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mms.c
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1 /*
2  * MMS protocol common definitions.
3  * Copyright (c) 2006,2007 Ryan Martell
4  * Copyright (c) 2007 Bj√∂rn Axelsson
5  * Copyright (c) 2010 Zhentan Feng <spyfeng at gmail dot com>
6  *
7  * This file is part of FFmpeg.
8  *
9  * FFmpeg is free software; you can redistribute it and/or
10  * modify it under the terms of the GNU Lesser General Public
11  * License as published by the Free Software Foundation; either
12  * version 2.1 of the License, or (at your option) any later version.
13  *
14  * FFmpeg is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17  * Lesser General Public License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with FFmpeg; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22  */
23 #include "mms.h"
24 #include "asf.h"
25 #include "libavutil/intreadwrite.h"
26 
27 #define MMS_MAX_STREAMS 256 /**< arbitrary sanity check value */
28 
30 {
31  char *pos;
32  int size_to_copy;
33  int remaining_size = mms->asf_header_size - mms->asf_header_read_size;
34  size_to_copy = FFMIN(size, remaining_size);
35  pos = mms->asf_header + mms->asf_header_read_size;
36  memcpy(buf, pos, size_to_copy);
37  if (mms->asf_header_read_size == mms->asf_header_size) {
38  av_freep(&mms->asf_header); // which contains asf header
39  }
40  mms->asf_header_read_size += size_to_copy;
41  return size_to_copy;
42 }
43 
44 int ff_mms_read_data(MMSContext *mms, uint8_t *buf, const int size)
45 {
46  int read_size;
47  read_size = FFMIN(size, mms->remaining_in_len);
48  memcpy(buf, mms->read_in_ptr, read_size);
49  mms->remaining_in_len -= read_size;
50  mms->read_in_ptr += read_size;
51  return read_size;
52 }
53 
55 {
56  uint8_t *p = mms->asf_header;
57  uint8_t *end;
58  int flags, stream_id;
59  mms->stream_num = 0;
60 
61  if (mms->asf_header_size < sizeof(ff_asf_guid) * 2 + 22 ||
62  memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
63  av_log(NULL, AV_LOG_ERROR,
64  "Corrupt stream (invalid ASF header, size=%d)\n",
65  mms->asf_header_size);
66  return AVERROR_INVALIDDATA;
67  }
68 
69  end = mms->asf_header + mms->asf_header_size;
70 
71  p += sizeof(ff_asf_guid) + 14;
72  while(end - p >= sizeof(ff_asf_guid) + 8) {
73  uint64_t chunksize;
74  if (!memcmp(p, ff_asf_data_header, sizeof(ff_asf_guid))) {
75  chunksize = 50; // see Reference [2] section 5.1
76  } else {
77  chunksize = AV_RL64(p + sizeof(ff_asf_guid));
78  }
79  if (!chunksize || chunksize > end - p) {
80  av_log(NULL, AV_LOG_ERROR,
81  "Corrupt stream (header chunksize %"PRId64" is invalid)\n",
82  chunksize);
83  return AVERROR_INVALIDDATA;
84  }
85  if (!memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
86  /* read packet size */
87  if (end - p > sizeof(ff_asf_guid) * 2 + 68) {
88  mms->asf_packet_len = AV_RL32(p + sizeof(ff_asf_guid) * 2 + 64);
89  if (mms->asf_packet_len <= 0 || mms->asf_packet_len > sizeof(mms->in_buffer)) {
90  av_log(NULL, AV_LOG_ERROR,
91  "Corrupt stream (too large pkt_len %d)\n",
92  mms->asf_packet_len);
93  return AVERROR_INVALIDDATA;
94  }
95  }
96  } else if (!memcmp(p, ff_asf_stream_header, sizeof(ff_asf_guid))) {
97  flags = AV_RL16(p + sizeof(ff_asf_guid)*3 + 24);
98  stream_id = flags & 0x7F;
99  //The second condition is for checking CS_PKT_STREAM_ID_REQUEST packet size,
100  //we can calcuate the packet size by stream_num.
101  //Please see function send_stream_selection_request().
102  if (mms->stream_num < MMS_MAX_STREAMS &&
103  46 + mms->stream_num * 6 < sizeof(mms->out_buffer)) {
104  mms->streams = av_fast_realloc(mms->streams,
105  &mms->nb_streams_allocated,
106  (mms->stream_num + 1) * sizeof(MMSStream));
107  mms->streams[mms->stream_num].id = stream_id;
108  mms->stream_num++;
109  } else {
110  av_log(NULL, AV_LOG_ERROR,
111  "Corrupt stream (too many A/V streams)\n");
112  return AVERROR_INVALIDDATA;
113  }
114  } else if (!memcmp(p, ff_asf_ext_stream_header, sizeof(ff_asf_guid))) {
115  if (end - p >= 88) {
116  int stream_count = AV_RL16(p + 84), ext_len_count = AV_RL16(p + 86);
117  uint64_t skip_bytes = 88;
118  while (stream_count--) {
119  if (end - p < skip_bytes + 4) {
120  av_log(NULL, AV_LOG_ERROR,
121  "Corrupt stream (next stream name length is not in the buffer)\n");
122  return AVERROR_INVALIDDATA;
123  }
124  skip_bytes += 4 + AV_RL16(p + skip_bytes + 2);
125  }
126  while (ext_len_count--) {
127  if (end - p < skip_bytes + 22) {
128  av_log(NULL, AV_LOG_ERROR,
129  "Corrupt stream (next extension system info length is not in the buffer)\n");
130  return AVERROR_INVALIDDATA;
131  }
132  skip_bytes += 22 + AV_RL32(p + skip_bytes + 18);
133  }
134  if (end - p < skip_bytes) {
135  av_log(NULL, AV_LOG_ERROR,
136  "Corrupt stream (the last extension system info length is invalid)\n");
137  return AVERROR_INVALIDDATA;
138  }
139  if (chunksize - skip_bytes > 24)
140  chunksize = skip_bytes;
141  }
142  } else if (!memcmp(p, ff_asf_head1_guid, sizeof(ff_asf_guid))) {
143  chunksize = 46; // see references [2] section 3.4. This should be set 46.
144  }
145  p += chunksize;
146  }
147 
148  return 0;
149 }