summaryrefslogtreecommitdiffstats
path: root/cryptfs_hw.c
blob: ce522e57874c521bdbf96587561260957f5b2175 (plain)
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
/* Copyright (c) 2014, The Linux Foundation. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   * Neither the name of The Linux Foundation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <cryptfs_hw.h>
#include <stdlib.h>
#include <sys/limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <dlfcn.h>
#include "cutils/log.h"
#include "cutils/properties.h"
#include "cutils/android_reboot.h"

#if defined(__LP64__)
#define QSEECOM_LIBRARY_PATH "/vendor/lib64/libQSEEComAPI.so"
#else
#define QSEECOM_LIBRARY_PATH "/vendor/lib/libQSEEComAPI.so"
#endif


// When device comes up or when user tries to change the password, user can
// try wrong password upto a certain number of times. If user enters wrong
// password further, HW would wipe all disk encryption related crypto data
// and would return an error ERR_MAX_PASSWORD_ATTEMPTS to VOLD. VOLD would
// wipe userdata partition once this error is received.
#define ERR_MAX_PASSWORD_ATTEMPTS -10
#define QSEECOM_DISK_ENCRYPTION 1
#define QSEECOM_UFS_ICE_DISK_ENCRYPTION 3
#define QSEECOM_SDCC_ICE_DISK_ENCRYPTION 4
#define MAX_PASSWORD_LEN 32
#define QCOM_ICE_STORAGE_UFS 1
#define QCOM_ICE_STORAGE_SDCC 2

/* Operations that be performed on HW based device encryption key */
#define SET_HW_DISK_ENC_KEY 1
#define UPDATE_HW_DISK_ENC_KEY 2

static int loaded_library = 0;
static int (*qseecom_create_key)(int, void*);
static int (*qseecom_update_key)(int, void*, void*);
static int (*qseecom_wipe_key)(int);

static int map_usage(int usage)
{
    int storage_type = is_ice_enabled();
    if (usage == QSEECOM_DISK_ENCRYPTION) {
        if (storage_type == QCOM_ICE_STORAGE_UFS) {
            return QSEECOM_UFS_ICE_DISK_ENCRYPTION;
        }
        else if (storage_type == QCOM_ICE_STORAGE_SDCC) {
            return QSEECOM_SDCC_ICE_DISK_ENCRYPTION ;
        }
    }
    return usage;
}

static unsigned char* get_tmp_passwd(const char* passwd)
{
    int passwd_len = 0;
    unsigned char * tmp_passwd = NULL;
    if(passwd) {
        tmp_passwd = (unsigned char*)malloc(MAX_PASSWORD_LEN);
        if(tmp_passwd) {
            memset(tmp_passwd, 0, MAX_PASSWORD_LEN);
            passwd_len = (strlen(passwd) > MAX_PASSWORD_LEN) ? MAX_PASSWORD_LEN : strlen(passwd);
            memcpy(tmp_passwd, passwd, passwd_len);
        } else {
            SLOGE("%s: Failed to allocate memory for tmp passwd \n", __func__);
        }
    } else {
        SLOGE("%s: Passed argument is NULL \n", __func__);
    }
    return tmp_passwd;
}

static void wipe_userdata()
{
    mkdir("/cache/recovery", 0700);
    int fd = open("/cache/recovery/command", O_RDWR|O_CREAT|O_TRUNC|O_NOFOLLOW, 0600);
    if (fd >= 0) {
        write(fd, "--wipe_data", strlen("--wipe_data") + 1);
        close(fd);
    } else {
        SLOGE("could not open /cache/recovery/command\n");
    }
    android_reboot(ANDROID_RB_RESTART2, 0, "recovery");
}

static int load_qseecom_library()
{
    const char *error = NULL;
    if (loaded_library)
        return loaded_library;

    void * handle = dlopen(QSEECOM_LIBRARY_PATH, RTLD_NOW);
    if(handle) {
        dlerror(); /* Clear any existing error */
        *(void **) (&qseecom_create_key) = dlsym(handle,"QSEECom_create_key");

        if((error = dlerror()) == NULL) {
            SLOGD("Success loading QSEECom_create_key \n");
            *(void **) (&qseecom_update_key) = dlsym(handle,"QSEECom_update_key_user_info");
            if ((error = dlerror()) == NULL) {
                SLOGD("Success loading QSEECom_update_key_user_info\n");
                *(void **) (&qseecom_wipe_key) = dlsym(handle,"QSEECom_wipe_key");
                if ((error = dlerror()) == NULL) {
                    loaded_library = 1;
                    SLOGD("Success loading QSEECom_wipe_key \n");
                }
                else
                    SLOGE("Error %s loading symbols for QSEECom APIs \n", error);
            }
            else
                SLOGE("Error %s loading symbols for QSEECom APIs \n", error);
        }
    } else {
        SLOGE("Could not load libQSEEComAPI.so \n");
    }

    if(error)
        dlclose(handle);

    return loaded_library;
}

/*
 * For NON-ICE targets, it would return 0 on success. On ICE based targets,
 * it would return key index in the ICE Key LUT
 */
static int set_key(const char* currentpasswd, const char* passwd, const char* enc_mode, int operation)
{
    int err = -1;
    if (is_hw_disk_encryption(enc_mode) && load_qseecom_library()) {
        unsigned char* tmp_passwd = get_tmp_passwd(passwd);
        unsigned char* tmp_currentpasswd = get_tmp_passwd(currentpasswd);
        if(tmp_passwd) {
            if (operation == UPDATE_HW_DISK_ENC_KEY) {
                if (tmp_currentpasswd)
                   err = qseecom_update_key(map_usage(QSEECOM_DISK_ENCRYPTION), tmp_currentpasswd, tmp_passwd);
            } else if (operation == SET_HW_DISK_ENC_KEY) {
                err = qseecom_create_key(map_usage(QSEECOM_DISK_ENCRYPTION), tmp_passwd);
            }
            if(err < 0) {
                if(ERR_MAX_PASSWORD_ATTEMPTS == err)
                    wipe_userdata();
            }
            free(tmp_passwd);
            free(tmp_currentpasswd);
        }
    }
    return err;
}

int set_hw_device_encryption_key(const char* passwd, const char* enc_mode)
{
    return set_key(NULL, passwd, enc_mode, SET_HW_DISK_ENC_KEY);
}

int update_hw_device_encryption_key(const char* oldpw, const char* newpw, const char* enc_mode)
{
    return set_key(oldpw, newpw, enc_mode, UPDATE_HW_DISK_ENC_KEY);
}

unsigned int is_hw_disk_encryption(const char* encryption_mode)
{
    int ret = 0;
    if(encryption_mode) {
        if (!strcmp(encryption_mode, "aes-xts")) {
            SLOGD("HW based disk encryption is enabled \n");
            ret = 1;
        }
    }
    return ret;
}

int is_ice_enabled(void)
{
  char prop_storage[PATH_MAX];
  int storage_type = 0;
  int fd;

  if (property_get("ro.boot.bootdevice", prop_storage, "")) {
    if (strstr(prop_storage, "ufs")) {
      /* All UFS based devices has ICE in it. So we dont need
       * to check if corresponding device exists or not
       */
      storage_type = QCOM_ICE_STORAGE_UFS;
    } else if (strstr(prop_storage, "sdhc")) {
      if (access("/dev/icesdcc", F_OK) != -1)
        storage_type = QCOM_ICE_STORAGE_SDCC;
    }
  }
  return storage_type;
}

int wipe_hw_device_encryption_key(const char* enc_mode)
{
    if (!enc_mode)
        return -1;

    if (is_hw_disk_encryption(enc_mode) && load_qseecom_library())
        return qseecom_wipe_key(map_usage(QSEECOM_DISK_ENCRYPTION));

    return 0;
}