Added verbose flag

Signed-off-by: Tyrolyean <tyrolyean@tyrolyean.net>
This commit is contained in:
Tyrolyean 2020-04-29 13:43:45 +02:00
parent 13b32a48b1
commit 8742db0b36
No known key found for this signature in database
GPG Key ID: 81EC9BAC5E9667C6
5 changed files with 109 additions and 28 deletions

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@ -23,10 +23,11 @@
#include "mail.h"
struct email_t mail_from_text(char* message, size_t length);
struct email_t* mail_from_text(char* message, size_t length);
void redetect_body_head(struct email_t* mail);
void unravel_multipart_mail(struct email_t* mail, char* boundary,
size_t boundary_len);
void unravel_multipart_mail(struct email_t* mail);
void free_submails(struct email_t* mail);
char* attach_files(char* message, size_t len);

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@ -28,4 +28,6 @@ extern int abort_on_pgp, abort_on_dkim;
extern char* instance_id;
extern bool verbose;
#endif /* CONFIG_H */

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@ -30,7 +30,14 @@ struct email_t{
* there was no clear distinction between header and body...
*/
size_t header_len, body_offset, message_length;
/* Apparently emails consist of several smaller emails if you send an
* attachment alongside them. This also happens when you send an email
* as html. Therefore emails are recursive. Ask apple, their mail client
* is basically insane by this point...
*/
bool is_multipart;
size_t boundary_len;
char* boundary;
size_t submes_cnt;
struct email_t** submes;

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@ -28,39 +28,50 @@
#include <ctype.h>
#include <stdlib.h>
struct email_t mail_from_text(char* message, size_t length){
struct email_t* mail_from_text(char* message, size_t length){
struct email_t mail;
memset(&mail, 0, sizeof(mail));
mail.message = message;
mail.message_length = length;
mail.submes_cnt = 0;
mail.submes = NULL;
struct email_t* mail = malloc(sizeof(struct email_t));;
memset(mail, 0, sizeof(struct email_t));
mail->message = message;
mail->message_length = length;
mail->submes_cnt = 0;
mail->submes = NULL;
mail->is_multipart = false;
mail->boundary = NULL;
mail->boundary_len = 0;
redetect_body_head(&mail);
char* cont_type = search_header_key(&mail, "Content-Type");
redetect_body_head(mail);
char* cont_type = search_header_key(mail, "Content-Type");
if(cont_type == NULL){
/* Halleluja, I've got nothing to do! WOO */
mail.is_multipart = false;
mail->is_multipart = false;
return mail;
}else{
size_t value_length = 0;
char * mime_type = get_value_from_key(&value_length,
cont_type - mail.message, &mail);
cont_type - mail->message, mail);
if(mime_type != NULL){
if(strncasecmp(mime_type, MULTIPART_MIME,
strlen(MULTIPART_MIME)) == 0){
/* We have multiple messages cramped inside this
* one. Let's unravel em!
*/
mail->is_multipart = true;
size_t bd_len = 0;
char* bd = get_multipart_boundary(
mime_type, value_length, &bd_len);
if(bd != NULL){
printf("Received boundary: [%.*s]\n",
(int)bd_len, bd);
mail->boundary = bd;
mail->boundary_len = bd_len;
if(verbose){
printf("Received boundary: "
"[%.*s]\n",
(int)bd_len, bd);
}
}
unravel_multipart_mail(&mail, bd, bd_len);
unravel_multipart_mail(mail);
}
}
@ -106,9 +117,62 @@ void redetect_body_head(struct email_t* mail){
}
void unravel_multipart_mail(struct email_t* mail, char* boundary,
size_t boundary_len){
/* This function creates the submail-messages from the boundary defined for
* multipart messages. This function doesN'T perform header checks for that
* boundary!
*/
void unravel_multipart_mail(struct email_t* mail){
if(mail == NULL || !mail->is_multipart || mail->boundary == NULL){
return;
}
char ** mail_boundarys = NULL;
size_t mb_cnt = 0;
char* boundary = malloc(mail->boundary_len+1);
memset(boundary, 0, mail->boundary_len+1);
memcpy(boundary,mail->boundary, mail->boundary_len);
char* newloc = mail->message + mail->body_offset;
for(;newloc < mail->message + mail->message_length;){
newloc = strstr(newloc,
boundary);
if(newloc == NULL || newloc >
(mail->message + mail->message_length)){
break;
}else{
mail_boundarys = realloc(mail_boundarys,
++mb_cnt*(sizeof(char*)));
mail_boundarys[mb_cnt-1] = newloc;
}
newloc++;
}
if(verbose){
printf("Found %lu boundarys inside mail, which means %li "
"submessages\n", mb_cnt, mb_cnt-1);
}
free(mail_boundarys);
free(boundary);
return;
}
void free_submails(struct email_t* mail){
if(!mail->is_multipart){
return;
}
for(size_t i = 0; i < mail->submes_cnt; i++){
free_submails(mail->submes[i]);
free(mail->submes[i]);
}
free(mail->submes);
return;
}
@ -118,27 +182,32 @@ void unravel_multipart_mail(struct email_t* mail, char* boundary,
* Attempts to replace files inside the email with links to it on a webserver
*/
char* attach_files(char* message, size_t len){
struct email_t email = mail_from_text(message,len);
char* mess;
struct email_t *email = mail_from_text(message,len);
/* Check if mails are signed/encrypted, and abort if nescessary */
if(abort_on_pgp && detect_pgp(&email)){
if(abort_on_pgp && detect_pgp(email)){
printf("PGP detected, aborting...");
return email.message;
goto finish;
}
/* Check if mails are signed/encrypted, and abort if nescessary */
if(abort_on_dkim && detect_dkim(&email)){
if(abort_on_dkim && detect_dkim(email)){
printf("DKIM signature detected, aborting...");
return email.message;
goto finish;
}
/* Now we can start the real work! */
/* Announce our presence via header */
if(append_header(&email,"X-Mailattached", instance_id) < 0){
if(append_header(email,"X-Mailattached", instance_id) < 0){
fprintf(stderr, "Failed to attach header!\n");
return email.message;
goto finish;
}
return email.message;
finish:
mess = email->message;
free_submails(email);
free(email);
return mess;
}

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@ -22,3 +22,5 @@
uint16_t listen_port = 4269, forward_port = 4270;
int abort_on_pgp = true, abort_on_dkim = true;
char* instance_id = NULL;
bool verbose = false;