1/*
2 * RTMPE network protocol
3 * Copyright (c) 2008-2009 Andrej Stepanchuk
4 * Copyright (c) 2009-2010 Howard Chu
5 * Copyright (c) 2012 Samuel Pitoiset
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
24/**
25 * @file
26 * RTMPE protocol
27 */
28
29#include "libavutil/blowfish.h"
30#include "libavutil/intreadwrite.h"
31#include "libavutil/opt.h"
32#include "libavutil/rc4.h"
33#include "libavutil/xtea.h"
34
35#include "internal.h"
36#include "rtmp.h"
37#include "rtmpdh.h"
38#include "rtmpcrypt.h"
39#include "url.h"
40
41/* protocol handler context */
42typedef struct RTMPEContext {
43    const AVClass *class;
44    URLContext   *stream;            ///< TCP stream
45    FF_DH        *dh;                ///< Diffie-Hellman context
46    struct AVRC4 key_in;             ///< RC4 key used for decrypt data
47    struct AVRC4 key_out;            ///< RC4 key used for encrypt data
48    int          handshaked;         ///< flag indicating when the handshake is performed
49    int          tunneling;          ///< use a HTTP connection (RTMPTE)
50} RTMPEContext;
51
52static const uint8_t rtmpe8_keys[16][16] = {
53    { 0xbf, 0xf0, 0x34, 0xb2, 0x11, 0xd9, 0x08, 0x1f,
54      0xcc, 0xdf, 0xb7, 0x95, 0x74, 0x8d, 0xe7, 0x32 },
55    { 0x08, 0x6a, 0x5e, 0xb6, 0x17, 0x43, 0x09, 0x0e,
56      0x6e, 0xf0, 0x5a, 0xb8, 0xfe, 0x5a, 0x39, 0xe2 },
57    { 0x7b, 0x10, 0x95, 0x6f, 0x76, 0xce, 0x05, 0x21,
58      0x23, 0x88, 0xa7, 0x3a, 0x44, 0x01, 0x49, 0xa1 },
59    { 0xa9, 0x43, 0xf3, 0x17, 0xeb, 0xf1, 0x1b, 0xb2,
60      0xa6, 0x91, 0xa5, 0xee, 0x17, 0xf3, 0x63, 0x39 },
61    { 0x7a, 0x30, 0xe0, 0x0a, 0xb5, 0x29, 0xe2, 0x2c,
62      0xa0, 0x87, 0xae, 0xa5, 0xc0, 0xcb, 0x79, 0xac },
63    { 0xbd, 0xce, 0x0c, 0x23, 0x2f, 0xeb, 0xde, 0xff,
64      0x1c, 0xfa, 0xae, 0x16, 0x11, 0x23, 0x23, 0x9d },
65    { 0x55, 0xdd, 0x3f, 0x7b, 0x77, 0xe7, 0xe6, 0x2e,
66      0x9b, 0xb8, 0xc4, 0x99, 0xc9, 0x48, 0x1e, 0xe4 },
67    { 0x40, 0x7b, 0xb6, 0xb4, 0x71, 0xe8, 0x91, 0x36,
68      0xa7, 0xae, 0xbf, 0x55, 0xca, 0x33, 0xb8, 0x39 },
69    { 0xfc, 0xf6, 0xbd, 0xc3, 0xb6, 0x3c, 0x36, 0x97,
70      0x7c, 0xe4, 0xf8, 0x25, 0x04, 0xd9, 0x59, 0xb2 },
71    { 0x28, 0xe0, 0x91, 0xfd, 0x41, 0x95, 0x4c, 0x4c,
72      0x7f, 0xb7, 0xdb, 0x00, 0xe3, 0xa0, 0x66, 0xf8 },
73    { 0x57, 0x84, 0x5b, 0x76, 0x4f, 0x25, 0x1b, 0x03,
74      0x46, 0xd4, 0x5b, 0xcd, 0xa2, 0xc3, 0x0d, 0x29 },
75    { 0x0a, 0xcc, 0xee, 0xf8, 0xda, 0x55, 0xb5, 0x46,
76      0x03, 0x47, 0x34, 0x52, 0x58, 0x63, 0x71, 0x3b },
77    { 0xb8, 0x20, 0x75, 0xdc, 0xa7, 0x5f, 0x1f, 0xee,
78      0xd8, 0x42, 0x68, 0xe8, 0xa7, 0x2a, 0x44, 0xcc },
79    { 0x07, 0xcf, 0x6e, 0x9e, 0xa1, 0x6d, 0x7b, 0x25,
80      0x9f, 0xa7, 0xae, 0x6c, 0xd9, 0x2f, 0x56, 0x29 },
81    { 0xfe, 0xb1, 0xea, 0xe4, 0x8c, 0x8c, 0x3c, 0xe1,
82      0x4e, 0x00, 0x64, 0xa7, 0x6a, 0x38, 0x7c, 0x2a },
83    { 0x89, 0x3a, 0x94, 0x27, 0xcc, 0x30, 0x13, 0xa2,
84      0xf1, 0x06, 0x38, 0x5b, 0xa8, 0x29, 0xf9, 0x27 }
85};
86
87static const uint8_t rtmpe9_keys[16][24] = {
88    { 0x79, 0x34, 0x77, 0x4c, 0x67, 0xd1, 0x38, 0x3a, 0xdf, 0xb3, 0x56, 0xbe,
89      0x8b, 0x7b, 0xd0, 0x24, 0x38, 0xe0, 0x73, 0x58, 0x41, 0x5d, 0x69, 0x67, },
90    { 0x46, 0xf6, 0xb4, 0xcc, 0x01, 0x93, 0xe3, 0xa1, 0x9e, 0x7d, 0x3c, 0x65,
91      0x55, 0x86, 0xfd, 0x09, 0x8f, 0xf7, 0xb3, 0xc4, 0x6f, 0x41, 0xca, 0x5c, },
92    { 0x1a, 0xe7, 0xe2, 0xf3, 0xf9, 0x14, 0x79, 0x94, 0xc0, 0xd3, 0x97, 0x43,
93      0x08, 0x7b, 0xb3, 0x84, 0x43, 0x2f, 0x9d, 0x84, 0x3f, 0x21, 0x01, 0x9b, },
94    { 0xd3, 0xe3, 0x54, 0xb0, 0xf7, 0x1d, 0xf6, 0x2b, 0x5a, 0x43, 0x4d, 0x04,
95      0x83, 0x64, 0x3e, 0x0d, 0x59, 0x2f, 0x61, 0xcb, 0xb1, 0x6a, 0x59, 0x0d, },
96    { 0xc8, 0xc1, 0xe9, 0xb8, 0x16, 0x56, 0x99, 0x21, 0x7b, 0x5b, 0x36, 0xb7,
97      0xb5, 0x9b, 0xdf, 0x06, 0x49, 0x2c, 0x97, 0xf5, 0x95, 0x48, 0x85, 0x7e, },
98    { 0xeb, 0xe5, 0xe6, 0x2e, 0xa4, 0xba, 0xd4, 0x2c, 0xf2, 0x16, 0xe0, 0x8f,
99      0x66, 0x23, 0xa9, 0x43, 0x41, 0xce, 0x38, 0x14, 0x84, 0x95, 0x00, 0x53, },
100    { 0x66, 0xdb, 0x90, 0xf0, 0x3b, 0x4f, 0xf5, 0x6f, 0xe4, 0x9c, 0x20, 0x89,
101      0x35, 0x5e, 0xd2, 0xb2, 0xc3, 0x9e, 0x9f, 0x7f, 0x63, 0xb2, 0x28, 0x81, },
102    { 0xbb, 0x20, 0xac, 0xed, 0x2a, 0x04, 0x6a, 0x19, 0x94, 0x98, 0x9b, 0xc8,
103      0xff, 0xcd, 0x93, 0xef, 0xc6, 0x0d, 0x56, 0xa7, 0xeb, 0x13, 0xd9, 0x30, },
104    { 0xbc, 0xf2, 0x43, 0x82, 0x09, 0x40, 0x8a, 0x87, 0x25, 0x43, 0x6d, 0xe6,
105      0xbb, 0xa4, 0xb9, 0x44, 0x58, 0x3f, 0x21, 0x7c, 0x99, 0xbb, 0x3f, 0x24, },
106    { 0xec, 0x1a, 0xaa, 0xcd, 0xce, 0xbd, 0x53, 0x11, 0xd2, 0xfb, 0x83, 0xb6,
107      0xc3, 0xba, 0xab, 0x4f, 0x62, 0x79, 0xe8, 0x65, 0xa9, 0x92, 0x28, 0x76, },
108    { 0xc6, 0x0c, 0x30, 0x03, 0x91, 0x18, 0x2d, 0x7b, 0x79, 0xda, 0xe1, 0xd5,
109      0x64, 0x77, 0x9a, 0x12, 0xc5, 0xb1, 0xd7, 0x91, 0x4f, 0x96, 0x4c, 0xa3, },
110    { 0xd7, 0x7c, 0x2a, 0xbf, 0xa6, 0xe7, 0x85, 0x7c, 0x45, 0xad, 0xff, 0x12,
111      0x94, 0xd8, 0xde, 0xa4, 0x5c, 0x3d, 0x79, 0xa4, 0x44, 0x02, 0x5d, 0x22, },
112    { 0x16, 0x19, 0x0d, 0x81, 0x6a, 0x4c, 0xc7, 0xf8, 0xb8, 0xf9, 0x4e, 0xcd,
113      0x2c, 0x9e, 0x90, 0x84, 0xb2, 0x08, 0x25, 0x60, 0xe1, 0x1e, 0xae, 0x18, },
114    { 0xe9, 0x7c, 0x58, 0x26, 0x1b, 0x51, 0x9e, 0x49, 0x82, 0x60, 0x61, 0xfc,
115      0xa0, 0xa0, 0x1b, 0xcd, 0xf5, 0x05, 0xd6, 0xa6, 0x6d, 0x07, 0x88, 0xa3, },
116    { 0x2b, 0x97, 0x11, 0x8b, 0xd9, 0x4e, 0xd9, 0xdf, 0x20, 0xe3, 0x9c, 0x10,
117      0xe6, 0xa1, 0x35, 0x21, 0x11, 0xf9, 0x13, 0x0d, 0x0b, 0x24, 0x65, 0xb2, },
118    { 0x53, 0x6a, 0x4c, 0x54, 0xac, 0x8b, 0x9b, 0xb8, 0x97, 0x29, 0xfc, 0x60,
119      0x2c, 0x5b, 0x3a, 0x85, 0x68, 0xb5, 0xaa, 0x6a, 0x44, 0xcd, 0x3f, 0xa7, },
120};
121
122int ff_rtmpe_gen_pub_key(URLContext *h, uint8_t *buf)
123{
124    RTMPEContext *rt = h->priv_data;
125    int offset, ret;
126
127    if (!(rt->dh = ff_dh_init(1024)))
128        return AVERROR(ENOMEM);
129
130    offset = ff_rtmp_calc_digest_pos(buf, 768, 632, 8);
131    if (offset < 0)
132        return offset;
133
134    /* generate a Diffie-Hellmann public key */
135    if ((ret = ff_dh_generate_public_key(rt->dh)) < 0)
136        return ret;
137
138    /* write the public key into the handshake buffer */
139    if ((ret = ff_dh_write_public_key(rt->dh, buf + offset, 128)) < 0)
140        return ret;
141
142    return 0;
143}
144
145int ff_rtmpe_compute_secret_key(URLContext *h, const uint8_t *serverdata,
146                                const uint8_t *clientdata, int type)
147{
148    RTMPEContext *rt = h->priv_data;
149    uint8_t secret_key[128], digest[32];
150    int server_pos, client_pos;
151    int ret;
152
153    if (type) {
154        if ((server_pos = ff_rtmp_calc_digest_pos(serverdata, 1532, 632, 772)) < 0)
155            return server_pos;
156    } else {
157        if ((server_pos = ff_rtmp_calc_digest_pos(serverdata, 768, 632, 8)) < 0)
158            return server_pos;
159    }
160
161    if ((client_pos = ff_rtmp_calc_digest_pos(clientdata, 768, 632, 8)) < 0)
162        return client_pos;
163
164    /* compute the shared secret secret in order to compute RC4 keys */
165    if ((ret = ff_dh_compute_shared_secret_key(rt->dh, serverdata + server_pos,
166                                               128, secret_key)) < 0)
167        return ret;
168
169    /* set output key */
170    if ((ret = ff_rtmp_calc_digest(serverdata + server_pos, 128, 0, secret_key,
171                                   128, digest)) < 0)
172        return ret;
173    av_rc4_init(&rt->key_out, digest, 16 * 8, 1);
174
175    /* set input key */
176    if ((ret = ff_rtmp_calc_digest(clientdata + client_pos, 128, 0, secret_key,
177                                   128, digest)) < 0)
178        return ret;
179    av_rc4_init(&rt->key_in, digest, 16 * 8, 1);
180
181    return 0;
182}
183
184static void rtmpe8_sig(const uint8_t *in, uint8_t *out, int key_id)
185{
186    struct AVXTEA ctx;
187
188    av_xtea_init(&ctx, rtmpe8_keys[key_id]);
189    av_xtea_crypt(&ctx, out, in, 1, NULL, 0);
190}
191
192static void rtmpe9_sig(const uint8_t *in, uint8_t *out, int key_id)
193{
194    struct AVBlowfish ctx;
195    uint32_t xl, xr;
196
197    xl = AV_RL32(in);
198    xr = AV_RL32(in + 4);
199
200    av_blowfish_init(&ctx, rtmpe9_keys[key_id], 24);
201    av_blowfish_crypt_ecb(&ctx, &xl, &xr, 0);
202
203    AV_WL32(out, xl);
204    AV_WL32(out + 4, xr);
205}
206
207void ff_rtmpe_encrypt_sig(URLContext *h, uint8_t *sig, const uint8_t *digest,
208                          int type)
209{
210    int i;
211
212    for (i = 0; i < 32; i += 8) {
213        if (type == 8) {
214            /* RTMPE type 8 uses XTEA on the signature */
215            rtmpe8_sig(sig + i, sig + i, digest[i] % 15);
216        } else if (type == 9) {
217            /* RTMPE type 9 uses Blowfish on the signature */
218            rtmpe9_sig(sig + i, sig + i, digest[i] % 15);
219        }
220    }
221}
222
223int ff_rtmpe_update_keystream(URLContext *h)
224{
225    RTMPEContext *rt = h->priv_data;
226    char buf[RTMP_HANDSHAKE_PACKET_SIZE];
227
228    /* skip past 1536 bytes of the RC4 bytestream */
229    av_rc4_crypt(&rt->key_in, buf, NULL, sizeof(buf), NULL, 1);
230    av_rc4_crypt(&rt->key_out, buf, NULL, sizeof(buf), NULL, 1);
231
232    /* the next requests will be encrypted using RC4 keys */
233    rt->handshaked = 1;
234
235    return 0;
236}
237
238static int rtmpe_close(URLContext *h)
239{
240    RTMPEContext *rt = h->priv_data;
241
242    ff_dh_free(rt->dh);
243    ffurl_close(rt->stream);
244
245    return 0;
246}
247
248static int rtmpe_open(URLContext *h, const char *uri, int flags)
249{
250    RTMPEContext *rt = h->priv_data;
251    char host[256], url[1024];
252    int ret, port;
253
254    av_url_split(NULL, 0, NULL, 0, host, sizeof(host), &port, NULL, 0, uri);
255
256    if (rt->tunneling) {
257        if (port < 0)
258            port = 80;
259        ff_url_join(url, sizeof(url), "ffrtmphttp", NULL, host, port, NULL);
260    } else {
261        if (port < 0)
262            port = 1935;
263        ff_url_join(url, sizeof(url), "tcp", NULL, host, port, NULL);
264    }
265
266    /* open the tcp or ffrtmphttp connection */
267    if ((ret = ffurl_open(&rt->stream, url, AVIO_FLAG_READ_WRITE,
268                          &h->interrupt_callback, NULL)) < 0) {
269        rtmpe_close(h);
270        return ret;
271    }
272
273    return 0;
274}
275
276static int rtmpe_read(URLContext *h, uint8_t *buf, int size)
277{
278    RTMPEContext *rt = h->priv_data;
279    int ret;
280
281    rt->stream->flags |= h->flags & AVIO_FLAG_NONBLOCK;
282    ret = ffurl_read(rt->stream, buf, size);
283    rt->stream->flags &= ~AVIO_FLAG_NONBLOCK;
284
285    if (ret < 0 && ret != AVERROR_EOF)
286        return ret;
287
288    if (rt->handshaked && ret > 0) {
289        /* decrypt data received by the server */
290        av_rc4_crypt(&rt->key_in, buf, buf, ret, NULL, 1);
291    }
292
293    return ret;
294}
295
296static int rtmpe_write(URLContext *h, const uint8_t *buf, int size)
297{
298    RTMPEContext *rt = h->priv_data;
299    int ret;
300
301    if (rt->handshaked) {
302        /* encrypt data to send to the server */
303        av_rc4_crypt(&rt->key_out, buf, buf, size, NULL, 1);
304    }
305
306    if ((ret = ffurl_write(rt->stream, buf, size)) < 0)
307        return ret;
308
309    return size;
310}
311
312#define OFFSET(x) offsetof(RTMPEContext, x)
313#define DEC AV_OPT_FLAG_DECODING_PARAM
314
315static const AVOption ffrtmpcrypt_options[] = {
316    {"ffrtmpcrypt_tunneling", "Use a HTTP tunneling connection (RTMPTE).", OFFSET(tunneling), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, DEC},
317    { NULL },
318};
319
320static const AVClass ffrtmpcrypt_class = {
321    .class_name = "ffrtmpcrypt",
322    .item_name  = av_default_item_name,
323    .option     = ffrtmpcrypt_options,
324    .version    = LIBAVUTIL_VERSION_INT,
325};
326
327URLProtocol ff_ffrtmpcrypt_protocol = {
328    .name            = "ffrtmpcrypt",
329    .url_open        = rtmpe_open,
330    .url_read        = rtmpe_read,
331    .url_write       = rtmpe_write,
332    .url_close       = rtmpe_close,
333    .priv_data_size  = sizeof(RTMPEContext),
334    .flags           = URL_PROTOCOL_FLAG_NETWORK,
335    .priv_data_class = &ffrtmpcrypt_class,
336};
337