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Added base 64 en-decode logic, detection

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Signed-off-by: Tyrolyean <tyrolyean@tyrolyean.net>
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Tyrolyean 2020-04-29 19:19:38 +02:00
parent 5c71c8895c
commit 60c0050a9b
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8 changed files with 361 additions and 4 deletions
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12
README
View file

@ -26,6 +26,18 @@ You can specify the following command line options:
--out-port -o
The outgoing smtp port/the port to which mail ist passed through.
--directory -d
The directory inside of which the attachments will be stored in.
--url -u
The base which should point to the same location as the directory does,
for exaple if the directory is /var/www/html and the URL base is
https://example.com then a file in /var/www/html/attachment01.pdf should
be linkable via https://example.com/attachment01.pdf
Ah and please, please, pretty please disable directory indexing on your
webserver!
That WILL BE a security riks!
HOWTO
We essentially are MITM sniffing your email traffic and playing proxy from your

97
include/base64.h Normal file
View file

@ -0,0 +1,97 @@
/*
* Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/* ====================================================================
* Copyright (c) 1995-1999 The Apache Group. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* 4. The names "Apache Server" and "Apache Group" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE APACHE GROUP OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Group and was originally based
* on public domain software written at the National Center for
* Supercomputing Applications, University of Illinois, Urbana-Champaign.
* For more information on the Apache Group and the Apache HTTP server
* project, please see <http://www.apache.org/>.
*
*/
/* Base64 encoder/decoder. Originally Apache file ap_base64.c
*/
#ifndef BASE64_H
#define BASE64_H
extern const unsigned char pr2six[256];
int Base64decode_len(const char *bufcoded);
int Base64decode(char *bufplain, const char *bufcoded);
extern const char basis_64[];
int Base64encode_len(int len);
int Base64encode(char *encoded, const char *string, int len);
#endif /* BASE64_H */

2
include/mail.h
View file

@ -52,6 +52,7 @@ struct email_t{
size_t submes_cnt;
struct email_t** submes;
struct email_t* parent;
bool base64_encoded;
};
int append_header(struct email_t* mail, const char* key, const char* value);
@ -64,5 +65,6 @@ void propagate_insert_delete(struct email_t* mail, char* change_p,
void propagate_root_pointer(struct email_t* mail, char* change_p, char* old_p);
#define MULTIPART_MIME "multipart/"
#define BASE64_ENC "base64"
#endif /* MAIL_H */

6
include/tools.h
View file

@ -24,14 +24,16 @@
char* insert_string(char * destination, const char* source,
size_t dest_orig_len, size_t offset);
char* search_header_key(struct email_t* mail, const char* key);
char* search_header_key(const struct email_t* mail, const char* key);
char* get_value_from_key(size_t* val_len, size_t key_offset,
struct email_t* mail);
const struct email_t* mail);
char* get_multipart_boundary(char* content_type, size_t content_len,
size_t* boundary_len);
const char* get_next_line(const char* message, size_t len);
const char* get_prev_line(const char* message, size_t len_neg);
bool detect_base64(const struct email_t* mail);
#endif /* TOOLS_H */

2
src/attach.c
View file

@ -96,6 +96,7 @@ struct email_t* mail_from_text(char* message, size_t length,
}
}
}
mail->base64_encoded = detect_base64(mail);
return mail;
}
@ -272,6 +273,7 @@ char* attach_files(char* message, size_t len){
fprintf(stderr, "Failed to attach header!\n");
goto finish;
}
finish:
mess = email->message;
free_submails(email);

209
src/base64.c Normal file
View file

@ -0,0 +1,209 @@
/*
* Copyright (c) 2003 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this
* file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_LICENSE_HEADER_END@
*/
/* ====================================================================
* Copyright (c) 1995-1999 The Apache Group. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* 4. The names "Apache Server" and "Apache Group" must not be used to
* endorse or promote products derived from this software without
* prior written permission. For written permission, please contact
* apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Group.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by the Apache Group
* for use in the Apache HTTP server project (http://www.apache.org/)."
*
* THIS SOFTWARE IS PROVIDED BY THE APACHE GROUP ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE APACHE GROUP OR
* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Group and was originally based
* on public domain software written at the National Center for
* Supercomputing Applications, University of Illinois, Urbana-Champaign.
* For more information on the Apache Group and the Apache HTTP server
* project, please see <http://www.apache.org/>.
*
*/
/* Base64 encoder/decoder. Originally Apache file ap_base64.c
*/
#include <string.h>
#include "base64.h"
/* aaaack but it's fast and const should make it shared text page. */
const unsigned char pr2six[256] =
{
/* ASCII table */
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 62, 64, 64, 64, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 64, 64, 64, 64, 64, 64,
64, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 64, 64, 64, 64, 64,
64, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64,
64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64, 64
};
int Base64decode_len(const char *bufcoded)
{
int nbytesdecoded;
register const unsigned char *bufin;
register int nprbytes;
bufin = (const unsigned char *) bufcoded;
while (pr2six[*(bufin++)] <= 63);
nprbytes = (bufin - (const unsigned char *) bufcoded) - 1;
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
return nbytesdecoded + 1;
}
int Base64decode(char *bufplain, const char *bufcoded)
{
int nbytesdecoded;
register const unsigned char *bufin;
register unsigned char *bufout;
register int nprbytes;
bufin = (const unsigned char *) bufcoded;
while (pr2six[*(bufin++)] <= 63);
nprbytes = (bufin - (const unsigned char *) bufcoded) - 1;
nbytesdecoded = ((nprbytes + 3) / 4) * 3;
bufout = (unsigned char *) bufplain;
bufin = (const unsigned char *) bufcoded;
while (nprbytes > 4) {
*(bufout++) =
(unsigned char) (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
*(bufout++) =
(unsigned char) (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
*(bufout++) =
(unsigned char) (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
bufin += 4;
nprbytes -= 4;
}
/* Note: (nprbytes == 1) would be an error, so just ingore that case */
if (nprbytes > 1) {
*(bufout++) =
(unsigned char) (pr2six[*bufin] << 2 | pr2six[bufin[1]] >> 4);
}
if (nprbytes > 2) {
*(bufout++) =
(unsigned char) (pr2six[bufin[1]] << 4 | pr2six[bufin[2]] >> 2);
}
if (nprbytes > 3) {
*(bufout++) =
(unsigned char) (pr2six[bufin[2]] << 6 | pr2six[bufin[3]]);
}
*(bufout++) = '\0';
nbytesdecoded -= (4 - nprbytes) & 3;
return nbytesdecoded;
}
const char basis_64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int Base64encode_len(int len)
{
return ((len + 2) / 3 * 4) + 1;
}
int Base64encode(char *encoded, const char *string, int len)
{
int i;
char *p;
p = encoded;
for (i = 0; i < len - 2; i += 3) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
*p++ = basis_64[((string[i] & 0x3) << 4) |
((int) (string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2) |
((int) (string[i + 2] & 0xC0) >> 6)];
*p++ = basis_64[string[i + 2] & 0x3F];
}
if (i < len) {
*p++ = basis_64[(string[i] >> 2) & 0x3F];
if (i == (len - 1)) {
*p++ = basis_64[((string[i] & 0x3) << 4)];
*p++ = '=';
}
else {
*p++ = basis_64[((string[i] & 0x3) << 4) |
((int) (string[i + 1] & 0xF0) >> 4)];
*p++ = basis_64[((string[i + 1] & 0xF) << 2)];
}
*p++ = '=';
}
*p++ = '\0';
return p - encoded;
}

33
src/detect.c
View file

@ -20,6 +20,7 @@
#include <string.h>
#include "detect.h"
#include "tools.h"
char* pgp_signatures[] =
{
@ -111,3 +112,35 @@ char* detect_end_of_body(char* message){
return strstr(message, data);
}
bool detect_base64(const struct email_t* mail){
char* encoding = search_header_key(mail, "Content-Transfer-Encoding");
if(encoding == NULL){
return false;
}else{
size_t value_length = 0;
char * type = get_value_from_key(&value_length,
encoding - mail->message, mail);
if(type != NULL){
if(strncasecmp(type, BASE64_ENC, strlen(BASE64_ENC))
== 0){
return true;
}else{
return false;
}
}else{
return false;
}
}
}

4
src/tools.c
View file

@ -52,7 +52,7 @@ char* insert_string(char * destination, const char* source,
/* Searches the given header for the key provided and, if found, returns the
* pointer to that key NOT the value
*/
char* search_header_key(struct email_t* mail, const char* key){
char* search_header_key(const struct email_t* mail, const char* key){
if(mail == NULL || key == NULL){
return NULL;
@ -79,7 +79,7 @@ char* search_header_key(struct email_t* mail, const char* key){
* otherwise a pointer to the first character of the value is returned.
*/
char* get_value_from_key(size_t* val_len, size_t key_offset,
struct email_t* mail){
const struct email_t* mail){
if(val_len == NULL || mail == NULL){