feat: add --report-body-file to customize aggregate report mail body (#437)

Lets operators replace the hardcoded plain-text body of RUA report
emails with the contents of a file, with %DOMAIN%/%DATE% token
substitution. Falls back to the existing boilerplate text when unset,
so default behavior is unchanged. Works from the command line or
opendmarc-reports.conf via the existing generic key=value loader.

Author: thegushi

reports/opendmarc-reports.8.in

@@ -189,6 +189,24 @@ Normally this would be done to prevent reports from being sent too close
 together.  Implied by
 .IR --test .
 .TP
+.I --report-body-file=file
+Replaces the default plain-text body of aggregate report e-mail messages
+with the contents of
+.IR file ,
+read once at startup.  The tokens
+.B %DOMAIN%
+and
+.B %DATE%
+are substituted, if present, with the reporting domain and the message's
+.I Date:
+header value, respectively.  If not specified, the default body is
+.RS
+.nf
+This is a DMARC aggregate report for <domain>
+generated at <timestamp>
+.fi
+.RE
+.TP
 .I --report-contact=addr
 Specifies the contact address written into the
 .I <email>

reports/opendmarc-reports.in

@@ -162,6 +162,8 @@ my $dbscheme     = $def_dbscheme;
 my $repdom       = hostdomain();
 my $repemail     = "postmaster@" . $repdom;
 my $repcontact;
+my $repbodyfile;
+my $repbodytemplate;
 
 my $smtp_server  = '127.0.0.1';
 my $smtp_port    = 25;
@@ -405,6 +407,8 @@ sub usage
 	print STDERR "\t--nodomain=name    omit a report for named domain\n";
 	print STDERR "\t--noupdate         don't record report transmission\n";
 	print STDERR "\t--report-bcc       bcc address for aggregate reports\n";
+	print STDERR "\t--report-body-file=file  custom plain-text body for aggregate\n";
+	print STDERR "\t                   reports (%DOMAIN%/%DATE% tokens substituted)\n";
 	print STDERR "\t--report-contact   contact address for report metadata (default: --report-email)\n";
 	print STDERR "\t--report-email     envelope/From address for outgoing reports [$repemail]\n";
 	print STDERR "\t--report-org       reporting organization [$repdom]\n";
@@ -512,6 +516,7 @@ my $opt_retval = &Getopt::Long::GetOptions ('archive-dir=s' => \$archive_dir,
                                             'n|test' => \$testmode,
                                             'nodomain=s' => \@skipdomains,
                                             'report-bcc=s' => \$repbcc,
+                                            'report-body-file=s' => \$repbodyfile,
                                             'report-contact=s' => \$repcontact,
                                             'report-email=s' => \$repemail,
                                             'report-org=s' => \$repdom,
@@ -656,6 +661,14 @@ if (defined($noreports_file))
 	close($nrf);
 }
 
+if (defined($repbodyfile))
+{
+	open(my $rbf, '<', $repbodyfile)
+		or die "$progname: can't open report body file $repbodyfile: $!\n";
+	$repbodytemplate = do { local $/; <$rbf> };
+	close($rbf);
+}
+
 # Test mode requested, don't update last sent and keep xml files
 $doupdate  = ($testmode == 1) ? 0 : $doupdate;
 $keepfiles = ($testmode == 1) ? 1 : $keepfiles;
@@ -1700,8 +1713,18 @@ foreach (@$domainset)
 			$mailout .= "--$boundary\n";
 			$mailout .= "Content-Type: text/plain;\n";
 			$mailout .= "\n";
-			$mailout .= "This is a DMARC aggregate report for $domain\n";
-			$mailout .= "generated at " . localtime() . "\n";
+			if (defined($repbodytemplate))
+			{
+				my $body = $repbodytemplate;
+				$body =~ s/%DOMAIN%/$domain/g;
+				$body =~ s/%DATE%/$datestr/g;
+				$mailout .= $body;
+			}
+			else
+			{
+				$mailout .= "This is a DMARC aggregate report for $domain\n";
+				$mailout .= "generated at " . localtime() . "\n";
+			}
 			$mailout .= "\n";
 			$mailout .= "--$boundary\n";
 			$mailout .= "Content-Type: application/gzip\n";