#!/bin/bash
# No way I try to deal with a crippled sh just for POSIX foo.

# Copyright (C) 2011 Joerg Jaspert <joerg@debian.org>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License as
# published by the Free Software Foundation; version 2.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.


# exit on errors
set -e
# make sure to only use defined variables
set -u
# ERR traps should be inherited from functions too.
set -E

# import the general variable set.
export SCRIPTVARS=/srv/ftp-master.debian.org/dak/config/debian/vars
. $SCRIPTVARS

umask 027

# And use one locale, no matter what the caller has set
export LANG=C
export LC_ALL=C
PROGRAM="buildd-add-keys"

# common functions are "outsourced"
. "${configdir}/common"

function cleanup() {
    ERRVAL=$?
    trap - ERR EXIT TERM HUP INT QUIT

    for TEMPFILE in GPGSTATUS GPGLOGS GPGOUTF TEMPKEYDATA; do
        TFILE=${TEMPFILE:=$TEMPFILE}
        DELF=${!TFILE:-""}
        if [ -n "${DELF}" ] && [ -f "${DELF}" ]; then
            rm -f "${DELF}"
        fi
    done
    exit $ERRVAL
}
trap cleanup ERR EXIT TERM HUP INT QUIT

base="${base}/scripts/builddkeyrings"
INCOMING="${base}/incoming"
ERRORS="${base}/errors"
ADMINS="${base}/adminkeys.gpg"

# Default options for our gpg calls
DEFGPGOPT="--no-default-keyring --batch --no-tty --no-options --exit-on-status-write-error --no-greeting"

if ! [ -d "${INCOMING}" ]; then
    log "Missing incoming dir, nothing to do"
    exit 1
fi

# Whenever something goes wrong, its put in there.
mkdir -p "${ERRORS}"

# We process all new files in our incoming directory
for file in $(ls -1 ${INCOMING}/*.key); do
    file=${file##*/}
    # First we want to see if we recognize the filename. The buildd people have
    # to follow a certain schema:
    # architecture_builddname.YEAR-MONTH-DAY_HOUR:MINUTE.key
    if [[ $file =~ (.*)_(.*).([0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{2}:[0-9]{2}).key ]]; then
        ARCH=${BASH_REMATCH[1]}
        BUILDD=${BASH_REMATCH[2]}
        # Right now timestamp is unused
        TIMESTAMP=${BASH_REMATCH[3]}
    else
        log "Unknown file ${file}, not processing"
        mv "${INCOMING}/${file}" "${ERRORS}/unknown.${file}.$(date -Is)"
        continue
    fi

    # Do we know the architecture?
    found=0
    for carch in ${archs}; do
        if [ "${ARCH}" == "${carch}" ]; then
            log "Known arch ${ARCH}, buildd ${BUILDD}"
            found=1
            break
        fi
    done

    if [ ${found} -eq 0 ]; then
        log "Unknown architecture ${ARCH}"
        mv "${INCOMING}/${file}" "${ERRORS}/unknownarch.${file}.$(date -Is)"
        continue
    fi

    # If we did have a file with this name already somethings wrong
    if [ -f "${base}/${ARCH}/${file}" ]; then
        log "Already processed this file"
        mv "${INCOMING}/${file}" "${ERRORS}/duplicate.${file}.$(date -Is)"
        continue
    fi

    # Where we want the status-fd from gpgv turn up
    GPGSTATUS=$(mktemp -p "${TMPDIR}" GPGSTATUS.XXXXXX)
    # Same for the loggger-fd
    GPGLOGS=$(mktemp -p "${TMPDIR}" GPGLOGS.XXXXXX)
    # And "decrypt" gives us output, the key without the pgp sig around it
    GPGOUTF=$(mktemp -p "${TMPDIR}" GPGOUTF.XXXXXX)

    # Open the filehandles, assigning them to the two files, so we can let gpg use them
    exec 4> "${GPGSTATUS}"
    exec 5> "${GPGLOGS}"

    # So lets run gpg, status/logger into the two files, to "decrypt" the keyfile
    if ! gpg ${DEFGPGOPT} --keyring "${ADMINS}" --status-fd 4 --logger-fd 5 --decrypt "${INCOMING}/${file}" > "${GPGOUTF}"; then
        ret=$?
        log "gpg returned with ${ret}, not adding key from file ${file}"
        DATE=$(date -Is)
        mv "${INCOMING}/${file}" "${ERRORS}/gpgerror.${file}.${DATE}"
        mv "${GPGSTATUS}" "${ERRORS}/gpgerror.${file}.gpgstatus.${DATE}"
        mv "${GPGLOGS}" "${ERRORS}/gpgerror.${file}.gpglogs.${DATE}"
        rm -f "${GPGOUTF}"
        continue
    fi

    # Read in the status output
    GPGSTAT=$(cat "${GPGSTATUS}")
    # And check if we like the sig. It has to be both, GOODISG and VALIDSIG or we don't accept it
    if [[ ${GPGSTAT} =~ "GOODSIG" ]] && [[ ${GPGSTAT} =~ "VALIDSIG" ]]; then
        log "Signature for ${file} accepted"
    else
        log "We are missing one of GOODSIG or VALIDSIG"
        DATE=$(date -Is)
        mv "${INCOMING}/${file}" "${ERRORS}/badsig.${file}.${DATE}"
        mv "${GPGSTATUS}" "${ERRORS}/badsig.${file}.gpgstatus.${DATE}"
        mv "${GPGLOGS}" "${ERRORS}/badsig.${file}.gpglogs.${DATE}"
        rm -f "${GPGOUTF}"
        continue
    fi

    # So at this point we know we accepted the signature of the file as valid,
    # that is it is from a key allowed for this architecture. Which only
    # leaves us with the task of checking if the key fulfills the requirements
    # before we add it to the architectures keyring.

    # Those currently are:
    # - keysize 4096 or larger
    # - RSA key, no encryption capability
    # - UID matching "buildd autosigning key BUILDDNAME <buildd_ARCH-BUILDDNAME@buildd.debian.org>
    # - expire within a 120 days
    # - maximum 2 keys per architecture and buildd

    TEMPKEYDATA=$(mktemp -p "${TMPDIR}" BDKEYS.XXXXXX)

    gpg ${DEFGPGOPT} --with-colons "${GPGOUTF}" > "${TEMPKEYDATA}"

    # Read in the TEMPKEYDATAFILE, but avoid using a subshell like a
    # while read line otherwise would do
    exec 4<> "${TEMPKEYDATA}"
    error=""
    while read line <&4; do
        #pub:-:4096:1:FAB983612A6554FA:2011-03-24:2011-07-22::-:buildd autosigning key poulenc <buildd_powerpc-poulenc@buildd.debian.org>:

        # Besides fiddling out the data we need to check later, this regex also check:
        # - the keytype (:1:, 1 there means RSA)
        # - the UID
        # - that the key does have an expiration date (or it wont match, the second date
        #   field would be empty
        regex="^pub:-:([0-9]{4}):1:([0-9A-F]{16}):([0-9]{4}-[0-9]{2}-[0-9]{2}):([0-9]{4}-[0-9]{2}-[0-9]{2})::-:buildd autosigning key ${BUILDD} <buildd_${ARCH}-${BUILDD}@buildd.debian.org>:$"
        if [[ $line =~ $regex ]]; then
            KEYSIZE=${BASH_REMATCH[1]}
            KEYID=${BASH_REMATCH[2]}
            KEYCREATE=${BASH_REMATCH[3]}
            KEYEXPIRE=${BASH_REMATCH[4]}

            # We do want 4096 or anything above
            if [ ${KEYSIZE} -lt 4096 ]; then
                log "Keysize ${KEYSIZE} too small"
                error="${error} Keysize ${KEYSIZE} too small"
                continue
            fi

            # We want a maximum lifetime of 120 days, so check that.
            # Easiest to compare in epoch, so lets see, 120 days midnight from now,
            # compared with their set expiration date at midnight
            # maxdate should turn out higher. just in case we make it 121 for this check
            maxdate=$(date -d '121 day 00:00:00' +%s)
            theirexpire=$(date -d "${KEYEXPIRE} 00:00:00" +%s)
            if [ ${theirexpire} -gt ${maxdate} ]; then
                log "Key expiry ${KEYEXPIRE} wrong"
                error="${error} Key expiry ${KEYEXPIRE} wrong"
                continue
            fi
        else
            log "Unknown line $line, sod off"
            error="${error} Unknown line $line, sod off"
            continue
        fi
    done
    if [ -n "${error}" ]; then
        log ${error}
        DATE=$(date -Is)
        mv "${INCOMING}/${file}" "${ERRORS}/badkey.${file}.${DATE}"
        mv "${GPGSTATUS}" "${ERRORS}/badkey.${file}.gpgstatus.${DATE}"
        mv "${GPGLOGS}" "${ERRORS}/badkey.${file}.gpglogs.${DATE}"
        echo "${error}" >> "${ERRORS}/badkey.${file}.error.${DATE}"
        rm -f "${GPGOUTF}"
        continue
    fi

    # And now lets check how many keys this buildd already has. 2 is the maximum, so key
    # rollover works. 3 won't, they have to rm one first
    # We need to check for the amount of keys
    ARCHKEYRING="${base}/${ARCH}/keyring.gpg"
    trap - ERR EXIT TERM HUP INT QUIT

    KEYNO=$(gpg ${DEFGPGOPT} --keyring "${ARCHKEYRING}" --with-colons --list-keys "buildd_${ARCH}-${BUILDD}@buildd.debian.org" | grep -c '^pub:' || /bin/true )
    if [ ${KEYNO} -gt 2 ]; then
        DATE=$(date -Is)
        mv "${INCOMING}/${file}" "${ERRORS}/toomany.${file}.${DATE}"
        mv "${GPGSTATUS}" "${ERRORS}/toomany.${file}.gpgstatus.${DATE}"
        mv "${GPGLOGS}" "${ERRORS}/toomany.${file}.gpglogs.${DATE}"
        rm -f "${GPGOUTF}"
        continue
    fi

    # Right. At this point everything should be in order, which means we should put the key into
    # the keyring
    log "Accepting key ${KEYID} for ${ARCH} buildd ${BUILDD}, expire ${KEYEXPIRE}"
    gpg ${DEFGPGOPT} --status-fd 4 --logger-fd 5 --keyring "${ARCHKEYRING}" --import "${GPGOUTF}" 2>/dev/null

    mv "${INCOMING}/${file}" "${base}/${ARCH}"
done