# -*-shell-script-*- # Shared sh functions for the monkeysphere # # Written by # Jameson Rollins # # Copyright 2008, released under the GPL, version 3 or later # all-caps variables are meant to be user supplied (ie. from config # file) and are considered global ######################################################################## ### COMMON VARIABLES # managed directories ETC="/etc/monkeysphere" export ETC CACHE="/var/cache/monkeysphere" export CACHE ######################################################################## ### UTILITY FUNCTIONS error() { log "$1" ERR=${2:-'1'} } failure() { echo "$1" >&2 exit ${2:-'1'} } # write output to stderr log() { echo -n "ms: " >&2 echo "$@" >&2 } loge() { echo "$@" >&2 } # cut out all comments(#) and blank lines from standard input meat() { grep -v -e "^[[:space:]]*#" -e '^$' } # cut a specified line from standard input cutline() { head --line="$1" | tail -1 } # check that characters are in a string (in an AND fashion). # used for checking key capability # check_capability capability a [b...] check_capability() { local usage local capcheck usage="$1" shift 1 for capcheck ; do if echo "$usage" | grep -q -v "$capcheck" ; then return 1 fi done return 0 } # convert escaped characters from gpg output back into original # character # FIXME: undo all escape character translation in with-colons gpg output unescape() { echo "$1" | sed 's/\\x3a/:/' } # remove all lines with specified string from specified file remove_line() { local file local string file="$1" string="$2" if [ "$file" -a "$string" ] ; then grep -v "$string" "$file" | sponge "$file" fi } # translate ssh-style path variables %h and %u translate_ssh_variables() { local uname local home uname="$1" path="$2" # get the user's home directory userHome=$(getent passwd "$uname" | cut -d: -f6) # translate '%u' to user name path=${path/\%u/"$uname"} # translate '%h' to user home directory path=${path/\%h/"$userHome"} echo "$path" } ### CONVERSION UTILITIES # output the ssh key for a given key ID gpg2ssh() { local keyID #keyID="$1" #TMP # only use last 16 characters until openpgp2ssh can take all 40 #TMP keyID=$(echo "$1" | cut -c 25-) #TMP gpg --export "$keyID" | openpgp2ssh "$keyID" 2> /dev/null } # output the ssh key for a given secret key ID gpgsecret2ssh() { local keyID #keyID="$1" #TMP # only use last 16 characters until openpgp2ssh can take all 40 #TMP keyID=$(echo "$1" | cut -c 25-) #TMP gpg --export-secret-key "$keyID" | openpgp2ssh "$keyID" 2> /dev/null } # output known_hosts line from ssh key ssh2known_hosts() { local host local key host="$1" key="$2" echo -n "$host " echo -n "$key" | tr -d '\n' echo " MonkeySphere${DATE}" } # output authorized_keys line from ssh key ssh2authorized_keys() { local userID local key userID="$1" key="$2" echo -n "$key" | tr -d '\n' echo " MonkeySphere${DATE} ${userID}" } # convert key from gpg to ssh known_hosts format gpg2known_hosts() { local host local keyID host="$1" keyID="$2" # NOTE: it seems that ssh-keygen -R removes all comment fields from # all lines in the known_hosts file. why? # NOTE: just in case, the COMMENT can be matched with the # following regexp: # '^MonkeySphere[[:digit:]]{4}(-[[:digit:]]{2}){2}T[[:digit:]]{2}(:[[:digit:]]{2}){2}$' echo -n "$host " gpg2ssh "$keyID" | tr -d '\n' echo " MonkeySphere${DATE}" } # convert key from gpg to ssh authorized_keys format gpg2authorized_keys() { local userID local keyID userID="$1" keyID="$2" # NOTE: just in case, the COMMENT can be matched with the # following regexp: # '^MonkeySphere[[:digit:]]{4}(-[[:digit:]]{2}){2}T[[:digit:]]{2}(:[[:digit:]]{2}){2}$' gpg2ssh "$keyID" | tr -d '\n' echo " MonkeySphere${DATE} ${userID}" } ### GPG UTILITIES # retrieve all keys with given user id from keyserver # FIXME: need to figure out how to retrieve all matching keys # (not just first N (5 in this case)) gpg_fetch_userid() { local userID userID="$1" log -n " checking keyserver $KEYSERVER... " echo 1,2,3,4,5 | \ gpg --quiet --batch --with-colons \ --command-fd 0 --keyserver "$KEYSERVER" \ --search ="$userID" > /dev/null 2>&1 loge "done." } # get the full fingerprint of a key ID get_key_fingerprint() { local keyID keyID="$1" gpg --list-key --with-colons --fixed-list-mode \ --with-fingerprint --with-fingerprint "$keyID" | \ grep '^fpr:' | grep "$keyID" | cut -d: -f10 } ######################################################################## ### PROCESSING FUNCTIONS # userid and key policy checking # the following checks policy on the returned keys # - checks that full key has appropriate valididy (u|f) # - checks key has specified capability (REQUIRED_*_KEY_CAPABILITY) # - checks that requested user ID has appropriate validity # (see /usr/share/doc/gnupg/DETAILS.gz) # output is one line for every found key, in the following format: # # flag fingerprint # # "flag" is an acceptability flag, 0 = ok, 1 = bad # "fingerprint" is the fingerprint of the key # # expects global variable: "MODE" process_user_id() { local userID local requiredCapability local requiredPubCapability local gpgOut local type local validity local keyid local uidfpr local usage local keyOK local uidOK local lastKey local lastKeyOK local fingerprint userID="$1" # set the required key capability based on the mode if [ "$MODE" = 'known_hosts' ] ; then requiredCapability="$REQUIRED_HOST_KEY_CAPABILITY" elif [ "$MODE" = 'authorized_keys' ] ; then requiredCapability="$REQUIRED_USER_KEY_CAPABILITY" fi requiredPubCapability=$(echo "$requiredCapability" | tr "[:lower:]" "[:upper:]") # if CHECK_KEYSERVER variable set to true, check the keyserver # for the user ID if [ "$CHECK_KEYSERVER" = "true" ] ; then gpg_fetch_userid "$userID" fi # output gpg info for (exact) userid and store gpgOut=$(gpg --list-key --fixed-list-mode --with-colon \ --with-fingerprint --with-fingerprint \ ="$userID" 2>/dev/null) # if the gpg query return code is not 0, return 1 if [ "$?" -ne 0 ] ; then log " - key not found." return 1 fi # loop over all lines in the gpg output and process. # need to do it this way (as opposed to "while read...") so that # variables set in loop will be visible outside of loop echo "$gpgOut" | cut -d: -f1,2,5,10,12 | \ while IFS=: read -r type validity keyid uidfpr usage ; do # process based on record type case $type in 'pub') # primary keys # new key, wipe the slate keyOK= uidOK= lastKey=pub lastKeyOK= fingerprint= log " primary key found: $keyid" # if overall key is not valid, skip if [ "$validity" != 'u' -a "$validity" != 'f' ] ; then log " - unacceptable primary key validity ($validity)." continue fi # if overall key is disabled, skip if check_capability "$usage" 'D' ; then log " - key disabled." continue fi # if overall key capability is not ok, skip if ! check_capability "$usage" $requiredPubCapability ; then log " - unacceptable primary key capability ($usage)." continue fi # mark overall key as ok keyOK=true # mark primary key as ok if capability is ok if check_capability "$usage" $requiredCapability ; then lastKeyOK=true fi ;; 'uid') # user ids # if an acceptable user ID was already found, skip if [ "$uidOK" ] ; then continue fi # if the user ID does not match, skip if [ "$(unescape "$uidfpr")" != "$userID" ] ; then continue fi # if the user ID validity is not ok, skip if [ "$validity" != 'u' -a "$validity" != 'f' ] ; then continue fi # mark user ID acceptable uidOK=true # output a line for the primary key # 0 = ok, 1 = bad if [ "$keyOK" -a "$uidOK" -a "$lastKeyOK" ] ; then log " * acceptable key found." echo "0:${fingerprint}" else echo "1:${fingerprint}" fi ;; 'sub') # sub keys # unset acceptability of last key lastKey=sub lastKeyOK= fingerprint= # if sub key validity is not ok, skip if [ "$validity" != 'u' -a "$validity" != 'f' ] ; then continue fi # if sub key capability is not ok, skip if ! check_capability "$usage" $requiredCapability ; then continue fi # mark sub key as ok lastKeyOK=true ;; 'fpr') # key fingerprint fingerprint="$uidfpr" # if the last key was the pub key, skip if [ "$lastKey" = pub ] ; then continue fi # output a line for the last subkey # 0 = ok, 1 = bad if [ "$keyOK" -a "$uidOK" -a "$lastKeyOK" ] ; then log " * acceptable key found." echo "0:${fingerprint}" else echo "1:${fingerprint}" fi ;; esac done } # process a single host in the known_host file process_host_known_hosts() { local host local userID local ok local keyid local tmpfile local returnCode # default return code is 1, which assumes no key was found returnCode=1 host="$1" log "processing host: $host" userID="ssh://${host}" for line in $(process_user_id "ssh://${host}") ; do ok=$(echo "$line" | cut -d: -f1) keyid=$(echo "$line" | cut -d: -f2) sshKey=$(gpg2ssh "$keyid") # remove the old host key line remove_line "$KNOWN_HOSTS" "$sshKey" # if key OK, add new host line if [ "$ok" -eq '0' ] ; then # hash if specified if [ "$HASH_KNOWN_HOSTS" = 'true' ] ; then # FIXME: this is really hackish cause ssh-keygen won't # hash from stdin to stdout tmpfile=$(mktemp) ssh2known_hosts "$host" "$sshKey" > "$tmpfile" ssh-keygen -H -f "$tmpfile" 2> /dev/null cat "$tmpfile" >> "$KNOWN_HOSTS" rm -f "$tmpfile" "${tmpfile}.old" else ssh2known_hosts "$host" "$sshKey" >> "$KNOWN_HOSTS" fi # set return code to be 0, since a key was found returnCode=0 fi return "$returnCode" done return "$returnCode" } # update the known_hosts file for a set of hosts listed on command # line update_known_hosts() { local host local returnCode # default return code is 0, which assumes a key was found for # every host. code will be set to 1 if a key is not found for at # least one host returnCode=0 # set the trap to remove any lockfiles on exit trap "lockfile-remove $KNOWN_HOSTS" EXIT # create a lockfile on known_hosts lockfile-create "$KNOWN_HOSTS" for host ; do # process the host, change return code if host key not found process_host_known_hosts "$host" || returnCode=1 # touch the lockfile, for good measure. lockfile-touch --oneshot "$KNOWN_HOSTS" done # remove the lockfile lockfile-remove "$KNOWN_HOSTS" return "$returnCode" } # process known_hosts file, going through line-by-line, extract each # host, and process with the host processing function process_known_hosts() { local returnCode # default return code is 0, which assumes a key was found for # every host. code will be set to 1 if a key is not found for at # least one host returnCode=0 # take all the hosts from the known_hosts file (first field), grep # out all the hashed hosts (lines starting with '|')... for line in $(cat "$KNOWN_HOSTS" | meat | cut -d ' ' -f 1 | grep -v '^|.*$') ; do # break up hosts into separate words update_known_hosts $(echo "$line" | tr , ' ') || returnCode=1 done return "$returnCode" } # process uids for the authorized_keys file process_uid_authorized_keys() { local userID local ok local keyid local returnCode # default return code is 1, which assumes no key was found returnCode=1 userID="$1" log "processing user ID: $userID" for line in $(process_user_id "$userID") ; do ok=$(echo "$line" | cut -d: -f1) keyid=$(echo "$line" | cut -d: -f2) sshKey=$(gpg2ssh "$keyid") # remove the old host key line remove_line "$AUTHORIZED_KEYS" "$sshKey" # if key OK, add new host line if [ "$ok" -eq '0' ] ; then ssh2authorized_keys "$userID" "$sshKey" >> "$AUTHORIZED_KEYS" # set return code to be 0, since a key was found returnCode=0 fi done return "$returnCode" } # update the authorized_keys files from a list of user IDs on command # line update_authorized_keys() { local userID local returnCode # default return code is 0, which assumes a key was found for # every user ID. code will be set to 1 if a key is not found for # at least one user ID returnCode=0 # set the trap to remove any lockfiles on exit trap "lockfile-remove $AUTHORIZED_KEYS" EXIT # create a lockfile on authorized_keys lockfile-create "$AUTHORIZED_KEYS" for userID ; do # process the user ID, change return code if key not found for # user ID process_uid_authorized_keys "$userID" || returnCode=1 # touch the lockfile, for good measure. lockfile-touch --oneshot "$AUTHORIZED_KEYS" done # remove the lockfile lockfile-remove "$AUTHORIZED_KEYS" return "$returnCode" } # process an authorized_user_ids file for authorized_keys process_authorized_user_ids() { local userid local returnCode # default return code is 0, and is set to 1 if a key for a user ID # is not found returnCode=0 authorizedUserIDs="$1" # set the IFS to be newline for parsing the authorized_user_ids # file. can't find it in BASH(1) (found it on the net), but it # works. IFS=$'\n' for userid in $(cat "$authorizedUserIDs" | meat) ; do update_authorized_keys "$userid" || returnCode=1 done return "$returnCode" } # EXPERIMENTAL (unused) process userids found in authorized_keys file # go through line-by-line, extract monkeysphere userids from comment # fields, and process each userid # NOT WORKING process_authorized_keys() { local authorizedKeys local userID local returnCode # default return code is 0, and is set to 1 if a key for a user # is not found returnCode=0 authorizedKeys="$1" # take all the monkeysphere userids from the authorized_keys file # comment field (third field) that starts with "MonkeySphere uid:" # FIXME: needs to handle authorized_keys options (field 0) cat "$authorizedKeys" | meat | \ while read -r options keytype key comment ; do # if the comment field is empty, assume the third field was # the comment if [ -z "$comment" ] ; then comment="$key" fi if echo "$comment" | egrep -v -q '^MonkeySphere[[:digit:]]{4}(-[[:digit:]]{2}){2}T[[:digit:]]{2}(:[[:digit:]]{2}){2}' ; then continue fi userID=$(echo "$comment" | awk "{ print $2 }") if [ -z "$userID" ] ; then continue fi # process the userid log "processing userid: '$userID'" process_user_id "$userID" > /dev/null || returnCode=1 done return "$returnCode" } ################################################## ### GPG HELPER FUNCTIONS # retrieve key from web of trust, and set owner trust to "full" # if key is found. trust_key() { local keyID local trustLevel keyID="$1" trustLevel="$2" if [ -z "$keyID" ] ; then failure "You must specify key to trust." fi # get the key from the key server if ! gpg --keyserver "$KEYSERVER" --recv-key "$keyID" ; then failure "Could not retrieve key '$keyID'." fi # get key fingerprint fingerprint=$(get_key_fingerprint "$keyID") echo "key found:" gpg --fingerprint "$fingerprint" while [ -z "$trustLevel" ] ; do cat <