Verify GPG signature using OpenPGP Perl module.

1 files changed, 54 insertions, 73 deletions

diff --git a/lex.cgi b/lex.cgi
index e4a1994..9c11b28 100755
--- a/lex.cgi
+++ b/lex.cgi
@@ -2,22 +2,48 @@
 
 use strict;
 use warnings;
+use File::Spec;
+use File::Find;
 use File::Path qw(make_path);
 use Time::HiRes qw(time);
 use Email::MIME;
 use OpenBSD::Pledge;
 use OpenBSD::Unveil;
 
+my $start_time = time();
+
+# Load Crypt::OpenPGP and all Crypt:: sub-modules before unveil()
+BEGIN {
+	require Crypt::OpenPGP;
+
+	for my $inc_dir (@INC) {
+		next unless -d $inc_dir;
+		my $crypt_dir = File::Spec->catdir($inc_dir, 'Crypt');
+		next unless -d $crypt_dir;
+
+		find(sub {
+			return unless /\.pm$/;
+			my $rel = File::Spec->abs2rel($File::Find::name, $inc_dir);
+			$rel =~ s/\.pm$//;
+			my $module = join('::', File::Spec->splitdir($rel));
+			eval "require $module;";
+		}, $crypt_dir);
+	}
+
+	# Trigger backend instantiation (Math::BigInt, AutoLoader, Ciphers)
+	eval {
+		my $pgp = Crypt::OpenPGP->new();
+	};
+}
+
 my $base_dir = "/var/lex";
 my $keyring_file = "$base_dir/pubring.gpg";
 
-unveil("/usr/local/bin/gpg", "rx") or die "unveil gpg failed: $!";
-unveil("/dev/null", "rw")            or die "unveil /dev/null failed: $!";
-unveil("/tmp", "rwc")                or die "unveil /tmp failed: $!";
-unveil($base_dir, "rwc")            or die "unveil $base_dir failed: $!";
-unveil()                            or die "unveil lock failed: $!";
+unveil("/dev/null", "rw") or die "unveil /dev/null failed: $!";
+unveil($base_dir, "rwc") or die "unveil $base_dir failed: $!";
+unveil() or die "unveil lock failed: $!";
 
-pledge('stdio rpath wpath cpath proc exec') or die "pledge failed: $!";
+pledge('stdio rpath wpath cpath') or die "pledge failed: $!";
 
 my $log_file = "$base_dir/debug.log";
 my $max_log_bytes = 1024 * 1024; # 1 MB cap
@@ -25,6 +51,7 @@ my $max_log_bytes = 1024 * 1024; # 1 MB cap
 sub log_msg {
 	my ($msg) = @_;
 
+	# Truncate if >$max_log_bytes
 	if (-e $log_file && -s $log_file >= $max_log_bytes) {
 		my $clrh;
 		if (open($clrh, '>', $log_file)) {
@@ -36,7 +63,6 @@ sub log_msg {
 	if (open($lh, '>>', $log_file)) {
 		my $tz_offset = 8 * 3600;
 		my ($sec, $min, $hour, $mday, $mon, $year) = gmtime(time() + $tz_offset);
-
 		my $timestamp = sprintf(
 			"%04d-%02d-%02d %02d:%02d:%02d",
 			$year + 1900, $mon + 1, $mday, $hour, $min, $sec
@@ -57,74 +83,28 @@ sub verify_pgp_signature {
 	my ($signed_data, $signature) = @_;
 
 	unless (-f $keyring_file) {
-		log_msg("ERROR: Keyring missing at $keyring_file");
+		log_msg("ERROR: No keyring at $keyring_file");
 		return 0;
 	}
 
-	my $tmp_dir = "/tmp/lex";
-	unless (-d $tmp_dir) {
-		make_path($tmp_dir);
-	}
-
-	my $msg_id   = sprintf("msg_%.6f_$$", time());
-	my $tmp_data = "${tmp_dir}/${msg_id}.mime";
-	my $tmp_sig  = "${tmp_dir}/${msg_id}.sig";
-
-	# Ensure CRLF line endings on the signed data block
+	# Ensure CRLF line endings per OpenPGP canonical specification
 	$signed_data =~ s/\r?\n/\r\n/g;
 
-	my $dh;
-	unless (open($dh, '>:raw', $tmp_data)) {
-		log_msg("ERROR: Could not create temp data file: $!");
-		return 0;
-	}
-	print $dh $signed_data;
-	close($dh);
-
-	# Write sig file with trailing CRLF
-	my $sh;
-	unless (open($sh, '>:raw', $tmp_sig)) {
-		log_msg("ERROR: Could not create temp sig file: $!");
-		unlink($tmp_data);
-		return 0;
-	}
-	print $sh $signature . "\r\n";
-	close($sh);
-
-	my $pipe;
-	my $gpg_output = "";
-	my $pid = open($pipe, "-|") // die "Cannot fork: $!";
-
-	if ($pid == 0) {
-		open(STDERR, '>&', STDOUT);
-		exec(
-			'/usr/local/bin/gpg',
-			'--batch',
-			'--no-default-keyring',
-			'--keyring', $keyring_file,
-			'--trust-model', 'always',
-			'--verify',
-			$tmp_sig,
-			$tmp_data
-		) or exit(127);
-	}
+	my $pgp = Crypt::OpenPGP->new(
+		PubRing => $keyring_file,
+	);
 
-	while (my $line = <$pipe>) {
-		$gpg_output .= $line;
+	unless ($pgp) {
+		log_msg("ERROR: Failed to initialize PGP");
+		return 0;
 	}
-	close($pipe);
-	my $exit_code = $? >> 8;
 
-	unlink($tmp_data, $tmp_sig);
+	my $verified = $pgp->verify(
+		Data      => $signed_data,
+		Signature => $signature,
+	);
 
-	if ($exit_code == 0) {
-		return 1;
-	} else {
-		$gpg_output =~ s/\r?\n/ /g;
-		log_msg("DEBUG: gpg output: $gpg_output");
-		log_msg("DEBUG: gpg exited with code $exit_code");
-		return 0;
-	}
+	return $verified ? 1 : 0;
 }
 
 my $content_type   = $ENV{'CONTENT_TYPE'} // '';
@@ -132,7 +112,7 @@ my $content_length = $ENV{'CONTENT_LENGTH'} // 0;
 
 my $remote_ip  = $ENV{'REMOTE_ADDR'} // 'unknown';
 my $user_agent = $ENV{'HTTP_USER_AGENT'} // 'unknown';
-log_msg("INFO: Request received from $remote_ip [$user_agent]");
+log_msg("INFO: New request from $remote_ip [$user_agent]");
 
 unless ($content_length > 0) {
 	log_msg("WARN: content_length is 0 or missing");
@@ -165,7 +145,7 @@ for my $pair (split(/&/, $raw_data)) {
 
 my $mime_raw = $params{'body-mime'} // '';
 if ($mime_raw eq '') {
-	log_msg("WARN: 'body-mime' parameter is empty or missing");
+	log_msg("WARN: No MIME message in payload");
 	respond_ok();
 }
 
@@ -191,7 +171,7 @@ unless ($pgp_sig) {
 }
 
 unless (length($signed_part) > 0 && $pgp_sig) {
-	log_msg("WARN: Missing signed_part content or PGP signature block");
+	log_msg("WARN: Missing PGP signature block");
 	respond_ok();
 }
 
@@ -206,7 +186,7 @@ $plain_text =~ s/\n-- \n.*$//s;
 $plain_text =~ s/^\s+|\s+$//g;
 
 unless (length($plain_text) > 0) {
-	log_msg("WARN: Extracted plain_text is empty after stripping");
+	log_msg("WARN: Message is empty after stripping");
 	respond_ok();
 }
 
@@ -219,8 +199,9 @@ unless (open($qfh, '>>:utf8', $queue_file)) {
 print $qfh $plain_text . "\n";
 close($qfh);
 
-my $msg_id            = sprintf("msg_%.6f_$$", time());
+my $elapsed_ms = sprintf("%.2fms", (time() - $start_time) * 1000);
+my $msg_id = sprintf("msg_%.6f_$$", time());
 my $content_length_kb = sprintf("%.2f KB", $content_length / 1024);
-log_msg("INFO: Processed $msg_id successfully ($content_length_kb)");
-respond_ok();
 
+log_msg("INFO: Processed $msg_id ($content_length_kb) in $elapsed_ms");
+respond_ok();