#!/bin/sh

set -ue
PATH=/usr/bin:/bin

if [ -n "${GNUPGBIN:-}" ]; then
    GPG="$GNUPGBIN"
elif [ -x /usr/bin/gpg2 ]; then
    GPG=/usr/bin/gpg2
else
    GPG=gpg
fi
GPG_OPTS='--no-auto-check-trustdb --batch --no-verbose --yes'

usage() {
    echo "Usage: $0 /path/to/certs.asc" >&2
    exit 1
}

x509fpr() {
    local msg="$1" host cert h spki
    host="${msg%%,*}"; host="${msg%% *}"
    cert="$DIR/${host%%:*}.pem"
    spki=$(openssl x509 -noout -pubkey<"$cert" | openssl pkey -pubin -outform DER | openssl dgst -sha1  | sed -nr 's/^[^=]+=\s*//p')
    [ "$typ" = mdwn ] && printf '\n    [[%s|https://crt.sh/?spkisha1=%s&iCAID=7395]]\n\n' "$msg" "$spki" \
                      || printf '    %s\n    X.509: https://crt.sh/?spkisha1=%s&iCAID=7395\n    SPKI:\n' "$msg" "$spki"
    for h in sha1 sha256; do
        [ "$typ" = mdwn ] || echo -n '  '
        echo -n "$h" | tr '[a-z]' '[A-Z]'
        for i in $(seq 1 $((7 - ${#h}))); do echo -n ' '; done
        openssl x509 -noout -pubkey<"$cert" | openssl pkey -pubin -outform DER | openssl dgst -"$h" -c | sed -nr 's/^[^=]+=\s*//p'
    done | sed -r "s/(\S+)(.*)/$indent\1\U\2/"
}

sshfpr() {
    local msg="$1" host t h fpr
    host="${msg%%,*}"; host="${msg%% *}"; host="${host#*@}"
    [ "$typ" = mdwn ] && { echo; echo "    $msg"; echo; } || echo "    $msg"
    [ "${host#*:}" != 22 ] || host="${host%%:*}"
    for h in MD5 SHA256; do
        ssh-keygen -E "$h" -f "$DIR/../ssh_known_hosts" -lF "${host#*@}"
    done | sed -nr 's/^[^ #]+\s+//p' | sed -r 's/^(\S+)\s+(MD5|SHA256):/\1 \2 /' |
    while read t h fpr; do
        echo -n "$indent$t"
        for i in $(seq 1 $((7 - ${#h}))); do echo -n ' '; done
        echo "$h:$fpr"
    done
}

allfpr() {
    local typ="$1"
    [ "$typ" = mdwn ] && indent='        ' || indent='    '
	cat <<- EOF
	 * IMAP server
		$(x509fpr 'imap.fripost.org:993 (IMAP over SSL), sieve.fripost.org:4190 (ManageSieve, STARTTLS)')

	 * SMTP servers (STARTTLS)
		$(x509fpr 'smtp.fripost.org:587 (Mail Submission Agent)')
	
		$(x509fpr 'mx1.fripost.org:25 (1st Mail eXchange)')
	
		$(x509fpr 'mx2.fripost.org:25 (2nd Mail eXchange)')

	 * Web servers
		$(x509fpr 'fripost.org:443 (website), wiki.fripost.org:443 (wiki)')
	
		$(x509fpr 'mail.fripost.org:443 (webmail)')
	
		$(x509fpr 'lists.fripost.org:443 (list manager)')
	
		$(x509fpr 'git.fripost.org:443 (git server and its web interface)')

	 * SSH server
		$(sshfpr 'gitolite@git.fripost.org:22')
	EOF
}


[ $# -eq 1 ] || usage

asc="$1"
asc2=$(mktemp --tmpdir)
src=$(mktemp --tmpdir)
src2=$(mktemp --tmpdir)
mdwn="${asc%.asc}.mdwn"
mdwn2=$(mktemp --tmpdir)
DIR="$(dirname "$0")/public"
VCS_BROWSER='https://git.fripost.org/fripost-ansible'
trap 'rm -f "$src" "$src2" "$asc2" "$mdwn2"' EXIT

if [ -s "$asc" ]; then
    "$GPG" $GPG_OPTS --logger-file=/dev/null --output="$src" -- "$asc"
fi


# Generate ASCII file to be clearsigned
cat >"$src2" << EOF
The following is an up-to date list of SHA-1 and SHA-256 fingerprints of
all SPKI (Subject Public Key Info) of each X.509 certificate Fripost
uses on its publicly available services.  Please consider any mismatch
as a man-in-the-middle attack, and let us know immediately! --
admin@fripost.org


These certificates are all issued by the Let's Encrypt Certificate
Authority, and are submitted to Certificate Transparency logs. You can
view all issued Let's Encrypt certificates at crt.sh:

    https://crt.sh/?Identity=%25fripost.org&iCAID=7395

Our X.509 certificates are also available in PEM format at:

    $VCS_BROWSER/tree/certs/public ,

Git repository from which this fingerprint list was generated, at commit ID
$(git --no-pager --git-dir="$DIR/../../.git" --work-tree="$DIR" log -1 --pretty=format:'%h from %aD' -- "$DIR").


EOF
allfpr asc >>"$src2"


# Generate markdown file
cat >"$mdwn2" << EOF
# Certificates at Fripost

The following is an up-to date list of SHA-1 and SHA-256 fingerprints of
all SPKI (Subject Public Key Info) of each X.509 certificate Fripost
uses on its publicly available services.  Please consider any mismatch
as a man-in-the-middle attack, and let us know immediately!  (See also
the [[signed version of this page|certs.asc]].)
-- [[admin@fripost.org|mailto:admin@fripost.org]]


These certificates are all issued by the [[Let's Encrypt Certificate
Authority|https://letsencrypt.org]], and are submitted to [[Certificate
Transparency logs|https://www.certificate-transparency.org]].
You can view all issued Let's Encrypt certificates at
[[crt.sh|https://crt.sh/?Identity=%25fripost.org&iCAID=7395]].
Our X.509 certificates are also available in PEM format under our
[[Git repository|$VCS_BROWSER/tree/certs/public]],
from which this fingerprint list was [[generated|$VCS_BROWSER/tree/certs/gencerts.sh]], at
$(git --no-pager --git-dir="$DIR/../../.git" --work-tree="$DIR" log -1 --pretty=format:"[[Commit ID %h from %aD|$VCS_BROWSER/tree/certs/public?id=%H]]" -- "$DIR").


EOF
allfpr mdwn >>"$mdwn2"
echo >>"$src2"


if diff -u --label "a/${asc%.asc}" --label "b/${asc%.asc}" -- "$src" "$src2" &&
   diff -q -- "$mdwn" "$mdwn2" >/dev/null; then
    echo 'The fingerprint list is up to date.'
else
    "$GPG" $GPG_OPTS --output="$asc2" --clearsign -- "$src2"
    cp -f "$asc2" "$asc"
    cp -f "$mdwn2" "$mdwn"
    echo ================================ 
    echo "The fingerprint lists ($asc and $mdwn) have been updated!"
    echo '/!\ You should now push the changes to the wiki. /!\'
fi