+# generate a subkey with the 'a' usage flags set
+gen_subkey(){
+ local keyLength
+ local keyExpire
+ local keyID
+ local gpgOut
+ local userID
+
+ # set default key parameter values
+ keyLength=
+ keyExpire=
+
+ # get options
+ TEMP=$(PATH="/usr/local/bin:$PATH" getopt -o l:e: -l length:,expire: -n "$PGRM" -- "$@") || failure "getopt failed! Does your getopt support GNU-style long options?"
+
+ if [ $? != 0 ] ; then
+ exit 1
+ fi
+
+ # Note the quotes around `$TEMP': they are essential!
+ eval set -- "$TEMP"
+
+ while true ; do
+ case "$1" in
+ -l|--length)
+ keyLength="$2"
+ shift 2
+ ;;
+ -e|--expire)
+ keyExpire="$2"
+ shift 2
+ ;;
+ --)
+ shift
+ ;;
+ *)
+ break
+ ;;
+ esac
+ done
+
+ if [ -z "$1" ] ; then
+ # find all secret keys
+ keyID=$(gpg --with-colons --list-secret-keys | grep ^sec | cut -f5 -d: | sort -u)
+ # if multiple sec keys exist, fail
+ if (( $(echo "$keyID" | wc -l) > 1 )) ; then
+ echo "Multiple secret keys found:"
+ echo "$keyID"
+ failure "Please specify which primary key to use."
+ fi
+ else
+ keyID="$1"
+ fi
+ if [ -z "$keyID" ] ; then
+ failure "You have no secret key available. You should create an OpenPGP
+key before joining the monkeysphere. You can do this with:
+ gpg --gen-key"
+ fi
+
+ # get key output, and fail if not found
+ gpgOut=$(gpg --quiet --fixed-list-mode --list-secret-keys --with-colons \
+ "$keyID") || failure
+
+ # fail if multiple sec lines are returned, which means the id
+ # given is not unique
+ if [ $(echo "$gpgOut" | grep -c '^sec:') -gt '1' ] ; then
+ failure "Key ID '$keyID' is not unique."
+ fi
+
+ # prompt if an authentication subkey already exists
+ if echo "$gpgOut" | egrep "^(sec|ssb):" | cut -d: -f 12 | grep -q a ; then
+ echo "An authentication subkey already exists for key '$keyID'."
+ read -p "Are you sure you would like to generate another one? (y/N) " OK; OK=${OK:N}
+ if [ "${OK/y/Y}" != 'Y' ] ; then
+ failure "aborting."
+ fi
+ fi
+
+ # set subkey defaults
+ # prompt about key expiration if not specified
+ keyExpire=$(get_gpg_expiration "$keyExpire")
+
+ # generate the list of commands that will be passed to edit-key
+ editCommands=$(cat <<EOF
+addkey
+7
+S
+E
+A
+Q
+$keyLength
+$keyExpire
+save
+EOF
+)
+
+ log verbose "generating subkey..."
+ fifoDir=$(mktemp -d ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX)
+ (umask 077 && mkfifo "$fifoDir/pass")
+ echo "$editCommands" | gpg --passphrase-fd 3 3< "$fifoDir/pass" --expert --command-fd 0 --edit-key "$keyID" &
+
+ passphrase_prompt "Please enter your passphrase for $keyID: " "$fifoDir/pass"
+
+ rm -rf "$fifoDir"
+ wait
+ log verbose "done."
+}
+
+function subkey_to_ssh_agent() {
+ # try to add all authentication subkeys to the agent:
+
+ local sshaddresponse
+ local secretkeys
+ local authsubkeys
+ local workingdir
+ local keysuccess
+ local subkey
+ local publine
+ local kname
+
+ if ! test_gnu_dummy_s2k_extension ; then
+ failure "Your version of GnuTLS does not seem capable of using with gpg's exported subkeys.
+You may want to consider patching or upgrading.
+
+For more details, see:
+ http://lists.gnu.org/archive/html/gnutls-devel/2008-08/msg00005.html"
+ fi
+
+ # if there's no agent running, don't bother:
+ if [ -z "$SSH_AUTH_SOCK" ] || ! which ssh-add >/dev/null ; then
+ failure "No ssh-agent available."
+ fi
+
+ # and if it looks like it's running, but we can't actually talk to
+ # it, bail out:
+ ssh-add -l >/dev/null
+ sshaddresponse="$?"
+ if [ "$sshaddresponse" = "2" ]; then
+ failure "Could not connect to ssh-agent"
+ fi
+
+ # get list of secret keys (to work around https://bugs.g10code.com/gnupg/issue945):
+ secretkeys=$(gpg --list-secret-keys --with-colons --fixed-list-mode --fingerprint | \
+ grep '^fpr:' | cut -f10 -d: | awk '{ print "0x" $1 "!" }')
+
+ if [ -z "$secretkeys" ]; then
+ failure "You have no secret keys in your keyring!
+You might want to run 'gpg --gen-key'."
+ fi
+
+ authsubkeys=$(gpg --list-secret-keys --with-colons --fixed-list-mode \
+ --fingerprint --fingerprint $secretkeys | \
+ cut -f1,5,10,12 -d: | grep -A1 '^ssb:[^:]*::[^:]*a[^:]*$' | \
+ grep '^fpr::' | cut -f3 -d: | sort -u)
+
+ if [ -z "$authsubkeys" ]; then
+ failure "no authentication-capable subkeys available.
+You might want to 'monkeysphere gen-subkey'"
+ fi
+
+ workingdir=$(mktemp -d ${TMPDIR:-/tmp}/tmp.XXXXXXXXXX)
+ umask 077
+ mkfifo "$workingdir/passphrase"
+ keysuccess=1
+
+ # FIXME: we're currently allowing any other options to get passed
+ # through to ssh-add. should we limit it to known ones? For
+ # example: -d or -c and/or -t <lifetime>
+
+ for subkey in $authsubkeys; do
+ # choose a label by which this key will be known in the agent:
+ # we are labelling the key by User ID instead of by
+ # fingerprint, but filtering out all / characters to make sure
+ # the filename is legit.
+
+ primaryuid=$(gpg --with-colons --list-key "0x${subkey}!" | grep '^pub:' | cut -f10 -d: | tr -d /)
+
+ #kname="[monkeysphere] $primaryuid"
+ kname="$primaryuid"
+
+ if [ "$1" = '-d' ]; then
+ # we're removing the subkey:
+ gpg --export "0x${subkey}!" | openpgp2ssh "$subkey" > "$workingdir/$kname"
+ (cd "$workingdir" && ssh-add -d "$kname")
+ else
+ # we're adding the subkey:
+ mkfifo "$workingdir/$kname"
+ gpg --quiet --passphrase-fd 3 3<"$workingdir/passphrase" \
+ --export-options export-reset-subkey-passwd,export-minimal,no-export-attributes \
+ --export-secret-subkeys "0x${subkey}!" | openpgp2ssh "$subkey" > "$workingdir/$kname" &
+ (cd "$workingdir" && DISPLAY=nosuchdisplay SSH_ASKPASS=/bin/false ssh-add "$@" "$kname" </dev/null )&
+
+ passphrase_prompt "Enter passphrase for key $kname: " "$workingdir/passphrase"
+ wait %2
+ fi
+ keysuccess="$?"
+
+ rm -f "$workingdir/$kname"
+ done
+
+ rm -rf "$workingdir"
+
+ # FIXME: sort out the return values: we're just returning the
+ # success or failure of the final authentication subkey in this
+ # case. What if earlier ones failed?
+ exit "$keysuccess"
+}
+