1 /**
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #include "encryption_info.h"
20 #include "mem.h"
21 #include "intreadwrite.h"
22
23 #define FF_ENCRYPTION_INFO_EXTRA 24
24
25 // The format of the AVEncryptionInfo side data:
26 // u32be scheme
27 // u32be crypt_byte_block
28 // u32be skip_byte_block
29 // u32be key_id_size
30 // u32be iv_size
31 // u32be subsample_count
32 // u8[key_id_size] key_id
33 // u8[iv_size] iv
34 // {
35 // u32be bytes_of_clear_data
36 // u32be bytes_of_protected_data
37 // }[subsample_count]
38
av_encryption_info_alloc(uint32_t subsample_count,uint32_t key_id_size,uint32_t iv_size)39 AVEncryptionInfo *av_encryption_info_alloc(uint32_t subsample_count, uint32_t key_id_size, uint32_t iv_size)
40 {
41 AVEncryptionInfo *info;
42
43 info = av_mallocz(sizeof(*info));
44 if (!info)
45 return NULL;
46
47 info->key_id = av_mallocz(key_id_size);
48 info->key_id_size = key_id_size;
49 info->iv = av_mallocz(iv_size);
50 info->iv_size = iv_size;
51 info->subsamples = av_mallocz_array(subsample_count, sizeof(*info->subsamples));
52 info->subsample_count = subsample_count;
53
54 // Allow info->subsamples to be NULL if there are no subsamples.
55 if (!info->key_id || !info->iv || (!info->subsamples && subsample_count)) {
56 av_encryption_info_free(info);
57 return NULL;
58 }
59
60 return info;
61 }
62
av_encryption_info_clone(const AVEncryptionInfo * info)63 AVEncryptionInfo *av_encryption_info_clone(const AVEncryptionInfo *info)
64 {
65 AVEncryptionInfo *ret;
66
67 ret = av_encryption_info_alloc(info->subsample_count, info->key_id_size, info->iv_size);
68 if (!ret)
69 return NULL;
70
71 ret->scheme = info->scheme;
72 ret->crypt_byte_block = info->crypt_byte_block;
73 ret->skip_byte_block = info->skip_byte_block;
74 memcpy(ret->iv, info->iv, info->iv_size);
75 memcpy(ret->key_id, info->key_id, info->key_id_size);
76 memcpy(ret->subsamples, info->subsamples, sizeof(*info->subsamples) * info->subsample_count);
77 return ret;
78 }
79
av_encryption_info_free(AVEncryptionInfo * info)80 void av_encryption_info_free(AVEncryptionInfo *info)
81 {
82 if (info) {
83 av_free(info->key_id);
84 av_free(info->iv);
85 av_free(info->subsamples);
86 av_free(info);
87 }
88 }
89
av_encryption_info_get_side_data(const uint8_t * buffer,size_t size)90 AVEncryptionInfo *av_encryption_info_get_side_data(const uint8_t* buffer, size_t size)
91 {
92 AVEncryptionInfo *info;
93 uint64_t key_id_size, iv_size, subsample_count, i;
94
95 if (!buffer || size < FF_ENCRYPTION_INFO_EXTRA)
96 return NULL;
97
98 key_id_size = AV_RB32(buffer + 12);
99 iv_size = AV_RB32(buffer + 16);
100 subsample_count = AV_RB32(buffer + 20);
101
102 if (size < FF_ENCRYPTION_INFO_EXTRA + key_id_size + iv_size + subsample_count * 8)
103 return NULL;
104
105 info = av_encryption_info_alloc(subsample_count, key_id_size, iv_size);
106 if (!info)
107 return NULL;
108
109 info->scheme = AV_RB32(buffer);
110 info->crypt_byte_block = AV_RB32(buffer + 4);
111 info->skip_byte_block = AV_RB32(buffer + 8);
112 memcpy(info->key_id, buffer + 24, key_id_size);
113 memcpy(info->iv, buffer + key_id_size + 24, iv_size);
114
115 buffer += key_id_size + iv_size + 24;
116 for (i = 0; i < subsample_count; i++) {
117 info->subsamples[i].bytes_of_clear_data = AV_RB32(buffer);
118 info->subsamples[i].bytes_of_protected_data = AV_RB32(buffer + 4);
119 buffer += 8;
120 }
121
122 return info;
123 }
124
av_encryption_info_add_side_data(const AVEncryptionInfo * info,size_t * size)125 uint8_t *av_encryption_info_add_side_data(const AVEncryptionInfo *info, size_t *size)
126 {
127 uint8_t *buffer, *cur_buffer;
128 uint32_t i;
129
130 if (UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA < info->key_id_size ||
131 UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA - info->key_id_size < info->iv_size ||
132 (UINT32_MAX - FF_ENCRYPTION_INFO_EXTRA - info->key_id_size - info->iv_size) / 8 < info->subsample_count) {
133 return NULL;
134 }
135
136 *size = FF_ENCRYPTION_INFO_EXTRA + info->key_id_size + info->iv_size +
137 (info->subsample_count * 8);
138 cur_buffer = buffer = av_malloc(*size);
139 if (!buffer)
140 return NULL;
141
142 AV_WB32(cur_buffer, info->scheme);
143 AV_WB32(cur_buffer + 4, info->crypt_byte_block);
144 AV_WB32(cur_buffer + 8, info->skip_byte_block);
145 AV_WB32(cur_buffer + 12, info->key_id_size);
146 AV_WB32(cur_buffer + 16, info->iv_size);
147 AV_WB32(cur_buffer + 20, info->subsample_count);
148 cur_buffer += 24;
149 memcpy(cur_buffer, info->key_id, info->key_id_size);
150 cur_buffer += info->key_id_size;
151 memcpy(cur_buffer, info->iv, info->iv_size);
152 cur_buffer += info->iv_size;
153 for (i = 0; i < info->subsample_count; i++) {
154 AV_WB32(cur_buffer, info->subsamples[i].bytes_of_clear_data);
155 AV_WB32(cur_buffer + 4, info->subsamples[i].bytes_of_protected_data);
156 cur_buffer += 8;
157 }
158
159 return buffer;
160 }
161
162 // The format of the AVEncryptionInitInfo side data:
163 // u32be init_info_count
164 // {
165 // u32be system_id_size
166 // u32be num_key_ids
167 // u32be key_id_size
168 // u32be data_size
169 // u8[system_id_size] system_id
170 // u8[key_id_size][num_key_id] key_ids
171 // u8[data_size] data
172 // }[init_info_count]
173
174 #define FF_ENCRYPTION_INIT_INFO_EXTRA 16
175
av_encryption_init_info_alloc(uint32_t system_id_size,uint32_t num_key_ids,uint32_t key_id_size,uint32_t data_size)176 AVEncryptionInitInfo *av_encryption_init_info_alloc(
177 uint32_t system_id_size, uint32_t num_key_ids, uint32_t key_id_size, uint32_t data_size)
178 {
179 AVEncryptionInitInfo *info;
180 uint32_t i;
181
182 info = av_mallocz(sizeof(*info));
183 if (!info)
184 return NULL;
185
186 info->system_id = av_mallocz(system_id_size);
187 info->system_id_size = system_id_size;
188 info->key_ids = key_id_size ? av_mallocz_array(num_key_ids, sizeof(*info->key_ids)) : NULL;
189 info->num_key_ids = num_key_ids;
190 info->key_id_size = key_id_size;
191 info->data = av_mallocz(data_size);
192 info->data_size = data_size;
193
194 // Allow pointers to be NULL if the size is 0.
195 if ((!info->system_id && system_id_size) || (!info->data && data_size) ||
196 (!info->key_ids && num_key_ids && key_id_size)) {
197 av_encryption_init_info_free(info);
198 return NULL;
199 }
200
201 if (key_id_size) {
202 for (i = 0; i < num_key_ids; i++) {
203 info->key_ids[i] = av_mallocz(key_id_size);
204 if (!info->key_ids[i]) {
205 av_encryption_init_info_free(info);
206 return NULL;
207 }
208 }
209 }
210
211 return info;
212 }
213
av_encryption_init_info_free(AVEncryptionInitInfo * info)214 void av_encryption_init_info_free(AVEncryptionInitInfo *info)
215 {
216 uint32_t i;
217 if (info) {
218 for (i = 0; i < info->num_key_ids; i++) {
219 av_free(info->key_ids[i]);
220 }
221 av_encryption_init_info_free(info->next);
222 av_free(info->system_id);
223 av_free(info->key_ids);
224 av_free(info->data);
225 av_free(info);
226 }
227 }
228
av_encryption_init_info_get_side_data(const uint8_t * side_data,size_t side_data_size)229 AVEncryptionInitInfo *av_encryption_init_info_get_side_data(
230 const uint8_t *side_data, size_t side_data_size)
231 {
232 // |ret| tracks the front of the list, |info| tracks the back.
233 AVEncryptionInitInfo *ret = NULL, *info, *temp_info;
234 uint64_t system_id_size, num_key_ids, key_id_size, data_size, i, j;
235 uint64_t init_info_count;
236
237 if (!side_data || side_data_size < 4)
238 return NULL;
239
240 init_info_count = AV_RB32(side_data);
241 side_data += 4;
242 side_data_size -= 4;
243 for (i = 0; i < init_info_count; i++) {
244 if (side_data_size < FF_ENCRYPTION_INIT_INFO_EXTRA) {
245 av_encryption_init_info_free(ret);
246 return NULL;
247 }
248
249 system_id_size = AV_RB32(side_data);
250 num_key_ids = AV_RB32(side_data + 4);
251 key_id_size = AV_RB32(side_data + 8);
252 data_size = AV_RB32(side_data + 12);
253
254 // UINT32_MAX + UINT32_MAX + UINT32_MAX * UINT32_MAX == UINT64_MAX
255 if (side_data_size - FF_ENCRYPTION_INIT_INFO_EXTRA < system_id_size + data_size + num_key_ids * key_id_size) {
256 av_encryption_init_info_free(ret);
257 return NULL;
258 }
259 side_data += FF_ENCRYPTION_INIT_INFO_EXTRA;
260 side_data_size -= FF_ENCRYPTION_INIT_INFO_EXTRA;
261
262 temp_info = av_encryption_init_info_alloc(system_id_size, num_key_ids, key_id_size, data_size);
263 if (!temp_info) {
264 av_encryption_init_info_free(ret);
265 return NULL;
266 }
267 if (i == 0) {
268 info = ret = temp_info;
269 } else {
270 info->next = temp_info;
271 info = temp_info;
272 }
273
274 memcpy(info->system_id, side_data, system_id_size);
275 side_data += system_id_size;
276 side_data_size -= system_id_size;
277 for (j = 0; j < num_key_ids; j++) {
278 memcpy(info->key_ids[j], side_data, key_id_size);
279 side_data += key_id_size;
280 side_data_size -= key_id_size;
281 }
282 memcpy(info->data, side_data, data_size);
283 side_data += data_size;
284 side_data_size -= data_size;
285 }
286
287 return ret;
288 }
289
av_encryption_init_info_add_side_data(const AVEncryptionInitInfo * info,size_t * side_data_size)290 uint8_t *av_encryption_init_info_add_side_data(const AVEncryptionInitInfo *info, size_t *side_data_size)
291 {
292 const AVEncryptionInitInfo *cur_info;
293 uint8_t *buffer, *cur_buffer;
294 uint32_t i, init_info_count;
295 uint64_t temp_side_data_size;
296
297 temp_side_data_size = 4;
298 init_info_count = 0;
299 for (cur_info = info; cur_info; cur_info = cur_info->next) {
300 temp_side_data_size += (uint64_t)FF_ENCRYPTION_INIT_INFO_EXTRA + cur_info->system_id_size + cur_info->data_size;
301 if (init_info_count == UINT32_MAX || temp_side_data_size > UINT32_MAX) {
302 return NULL;
303 }
304 init_info_count++;
305
306 if (cur_info->num_key_ids) {
307 temp_side_data_size += (uint64_t)cur_info->num_key_ids * cur_info->key_id_size;
308 if (temp_side_data_size > UINT32_MAX) {
309 return NULL;
310 }
311 }
312 }
313 *side_data_size = temp_side_data_size;
314
315 cur_buffer = buffer = av_malloc(*side_data_size);
316 if (!buffer)
317 return NULL;
318
319 AV_WB32(cur_buffer, init_info_count);
320 cur_buffer += 4;
321 for (cur_info = info; cur_info; cur_info = cur_info->next) {
322 AV_WB32(cur_buffer, cur_info->system_id_size);
323 AV_WB32(cur_buffer + 4, cur_info->num_key_ids);
324 AV_WB32(cur_buffer + 8, cur_info->key_id_size);
325 AV_WB32(cur_buffer + 12, cur_info->data_size);
326 cur_buffer += 16;
327
328 memcpy(cur_buffer, cur_info->system_id, cur_info->system_id_size);
329 cur_buffer += cur_info->system_id_size;
330 for (i = 0; i < cur_info->num_key_ids; i++) {
331 memcpy(cur_buffer, cur_info->key_ids[i], cur_info->key_id_size);
332 cur_buffer += cur_info->key_id_size;
333 }
334 if (cur_info->data_size > 0) {
335 memcpy(cur_buffer, cur_info->data, cur_info->data_size);
336 cur_buffer += cur_info->data_size;
337 }
338 }
339
340 return buffer;
341 }
342