aboutsummaryrefslogtreecommitdiffstats
path: root/libavformat/rtmpcrypt.c
blob: fb46449a67f37ff5f7d492070a49c345fd9e4479 (plain) (blame)
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
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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
/*
 * RTMPE network protocol
 * Copyright (c) 2008-2009 Andrej Stepanchuk
 * Copyright (c) 2009-2010 Howard Chu
 * Copyright (c) 2012 Samuel Pitoiset
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * RTMPE protocol
 */

#include "libavutil/blowfish.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/rc4.h"
#include "libavutil/xtea.h"

#include "internal.h"
#include "rtmp.h"
#include "rtmpdh.h"
#include "rtmpcrypt.h"
#include "url.h"

/* protocol handler context */
typedef struct RTMPEContext {
    const AVClass *class;
    URLContext   *stream;            ///< TCP stream
    FF_DH        *dh;                ///< Diffie-Hellman context
    struct AVRC4 key_in;             ///< RC4 key used for decrypt data
    struct AVRC4 key_out;            ///< RC4 key used for encrypt data
    int          handshaked;         ///< flag indicating when the handshake is performed
    int          tunneling;          ///< use a HTTP connection (RTMPTE)
} RTMPEContext;

static const uint8_t rtmpe8_keys[16][16] = {
    { 0xbf, 0xf0, 0x34, 0xb2, 0x11, 0xd9, 0x08, 0x1f,
      0xcc, 0xdf, 0xb7, 0x95, 0x74, 0x8d, 0xe7, 0x32 },
    { 0x08, 0x6a, 0x5e, 0xb6, 0x17, 0x43, 0x09, 0x0e,
      0x6e, 0xf0, 0x5a, 0xb8, 0xfe, 0x5a, 0x39, 0xe2 },
    { 0x7b, 0x10, 0x95, 0x6f, 0x76, 0xce, 0x05, 0x21,
      0x23, 0x88, 0xa7, 0x3a, 0x44, 0x01, 0x49, 0xa1 },
    { 0xa9, 0x43, 0xf3, 0x17, 0xeb, 0xf1, 0x1b, 0xb2,
      0xa6, 0x91, 0xa5, 0xee, 0x17, 0xf3, 0x63, 0x39 },
    { 0x7a, 0x30, 0xe0, 0x0a, 0xb5, 0x29, 0xe2, 0x2c,
      0xa0, 0x87, 0xae, 0xa5, 0xc0, 0xcb, 0x79, 0xac },
    { 0xbd, 0xce, 0x0c, 0x23, 0x2f, 0xeb, 0xde, 0xff,
      0x1c, 0xfa, 0xae, 0x16, 0x11, 0x23, 0x23, 0x9d },
    { 0x55, 0xdd, 0x3f, 0x7b, 0x77, 0xe7, 0xe6, 0x2e,
      0x9b, 0xb8, 0xc4, 0x99, 0xc9, 0x48, 0x1e, 0xe4 },
    { 0x40, 0x7b, 0xb6, 0xb4, 0x71, 0xe8, 0x91, 0x36,
      0xa7, 0xae, 0xbf, 0x55, 0xca, 0x33, 0xb8, 0x39 },
    { 0xfc, 0xf6, 0xbd, 0xc3, 0xb6, 0x3c, 0x36, 0x97,
      0x7c, 0xe4, 0xf8, 0x25, 0x04, 0xd9, 0x59, 0xb2 },
    { 0x28, 0xe0, 0x91, 0xfd, 0x41, 0x95, 0x4c, 0x4c,
      0x7f, 0xb7, 0xdb, 0x00, 0xe3, 0xa0, 0x66, 0xf8 },
    { 0x57, 0x84, 0x5b, 0x76, 0x4f, 0x25, 0x1b, 0x03,
      0x46, 0xd4, 0x5b, 0xcd, 0xa2, 0xc3, 0x0d, 0x29 },
    { 0x0a, 0xcc, 0xee, 0xf8, 0xda, 0x55, 0xb5, 0x46,
      0x03, 0x47, 0x34, 0x52, 0x58, 0x63, 0x71, 0x3b },
    { 0xb8, 0x20, 0x75, 0xdc, 0xa7, 0x5f, 0x1f, 0xee,
      0xd8, 0x42, 0x68, 0xe8, 0xa7, 0x2a, 0x44, 0xcc },
    { 0x07, 0xcf, 0x6e, 0x9e, 0xa1, 0x6d, 0x7b, 0x25,
      0x9f, 0xa7, 0xae, 0x6c, 0xd9, 0x2f, 0x56, 0x29 },
    { 0xfe, 0xb1, 0xea, 0xe4, 0x8c, 0x8c, 0x3c, 0xe1,
      0x4e, 0x00, 0x64, 0xa7, 0x6a, 0x38, 0x7c, 0x2a },
    { 0x89, 0x3a, 0x94, 0x27, 0xcc, 0x30, 0x13, 0xa2,
      0xf1, 0x06, 0x38, 0x5b, 0xa8, 0x29, 0xf9, 0x27 }
};

static const uint8_t rtmpe9_keys[16][24] = {
    { 0x79, 0x34, 0x77, 0x4c, 0x67, 0xd1, 0x38, 0x3a, 0xdf, 0xb3, 0x56, 0xbe,
      0x8b, 0x7b, 0xd0, 0x24, 0x38, 0xe0, 0x73, 0x58, 0x41, 0x5d, 0x69, 0x67, },
    { 0x46, 0xf6, 0xb4, 0xcc, 0x01, 0x93, 0xe3, 0xa1, 0x9e, 0x7d, 0x3c, 0x65,
      0x55, 0x86, 0xfd, 0x09, 0x8f, 0xf7, 0xb3, 0xc4, 0x6f, 0x41, 0xca, 0x5c, },
    { 0x1a, 0xe7, 0xe2, 0xf3, 0xf9, 0x14, 0x79, 0x94, 0xc0, 0xd3, 0x97, 0x43,
      0x08, 0x7b, 0xb3, 0x84, 0x43, 0x2f, 0x9d, 0x84, 0x3f, 0x21, 0x01, 0x9b, },
    { 0xd3, 0xe3, 0x54, 0xb0, 0xf7, 0x1d, 0xf6, 0x2b, 0x5a, 0x43, 0x4d, 0x04,
      0x83, 0x64, 0x3e, 0x0d, 0x59, 0x2f, 0x61, 0xcb, 0xb1, 0x6a, 0x59, 0x0d, },
    { 0xc8, 0xc1, 0xe9, 0xb8, 0x16, 0x56, 0x99, 0x21, 0x7b, 0x5b, 0x36, 0xb7,
      0xb5, 0x9b, 0xdf, 0x06, 0x49, 0x2c, 0x97, 0xf5, 0x95, 0x48, 0x85, 0x7e, },
    { 0xeb, 0xe5, 0xe6, 0x2e, 0xa4, 0xba, 0xd4, 0x2c, 0xf2, 0x16, 0xe0, 0x8f,
      0x66, 0x23, 0xa9, 0x43, 0x41, 0xce, 0x38, 0x14, 0x84, 0x95, 0x00, 0x53, },
    { 0x66, 0xdb, 0x90, 0xf0, 0x3b, 0x4f, 0xf5, 0x6f, 0xe4, 0x9c, 0x20, 0x89,
      0x35, 0x5e, 0xd2, 0xb2, 0xc3, 0x9e, 0x9f, 0x7f, 0x63, 0xb2, 0x28, 0x81, },
    { 0xbb, 0x20, 0xac, 0xed, 0x2a, 0x04, 0x6a, 0x19, 0x94, 0x98, 0x9b, 0xc8,
      0xff, 0xcd, 0x93, 0xef, 0xc6, 0x0d, 0x56, 0xa7, 0xeb, 0x13, 0xd9, 0x30, },
    { 0xbc, 0xf2, 0x43, 0x82, 0x09, 0x40, 0x8a, 0x87, 0x25, 0x43, 0x6d, 0xe6,
      0xbb, 0xa4, 0xb9, 0x44, 0x58, 0x3f, 0x21, 0x7c, 0x99, 0xbb, 0x3f, 0x24, },
    { 0xec, 0x1a, 0xaa, 0xcd, 0xce, 0xbd, 0x53, 0x11, 0xd2, 0xfb, 0x83, 0xb6,
      0xc3, 0xba, 0xab, 0x4f, 0x62, 0x79, 0xe8, 0x65, 0xa9, 0x92, 0x28, 0x76, },
    { 0xc6, 0x0c, 0x30, 0x03, 0x91, 0x18, 0x2d, 0x7b, 0x79, 0xda, 0xe1, 0xd5,
      0x64, 0x77, 0x9a, 0x12, 0xc5, 0xb1, 0xd7, 0x91, 0x4f, 0x96, 0x4c, 0xa3, },
    { 0xd7, 0x7c, 0x2a, 0xbf, 0xa6, 0xe7, 0x85, 0x7c, 0x45, 0xad, 0xff, 0x12,
      0x94, 0xd8, 0xde, 0xa4, 0x5c, 0x3d, 0x79, 0xa4, 0x44, 0x02, 0x5d, 0x22, },
    { 0x16, 0x19, 0x0d, 0x81, 0x6a, 0x4c, 0xc7, 0xf8, 0xb8, 0xf9, 0x4e, 0xcd,
      0x2c, 0x9e, 0x90, 0x84, 0xb2, 0x08, 0x25, 0x60, 0xe1, 0x1e, 0xae, 0x18, },
    { 0xe9, 0x7c, 0x58, 0x26, 0x1b, 0x51, 0x9e, 0x49, 0x82, 0x60, 0x61, 0xfc,
      0xa0, 0xa0, 0x1b, 0xcd, 0xf5, 0x05, 0xd6, 0xa6, 0x6d, 0x07, 0x88, 0xa3, },
    { 0x2b, 0x97, 0x11, 0x8b, 0xd9, 0x4e, 0xd9, 0xdf, 0x20, 0xe3, 0x9c, 0x10,
      0xe6, 0xa1, 0x35, 0x21, 0x11, 0xf9, 0x13, 0x0d, 0x0b, 0x24, 0x65, 0xb2, },
    { 0x53, 0x6a, 0x4c, 0x54, 0xac, 0x8b, 0x9b, 0xb8, 0x97, 0x29, 0xfc, 0x60,
      0x2c, 0x5b, 0x3a, 0x85, 0x68, 0xb5, 0xaa, 0x6a, 0x44, 0xcd, 0x3f, 0xa7, },
};

int ff_rtmpe_gen_pub_key(URLContext *h, uint8_t *buf)
{
    RTMPEContext *rt = h->priv_data;
    int offset, ret;

    if (!(rt->dh = ff_dh_init(1024)))
        return AVERROR(ENOMEM);

    offset = ff_rtmp_calc_digest_pos(buf, 768, 632, 8);
    if (offset < 0)
        return offset;

    /* generate a Diffie-Hellmann public key */
    if ((ret = ff_dh_generate_public_key(rt->dh)) < 0)
        return ret;

    /* write the public key into the handshake buffer */
    if ((ret = ff_dh_write_public_key(rt->dh, buf + offset, 128)) < 0)
        return ret;

    return 0;
}

int ff_rtmpe_compute_secret_key(URLContext *h, const uint8_t *serverdata,
                                const uint8_t *clientdata, int type)
{
    RTMPEContext *rt = h->priv_data;
    uint8_t secret_key[128], digest[32];
    int server_pos, client_pos;
    int ret;

    if (type) {
        if ((server_pos = ff_rtmp_calc_digest_pos(serverdata, 1532, 632, 772)) < 0)
            return server_pos;
    } else {
        if ((server_pos = ff_rtmp_calc_digest_pos(serverdata, 768, 632, 8)) < 0)
            return server_pos;
    }

    if ((client_pos = ff_rtmp_calc_digest_pos(clientdata, 768, 632, 8)) < 0)
        return client_pos;

    /* compute the shared secret secret in order to compute RC4 keys */
    if ((ret = ff_dh_compute_shared_secret_key(rt->dh, serverdata + server_pos,
                                               128, secret_key)) < 0)
        return ret;

    /* set output key */
    if ((ret = ff_rtmp_calc_digest(serverdata + server_pos, 128, 0, secret_key,
                                   128, digest)) < 0)
        return ret;
    av_rc4_init(&rt->key_out, digest, 16 * 8, 1);

    /* set input key */
    if ((ret = ff_rtmp_calc_digest(clientdata + client_pos, 128, 0, secret_key,
                                   128, digest)) < 0)
        return ret;
    av_rc4_init(&rt->key_in, digest, 16 * 8, 1);

    return 0;
}

static void rtmpe8_sig(const uint8_t *in, uint8_t *out, int key_id)
{
    struct AVXTEA ctx;
    uint8_t tmpbuf[8];

    av_xtea_init(&ctx, rtmpe8_keys[key_id]);
    AV_WB32(tmpbuf, AV_RL32(in));
    AV_WB32(tmpbuf + 4, AV_RL32(in + 4));
    av_xtea_crypt(&ctx, tmpbuf, tmpbuf, 1, NULL, 0);
    AV_WL32(out, AV_RB32(tmpbuf));
    AV_WL32(out + 4, AV_RB32(tmpbuf + 4));
}

static void rtmpe9_sig(const uint8_t *in, uint8_t *out, int key_id)
{
    struct AVBlowfish ctx;
    uint32_t xl, xr;

    xl = AV_RL32(in);
    xr = AV_RL32(in + 4);

    av_blowfish_init(&ctx, rtmpe9_keys[key_id], 24);
    av_blowfish_crypt_ecb(&ctx, &xl, &xr, 0);

    AV_WL32(out, xl);
    AV_WL32(out + 4, xr);
}

void ff_rtmpe_encrypt_sig(URLContext *h, uint8_t *sig, const uint8_t *digest,
                          int type)
{
    int i;

    for (i = 0; i < 32; i += 8) {
        if (type == 8) {
            /* RTMPE type 8 uses XTEA on the signature */
            rtmpe8_sig(sig + i, sig + i, digest[i] % 15);
        } else if (type == 9) {
            /* RTMPE type 9 uses Blowfish on the signature */
            rtmpe9_sig(sig + i, sig + i, digest[i] % 15);
        }
    }
}

int ff_rtmpe_update_keystream(URLContext *h)
{
    RTMPEContext *rt = h->priv_data;
    char buf[RTMP_HANDSHAKE_PACKET_SIZE];

    /* skip past 1536 bytes of the RC4 bytestream */
    av_rc4_crypt(&rt->key_in, buf, NULL, sizeof(buf), NULL, 1);
    av_rc4_crypt(&rt->key_out, buf, NULL, sizeof(buf), NULL, 1);

    /* the next requests will be encrypted using RC4 keys */
    rt->handshaked = 1;

    return 0;
}

static int rtmpe_close(URLContext *h)
{
    RTMPEContext *rt = h->priv_data;

    ff_dh_free(rt->dh);
    ffurl_close(rt->stream);

    return 0;
}

static int rtmpe_open(URLContext *h, const char *uri, int flags)
{
    RTMPEContext *rt = h->priv_data;
    char host[256], url[1024];
    int ret, port;

    av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port, NULL, 0, uri);

    if (rt->tunneling) {
        if (port < 0)
            port = 80;
        ff_url_join(url, sizeof(url), "ffrtmphttp", NULL, host, port, NULL);
    } else {
        if (port < 0)
            port = 1935;
        ff_url_join(url, sizeof(url), "tcp", NULL, host, port, NULL);
    }

    /* open the tcp or ffrtmphttp connection */
    if ((ret = ffurl_open(&rt->stream, url, AVIO_FLAG_READ_WRITE,
                          &h->interrupt_callback, NULL)) < 0) {
        rtmpe_close(h);
        return ret;
    }

    return 0;
}

static int rtmpe_read(URLContext *h, uint8_t *buf, int size)
{
    RTMPEContext *rt = h->priv_data;
    int ret;

    rt->stream->flags |= h->flags & AVIO_FLAG_NONBLOCK;
    ret = ffurl_read(rt->stream, buf, size);
    rt->stream->flags &= ~AVIO_FLAG_NONBLOCK;

    if (ret < 0 && ret != AVERROR_EOF)
        return ret;

    if (rt->handshaked && ret > 0) {
        /* decrypt data received by the server */
        av_rc4_crypt(&rt->key_in, buf, buf, ret, NULL, 1);
    }

    return ret;
}

static int rtmpe_write(URLContext *h, const uint8_t *buf, int size)
{
    RTMPEContext *rt = h->priv_data;
    int ret;

    if (rt->handshaked) {
        /* encrypt data to send to the server */
        av_rc4_crypt(&rt->key_out, buf, buf, size, NULL, 1);
    }

    if ((ret = ffurl_write(rt->stream, buf, size)) < 0)
        return ret;

    return size;
}

#define OFFSET(x) offsetof(RTMPEContext, x)
#define DEC AV_OPT_FLAG_DECODING_PARAM

static const AVOption ffrtmpcrypt_options[] = {
    {"ffrtmpcrypt_tunneling", "Use a HTTP tunneling connection (RTMPTE).", OFFSET(tunneling), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC},
    { NULL },
};

static const AVClass ffrtmpcrypt_class = {
    .class_name = "ffrtmpcrypt",
    .item_name  = av_default_item_name,
    .option     = ffrtmpcrypt_options,
    .version    = LIBAVUTIL_VERSION_INT,
};

URLProtocol ff_ffrtmpcrypt_protocol = {
    .name            = "ffrtmpcrypt",
    .url_open        = rtmpe_open,
    .url_read        = rtmpe_read,
    .url_write       = rtmpe_write,
    .url_close       = rtmpe_close,
    .priv_data_size  = sizeof(RTMPEContext),
    .flags           = URL_PROTOCOL_FLAG_NETWORK,
    .priv_data_class = &ffrtmpcrypt_class,
};