android_device_qcom_common/cryptfs_hw/cryptfs_hw.c

/* 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 <stdlib.h>
#include <string.h>
#include <sys/limits.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <dirent.h>
#include <dlfcn.h>
#include <linux/qseecom.h>
#include "cutils/log.h"
#include "cutils/properties.h"
#include "cutils/android_reboot.h"
#include "keymaster_common.h"
#include "hardware.h"
#include "cryptfs_hw.h"

/*
 * 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 MAX_PASSWORD_LEN				32
#define QCOM_ICE_STORAGE_UFS				1
#define QCOM_ICE_STORAGE_SDCC				2
#define SET_HW_DISK_ENC_KEY				1
#define UPDATE_HW_DISK_ENC_KEY				2

#define CRYPTFS_HW_KMS_CLEAR_KEY			0
#define CRYPTFS_HW_KMS_WIPE_KEY				1
#define CRYPTFS_HW_UP_CHECK_COUNT			10
#define CRYPTFS_HW_CLEAR_KEY_FAILED			-11
#define CRYPTFS_HW_KMS_MAX_FAILURE			-10
#define CRYPTFS_HW_UPDATE_KEY_FAILED			-9
#define CRYPTFS_HW_WIPE_KEY_FAILED			-8
#define CRYPTFS_HW_CREATE_KEY_FAILED			-7

enum cryptfs_hw_key_management_usage_type {
	CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION		= 0x01,
	CRYPTFS_HW_KM_USAGE_FILE_ENCRYPTION		= 0x02,
	CRYPTFS_HW_KM_USAGE_UFS_ICE_DISK_ENCRYPTION	= 0x03,
	CRYPTFS_HW_KM_USAGE_SDCC_ICE_DISK_ENCRYPTION	= 0x04,
	CRYPTFS_HW_KM_USAGE_MAX
};

static inline void* secure_memset(void* v, int c , size_t n)
{
	volatile unsigned char* p = (volatile unsigned char* )v;
	while (n--) *p++ = c;
	return v;
}

static size_t memscpy(void *dst, size_t dst_size, const void *src, size_t src_size)
{
	size_t min_size = (dst_size < src_size) ? dst_size : src_size;
	memcpy(dst, src, min_size);
	return min_size;
}

static int cryptfs_hw_create_key(enum cryptfs_hw_key_management_usage_type usage,
					unsigned char *hash32)
{
	struct qseecom_create_key_req req;
	int qseecom_fd;
	int32_t ret;

	if (usage < CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION ||
		usage >= CRYPTFS_HW_KM_USAGE_MAX) {
		SLOGE("Error:: unsupported usage %d\n", usage);
		return CRYPTFS_HW_CREATE_KEY_FAILED;
	}

	qseecom_fd = open("/dev/qseecom", O_RDWR);
	if (qseecom_fd < 0) {
		SLOGE("Error::Failed to open /dev/qseecom device\n");
		return CRYPTFS_HW_CREATE_KEY_FAILED;;
	}

	if (!hash32) {
		secure_memset((void *)req.hash32, 0, QSEECOM_HASH_SIZE);
	} else {
		memscpy((void *)req.hash32, QSEECOM_HASH_SIZE, (void *)hash32,
			QSEECOM_HASH_SIZE);
	}

	req.usage = (enum qseecom_key_management_usage_type)usage;
	ret = ioctl(qseecom_fd, QSEECOM_IOCTL_CREATE_KEY_REQ, &req);
	if (ret) {
		SLOGE("Error::ioctl call to create encryption key for usage %d failed with ret = %d, errno = %d\n",
			usage, ret, errno);
		if (errno == ERANGE)
			ret = CRYPTFS_HW_KMS_MAX_FAILURE;
		else
			ret = CRYPTFS_HW_CREATE_KEY_FAILED;
	} else {
		SLOGE("SUCESS::ioctl call to create encryption key for usage %d success with ret = %d\n",
			usage, ret);
	}
	close(qseecom_fd);
	return ret;
}

static int __cryptfs_hw_wipe_clear_key(enum cryptfs_hw_key_management_usage_type usage, int wipe_key_flag)
{
	struct qseecom_wipe_key_req req;
	int32_t ret;
	int qseecom_fd;

	if (usage < CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION ||
			usage >= CRYPTFS_HW_KM_USAGE_MAX) {
		SLOGE("Error:: unsupported usage %d\n", usage);
		return -1;
	}
	qseecom_fd = open("/dev/qseecom", O_RDWR);
	if (qseecom_fd < 0) {
		SLOGE("Error::Failed to open /dev/qseecom device\n");
		return -1;
	}

	req.usage = (enum qseecom_key_management_usage_type)usage;
	req.wipe_key_flag = wipe_key_flag;
	ret = ioctl(qseecom_fd, QSEECOM_IOCTL_WIPE_KEY_REQ, &req);
	close(qseecom_fd);
	return ret;
}

static int cryptfs_hw_wipe_key(enum cryptfs_hw_key_management_usage_type usage)
{
	int32_t ret;

	ret = __cryptfs_hw_wipe_clear_key(usage, CRYPTFS_HW_KMS_WIPE_KEY);
	if (ret) {
		SLOGE("Error::ioctl call to wipe the encryption key for usage %d failed with ret = %d, errno = %d\n",
			usage, ret, errno);
		ret = CRYPTFS_HW_WIPE_KEY_FAILED;
	} else {
		SLOGE("SUCCESS::ioctl call to wipe the encryption key for usage %d success with ret = %d\n",
			usage, ret);
	}
	return ret;
}

static int cryptfs_hw_clear_key(enum cryptfs_hw_key_management_usage_type usage)
{
	int32_t ret;

	ret = __cryptfs_hw_wipe_clear_key(usage, CRYPTFS_HW_KMS_CLEAR_KEY);
	if (ret) {
		SLOGE("Error::ioctl call to wipe the encryption key for usage %d failed with ret = %d, errno = %d\n",
			usage, ret, errno);
		ret = CRYPTFS_HW_CLEAR_KEY_FAILED;
	} else {
		SLOGE("SUCCESS::ioctl call to wipe the encryption key for usage %d success with ret = %d\n",
			usage, ret);
	}
	return ret;
}

static int cryptfs_hw_update_key(enum cryptfs_hw_key_management_usage_type usage,
			unsigned char *current_hash32, unsigned char *new_hash32)
{
	struct qseecom_update_key_userinfo_req req;
	int qseecom_fd;
	int32_t ret;

	if (usage < CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION ||
			usage >= CRYPTFS_HW_KM_USAGE_MAX) {
		SLOGE("Error:: unsupported usage %d\n", usage);
		return CRYPTFS_HW_UPDATE_KEY_FAILED;
	}
	qseecom_fd = open("/dev/qseecom", O_RDWR);
	if (qseecom_fd < 0) {
		SLOGE("Error::Failed to open /dev/qseecom device\n");
		return CRYPTFS_HW_UPDATE_KEY_FAILED;
	}

	req.usage = (enum qseecom_key_management_usage_type)usage;
	if (!current_hash32) {
		secure_memset((void *)req.current_hash32, 0, QSEECOM_HASH_SIZE);
	} else {
		memscpy((void *)req.current_hash32, QSEECOM_HASH_SIZE, (void *)current_hash32,
			QSEECOM_HASH_SIZE);
	}
	if (!new_hash32) {
		secure_memset((void *)req.new_hash32, 0, QSEECOM_HASH_SIZE);
	} else {
		memscpy((void *)req.new_hash32, QSEECOM_HASH_SIZE, (void *)new_hash32,
		QSEECOM_HASH_SIZE);
	}

	ret = ioctl(qseecom_fd, QSEECOM_IOCTL_UPDATE_KEY_USER_INFO_REQ, &req);
	if (ret) {
		SLOGE("Error::ioctl call to update the encryption key for usage %d failed with ret = %d, errno = %d\n",
			usage, ret, errno);
		if (errno == ERANGE)
			ret = CRYPTFS_HW_KMS_MAX_FAILURE;
		else
			ret = CRYPTFS_HW_UPDATE_KEY_FAILED;
	} else {
		SLOGE("SUCCESS::ioctl call to update the encryption key for usage %d success with ret = %d\n",
			usage, ret);
	}
	close(qseecom_fd);
	return ret;
}

static int map_usage(int usage)
{
    int storage_type = is_ice_enabled();
    if (usage == CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION) {
        if (storage_type == QCOM_ICE_STORAGE_UFS) {
            return CRYPTFS_HW_KM_USAGE_UFS_ICE_DISK_ENCRYPTION;
        }
        else if (storage_type == QCOM_ICE_STORAGE_SDCC) {
            return CRYPTFS_HW_KM_USAGE_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) {
            secure_memset(tmp_passwd, 0, MAX_PASSWORD_LEN);
            passwd_len = strnlen(passwd, MAX_PASSWORD_LEN);
            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 int is_qseecom_up()
{
    int i = 0;
    char value[PROPERTY_VALUE_MAX] = {0};

    for (; i<CRYPTFS_HW_UP_CHECK_COUNT; i++) {
        property_get("sys.keymaster.loaded", value, "");
        if (!strncmp(value, "true", PROPERTY_VALUE_MAX))
            return 1;
        usleep(100000);
    }
    return 0;
}

/*
 * 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)) {
        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 = cryptfs_hw_update_key(map_usage(CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION), tmp_currentpasswd, tmp_passwd);
                   secure_memset(tmp_currentpasswd, 0, MAX_PASSWORD_LEN);
                }
            } else if (operation == SET_HW_DISK_ENC_KEY) {
                err = cryptfs_hw_create_key(map_usage(CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION), tmp_passwd);
            }
            if(err < 0) {
                if(ERR_MAX_PASSWORD_ATTEMPTS == err)
                    SLOGI("Maximum wrong password attempts reached, will erase userdata\n");
            }
            secure_memset(tmp_passwd, 0, MAX_PASSWORD_LEN);
            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 clear_hw_device_encryption_key()
{
	return cryptfs_hw_wipe_key(map_usage(CRYPTFS_HW_KM_USAGE_DISK_ENCRYPTION));
}

static int get_keymaster_version()
{
    int rc = -1;
    const hw_module_t* mod;
    rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod);
    if (rc) {
        SLOGE("could not find any keystore module");
        return rc;
    }

    return mod->module_api_version;
}

int should_use_keymaster()
{
    /* HW FDE key would be tied to keymaster only if:
     * New Keymaster is available
     * keymaster partition exists on the device
     */
    int rc = 0;
    if (get_keymaster_version() != KEYMASTER_MODULE_API_VERSION_1_0) {
        SLOGI("Keymaster version is not 1.0");
        return rc;
    }

    return 1;
}