeyOffered=$(ssh-keyscan -t rsa -p "$PORT" "$HOST" 2>/dev/null | awk '{ print $2, $3 }')
+    # FIXME: should we do any checks for failed keyscans, eg host not
+    # found?
+
+    # output gpg info for userid and store
+    gpgOut=$(gpg --list-key --fixed-list-mode --with-colon \
+       --with-fingerprint --with-fingerprint \
+       ="$userID" 2>/dev/null)
+
+    # find all 'pub' and 'sub' lines in the gpg output, which each
+    # represent a retrieved key for the user ID
+    echo "$gpgOut" | cut -d: -f1,2,5,10,12 | \
+    while IFS=: read -r type validity keyid uidfpr usage ; do
+       case $type in
+           'pub'|'sub')
+               # get the ssh key of the gpg key
+               sshKeyGPG=$(gpg2ssh "$keyid")
+
+               # if one of keys found matches the one offered by the
+               # host, then output info
+               if [ "$sshKeyGPG" = "$sshKeyOffered" ] ; then
+
+                   # get the fingerprint of the ssh key
+                   tmpkey=$(mktemp ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX)
+                   echo "$sshKeyGPG" > "$tmpkey"
+                   sshFingerprint=$(ssh-keygen -l -f "$tmpkey" | awk '{ print $2 }')
+                   rm -rf "$tmpkey"
+
+                   # output gpg info
+                   gpg --check-sigs \
+                       --list-options show-uid-validity \
+                       "$keyid" >&2
+
+                   # output ssh fingerprint
+                   log "RSA key fingerprint is ${sshFingerprint}."
+                   log "Falling through to standard ssh host checking."
+                   log
+               fi
+               ;;
+       esac
+    done
+}
+
+########################################################################
+
+# export the monkeysphere log level
+export MONKEYSPHERE_LOG_LEVEL
+
 if [ "$1" = '--no-connect' ] ; then
     NO_CONNECT='true'
     shift 1
@@ -31,12 +108,10 @@ fi
 HOST="$1"
 PORT="$2"
 
-MS_HOME=${MS_HOME:-"${HOME}/.config/monkeysphere"}
-
 if [ -z "$HOST" ] ; then
-    log "host must be specified."
+    log "Host not specified."
     usage
-    exit 1
+    exit 255
 fi
 if [ -z "$PORT" ] ; then
     PORT=22
@@ -50,6 +125,12 @@ else
 fi
 URI="ssh://${HOSTP}"
 
+# 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.
+
 # if the host is in the gpg keyring...
 if gpg --list-key ="${URI}" 2>&1 >/dev/null ; then
     # do not check the keyserver
@@ -59,7 +140,7 @@ if gpg --list-key ="${URI}" 2>&1 >/dev/null ; then
 else
     # if the host key is found in the known_hosts file...
     # FIXME: this only works for default known_hosts location
-    hostKey=$(ssh-keygen -F "$HOST")
+    hostKey=$(ssh-keygen -F "$HOST" 2>/dev/null)
 
     if [ "$hostKey" ] ; then
        # do not check the keyserver
@@ -74,14 +155,45 @@ else
        CHECK_KEYSERVER="true"
     fi
 fi
-
+# set and export the variable for use by monkeysphere
 MONKEYSPHERE_CHECK_KEYSERVER=${MONKEYSPHERE_CHECK_KEYSERVER:="$CHECK_KEYSERVER"}
 export MONKEYSPHERE_CHECK_KEYSERVER
 
 # update the known_hosts file for the host
 monkeysphere update-known_hosts "$HOSTP"
 
+# output on depending on the return of the update-known_hosts
+# subcommand, which is (ultimately) the return code of the
+# update_known_hosts function in common
+case $? in
+    0)
+       # acceptable host key found so continue to ssh
+       true
+       ;;
+    1)
+       # no hosts at all found so also continue (drop through to
+       # regular ssh host verification)
+       true
+       ;;
+    2)
+       # at least one *bad* host key (and no good host keys) was
+       # found, so output some usefull information
+       output_no_valid_key
+       ;;
+    *)
+       # anything else drop through
+       true
+       ;;
+esac
+
 # exec a netcat passthrough to host for the ssh connection
 if [ -z "$NO_CONNECT" ] ; then
-    exec nc "$HOST" "$PORT"
+    if (which nc 2>/dev/null >/dev/null); then
+       exec nc "$HOST" "$PORT"
+    elif (which socat 2>/dev/null >/dev/null); then
+       exec socat STDIO "TCP:$HOST:$PORT"
+    else
+       echo "Neither netcat nor socat found -- could not complete monkeysphere-ssh-proxycommand connection to $HOST:$PORT" >&2
+       exit 255
+    fi
 fi