README

@@ -1,37 +1,5 @@
 MAILATTACH
 
-This program starts a process which listens on the LOOPBACKv4 address for
-incoming connections from postfix. The postfix master should view this as an
-advanced filter as explained in their documentation for post queue filtering:
-
-http://www.postfix.org/FILTER_README.html
-
-The original attempt was to implement this as a pre queue filter, but this
-required the milter protocol and postfix currently does not implement the
-replace body function from libmilter.
-
-You can specify the following command line options:
-
---abort-pgp --noabort-pgp
-	To either abort the attachment process if PGP encryption or signatures 
-	have been detected or not. If true, the mail will not be modified.
-
---abort-dkim --noabort-dkim
-	To either abort the attachment process if DKIM signatures have been
-	detected or not. If true, the mail will not be modified.
-
---in-port -i
-	The incoming smtp port/the port from which mail is received.
-
---out-port -o
-	The outgoing smtp port/the port to which mail ist passed through.
-
-HOWTO
-
-We essentially are MITM sniffing your email traffic and playing proxy from your
-postfix to your postfix. That's how this is intended to work according to the
-postfix website.
-
-This program needs to be started via it's own systemd service on system boot.
-You need to add the in and oputput ports to your postfix queue as described in
-the link above. More documentation is to a TODO
+This program starts a process which listens on a unix socket for incoming
+milter connections. Incoming mail is scanned for large files and files above a
+certain threshold are replaced with links which the user may specify.

include/config.h

@@ -22,8 +22,6 @@
 
 extern uint16_t listen_port, forward_port;
 
-/* Used as booleans, but integers for getops sake... */
-
-extern int abort_on_pgp, abort_on_dkim;
+extern bool abort_on_pgp, abort_on_dkim;
 
 #endif /* CONFIG_H */

include/detect.h

@@ -23,7 +23,6 @@
 #include "attach.h"
 
 bool detect_pgp(struct email_t* mail);
-bool detect_dkim(struct email_t* mail);
 char* detect_start_of_body(char* message);
 char* detect_end_of_body(char* message);
 #endif /* DETECT_H */

include/tools.h

@@ -23,5 +23,4 @@
 const char* insert_string(char * destination, const char* source, 
 	size_t dest_orig_len, size_t offset);
 
-
 #endif /* TOOLS_H */

src/attach.c

@@ -83,16 +83,17 @@ char* attach_files(char* message, size_t len){
 
 	struct email_t email = mail_from_text(message,len);
 	
+	printf("Received message header: [%.*s]\n", email.header_len, 
+		email.message);
+	printf("Received message body: [%.*s]\n", 
+		email.message_length-email.body_offset,
+		email.message + email.body_offset);
+
 	/* Check if mails are signed/encrypted, and abort if nescessary */
 	if(abort_on_pgp && detect_pgp(&email)){
 		printf("PGP detected, aborting...");
 		return email.message;
 	}
-	/* Check if mails are signed/encrypted, and abort if nescessary */
-	if(abort_on_dkim && detect_dkim(&email)){
-		printf("DKIM signature detected, aborting...");
-		return email.message;
-	}
 
 	return email.message;
 }

src/config.c

@@ -17,4 +17,4 @@
 #include "config.h"
 
 uint16_t listen_port = 4269, forward_port = 4270;
-int abort_on_pgp = true, abort_on_dkim = true;
+bool abort_on_pgp = true, abort_on_dkim = true;

src/detect.c

@@ -29,11 +29,6 @@ char* pgp_signatures[] =
 	"-----BEGIN PGP MESSAGE-----"
 };
 
-char* dkim_signatures[] = 
-{
-	"DKIM-Signature:"
-};
-
 bool detect_pgp(struct email_t* mail){
 		
 	size_t points = 0;
@@ -50,23 +45,6 @@ bool detect_pgp(struct email_t* mail){
 	return points >= 2;
 }
 
-bool detect_dkim(struct email_t* mail){
-		
-	size_t points = 0;
-	
-	for(size_t i = 0; i < (sizeof(dkim_signatures)/sizeof(char*));i++){
-		if(strcasestr(mail->message, dkim_signatures[i]) != NULL
-				&& strcasestr(mail->message, dkim_signatures[i])
-				<= (mail->message+mail->header_len)){
-			points++;
-		}
-		
-	}
-	
-
-	return points >= 1;
-}
-
 /* If body hasn't started yet, it returns NULL, if it has started, it returns
  * the pointer to the beginning of the newline.
  */

src/main.c

@@ -6,7 +6,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
-#include <getopt.h>
+
 
 #include "network.h"
 #include "config.h"
@@ -15,66 +15,11 @@
 int main(int argc, char* argv[]){
 	
 	printf("INIT\n");
-
-	int c;
-
-	while (1){
-		static struct option long_options[] =
-		{
-			{"abort-pgp",	no_argument, &abort_on_pgp, 1},
-			{"abort-dkim",	no_argument, &abort_on_dkim,1},
-			{"noabort-pgp",	no_argument, &abort_on_pgp, 0},
-			{"noabort-dkim",no_argument, &abort_on_dkim,0},
-			{"in-port",	required_argument, 0, 'i'},
-			{"out-port",	required_argument, 0, 'o'},
-			{0, 0, 0, 0}
-		};
-		/* getopt_long stores the option index here. */
-		int option_index = 0;
-
-		c = getopt_long (argc, argv, "i:o:pd",
-			       long_options, &option_index);
-
-		/* Detect the end of the options. */
-		if (c == -1){
-			break;
-		}
-
-		switch (c){
-		case 0:
-			break;
-		case 'i':
-			listen_port = atoi(optarg);
-			break;
-
-		case 'o':
-			forward_port = atoi(optarg);
-			break;
-
-		case '?':
-			/* getopt_long already printed an error message. */
-			return EXIT_FAILURE;
-			break;
-
-		default:
-			abort ();
-		}
-	}
-
-	printf("Incoming port: %u outgoing port: %u on loopback interface\n",
-		 listen_port, forward_port);
-
-	printf("Ignoring PGP signed/encrypted messages: %s\n",
-		abort_on_pgp ? "true":false);
-
-	printf("Ignoring DKIM signed messages: %s\n",
-		abort_on_dkim ? "true" : "false");
-
+	
 	if(init_net() < 0){
 		return EXIT_FAILURE;
 	}
 
-	loop_clients();
-	return EXIT_SUCCESS;
+
 
 }

src/network.c

@@ -273,6 +273,9 @@ void loop_clients(){
 	
 	while (1) {
 
+		/*
+		* accept: wait for a connection request
+		*/
 		childfd = accept(parentfd, (struct sockaddr *) &clientaddr, &clientlen);
 		if (childfd < 0){
 			perror("accept failed");