acme: add challenge plugins

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>

src/PVE/ACME/Challenge.pm

@@ -0,0 +1,22 @@
+package PVE::ACME::Challenge;
+
+use strict;
+use warnings;
+
+sub supported_challenge_types {
+    return {};
+}
+
+sub setup {
+    my ($class, $acme, $authorization) = @_;
+
+    die "implement me\n";
+}
+
+sub teardown {
+    my ($self) = @_;
+
+    die "implement me\n";
+}
+
+1;

src/PVE/ACME/StandAlone.pm

@@ -0,0 +1,71 @@
+package PVE::ACME::StandAlone;
+
+use strict;
+use warnings;
+
+use HTTP::Daemon;
+use HTTP::Response;
+
+use base qw(PVE::ACME::Challenge);
+
+sub supported_challenge_types {
+    return { 'http-01' => 1 };
+}
+
+sub setup {
+    my ($class, $acme, $authorization) = @_;
+
+    my $challenges = $authorization->{challenges};
+    die "no challenges defined in authorization\n" if !$challenges;
+
+    my $http_challenges = [ grep {$_->{type} eq 'http-01'} @$challenges ];
+    die "no http-01 challenge defined in authorization\n"
+	if ! scalar $http_challenges;
+
+    my $http_challenge = $http_challenges->[0];
+
+    die "no token found in http-01 challenge\n" if !$http_challenge->{token};
+
+    my $key_authorization = $acme->key_authorization($http_challenge->{token});
+
+    my $server = HTTP::Daemon->new(
+	LocalPort => 80,
+	ReuseAddr => 1,
+    ) or die "Failed to initialize HTTP daemon\n";
+    my $pid = fork() // die "Failed to fork HTTP daemon - $!\n";
+    if ($pid) {
+	my $self = {
+	    server => $server,
+	    pid => $pid,
+	    authorization => $authorization,
+	    key_auth => $key_authorization,
+	    url => $http_challenge->{url},
+	};
+
+	return bless $self, $class;
+    } else {
+	while (my $c = $server->accept()) {
+	    while (my $r = $c->get_request()) {
+		if ($r->method() eq 'GET' and $r->uri->path eq "/.well-known/acme-challenge/$http_challenge->{token}") {
+		    my $resp = HTTP::Response->new(200, 'OK', undef, $key_authorization);
+		    $resp->request($r);
+		    $c->send_response($resp);
+		} else {
+		    $c->send_error(404, 'Not found.')
+		}
+	    }
+	    $c->close();
+	    $c = undef;
+	}
+    }
+}
+
+sub teardown {
+    my ($self) = @_;
+
+    eval { $self->{server}->close() };
+    kill('KILL', $self->{pid});
+    waitpid($self->{pid}, 0);
+}
+
+1;