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Diffstat (limited to 'src/common')
-rw-r--r-- | src/common | 566 |
1 files changed, 566 insertions, 0 deletions
diff --git a/src/common b/src/common new file mode 100644 index 0000000..7a90453 --- /dev/null +++ b/src/common @@ -0,0 +1,566 @@ +# -*-shell-script-*- + +# Shared sh functions for the monkeysphere +# +# Written by +# Jameson Rollins <jrollins@fifthhorseman.net> +# +# 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 + +failure() { + echo "$1" >&2 + exit ${2:-'1'} +} + +# write output to stderr +log() { + echo -n "ms: " 1>&2 + echo "$@" 1>&2 +} + +loge() { + echo "$@" 1>&2 +} + +# cut out all comments(#) and blank lines from standard input +meat() { + grep -v -e "^[[:space:]]*#" -e '^$' +} + +# 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_file_line() { + local file + local string + + file="$1" + string="$2" + + if [ "$file" -a "$string" ] ; then + grep -v "$string" "$file" | sponge "$file" + fi +} + +### CONVERTION 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 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="$1" + + gpg --list-key --with-colons --fixed-list-mode \ + --with-fingerprint "$keyID" | grep "$keyID" | \ + grep '^fpr:' | 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 "$requiredCapability" | tr "[:lower:]" "[:upper:]") + + # if CHECK_KEYSERVER variable set, check the keyserver + # for the user ID + if [ "$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 +} + +# update the cache for userid, and prompt to add file to +# authorized_user_ids file if the userid is found in gpg +# and not already in file. +update_userid() { + local userID + + userID="$1" + + log "processing userid: '$userID'" + + # process the user ID to pull it from keyserver + process_user_id "$userID" | grep -q "^0 " + + # check if user ID is in the authorized_user_ids file + if ! grep -q "^${userID}\$" "$AUTHORIZED_USER_IDS" ; then + read -p "user ID not currently authorized. authorize? [Y|n]: " OK; OK=${OK:=Y} + if [ ${OK/y/Y} = 'Y' ] ; then + # add if specified + log -n " adding user ID to authorized_user_ids file... " + echo "$userID" >> "$AUTHORIZED_USER_IDS" + loge "done." + else + # else do nothing + log " authorized_user_ids file untouched." + fi + fi +} + +# remove a userid from the authorized_user_ids file +remove_userid() { + local userID + + userID="$1" + + log "processing userid: '$userID'" + + # check if user ID is in the authorized_user_ids file + if ! grep -q "^${userID}\$" "$AUTHORIZED_USER_IDS" ; then + log " user ID not currently authorized." + return 1 + fi + + # remove user ID from file + log -n " removing user ID '$userID'... " + remove_file_line "$AUTHORIZED_USER_IDS" "^${userID}$" + loge "done." +} + +# process a host in known_host file +process_host_known_hosts() { + local host + local userID + local ok + local keyid + local tmpfile + + host="$1" + userID="ssh://${host}" + + log "processing host: $host" + + process_user_id "ssh://${host}" | \ + while read -r ok keyid ; do + sshKey=$(gpg2ssh "$keyid") + # remove the old host key line + remove_file_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 + fi + done +} + +# process a uid in an authorized_keys file +process_uid_authorized_keys() { + local userID + local ok + local keyid + + userID="$1" + + log "processing user ID: $userID" + + process_user_id "$userID" | \ + while read -r ok keyid ; do + sshKey=$(gpg2ssh "$keyid") + # remove the old host key line + remove_file_line "$AUTHORIZED_KEYS" "$sshKey" + # if key OK, add new host line + if [ "$ok" -eq '0' ] ; then + ssh2authorized_keys "$userID" "$sshKey" >> "$AUTHORIZED_KEYS" + fi + done +} + +# process known_hosts file +# go through line-by-line, extract each host, and process with the +# host processing function +process_known_hosts() { + local hosts + local host + + # take all the hosts from the known_hosts file (first field), + # grep out all the hashed hosts (lines starting with '|')... + cat "$KNOWN_HOSTS" | meat | \ + cut -d ' ' -f 1 | grep -v '^|.*$' | \ + while IFS=, read -r -a hosts ; do + # and process each host + for host in ${hosts[*]} ; do + process_host_known_hosts "$host" + done + done +} + +# process an authorized_user_ids file for authorized_keys +process_authorized_user_ids() { + local userid + + cat "$AUTHORIZED_USER_IDS" | meat | \ + while read -r userid ; do + process_uid_authorized_keys "$userid" + done +} + +# 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 + + 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 + done +} + +################################################## +### GPG HELPER FUNCTIONS + +# retrieve key from web of trust, and set owner trust to "full" +# if key is found. +trust_key() { + # get the key from the key server + if ! gpg --keyserver "$KEYSERVER" --recv-key "$keyID" ; then + log "could not retrieve key '$keyID'" + return 1 + fi + + # get key fingerprint + fingerprint=$(get_key_fingerprint "$keyID") + + # attach a "non-exportable" signature to the key + # this is required for the key to have any validity at all + # the 'y's on stdin indicates "yes, i really want to sign" + echo -e 'y\ny' | gpg --lsign-key --command-fd 0 "$fingerprint" + + # import "full" trust for fingerprint into gpg + echo ${fingerprint}:5: | gpg --import-ownertrust + if [ $? = 0 ] ; then + log "owner trust updated." + else + failure "there was a problem changing owner trust." + fi +} + +# publish server key to keyserver +publish_server_key() { + read -p "really publish key to $KEYSERVER? [y|N]: " OK; OK=${OK:=N} + if [ ${OK/y/Y} != 'Y' ] ; then + failure "aborting." + fi + + # publish host key + # FIXME: need to figure out better way to identify host key + # dummy command so as not to publish fakes keys during testing + # eventually: + #gpg --send-keys --keyserver "$KEYSERVER" $(hostname -f) + echo "NOT PUBLISHED: gpg --send-keys --keyserver $KEYSERVER $(hostname -f)" +} |