diff options
| -rwxr-xr-x | acme-slave | 251 | ||||
| -rwxr-xr-x | acme-webserver | 32 | ||||
| -rwxr-xr-x | letsencrypt | 281 |
3 files changed, 564 insertions, 0 deletions
diff --git a/acme-slave b/acme-slave new file mode 100755 index 0000000..ee39f8d --- /dev/null +++ b/acme-slave @@ -0,0 +1,251 @@ +#!/usr/bin/perl -T + +use strict; +use warnings; + +use LWP::UserAgent (); +use Crypt::OpenSSL::RSA (); +use Crypt::OpenSSL::Bignum (); +use MIME::Base64 qw/encode_base64 encode_base64url/; +use JSON (); +use Digest::SHA qw/sha256 sha256_hex/; + +# Clean up PATH +$ENV{PATH} = join ':', qw{/usr/bin /bin}; +delete @ENV{qw/IFS CDPATH ENV BASH_ENV/}; + +my $COMMAND = shift @ARGV // die; +my $PUBKEY = shift @ARGV // die; +die unless grep {$COMMAND eq $_} qw/new-reg new-cert revoke-cert/; +my $TIMEOUT = 10; + + +# Read the public key and build the JSON Web Key (RFC 7517) +my $JWK = do { + open my $fh, '<', $PUBKEY or die "Can't open $PUBKEY: $!"; + my $str = do { local $/ = undef; <$fh> }; + my $pubkey = Crypt::OpenSSL::RSA->new_public_key($str) or die; + close $fh; + + my ($n, $e) = $pubkey->get_key_parameters(); + $_ = encode_base64url($_->to_bin()) foreach ($n, $e); + + { kty => 'RSA', n => $n, e => $e } +}; +my $JSON = JSON::->new->utf8->canonical(); # breaks hashes otherwise +my $JWK_dgst64 = encode_base64url(sha256($JSON->encode($JWK))); +my $NONCE; + + +# Send an HTTP request to the ACME server +my $UA = LWP::UserAgent::->new( ssl_opts => { + verify_hostname => 1, + SSL_version => 'SSLv23:!TLSv1_1:!TLSv1:!SSLv3:!SSLv2', + SSL_cipher_list => 'EECDH+AESGCM:!MEDIUM:!LOW:!EXP:!aNULL:!eNULL' +}); +sub request($$;$) { + my ($method, $uri, $json) = @_; + print STDERR ">>> $method $uri <<<\n" if $ENV{DEBUG}; + + my $req = HTTP::Request::->new($method => $uri) or die "Can't $method $uri"; + if (defined $json) { + $req->header('Content-Type' => 'application/json'); + $req->content($JSON->encode($json)); + } + my $r = $UA->request($req) or die "Can't $method $uri"; + print STDERR ">>> ", $r->status_line, "\n", $r->headers->as_string, "\n" if $ENV{DEBUG}; + $NONCE = $r->header('Replay-Nonce') // die; + my $t = $r->header('Content-Type'); + + my $content = $r->decoded_content(); + if (defined $t and $t =~ /\Aapplication\/(?:[a-z]+\+)?json\z/) { + $content = $JSON->decode($content); + print STDERR $JSON->pretty->encode($content), "\n" if $ENV{DEBUG}; + } + elsif (defined $t and $t eq 'application/pkix-cert') { + print STDERR encode_base64($content), "\n" if $ENV{DEBUG}; + } + else { + print STDERR $content, "\n" if $ENV{DEBUG}; + } + unless ($r->is_success) { + my $msg = $r->status_line; + $msg .= " (".$content->{detail}.")" if ref $content and defined $content->{detail}; + die $msg, "\n"; + } + + return $content; +} + + +# ACME client +# https://github.com/letsencrypt/acme-spec/blob/master/draft-barnes-acme.md +sub acme($$) { + my ($uri, $h) = @_; + + # Produce the JSON Web Signature: RFC 7515 section 5 + my $payload = encode_base64url($JSON->encode($h)); + my %header = ( alg => 'RS256', jwk => $JWK ); + my $protected = encode_base64url($JSON->encode({ %header, nonce => $NONCE })); + my $data = $protected .'.'. $payload; + print STDERR "Requesting a SHA-256 signature for ", $data, "\n" if $ENV{DEBUG}; + STDOUT->printflush($data, "\n"); + + # Ask for an (hex) sig + my $sig = do { local $_ = <STDIN>; chomp; $_ }; + $sig = encode_base64url(pack('H*', $sig)); + print STDERR "Got SHA-256 signature ", $sig, "\n" if $ENV{DEBUG}; + + # Flattened JSON Serialization, RFC 7515 section 7.2.2 + request(POST => $uri, { + payload => $payload, + protected => $protected, + header => \%header, + signature => $sig + }); +} + + +# Query the root ACME directory to initialize the nonce and get the resources URIs +my %RES = %{ request(GET => "https://acme-v01.api.letsencrypt.org/directory") }; + + +if ($COMMAND eq 'new-reg') { + print STDERR "Requesting new registration ".(@ARGV ? ("for ".join(', ', @ARGV)) : "")."\n"; + my $uri = "https://letsencrypt.org/documents/LE-SA-v1.0.1-July-27-2015.pdf"; + my $dgst = sha256_hex($UA->get($uri)->decoded_content()); + die "Error: The CA's subscriber agreement (URL $uri) has changed!\n" if + $dgst ne '33d233c8ab558ba6c8ebc370a509acdded8b80e5d587aa5d192193f35226540f'; + + acme($RES{'new-reg'}, { + resource => 'new-reg', + contact => [ map {"mailto:$_"} split(',', @ARGV) ], + agreement => $uri, + }); + exit; +} + + +if ($COMMAND eq 'revoke-cert') { + print STDERR "Requesting revocation for\n"; + for my $cert (@ARGV) { + open my $fh1, '-|', qw/openssl x509 -noout -subject -serial -fingerprint -sha256/, '-in', $cert + or die "Can't run x509(1ssl): $!"; + my ($subject, $serial, $fingerprint) = map { s/[^=]+=\s*//; chomp; $_ } <$fh1>; + close $fh1; + + print STDERR "\n\tSubject: $subject\n", + "\tSerial: $serial\n", + "\tSHA-256 fingerprint: $fingerprint\n"; + + open my $fh2, '-|', qw/openssl x509 -outform DER/, '-in', $cert or die "Can't run x509(1ssl): $!"; + my $der = do { local $/ = undef; <$fh2> }; + close $fh2; + + acme($RES{'revoke-cert'}, { + resource => 'revoke-cert', + certificate => encode_base64url($der) + }); + } + exit; +} + + +# $COMMAND eq 'new-cert' +my ($CSR, $CHALLENGE_DIR, $X509) = @ARGV; +$CHALLENGE_DIR = $CHALLENGE_DIR =~ /\A(\/\p{Print}+)\z/ ? $1 : + die "Error: Challenge directory is not absolute: $CHALLENGE_DIR"; + +# Parse the Certificate Signing Request +# XXX use a library instead, perhaps Crypt::OpenSSL::PKCS10 +my @domains = do { + my @req = (qw/openssl req -noout/, '-in', $CSR); + + my $RE_label = qr/[0-9a-z](?:[0-9a-z\x2D]{0,61}[0-9a-z])?/aai; + my $RE_domain = qr/$RE_label(?:\.$RE_label)+/; + my %domains; + + open my $fh1, '-|', @req, '-subject' or die "Can't run req(1ssl): $!"; + my $subject = <$fh1>; + close $fh1; + $domains{$1} = 1 if $subject =~ /\Asubject=\/CN=($RE_domain)(?:,.*)?\n\z/o; + + open my $fh2, '-|', @req, '-text', '-reqopt', 'no_header,no_version,no_subject,no_pubkey,no_sigdump' + or die "Can't run req(1ssl): $!"; + while (<$fh2>) { + /\A\s+X509v3 Subject Alternative Name:/ or next; + my $san = <$fh2>; + foreach (split /,/, $san) { + chomp; + s/\A\s*//; + next unless s/\ADNS://; + if (/\A$RE_domain\z/o) { + $domains{$_} = 1; + } + else { + warn "WARNING: Ignoring invalid domain $_\n"; + } + } + last; + } + close $fh2; + + keys %domains; +}; +print STDERR "Found domain(s): ".join(", ", @domains), "\n" if $ENV{DEBUG}; + + +# Process DNS Authorizations +foreach my $domain (@domains) { + print STDERR "Processing new DNS authz for $domain\n" if $ENV{DEBUG}; + my $challenges = acme($RES{'new-authz'}, { + resource => 'new-authz', + identifier => { type => 'dns', value => $domain } + }); + die "No challenge in server response" unless defined $challenges->{challenges}; + my ($challenge) = grep {$_->{type} eq 'http-01'} @{$challenges->{challenges}}; + my $keyAuthorization = $challenge->{token}.'.'.$JWK_dgst64; + + # serve $keyAuthorization at http://$domain/.well-known/acme-challenge/$challenge->{token} + my $filename = $CHALLENGE_DIR.'/'.$challenge->{token}; + if (-e $filename) { + warn "WARNING: File exists: $filename\n"; + } + else { + open my $fh, '>', $filename or die "Can't open $filename: $!"; + print $fh $keyAuthorization; + close $fh; + } + + acme($challenge->{uri}, { + resource => 'challenge', + keyAuthorization => $keyAuthorization + }); + + for (my $i=0;; $i++) { + my $status = request('GET' => $challenge->{uri})->{status} // 'pending'; + die "Invalid challenge for $domain" if $status eq 'invalid'; + last if $status eq 'valid'; + die "Timeout exceeded while waiting for challenge to pass ($domain)\n" if $i >= $TIMEOUT; + sleep 1; + } +} + + +do { + print STDERR "Processing new CSR\n" if $ENV{DEBUG}; + open my $fh1, '-|', qw/openssl req -outform DER/, '-in', $CSR or die "Can't run req(1ssl): $!"; + my $req = do { local $/ = undef; <$fh1> }; + close $fh1; + + # The server also gives the cert URI in its 'Location' header in + # https://acme-v01.api.letsencrypt.org/acme/cert/$serial + my $x509 = acme($RES{'new-cert'}, { + resource => 'new-cert', + csr => encode_base64url($req) + }); + + open my $fh2, '|-', qw/openssl x509 -inform DER/, '-out', $X509 or die "Can't run x509(1ssl): $!"; + print $fh2 $x509; + close $fh2; +}; diff --git a/acme-webserver b/acme-webserver new file mode 100755 index 0000000..57ea789 --- /dev/null +++ b/acme-webserver @@ -0,0 +1,32 @@ +#!/usr/bin/perl -T + +use strict; +use warnings; + +my $ROOT = '/.well-known/acme-challenge'; + +$_ = <STDIN> // exit; +my $proto = s/ HTTP\/(1\.[01])\r\n\z// ? $1 : die "Error: Bad request\n"; +my $method = s/\A(GET|HEAD) // ? $1 : die "Error: Bad request\n"; + +# Consume the headers (and ignore them) +while (defined (my $h = <STDIN>)) { last if $h eq "\r\n" }; + +my ($status_line, $content_type, $content); +if (/\A\Q$ROOT\E\/([A-Za-z0-9_-]+)\z/ and -f $1) { + if (open my $fh, '<', $1) { + ($status_line, $content_type) = ('200 OK', 'application/jose+json'); + $content = do { local $/ = undef; <$fh> }; + close $fh; + } + else { + $status_line = '403 Forbidden'; + } +} + +print "HTTP/$proto ", ($status_line // '404 Not Found'), "\r\n"; +print "Content-Type: $content_type\r\n" if defined $content_type; +print "Content-Length: ".length($content)."\r\n" if defined $content; +print "Connection: close\r\n"; +print "\r\n"; +print $content if defined $content and $method eq 'GET'; diff --git a/letsencrypt b/letsencrypt new file mode 100755 index 0000000..50406f7 --- /dev/null +++ b/letsencrypt @@ -0,0 +1,281 @@ +#!/bin/bash + +# Dependencies nc(1), openssl(1), socat(1) + +set -ue +set -o pipefail +PATH=/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin +NAME=$(basename $0) + +WWW_USER=www-data +WWW_GROUP=www-data +ACME_WEBSERVER=acme-webserver +ACME_CLIENT=acme-slave + +declare COMMAND ACCOUNTKEY +declare -l GENKEY +declare RUNAS QUIET= DEBUG= + +declare SRVCERT= CHAIN= CSR SRVKEY +declare -l HASH= +declare SUBJECT=/ +declare SAN= +# https://security.stackexchange.com/questions/24106/which-key-usages-are-required-by-each-key-exchange-method +declare KEYUSAGE='digitalSignature, keyEncipherment, keyCertSign' +declare -a NOTIFY=() + +usage() { + local msg="${1:-}" + if [ "$msg" ]; then + echo "$NAME: $msg" >&2 + echo "Try '$NAME --help' for more information." >&2 + exit 1 + fi + cat <<- EOF + Usage: $NAME [OPTIONS] new-reg ACCOUNTKEY [EMAIL ..] + or: $NAME [OPTIONS] new-cert ACCOUNTKEY --output=CERT {--csr=CSR | CSR Options } + or: $NAME [OPTIONS] revoke-cert ACCOUNTKEY CERT [CERT ..] + + ACCOUNTKEY is the private key file of the user's account. Generic options are: + --genkey[=ALGO[:BITS]] For 'new-*' commands, generate key pairs (with mode 0600) if they don't + exist already. (Default: "RSA".) RSA is the only algorithm curently supported. + --runas=USERNAME Username to run the ACME client as. (This user doesn't need access to + any private key material.) + --help, -? Display this help text and exit + --quiet, -q Be quiet + --debug Turn on debug mode + + $NAME new-reg ACCOUNTKEY [EMAIL ..] + Register a new ACCOUNTKEY; an optional list of EMAIL addresses can be supplied as contact information. + + $NAME new-cert ACCOUNTKEY --output=CERT --csr=FILE + $NAME new-cert ACCOUNTKEY --output=CERT --key=FILE [--hash=ALGO] [--subject=STRING] [--san=STRING] [--keyusage=STRING] + Request a new Certificate Issuance. The Certificate Signing Request can be supplied directly, or + generated from the server key. + + --csr=FILE Certificate Signing Request to send (alternatively, use --key to generate it) + --key=FILE Server private key (use --genkey to generate it) + --hash=DGST Message digest to sign the CSR with (in PEM format) + --subject=STRING Subject name, formatted as "/type0=value0/type1=value1/type2=..." (default: "/") + --san=STRING Comma-separated list of Subject Alternative Names formatted as "type:value" + --keyusage=STRING Comma-separated list of Key Usages, see x509v3_config(5ssl) + (default: "digitalSignature,keyEncipherment,keyCertSign") + --chain Store not only the server certificate in the file specified with --output, but + also the CA's + --output=FILE Where to store the issued (signed) X.509 certificate + --notify=COMMAND Command to run upon success. (This option can be repeated.) + + $NAME revoke-cert {ACCOUNTKEY|SVRKEY} FILE [FILE ..] + Request that the given certificate(s) FILE(s) be revoked. The first argument can be either the account + key file or the server's private key. + EOF + exit 0 +} + +# Generate a key pair with mode 0600 +genkey() { + local key="$1" genkey= bits= + case "$GENKEY" in + rsa) genkey=genrsa;; + rsa:*) genkey=genrsa; bits=${GENKEY#*:};; + *) echo "Error: invalid key type ${GENKEY%%:*}" >&2; exit 1;; + esac + install --mode=0600 /dev/null "$key" # atomic creation with mode 0600 + openssl "$genkey" $bits >"$key" +} + + +# Parse options +declare -a ARGV=() +while [ $# -gt 0 ]; do + case "$1" in + --genkey) GENKEY=RSA;; + --genkey=*) GENKEY="${1#*=}";; + --runas=*) RUNAS="${1#*=}";; + --help|-\?) usage;; + --quiet|-q) QUIET=1;; + --debug) DEBUG=1;; + + --output=*) SRVCERT="${1#*=}";; + --chain) CHAIN=1;; + --csr=*) CSR="${1#*=}";; + --key=*) SRVKEY="${1#*=}";; + --hash=*) HASH="${1#*=}";; + --subject=*) SUBJECT="${1#*=}";; + --san=*) SAN="${1#*=}";; + --keyusage=*) KEYUSAGE="${1#*=}";; + --notify=*) NOTIFY+=( "${1#*=}" );; + + --) shift; ARGV+=( "$@" ); break ;; + -*) usage "unknown option '${1%%=*}'";; + *) if [ ${ACCOUNTKEY+x} ]; then + ARGV+=( "$1" ) + else + [ ${COMMAND+x} ] && ACCOUNTKEY="$1" || COMMAND="$1" + fi + esac + shift +done + +[ "${COMMAND:-}" ] || usage "missing command" +[ "$COMMAND" = 'new-reg' -o "$COMMAND" = 'new-cert' -o "$COMMAND" = 'revoke-cert' ] || + usage "invalid command $COMMAND" +[ ${#ARGV[@]} -eq 0 -o "$COMMAND" = 'new-reg' -o "$COMMAND" = 'revoke-cert' ] || + usage "invalid argument ${ARGV[0]}" + +[ "${ACCOUNTKEY:-}" ] || usage "missing account key" +if ! [ -f "$ACCOUNTKEY" -a -s "$ACCOUNTKEY" ]; then + if [ "$COMMAND" = 'new-reg' -a "${GENKEY+x}" ]; then + genkey "$ACCOUNTKEY" + else + echo "Error: keyfile '$ACCOUNTKEY' does not exist." >&2 + [[ ! "$COMMAND" =~ ^new- ]] || echo "Use 'new-reg --genkey' to generate and register an RSA key with mode 0600." >&2 + exit 1 + fi +fi + + +declare -a TMPFILES=() +declare CHALLENGE_DIR IPTABLES_SAVE +cleanup() { + set +e + [ ! ${IPTABLES_SAVE+x} ] || iptables-restore -c <"$IPTABLES_SAVE" + pkill -TERM -P $$ + [ ${#TMPFILES[@]} -eq 0 ] || rm -${DEBUG:+v}f "${TMPFILES[@]}" + [ ! ${CHALLENGE_DIR+x} ] || rm -${DEBUG:+v}rf "$CHALLENGE_DIR" +} +trap cleanup EXIT SIGINT + + +# Extract the public part of the user key +accountpub=$(mktemp --tmpdir XXXXXX.pub) +TMPFILES+=( "$accountpub" ) +openssl pkey -pubout <"$ACCOUNTKEY" >"$accountpub" +chmod 0644 "$accountpub" + + +if [ "$COMMAND" = 'revoke-cert' ]; then + if [ ${#ARGV[@]} -eq 0 ]; then + echo "Error: Nothing to revoke" >&2 + exit 1 + fi +elif [ "$COMMAND" = 'new-cert' ]; then + if [ ! "${SRVCERT:-}" ]; then + echo "Error: Missing --output" >&2 + exit 1 + fi + + # Generate a Certificate Signing Request if need be + if [ ${CSR+x} ]; then + if [ -z "$CSR" -o ! -s "$CSR" ]; then + echo "Error: Missing Certificate Signing Request $CSR. (One of --csr or --key must be set.)" >&2 + exit 1 + fi + else + CSR=$(mktemp --tmpdir XXXXXX.csr) + config=$(mktemp --tmpdir XXXXXX.cnf) + TMPFILES+=( "$CSR" "$config" ) + chmod 0644 "$CSR" + + if [ "$HASH" ]; then + case "$HASH" in + md5|rmd160|sha1|sha224|sha256|sha384|sha512) HASH="-$HASH";; + *) echo "Invalid digest algorithm: $HASH" >&2; exit 1;; + esac + fi + if [ ! "${SRVKEY:-}" ] || [ ! -s "$SRVKEY" ]; then + if [ "${SRVKEY:-}" -a "${GENKEY+x}" ]; then + genkey "$SRVKEY" + else + echo "Error: Missing private server key. Use new-cert --genkey --key=... to generate" >&2 + exit 1 + fi + fi + + [ ! "$DEBUG" ] || echo 'Generating Certificate Signing Request...' >&2 + cat >"$config" <<- EOF + [ req ] + distinguished_name = req_distinguished_name + req_extensions = v3_req + + [ req_distinguished_name ] + + [ v3_req ] + ${SAN:+subjectAltName= $SAN} + # XXX Golang errors on extensions marked critical + # https://github.com/letsencrypt/boulder/issues/565 + #basicConstraints = critical, CA:FALSE + #keyUsage = critical${KEYUSAGE:+, $KEYUSAGE} + basicConstraints = CA:FALSE + keyUsage = $KEYUSAGE + subjectKeyIdentifier = hash + EOF + openssl req -new -batch -key "$SRVKEY" $HASH -subj "$SUBJECT" -config "$config" -reqexts v3_req >"$CSR" + fi + [ ! "$DEBUG" ] || openssl req -noout -text <"$CSR" + + CHALLENGE_DIR=$(mktemp --tmpdir -d acme-challenge.XXXXXX) + x509=$(mktemp --tmpdir XXXXXX.pem) + TMPFILES+=( "$x509" ) + + [ ! "${RUNAS:-}" ] || chown "$RUNAS" "$CHALLENGE_DIR" "$x509" + chgrp "$WWW_GROUP" "$CHALLENGE_DIR" + chmod 0750 "$CHALLENGE_DIR" + + # Make sure a webserver is configured to server ACME challenges + if nc -z 127.0.0.1 80; then + [ ! "$DEBUG" ] || echo "Using existing webserver" >&2 + ln -${DEBUG:+v}Ts "$CHALLENGE_DIR" /var/www/acme-challenge + TMPFILES+=( "/var/www/acme-challenge" ) + else + temp=$(mktemp --tmpdir) + TMPFILES+=( "$temp" ) + iptables-save -c >"$temp" + IPTABLES_SAVE="$temp" + iptables -I INPUT -p tcp -m tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT + iptables -I OUTPUT -p tcp -m tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT + ( + [ ! "$DEBUG" ] || echo "Starting ACME webserver in $CHALLENGE_DIR" >&2 + cd "$CHALLENGE_DIR" || exit 1 + exec socat \ + TCP-LISTEN:80,setgid="$WWW_GROUP",setuid="$WWW_USER",reuseaddr,fork,max-children=5 \ + EXEC:"$ACME_WEBSERVER" + )& + fi + + ARGV=( "$CSR" "$CHALLENGE_DIR" "$x509" ) +fi + + +pipe=$(mktemp --tmpdir -u XXXXXX.fifo) +mkfifo -m0600 "$pipe" +TMPFILES+=( "$pipe" ) + +# Wait for signing requests from the ACME slave +acme_client() { + if [ "${RUNAS:-}" ]; then + sudo -u "$RUNAS" ${DEBUG:+DEBUG="$DEBUG"} -- $ACME_CLIENT "$@" + else + [ ${RUNAS+x} ] || echo "WARNING: Use --runas=USER to specify a user to drop permissions to." >&2 + DEBUG="$DEBUG" $ACME_CLIENT "$@" + fi +} + +acme_client "$COMMAND" "$accountpub" ${ARGV[0]+"${ARGV[@]}"} <"$pipe" | +while read data; do + echo -n "$data" | openssl dgst -sha256 -sign "$ACCOUNTKEY" -hex | sed 's/.*=\s*//' +done >"$pipe" + +if [ "$COMMAND" = 'new-cert' ]; then + # TODO + # Verify: dump and compare public keys + # Valid cert, signed by the right CA + + # Copy "$x509" to "$SRVCERT", possibly chained + # https://crt.sh/?q=cse-fresti.cse.chalmers.se&iCAID=7395 + cp "$x509" "$SRVCERT" + + for (( i=0; i<${#NOTIFY[@]}; i++ )); do + ${NOTIFY[$i]} + done +fi |