-#!/bin/sh
+#!/bin/bash
# seckey2sshagent: this is a hack of a script to cope with the fact
# that openpgp2ssh currently cannot support encrypted secret keys.
# Authors: Daniel Kahn Gillmor <dkg@fifthhorseman.net>,
# Jameson Rollins <jrollins@fifthhorseman.net>
+explanation() {
+
+ cat <<EOF
+Usage: $0 [GPGID [FILE]]
+
+The basic strategy of seckey2sshagent is to dump your OpenPGP
+authentication key(s) into your agent or a file. With no arguments,
+it will add all secret keys in your keyring to the agent. With one
+argument, it adds only the specified key to the agent. With two
+arguments, it dumps the specified key to FILE, with the pub key in
+FILE.pub.
+
+This script is a gross hack at the moment. It is done by creating a
+new, temporary private keyring, letting the user remove the
+passphrases from the keys, and then exporting them. The temporary
+private keyring is purged from the system.
+
+When you use this command, you'll find yourself dropped into a GPG
+'edit-key' dialog relevant *only* to the temporary private keyring.
+
+At that point, you should clear the password from your key, with:
+
+ passwd
+ <enter your current password>
+
+followed by the empty string for the new password. GPG will ask you
+if you're really sure. Answer yes, because this is only relevant to
+the temporary keyring. Then, do:
+
+ save
+
+At this point, your key will be added to your running ssh-agent with
+the alias 'monkeysphere-key' and seckey2sshagent should terminate.
+You can check on it with:
+
+ ssh-add -l
+
+EOF
+}
cleanup() {
- echo -n "removing temp gpg home... "
- rm -rf $FOO
- echo "done."
+ echo -n "removing temp gpg home... " 1>&2
+ rm -rf "$TMPPRIVATE"
+ echo "done." 1>&2
}
-trap cleanup EXIT
+export_sec_key() {
+ gpg --export-secret-key "$GPGID" | GNUPGHOME="$TMPPRIVATE" gpg --import
+
+ GNUPGHOME="$TMPPRIVATE" gpg --edit-key "$GPGID"
+
+ # idea to script the password stuff. not working.
+ # read -s -p "enter gpg password: " PASSWD; echo
+ # cmd=$(cat <<EOF
+ # passwd
+ # $PASSWD
+ # \n
+ # \n
+ # \n
+ # yes
+ # save
+ # EOF
+ # )
+ # echo -e "$cmd" | GNUPGHOME="$TMPPRIVATE" gpg --command-fd 0 --edit-key $GPGID
+
+ # export secret key to file
+ GNUPGHOME="$TMPPRIVATE" gpg --export-secret-keys "$GPGID" | \
+ openpgp2ssh "$GPGID"
+}
+
+# if no hex string is supplied, just print an explanation.
+# this covers seckey2sshagent --help, --usage, -h, etc...
+if [ "$(echo "$1" | tr -d '0-9a-fA-F')" ]; then
+ explanation
+ exit
+fi
-GPGID="$1"
+# set the file creation umask
+umask 077
-idchars=$(echo $GPGID | wc -m)
-if [ "$idchars" -ne 17 ] ; then
- echo "GPGID is not 16 characters ($idchars)."
- exit 1
+GPGIDS="$1"
+if [ "$2" -a ! -e "$2" ] ; then
+ FILE="$2"
fi
-FOO=$(mktemp -d)
+if [ -z "$GPGIDS" ]; then
+ # hack: we need to get the list of secret keys, because if you
+ # --list-secret-keys with no arguments, GPG fails to print the
+ # capability flags (i've just filed this as
+ # https://bugs.g10code.com/gnupg/issue945)
+ KEYIDS=$(gpg --with-colons --list-secret-keys | grep ^sec | cut -f5 -d:)
+ # default to using all fingerprints of authentication-enabled keys
+ GPGIDS=$(gpg --with-colons --fingerprint --fingerprint --list-secret-keys $KEYIDS | egrep -A1 '^(ssb|sec):.*:[^:]*a[^:]*:$' | grep ^fpr: | cut -d: -f10)
+fi
+
+trap cleanup EXIT
+
+for GPGID in $GPGIDS; do
+
+ TMPPRIVATE=$(mktemp -d)
+
+ # if specified, write key to fail and passprotect
+ if [ "$FILE" ] ; then
+ # export secret key to file
+ export_sec_key > "$TMPPRIVATE/key"
+ # passprotect file
+ ssh-keygen -f "${TMPPRIVATE}/key" -p
+ # move into place
+ mv "${TMPPRIVATE}/key" "$FILE"
+
+ # export public key
+ gpg --export "$GPGID" | openpgp2ssh "$GPGID" > "${FILE}.pub"
+
+ # otherwise add to agent
+ else
+ KEYNAME='MonkeySphere Key '$(echo "$GPGID" | tr -c -d '0-9a-fA-F')''
-gpg --export-secret-key --export-options export-reset-subkey-passwd $GPGID | GNUPGHOME=$FOO gpg --import
+ # creating this alias so the key is named "monkeysphere-key" in the
+ # comment stored by the agent, while never being written to disk in
+ # SSH form:
+ ln -s /dev/stdin "${TMPPRIVATE}/${KEYNAME}"
-GNUPGHOME=$FOO gpg --edit-key $GPGID
+ # export secret key to agent
+ export_sec_key | (cd "$TMPPRIVATE" && ssh-add -c "$KEYNAME")
+ fi
-GNUPGHOME=$FOO gpg --export-secret-key $GPGID | openpgp2ssh $GPGID | ssh-add -c /dev/stdin
+done