src/libpttls/pt_tls.c

   1 /*
   2  * Copyright (C) 2012 Martin Willi
   3  * Copyright (C) 2012 revosec AG
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * for more details.
  14  */
  15
  16 #include "pt_tls.h"
  17
  18 #include <utils/debug.h>
  19
  20 /*
  21  * PT-TNC Message format:
  22  *                       1                   2                   3
  23  *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  24  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  25  *  |    Reserved   |           Message Type Vendor ID              |
  26  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  27  *  |                          Message Type                         |
  28  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  29  *  |                         Message Length                        |
  30  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  31  *  |                       Message Identifier                      |
  32  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *  |                Message Value (e.g. PB-TNC Batch) . . .        |
  34  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  */
  36
  37 /**
  38  * Read a chunk of data from TLS, returning a reader for it
  39  */
  40 static bio_reader_t* read_tls(tls_socket_t *tls, size_t len)
  41 {
  42         ssize_t got, total = 0;
  43         char *buf;
  44
  45         buf = malloc(len);
  46         while (total < len)
  47         {
  48                 got = tls->read(tls, buf + total, len - total, TRUE);
  49                 if (got <= 0)
  50                 {
  51                         free(buf);
  52                         return NULL;
  53                 }
  54                 total += got;
  55         }
  56         return bio_reader_create_own(chunk_create(buf, len));
  57 }
  58
  59 /**
  60  * Read a PT-TLS message, return header data
  61  */
  62 bio_reader_t* pt_tls_read(tls_socket_t *tls, u_int32_t *vendor,
  63                                                   u_int32_t *type, u_int32_t *identifier)
  64 {
  65         bio_reader_t *reader;
  66         u_int32_t len;
  67         u_int8_t reserved;
  68
  69         reader = read_tls(tls, PT_TLS_HEADER_LEN);
  70         if (!reader)
  71         {
  72                 return NULL;
  73         }
  74         if (!reader->read_uint8(reader, &reserved) ||
  75                 !reader->read_uint24(reader, vendor) ||
  76                 !reader->read_uint32(reader, type) ||
  77                 !reader->read_uint32(reader, &len) ||
  78                 !reader->read_uint32(reader, identifier))
  79         {
  80                 reader->destroy(reader);
  81                 return NULL;
  82         }
  83         reader->destroy(reader);
  84
  85         if (len < PT_TLS_HEADER_LEN)
  86         {
  87                 DBG1(DBG_TNC, "received short PT-TLS header (%d bytes)", len);
  88                 return NULL;
  89         }
  90         return read_tls(tls, len - PT_TLS_HEADER_LEN);
  91 }
  92
  93 /**
  94  * Prepend a PT-TLS header to a writer, send data, destroy writer
  95  */
  96 bool pt_tls_write(tls_socket_t *tls, bio_writer_t *writer,
  97                                   pt_tls_message_type_t type, u_int32_t identifier)
  98 {
  99         bio_writer_t *header;
 100         ssize_t len;
 101         chunk_t data;
 102
 103         data =  writer->get_buf(writer);
 104         len = PT_TLS_HEADER_LEN + data.len;
 105         header = bio_writer_create(len);
 106         header->write_uint8(header, 0);
 107         header->write_uint24(header, 0);
 108         header->write_uint32(header, type);
 109         header->write_uint32(header, len);
 110         header->write_uint32(header, identifier);
 111
 112         header->write_data(header, data);
 113         writer->destroy(writer);
 114
 115         data = header->get_buf(header);
 116         len = tls->write(tls, data.ptr, data.len);
 117         header->destroy(header);
 118
 119         return len == data.len;
 120 }