| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* TO DO: |
| * 1. Perhaps keep several copies of the encrypted key, in case something |
| * goes horribly wrong? |
| * |
| */ |
| |
| #include <sys/types.h> |
| #include <sys/wait.h> |
| #include <sys/stat.h> |
| #include <ctype.h> |
| #include <fcntl.h> |
| #include <inttypes.h> |
| #include <unistd.h> |
| #include <stdio.h> |
| #include <sys/ioctl.h> |
| #include <linux/dm-ioctl.h> |
| #include <libgen.h> |
| #include <stdlib.h> |
| #include <sys/param.h> |
| #include <string.h> |
| #include <sys/mount.h> |
| #include <openssl/evp.h> |
| #include <errno.h> |
| #include <linux/kdev_t.h> |
| #include <time.h> |
| #include "cryptfs.h" |
| #include "cutils/properties.h" |
| #include "crypto_scrypt.h" |
| #include <hardware/keymaster.h> |
| |
| #ifndef min /* already defined by windows.h */ |
| #define min(a, b) ((a) < (b) ? (a) : (b)) |
| #endif |
| |
| #define UNUSED __attribute__((unused)) |
| |
| #define UNUSED __attribute__((unused)) |
| |
| #define DM_CRYPT_BUF_SIZE 4096 |
| |
| #define HASH_COUNT 2000 |
| #define KEY_LEN_BYTES 16 |
| #define IV_LEN_BYTES 16 |
| |
| #define KEY_IN_FOOTER "footer" |
| |
| // "default_password" encoded into hex (d=0x64 etc) |
| #define DEFAULT_PASSWORD "64656661756c745f70617373776f7264" |
| |
| #define EXT4_FS 1 |
| #define F2FS_FS 2 |
| |
| #define TABLE_LOAD_RETRIES 10 |
| |
| #define RSA_KEY_SIZE 2048 |
| #define RSA_KEY_SIZE_BYTES (RSA_KEY_SIZE / 8) |
| #define RSA_EXPONENT 0x10001 |
| |
| #define RETRY_MOUNT_ATTEMPTS 10 |
| #define RETRY_MOUNT_DELAY_SECONDS 1 |
| |
| char *me = "cryptfs"; |
| |
| static unsigned char saved_master_key[KEY_LEN_BYTES]; |
| static char *saved_mount_point; |
| static int master_key_saved = 0; |
| static struct crypt_persist_data *persist_data = NULL; |
| static char key_fname[PROPERTY_VALUE_MAX] = ""; |
| static char real_blkdev[PROPERTY_VALUE_MAX] = ""; |
| static char file_system[PROPERTY_VALUE_MAX] = ""; |
| |
| void set_partition_data(const char* block_device, const char* key_location, const char* fs) |
| { |
| strcpy(key_fname, key_location); |
| strcpy(real_blkdev, block_device); |
| strcpy(file_system, fs); |
| } |
| |
| static int keymaster_init(keymaster_device_t **keymaster_dev) |
| { |
| int rc; |
| |
| const hw_module_t* mod; |
| rc = hw_get_module_by_class(KEYSTORE_HARDWARE_MODULE_ID, NULL, &mod); |
| if (rc) { |
| printf("could not find any keystore module\n"); |
| goto out; |
| } |
| |
| rc = keymaster_open(mod, keymaster_dev); |
| if (rc) { |
| printf("could not open keymaster device in %s (%s)\n", |
| KEYSTORE_HARDWARE_MODULE_ID, strerror(-rc)); |
| goto out; |
| } |
| |
| return 0; |
| |
| out: |
| *keymaster_dev = NULL; |
| return rc; |
| } |
| |
| /* Should we use keymaster? */ |
| static int keymaster_check_compatibility() |
| { |
| keymaster_device_t *keymaster_dev = 0; |
| int rc = 0; |
| |
| if (keymaster_init(&keymaster_dev)) { |
| printf("Failed to init keymaster\n"); |
| rc = -1; |
| goto out; |
| } |
| |
| printf("keymaster version is %d\n", keymaster_dev->common.module->module_api_version); |
| |
| #if (KEYMASTER_HEADER_VERSION >= 3) |
| if (keymaster_dev->common.module->module_api_version |
| < KEYMASTER_MODULE_API_VERSION_0_3) { |
| rc = 0; |
| goto out; |
| } |
| |
| if (keymaster_dev->flags & KEYMASTER_BLOBS_ARE_STANDALONE) { |
| rc = 1; |
| } |
| |
| #endif |
| out: |
| keymaster_close(keymaster_dev); |
| return rc; |
| } |
| |
| /* Create a new keymaster key and store it in this footer */ |
| static int keymaster_create_key(struct crypt_mnt_ftr *ftr) |
| { |
| uint8_t* key = 0; |
| keymaster_device_t *keymaster_dev = 0; |
| |
| if (keymaster_init(&keymaster_dev)) { |
| printf("Failed to init keymaster\n"); |
| return -1; |
| } |
| |
| int rc = 0; |
| |
| keymaster_rsa_keygen_params_t params; |
| memset(¶ms, '\0', sizeof(params)); |
| params.public_exponent = RSA_EXPONENT; |
| params.modulus_size = RSA_KEY_SIZE; |
| |
| size_t key_size; |
| if (keymaster_dev->generate_keypair(keymaster_dev, TYPE_RSA, ¶ms, |
| &key, &key_size)) { |
| printf("Failed to generate keypair\n"); |
| rc = -1; |
| goto out; |
| } |
| |
| if (key_size > KEYMASTER_BLOB_SIZE) { |
| printf("Keymaster key too large for crypto footer\n"); |
| rc = -1; |
| goto out; |
| } |
| |
| memcpy(ftr->keymaster_blob, key, key_size); |
| ftr->keymaster_blob_size = key_size; |
| |
| out: |
| keymaster_close(keymaster_dev); |
| free(key); |
| return rc; |
| } |
| |
| /* This signs the given object using the keymaster key. */ |
| static int keymaster_sign_object(struct crypt_mnt_ftr *ftr, |
| const unsigned char *object, |
| const size_t object_size, |
| unsigned char **signature, |
| size_t *signature_size) |
| { |
| int rc = 0; |
| keymaster_device_t *keymaster_dev = 0; |
| if (keymaster_init(&keymaster_dev)) { |
| printf("Failed to init keymaster\n"); |
| return -1; |
| } |
| |
| /* We currently set the digest type to DIGEST_NONE because it's the |
| * only supported value for keymaster. A similar issue exists with |
| * PADDING_NONE. Long term both of these should likely change. |
| */ |
| keymaster_rsa_sign_params_t params; |
| params.digest_type = DIGEST_NONE; |
| params.padding_type = PADDING_NONE; |
| |
| unsigned char to_sign[RSA_KEY_SIZE_BYTES]; |
| size_t to_sign_size = sizeof(to_sign); |
| memset(to_sign, 0, RSA_KEY_SIZE_BYTES); |
| |
| // To sign a message with RSA, the message must satisfy two |
| // constraints: |
| // |
| // 1. The message, when interpreted as a big-endian numeric value, must |
| // be strictly less than the public modulus of the RSA key. Note |
| // that because the most significant bit of the public modulus is |
| // guaranteed to be 1 (else it's an (n-1)-bit key, not an n-bit |
| // key), an n-bit message with most significant bit 0 always |
| // satisfies this requirement. |
| // |
| // 2. The message must have the same length in bits as the public |
| // modulus of the RSA key. This requirement isn't mathematically |
| // necessary, but is necessary to ensure consistency in |
| // implementations. |
| switch (ftr->kdf_type) { |
| case KDF_SCRYPT_KEYMASTER_UNPADDED: |
| // This is broken: It produces a message which is shorter than |
| // the public modulus, failing criterion 2. |
| memcpy(to_sign, object, object_size); |
| to_sign_size = object_size; |
| printf("Signing unpadded object\n"); |
| break; |
| case KDF_SCRYPT_KEYMASTER_BADLY_PADDED: |
| // This is broken: Since the value of object is uniformly |
| // distributed, it produces a message that is larger than the |
| // public modulus with probability 0.25. |
| memcpy(to_sign, object, min(RSA_KEY_SIZE_BYTES, object_size)); |
| printf("Signing end-padded object\n"); |
| break; |
| case KDF_SCRYPT_KEYMASTER: |
| // This ensures the most significant byte of the signed message |
| // is zero. We could have zero-padded to the left instead, but |
| // this approach is slightly more robust against changes in |
| // object size. However, it's still broken (but not unusably |
| // so) because we really should be using a proper RSA padding |
| // function, such as OAEP. |
| // |
| // TODO(paullawrence): When keymaster 0.4 is available, change |
| // this to use the padding options it provides. |
| memcpy(to_sign + 1, object, min(RSA_KEY_SIZE_BYTES - 1, object_size)); |
| printf("Signing safely-padded object\n"); |
| break; |
| default: |
| printf("Unknown KDF type %d\n", ftr->kdf_type); |
| return -1; |
| } |
| |
| rc = keymaster_dev->sign_data(keymaster_dev, |
| ¶ms, |
| ftr->keymaster_blob, |
| ftr->keymaster_blob_size, |
| to_sign, |
| to_sign_size, |
| signature, |
| signature_size); |
| |
| keymaster_close(keymaster_dev); |
| return rc; |
| } |
| |
| /* Store password when userdata is successfully decrypted and mounted. |
| * Cleared by cryptfs_clear_password |
| * |
| * To avoid a double prompt at boot, we need to store the CryptKeeper |
| * password and pass it to KeyGuard, which uses it to unlock KeyStore. |
| * Since the entire framework is torn down and rebuilt after encryption, |
| * we have to use a daemon or similar to store the password. Since vold |
| * is secured against IPC except from system processes, it seems a reasonable |
| * place to store this. |
| * |
| * password should be cleared once it has been used. |
| * |
| * password is aged out after password_max_age_seconds seconds. |
| */ |
| static char* password = 0; |
| static int password_expiry_time = 0; |
| static const int password_max_age_seconds = 60; |
| |
| static void ioctl_init(struct dm_ioctl *io, size_t dataSize, const char *name, unsigned flags) |
| { |
| memset(io, 0, dataSize); |
| io->data_size = dataSize; |
| io->data_start = sizeof(struct dm_ioctl); |
| io->version[0] = 4; |
| io->version[1] = 0; |
| io->version[2] = 0; |
| io->flags = flags; |
| if (name) { |
| strncpy(io->name, name, sizeof(io->name)); |
| } |
| } |
| |
| /** |
| * Gets the default device scrypt parameters for key derivation time tuning. |
| * The parameters should lead to about one second derivation time for the |
| * given device. |
| */ |
| static void get_device_scrypt_params(struct crypt_mnt_ftr *ftr) { |
| const int default_params[] = SCRYPT_DEFAULTS; |
| int params[] = SCRYPT_DEFAULTS; |
| char paramstr[PROPERTY_VALUE_MAX]; |
| char *token; |
| char *saveptr; |
| int i; |
| |
| property_get(SCRYPT_PROP, paramstr, ""); |
| if (paramstr[0] != '\0') { |
| /* |
| * The token we're looking for should be three integers separated by |
| * colons (e.g., "12:8:1"). Scan the property to make sure it matches. |
| */ |
| for (i = 0, token = strtok_r(paramstr, ":", &saveptr); |
| token != NULL && i < 3; |
| i++, token = strtok_r(NULL, ":", &saveptr)) { |
| char *endptr; |
| params[i] = strtol(token, &endptr, 10); |
| |
| /* |
| * Check that there was a valid number and it's 8-bit. If not, |
| * break out and the end check will take the default values. |
| */ |
| if ((*token == '\0') || (*endptr != '\0') || params[i] < 0 || params[i] > 255) { |
| break; |
| } |
| } |
| |
| /* |
| * If there were not enough tokens or a token was malformed (not an |
| * integer), it will end up here and the default parameters can be |
| * taken. |
| */ |
| if ((i != 3) || (token != NULL)) { |
| printf("bad scrypt parameters '%s' should be like '12:8:1'; using defaults", paramstr); |
| memcpy(params, default_params, sizeof(params)); |
| } |
| } |
| |
| ftr->N_factor = params[0]; |
| ftr->r_factor = params[1]; |
| ftr->p_factor = params[2]; |
| } |
| |
| static unsigned int get_blkdev_size(int fd) |
| { |
| unsigned int nr_sec; |
| |
| if ( (ioctl(fd, BLKGETSIZE, &nr_sec)) == -1) { |
| nr_sec = 0; |
| } |
| |
| return nr_sec; |
| } |
| |
| static int get_crypt_ftr_info(char **metadata_fname, off64_t *off) |
| { |
| static int cached_data = 0; |
| static off64_t cached_off = 0; |
| static char cached_metadata_fname[PROPERTY_VALUE_MAX] = ""; |
| int fd; |
| unsigned int nr_sec; |
| int rc = -1; |
| |
| if (!cached_data) { |
| printf("get_crypt_ftr_info crypto key location: '%s'\n", key_fname); |
| if (!strcmp(key_fname, KEY_IN_FOOTER)) { |
| if ( (fd = open(real_blkdev, O_RDWR)) < 0) { |
| printf("Cannot open real block device %s\n", real_blkdev); |
| return -1; |
| } |
| |
| if ((nr_sec = get_blkdev_size(fd))) { |
| /* If it's an encrypted Android partition, the last 16 Kbytes contain the |
| * encryption info footer and key, and plenty of bytes to spare for future |
| * growth. |
| */ |
| strlcpy(cached_metadata_fname, real_blkdev, sizeof(cached_metadata_fname)); |
| cached_off = ((off64_t)nr_sec * 512) - CRYPT_FOOTER_OFFSET; |
| cached_data = 1; |
| } else { |
| printf("Cannot get size of block device %s\n", real_blkdev); |
| } |
| close(fd); |
| } else { |
| strlcpy(cached_metadata_fname, key_fname, sizeof(cached_metadata_fname)); |
| cached_off = 0; |
| cached_data = 1; |
| } |
| } |
| |
| if (cached_data) { |
| if (metadata_fname) { |
| *metadata_fname = cached_metadata_fname; |
| } |
| if (off) { |
| *off = cached_off; |
| } |
| rc = 0; |
| } |
| |
| return rc; |
| } |
| |
| static inline int unix_read(int fd, void* buff, int len) |
| { |
| return TEMP_FAILURE_RETRY(read(fd, buff, len)); |
| } |
| |
| static inline int unix_write(int fd, const void* buff, int len) |
| { |
| return TEMP_FAILURE_RETRY(write(fd, buff, len)); |
| } |
| |
| static void init_empty_persist_data(struct crypt_persist_data *pdata, int len) |
| { |
| memset(pdata, 0, len); |
| pdata->persist_magic = PERSIST_DATA_MAGIC; |
| pdata->persist_valid_entries = 0; |
| } |
| |
| static int get_crypt_ftr_and_key(struct crypt_mnt_ftr *crypt_ftr) |
| { |
| int fd; |
| unsigned int nr_sec, cnt; |
| off64_t starting_off; |
| int rc = -1; |
| char *fname = NULL; |
| struct stat statbuf; |
| |
| if (get_crypt_ftr_info(&fname, &starting_off)) { |
| printf("Unable to get crypt_ftr_info\n"); |
| return -1; |
| } |
| if (fname[0] != '/') { |
| printf("Unexpected value for crypto key location\n"); |
| return -1; |
| } |
| if ( (fd = open(fname, O_RDWR)) < 0) { |
| printf("Cannot open footer file %s for get\n", fname); |
| return -1; |
| } |
| |
| /* Make sure it's 16 Kbytes in length */ |
| fstat(fd, &statbuf); |
| if (S_ISREG(statbuf.st_mode) && (statbuf.st_size != 0x4000)) { |
| printf("footer file %s is not the expected size!\n", fname); |
| goto errout; |
| } |
| |
| /* Seek to the start of the crypt footer */ |
| if (lseek64(fd, starting_off, SEEK_SET) == -1) { |
| printf("Cannot seek to real block device footer\n"); |
| goto errout; |
| } |
| |
| if ( (cnt = read(fd, crypt_ftr, sizeof(struct crypt_mnt_ftr))) != sizeof(struct crypt_mnt_ftr)) { |
| printf("Cannot read real block device footer\n"); |
| goto errout; |
| } |
| |
| if (crypt_ftr->magic != CRYPT_MNT_MAGIC) { |
| printf("Bad magic for real block device %s\n", fname); |
| goto errout; |
| } |
| |
| if (crypt_ftr->major_version != CURRENT_MAJOR_VERSION) { |
| printf("Cannot understand major version %d real block device footer; expected %d\n", |
| crypt_ftr->major_version, CURRENT_MAJOR_VERSION); |
| goto errout; |
| } |
| |
| if (crypt_ftr->minor_version > CURRENT_MINOR_VERSION) { |
| printf("Warning: crypto footer minor version %d, expected <= %d, continuing...\n", |
| crypt_ftr->minor_version, CURRENT_MINOR_VERSION); |
| } |
| |
| /* If this is a verion 1.0 crypt_ftr, make it a 1.1 crypt footer, and update the |
| * copy on disk before returning. |
| */ |
| /*if (crypt_ftr->minor_version < CURRENT_MINOR_VERSION) { |
| upgrade_crypt_ftr(fd, crypt_ftr, starting_off); |
| }*/ |
| |
| /* Success! */ |
| rc = 0; |
| |
| errout: |
| close(fd); |
| return rc; |
| } |
| |
| static int hexdigit (char c) |
| { |
| if (c >= '0' && c <= '9') return c - '0'; |
| c = tolower(c); |
| if (c >= 'a' && c <= 'f') return c - 'a' + 10; |
| return -1; |
| } |
| |
| static unsigned char* convert_hex_ascii_to_key(const char* master_key_ascii, |
| unsigned int* out_keysize) |
| { |
| unsigned int i; |
| *out_keysize = 0; |
| |
| size_t size = strlen (master_key_ascii); |
| if (size % 2) { |
| printf("Trying to convert ascii string of odd length"); |
| return NULL; |
| } |
| |
| unsigned char* master_key = (unsigned char*) malloc(size / 2); |
| if (master_key == 0) { |
| printf("Cannot allocate"); |
| return NULL; |
| } |
| |
| for (i = 0; i < size; i += 2) { |
| int high_nibble = hexdigit (master_key_ascii[i]); |
| int low_nibble = hexdigit (master_key_ascii[i + 1]); |
| |
| if(high_nibble < 0 || low_nibble < 0) { |
| printf("Invalid hex string"); |
| free (master_key); |
| return NULL; |
| } |
| |
| master_key[*out_keysize] = high_nibble * 16 + low_nibble; |
| (*out_keysize)++; |
| } |
| |
| return master_key; |
| } |
| |
| /* Convert a binary key of specified length into an ascii hex string equivalent, |
| * without the leading 0x and with null termination |
| */ |
| static void convert_key_to_hex_ascii(unsigned char *master_key, unsigned int keysize, |
| char *master_key_ascii) |
| { |
| unsigned int i, a; |
| unsigned char nibble; |
| |
| for (i=0, a=0; i<keysize; i++, a+=2) { |
| /* For each byte, write out two ascii hex digits */ |
| nibble = (master_key[i] >> 4) & 0xf; |
| master_key_ascii[a] = nibble + (nibble > 9 ? 0x37 : 0x30); |
| |
| nibble = master_key[i] & 0xf; |
| master_key_ascii[a+1] = nibble + (nibble > 9 ? 0x37 : 0x30); |
| } |
| |
| /* Add the null termination */ |
| master_key_ascii[a] = '\0'; |
| |
| } |
| |
| static int load_crypto_mapping_table(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, |
| char *real_blk_name, const char *name, int fd, |
| char *extra_params) |
| { |
| char buffer[DM_CRYPT_BUF_SIZE]; |
| struct dm_ioctl *io; |
| struct dm_target_spec *tgt; |
| char *crypt_params; |
| char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ |
| int i; |
| |
| io = (struct dm_ioctl *) buffer; |
| |
| /* Load the mapping table for this device */ |
| tgt = (struct dm_target_spec *) &buffer[sizeof(struct dm_ioctl)]; |
| |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| io->target_count = 1; |
| tgt->status = 0; |
| tgt->sector_start = 0; |
| tgt->length = crypt_ftr->fs_size; |
| strcpy(tgt->target_type, "crypt"); |
| |
| crypt_params = buffer + sizeof(struct dm_ioctl) + sizeof(struct dm_target_spec); |
| convert_key_to_hex_ascii(master_key, crypt_ftr->keysize, master_key_ascii); |
| sprintf(crypt_params, "%s %s 0 %s 0 %s", crypt_ftr->crypto_type_name, |
| master_key_ascii, real_blk_name, extra_params); |
| crypt_params += strlen(crypt_params) + 1; |
| crypt_params = (char *) (((unsigned long)crypt_params + 7) & ~8); /* Align to an 8 byte boundary */ |
| tgt->next = crypt_params - buffer; |
| |
| for (i = 0; i < TABLE_LOAD_RETRIES; i++) { |
| if (! ioctl(fd, DM_TABLE_LOAD, io)) { |
| break; |
| } |
| usleep(500000); |
| } |
| |
| if (i == TABLE_LOAD_RETRIES) { |
| /* We failed to load the table, return an error */ |
| return -1; |
| } else { |
| return i + 1; |
| } |
| } |
| |
| |
| static int get_dm_crypt_version(int fd, const char *name, int *version) |
| { |
| char buffer[DM_CRYPT_BUF_SIZE]; |
| struct dm_ioctl *io; |
| struct dm_target_versions *v; |
| int i; |
| |
| io = (struct dm_ioctl *) buffer; |
| |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| |
| if (ioctl(fd, DM_LIST_VERSIONS, io)) { |
| return -1; |
| } |
| |
| /* Iterate over the returned versions, looking for name of "crypt". |
| * When found, get and return the version. |
| */ |
| v = (struct dm_target_versions *) &buffer[sizeof(struct dm_ioctl)]; |
| while (v->next) { |
| if (! strcmp(v->name, "crypt")) { |
| /* We found the crypt driver, return the version, and get out */ |
| version[0] = v->version[0]; |
| version[1] = v->version[1]; |
| version[2] = v->version[2]; |
| return 0; |
| } |
| v = (struct dm_target_versions *)(((char *)v) + v->next); |
| } |
| |
| return -1; |
| } |
| |
| static int create_crypto_blk_dev(struct crypt_mnt_ftr *crypt_ftr, unsigned char *master_key, |
| char *real_blk_name, char *crypto_blk_name, const char *name) |
| { |
| char buffer[DM_CRYPT_BUF_SIZE]; |
| char master_key_ascii[129]; /* Large enough to hold 512 bit key and null */ |
| char *crypt_params; |
| struct dm_ioctl *io; |
| struct dm_target_spec *tgt; |
| unsigned int minor; |
| int fd; |
| int i; |
| int retval = -1; |
| int version[3]; |
| char *extra_params; |
| int load_count; |
| |
| if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { |
| printf("Cannot open device-mapper\n"); |
| goto errout; |
| } |
| |
| io = (struct dm_ioctl *) buffer; |
| |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| if (ioctl(fd, DM_DEV_CREATE, io)) { |
| printf("Cannot create dm-crypt device\n"); |
| goto errout; |
| } |
| |
| /* Get the device status, in particular, the name of it's device file */ |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| if (ioctl(fd, DM_DEV_STATUS, io)) { |
| printf("Cannot retrieve dm-crypt device status\n"); |
| goto errout; |
| } |
| minor = (io->dev & 0xff) | ((io->dev >> 12) & 0xfff00); |
| snprintf(crypto_blk_name, MAXPATHLEN, "/dev/block/dm-%u", minor); |
| |
| extra_params = ""; |
| if (! get_dm_crypt_version(fd, name, version)) { |
| /* Support for allow_discards was added in version 1.11.0 */ |
| if ((version[0] >= 2) || |
| ((version[0] == 1) && (version[1] >= 11))) { |
| extra_params = "1 allow_discards"; |
| printf("Enabling support for allow_discards in dmcrypt.\n"); |
| } |
| } |
| |
| load_count = load_crypto_mapping_table(crypt_ftr, master_key, real_blk_name, name, |
| fd, extra_params); |
| if (load_count < 0) { |
| printf("Cannot load dm-crypt mapping table.\n"); |
| goto errout; |
| } else if (load_count > 1) { |
| printf("Took %d tries to load dmcrypt table.\n", load_count); |
| } |
| |
| /* Resume this device to activate it */ |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| |
| if (ioctl(fd, DM_DEV_SUSPEND, io)) { |
| printf("Cannot resume the dm-crypt device\n"); |
| goto errout; |
| } |
| |
| /* We made it here with no errors. Woot! */ |
| retval = 0; |
| |
| errout: |
| close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ |
| |
| return retval; |
| } |
| |
| int delete_crypto_blk_dev(char *name) |
| { |
| int fd; |
| char buffer[DM_CRYPT_BUF_SIZE]; |
| struct dm_ioctl *io; |
| int retval = -1; |
| |
| if ((fd = open("/dev/device-mapper", O_RDWR)) < 0 ) { |
| printf("Cannot open device-mapper\n"); |
| goto errout; |
| } |
| |
| io = (struct dm_ioctl *) buffer; |
| |
| ioctl_init(io, DM_CRYPT_BUF_SIZE, name, 0); |
| if (ioctl(fd, DM_DEV_REMOVE, io)) { |
| printf("Cannot remove dm-crypt device\n"); |
| goto errout; |
| } |
| |
| /* We made it here with no errors. Woot! */ |
| retval = 0; |
| |
| errout: |
| close(fd); /* If fd is <0 from a failed open call, it's safe to just ignore the close error */ |
| |
| return retval; |
| |
| } |
| |
| static int pbkdf2(const char *passwd, const unsigned char *salt, |
| unsigned char *ikey, void *params UNUSED) |
| { |
| printf("Using pbkdf2 for cryptfs KDF"); |
| |
| /* Turn the password into a key and IV that can decrypt the master key */ |
| unsigned int keysize; |
| char* master_key = (char*)convert_hex_ascii_to_key(passwd, &keysize); |
| if (!master_key) return -1; |
| PKCS5_PBKDF2_HMAC_SHA1(master_key, keysize, salt, SALT_LEN, |
| HASH_COUNT, KEY_LEN_BYTES+IV_LEN_BYTES, ikey); |
| |
| memset(master_key, 0, keysize); |
| free (master_key); |
| return 0; |
| } |
| |
| static int scrypt(const char *passwd, const unsigned char *salt, |
| unsigned char *ikey, void *params) |
| { |
| printf("Using scrypt for cryptfs KDF\n"); |
| |
| struct crypt_mnt_ftr *ftr = (struct crypt_mnt_ftr *) params; |
| |
| int N = 1 << ftr->N_factor; |
| int r = 1 << ftr->r_factor; |
| int p = 1 << ftr->p_factor; |
| |
| /* Turn the password into a key and IV that can decrypt the master key */ |
| unsigned int keysize; |
| unsigned char* master_key = convert_hex_ascii_to_key(passwd, &keysize); |
| if (!master_key) return -1; |
| crypto_scrypt(master_key, keysize, salt, SALT_LEN, N, r, p, ikey, |
| KEY_LEN_BYTES + IV_LEN_BYTES); |
| |
| memset(master_key, 0, keysize); |
| free (master_key); |
| return 0; |
| } |
| |
| static int scrypt_keymaster(const char *passwd, const unsigned char *salt, |
| unsigned char *ikey, void *params) |
| { |
| printf("Using scrypt with keymaster for cryptfs KDF\n"); |
| |
| int rc; |
| unsigned int key_size; |
| size_t signature_size; |
| unsigned char* signature; |
| struct crypt_mnt_ftr *ftr = (struct crypt_mnt_ftr *) params; |
| |
| int N = 1 << ftr->N_factor; |
| int r = 1 << ftr->r_factor; |
| int p = 1 << ftr->p_factor; |
| |
| unsigned char* master_key = convert_hex_ascii_to_key(passwd, &key_size); |
| if (!master_key) { |
| printf("Failed to convert passwd from hex\n"); |
| return -1; |
| } |
| |
| rc = crypto_scrypt(master_key, key_size, salt, SALT_LEN, |
| N, r, p, ikey, KEY_LEN_BYTES + IV_LEN_BYTES); |
| memset(master_key, 0, key_size); |
| free(master_key); |
| |
| if (rc) { |
| printf("scrypt failed\n"); |
| return -1; |
| } |
| |
| if (keymaster_sign_object(ftr, ikey, KEY_LEN_BYTES + IV_LEN_BYTES, |
| &signature, &signature_size)) { |
| printf("Signing failed\n"); |
| return -1; |
| } |
| |
| rc = crypto_scrypt(signature, signature_size, salt, SALT_LEN, |
| N, r, p, ikey, KEY_LEN_BYTES + IV_LEN_BYTES); |
| free(signature); |
| |
| if (rc) { |
| printf("scrypt failed\n"); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static int encrypt_master_key(const char *passwd, const unsigned char *salt, |
| const unsigned char *decrypted_master_key, |
| unsigned char *encrypted_master_key, |
| struct crypt_mnt_ftr *crypt_ftr) |
| { |
| unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ |
| EVP_CIPHER_CTX e_ctx; |
| int encrypted_len, final_len; |
| int rc = 0; |
| |
| /* Turn the password into an intermediate key and IV that can decrypt the master key */ |
| get_device_scrypt_params(crypt_ftr); |
| |
| switch (crypt_ftr->kdf_type) { |
| case KDF_SCRYPT_KEYMASTER_UNPADDED: |
| case KDF_SCRYPT_KEYMASTER_BADLY_PADDED: |
| case KDF_SCRYPT_KEYMASTER: |
| if (keymaster_create_key(crypt_ftr)) { |
| printf("keymaster_create_key failed"); |
| return -1; |
| } |
| |
| if (scrypt_keymaster(passwd, salt, ikey, crypt_ftr)) { |
| printf("scrypt failed"); |
| return -1; |
| } |
| break; |
| |
| case KDF_SCRYPT: |
| if (scrypt(passwd, salt, ikey, crypt_ftr)) { |
| printf("scrypt failed"); |
| return -1; |
| } |
| break; |
| |
| default: |
| printf("Invalid kdf_type"); |
| return -1; |
| } |
| |
| /* Initialize the decryption engine */ |
| if (! EVP_EncryptInit(&e_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { |
| printf("EVP_EncryptInit failed\n"); |
| return -1; |
| } |
| EVP_CIPHER_CTX_set_padding(&e_ctx, 0); /* Turn off padding as our data is block aligned */ |
| |
| /* Encrypt the master key */ |
| if (! EVP_EncryptUpdate(&e_ctx, encrypted_master_key, &encrypted_len, |
| decrypted_master_key, KEY_LEN_BYTES)) { |
| printf("EVP_EncryptUpdate failed\n"); |
| return -1; |
| } |
| if (! EVP_EncryptFinal(&e_ctx, encrypted_master_key + encrypted_len, &final_len)) { |
| printf("EVP_EncryptFinal failed\n"); |
| return -1; |
| } |
| |
| if (encrypted_len + final_len != KEY_LEN_BYTES) { |
| printf("EVP_Encryption length check failed with %d, %d bytes\n", encrypted_len, final_len); |
| return -1; |
| } |
| |
| /* Store the scrypt of the intermediate key, so we can validate if it's a |
| password error or mount error when things go wrong. |
| Note there's no need to check for errors, since if this is incorrect, we |
| simply won't wipe userdata, which is the correct default behavior |
| */ |
| int N = 1 << crypt_ftr->N_factor; |
| int r = 1 << crypt_ftr->r_factor; |
| int p = 1 << crypt_ftr->p_factor; |
| |
| rc = crypto_scrypt(ikey, KEY_LEN_BYTES, |
| crypt_ftr->salt, sizeof(crypt_ftr->salt), N, r, p, |
| crypt_ftr->scrypted_intermediate_key, |
| sizeof(crypt_ftr->scrypted_intermediate_key)); |
| |
| if (rc) { |
| printf("encrypt_master_key: crypto_scrypt failed"); |
| } |
| |
| return 0; |
| } |
| |
| static int decrypt_master_key_aux(char *passwd, unsigned char *salt, |
| unsigned char *encrypted_master_key, |
| unsigned char *decrypted_master_key, |
| kdf_func kdf, void *kdf_params, |
| unsigned char** intermediate_key, |
| size_t* intermediate_key_size) |
| { |
| unsigned char ikey[32+32] = { 0 }; /* Big enough to hold a 256 bit key and 256 bit IV */ |
| EVP_CIPHER_CTX d_ctx; |
| int decrypted_len, final_len; |
| |
| /* Turn the password into an intermediate key and IV that can decrypt the |
| master key */ |
| if (kdf(passwd, salt, ikey, kdf_params)) { |
| printf("kdf failed"); |
| return -1; |
| } |
| |
| /* Initialize the decryption engine */ |
| if (! EVP_DecryptInit(&d_ctx, EVP_aes_128_cbc(), ikey, ikey+KEY_LEN_BYTES)) { |
| return -1; |
| } |
| EVP_CIPHER_CTX_set_padding(&d_ctx, 0); /* Turn off padding as our data is block aligned */ |
| /* Decrypt the master key */ |
| if (! EVP_DecryptUpdate(&d_ctx, decrypted_master_key, &decrypted_len, |
| encrypted_master_key, KEY_LEN_BYTES)) { |
| return -1; |
| } |
| if (! EVP_DecryptFinal(&d_ctx, decrypted_master_key + decrypted_len, &final_len)) { |
| return -1; |
| } |
| |
| if (decrypted_len + final_len != KEY_LEN_BYTES) { |
| return -1; |
| } |
| |
| /* Copy intermediate key if needed by params */ |
| if (intermediate_key && intermediate_key_size) { |
| *intermediate_key = (unsigned char*) malloc(KEY_LEN_BYTES); |
| if (intermediate_key) { |
| memcpy(*intermediate_key, ikey, KEY_LEN_BYTES); |
| *intermediate_key_size = KEY_LEN_BYTES; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static void get_kdf_func(struct crypt_mnt_ftr *ftr, kdf_func *kdf, void** kdf_params) |
| { |
| if (ftr->kdf_type == KDF_SCRYPT_KEYMASTER_UNPADDED || |
| ftr->kdf_type == KDF_SCRYPT_KEYMASTER_BADLY_PADDED || |
| ftr->kdf_type == KDF_SCRYPT_KEYMASTER) { |
| *kdf = scrypt_keymaster; |
| *kdf_params = ftr; |
| } else if (ftr->kdf_type == KDF_SCRYPT) { |
| *kdf = scrypt; |
| *kdf_params = ftr; |
| } else { |
| *kdf = pbkdf2; |
| *kdf_params = NULL; |
| } |
| } |
| |
| static int decrypt_master_key(char *passwd, unsigned char *decrypted_master_key, |
| struct crypt_mnt_ftr *crypt_ftr, |
| unsigned char** intermediate_key, |
| size_t* intermediate_key_size) |
| { |
| kdf_func kdf; |
| void *kdf_params; |
| int ret; |
| |
| get_kdf_func(crypt_ftr, &kdf, &kdf_params); |
| ret = decrypt_master_key_aux(passwd, crypt_ftr->salt, crypt_ftr->master_key, |
| decrypted_master_key, kdf, kdf_params, |
| intermediate_key, intermediate_key_size); |
| if (ret != 0) { |
| printf("failure decrypting master key"); |
| } |
| |
| return ret; |
| } |
| |
| static int test_mount_encrypted_fs(struct crypt_mnt_ftr* crypt_ftr, |
| char *passwd, char *mount_point, char *label) |
| { |
| /* Allocate enough space for a 256 bit key, but we may use less */ |
| unsigned char decrypted_master_key[32]; |
| char crypto_blkdev[MAXPATHLEN]; |
| char tmp_mount_point[64]; |
| unsigned int orig_failed_decrypt_count; |
| int rc; |
| kdf_func kdf; |
| void *kdf_params; |
| int use_keymaster = 0; |
| int upgrade = 0; |
| unsigned char* intermediate_key = 0; |
| size_t intermediate_key_size = 0; |
| |
| printf("crypt_ftr->fs_size = %lld\n", crypt_ftr->fs_size); |
| orig_failed_decrypt_count = crypt_ftr->failed_decrypt_count; |
| |
| if (! (crypt_ftr->flags & CRYPT_MNT_KEY_UNENCRYPTED) ) { |
| if (decrypt_master_key(passwd, decrypted_master_key, crypt_ftr, |
| &intermediate_key, &intermediate_key_size)) { |
| printf("Failed to decrypt master key\n"); |
| rc = -1; |
| goto errout; |
| } |
| } |
| |
| // Create crypto block device - all (non fatal) code paths |
| // need it |
| if (create_crypto_blk_dev(crypt_ftr, decrypted_master_key, |
| real_blkdev, crypto_blkdev, label)) { |
| printf("Error creating decrypted block device\n"); |
| rc = -1; |
| goto errout; |
| } |
| |
| /* Work out if the problem is the password or the data */ |
| unsigned char scrypted_intermediate_key[sizeof(crypt_ftr-> |
| scrypted_intermediate_key)]; |
| int N = 1 << crypt_ftr->N_factor; |
| int r = 1 << crypt_ftr->r_factor; |
| int p = 1 << crypt_ftr->p_factor; |
| |
| rc = crypto_scrypt(intermediate_key, intermediate_key_size, |
| crypt_ftr->salt, sizeof(crypt_ftr->salt), |
| N, r, p, scrypted_intermediate_key, |
| sizeof(scrypted_intermediate_key)); |
| |
| // Does the key match the crypto footer? |
| if (rc == 0 && memcmp(scrypted_intermediate_key, |
| crypt_ftr->scrypted_intermediate_key, |
| sizeof(scrypted_intermediate_key)) == 0) { |
| printf("Password matches\n"); |
| rc = 0; |
| } else { |
| /* Try mounting the file system anyway, just in case the problem's with |
| * the footer, not the key. */ |
| sprintf(tmp_mount_point, "%s/tmp_mnt", mount_point); |
| mkdir(tmp_mount_point, 0755); |
| if (mount(crypto_blkdev, tmp_mount_point, file_system, NULL, NULL) != 0) { |
| printf("Error temp mounting decrypted block device '%s'\n", crypto_blkdev); |
| delete_crypto_blk_dev(label); |
| |
| rc = ++crypt_ftr->failed_decrypt_count; |
| //put_crypt_ftr_and_key(crypt_ftr); // Do not penalize for attempting to decrypt in recovery |
| } else { |
| /* Success! */ |
| printf("Password did not match but decrypted drive mounted - continue\n"); |
| umount(tmp_mount_point); |
| rc = 0; |
| } |
| } |
| |
| if (rc == 0) { |
| /*crypt_ftr->failed_decrypt_count = 0; |
| if (orig_failed_decrypt_count != 0) { |
| put_crypt_ftr_and_key(crypt_ftr); |
| }*/ |
| |
| /* Save the name of the crypto block device |
| * so we can mount it when restarting the framework. */ |
| property_set("ro.crypto.fs_crypto_blkdev", crypto_blkdev); |
| |
| /* Also save a the master key so we can reencrypted the key |
| * the key when we want to change the password on it. */ |
| /*memcpy(saved_master_key, decrypted_master_key, KEY_LEN_BYTES); |
| saved_mount_point = strdup(mount_point); |
| master_key_saved = 1; |
| printf("%s(): Master key saved\n", __FUNCTION__);*/ |
| rc = 0; |
| |
| // Upgrade if we're not using the latest KDF. |
| /*use_keymaster = keymaster_check_compatibility(); |
| if (crypt_ftr->kdf_type == KDF_SCRYPT_KEYMASTER) { |
| // Don't allow downgrade |
| } else if (use_keymaster == 1 && crypt_ftr->kdf_type != KDF_SCRYPT_KEYMASTER) { |
| crypt_ftr->kdf_type = KDF_SCRYPT_KEYMASTER; |
| upgrade = 1; |
| } else if (use_keymaster == 0 && crypt_ftr->kdf_type != KDF_SCRYPT) { |
| crypt_ftr->kdf_type = KDF_SCRYPT; |
| upgrade = 1; |
| } |
| |
| if (upgrade) { |
| rc = encrypt_master_key(passwd, crypt_ftr->salt, saved_master_key, |
| crypt_ftr->master_key, crypt_ftr); |
| if (!rc) { |
| rc = put_crypt_ftr_and_key(crypt_ftr); |
| } |
| printf("Key Derivation Function upgrade: rc=%d\n", rc); |
| |
| // Do not fail even if upgrade failed - machine is bootable |
| // Note that if this code is ever hit, there is a *serious* problem |
| // since KDFs should never fail. You *must* fix the kdf before |
| // proceeding! |
| if (rc) { |
| printf("Upgrade failed with error %d," |
| " but continuing with previous state\n", |
| rc); |
| rc = 0; |
| } |
| }*/ |
| } |
| |
| errout: |
| if (intermediate_key) { |
| memset(intermediate_key, 0, intermediate_key_size); |
| free(intermediate_key); |
| } |
| return rc; |
| } |
| |
| /* Called by vold when it wants to undo the crypto mapping of a volume it |
| * manages. This is usually in response to a factory reset, when we want |
| * to undo the crypto mapping so the volume is formatted in the clear. |
| */ |
| int cryptfs_revert_volume(const char *label) |
| { |
| return delete_crypto_blk_dev((char *)label); |
| } |
| |
| int check_unmounted_and_get_ftr(struct crypt_mnt_ftr* crypt_ftr) |
| { |
| char encrypted_state[PROPERTY_VALUE_MAX]; |
| property_get("ro.crypto.state", encrypted_state, ""); |
| if ( master_key_saved || strcmp(encrypted_state, "encrypted") ) { |
| printf("encrypted fs already validated or not running with encryption," |
| " aborting\n"); |
| //return -1; |
| } |
| |
| if (get_crypt_ftr_and_key(crypt_ftr)) { |
| printf("Error getting crypt footer and key\n"); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * TODO - transition patterns to new format in calling code |
| * and remove this vile hack, and the use of hex in |
| * the password passing code. |
| * |
| * Patterns are passed in zero based (i.e. the top left dot |
| * is represented by zero, the top middle one etc), but we want |
| * to store them '1' based. |
| * This is to allow us to migrate the calling code to use this |
| * convention. It also solves a nasty problem whereby scrypt ignores |
| * trailing zeros, so patterns ending at the top left could be |
| * truncated, and similarly, you could add the top left to any |
| * pattern and still match. |
| * adjust_passwd is a hack function that returns the alternate representation |
| * if the password appears to be a pattern (hex numbers all less than 09) |
| * If it succeeds we need to try both, and in particular try the alternate |
| * first. If the original matches, then we need to update the footer |
| * with the alternate. |
| * All code that accepts passwords must adjust them first. Since |
| * cryptfs_check_passwd is always the first function called after a migration |
| * (and indeed on any boot) we only need to do the double try in this |
| * function. |
| */ |
| char* adjust_passwd(const char* passwd) |
| { |
| size_t index, length; |
| |
| if (!passwd) { |
| return 0; |
| } |
| |
| // Check even length. Hex encoded passwords are always |
| // an even length, since each character encodes to two characters. |
| length = strlen(passwd); |
| if (length % 2) { |
| printf("Password not correctly hex encoded."); |
| return 0; |
| } |
| |
| // Check password is old-style pattern - a collection of hex |
| // encoded bytes less than 9 (00 through 08) |
| for (index = 0; index < length; index +=2) { |
| if (passwd[index] != '0' |
| || passwd[index + 1] < '0' || passwd[index + 1] > '8') { |
| return 0; |
| } |
| } |
| |
| // Allocate room for adjusted passwd and null terminate |
| char* adjusted = malloc(length + 1); |
| adjusted[length] = 0; |
| |
| // Add 0x31 ('1') to each character |
| for (index = 0; index < length; index += 2) { |
| // output is 31 through 39 so set first byte to three, second to src + 1 |
| adjusted[index] = '3'; |
| adjusted[index + 1] = passwd[index + 1] + 1; |
| } |
| |
| return adjusted; |
| } |
| |
| /* |
| * Passwords in L get passed from Android to cryptfs in hex, so a '1' |
| * gets converted to '31' where 31 is 0x31 which is the ascii character |
| * code in hex of the character '1'. This function will convert the |
| * regular character codes to their hexadecimal representation to make |
| * decrypt work properly with Android 5.0 lollipop decryption. |
| */ |
| char* hexadj_passwd(const char* passwd) |
| { |
| size_t index, length; |
| char* ptr = passwd; |
| |
| if (!passwd) { |
| return 0; |
| } |
| |
| length = strlen(passwd); |
| |
| // Allocate room for hex passwd and null terminate |
| char* hex = malloc((length * 2) + 1); |
| hex[length * 2] = 0; |
| |
| // Convert to hex |
| for (index = 0; index < length; index++) { |
| sprintf(hex + (index * 2), "%02X", *ptr); |
| ptr++; |
| } |
| |
| return hex; |
| } |
| |
| int cryptfs_check_footer() |
| { |
| int rc = -1; |
| struct crypt_mnt_ftr crypt_ftr; |
| |
| rc = get_crypt_ftr_and_key(&crypt_ftr); |
| |
| return rc; |
| } |
| |
| int cryptfs_check_passwd(char *passwd) |
| { |
| struct crypt_mnt_ftr crypt_ftr; |
| int rc; |
| |
| rc = check_unmounted_and_get_ftr(&crypt_ftr); |
| if (rc) |
| return rc; |
| |
| char* adjusted_passwd = adjust_passwd(passwd); |
| char* hex_passwd = hexadj_passwd(passwd); |
| |
| if (adjusted_passwd) { |
| int failed_decrypt_count = crypt_ftr.failed_decrypt_count; |
| rc = test_mount_encrypted_fs(&crypt_ftr, adjusted_passwd, |
| DATA_MNT_POINT, "userdata"); |
| |
| // Maybe the original one still works? |
| if (rc) { |
| // Don't double count this failure |
| crypt_ftr.failed_decrypt_count = failed_decrypt_count; |
| rc = test_mount_encrypted_fs(&crypt_ftr, passwd, |
| DATA_MNT_POINT, "userdata"); |
| if (!rc) { |
| // cryptfs_changepw also adjusts so pass original |
| // Note that adjust_passwd only recognises patterns |
| // so we can safely use CRYPT_TYPE_PATTERN |
| printf("TWRP NOT Updating pattern to new format"); |
| //cryptfs_changepw(CRYPT_TYPE_PATTERN, passwd); |
| } else if (hex_passwd) { |
| rc = test_mount_encrypted_fs(&crypt_ftr, hex_passwd, |
| DATA_MNT_POINT, "userdata"); |
| } |
| } |
| free(adjusted_passwd); |
| } else { |
| rc = test_mount_encrypted_fs(&crypt_ftr, passwd, |
| DATA_MNT_POINT, "userdata"); |
| if (rc && hex_passwd) { |
| rc = test_mount_encrypted_fs(&crypt_ftr, hex_passwd, |
| DATA_MNT_POINT, "userdata"); |
| } |
| } |
| |
| if (hex_passwd) |
| free(hex_passwd); |
| |
| /*if (rc == 0 && crypt_ftr.crypt_type != CRYPT_TYPE_DEFAULT) { |
| printf("cryptfs_check_passwd update expiry time?\n"); |
| cryptfs_clear_password(); |
| password = strdup(passwd); |
| struct timespec now; |
| clock_gettime(CLOCK_BOOTTIME, &now); |
| password_expiry_time = now.tv_sec + password_max_age_seconds; |
| }*/ |
| |
| return rc; |
| } |
| |
| int cryptfs_verify_passwd(char *passwd) |
| { |
| struct crypt_mnt_ftr crypt_ftr; |
| /* Allocate enough space for a 256 bit key, but we may use less */ |
| unsigned char decrypted_master_key[32]; |
| char encrypted_state[PROPERTY_VALUE_MAX]; |
| int rc; |
| |
| property_get("ro.crypto.state", encrypted_state, ""); |
| if (strcmp(encrypted_state, "encrypted") ) { |
| printf("device not encrypted, aborting"); |
| return -2; |
| } |
| |
| if (!master_key_saved) { |
| printf("encrypted fs not yet mounted, aborting"); |
| return -1; |
| } |
| |
| if (!saved_mount_point) { |
| printf("encrypted fs failed to save mount point, aborting"); |
| return -1; |
| } |
| |
| if (get_crypt_ftr_and_key(&crypt_ftr)) { |
| printf("Error getting crypt footer and key\n"); |
| return -1; |
| } |
| |
| if (crypt_ftr.flags & CRYPT_MNT_KEY_UNENCRYPTED) { |
| /* If the device has no password, then just say the password is valid */ |
| rc = 0; |
| } else { |
| char* adjusted_passwd = adjust_passwd(passwd); |
| if (adjusted_passwd) { |
| passwd = adjusted_passwd; |
| } |
| |
| decrypt_master_key(passwd, decrypted_master_key, &crypt_ftr, 0, 0); |
| if (!memcmp(decrypted_master_key, saved_master_key, crypt_ftr.keysize)) { |
| /* They match, the password is correct */ |
| rc = 0; |
| } else { |
| /* If incorrect, sleep for a bit to prevent dictionary attacks */ |
| sleep(1); |
| rc = 1; |
| } |
| |
| free(adjusted_passwd); |
| } |
| |
| return rc; |
| } |
| |
| /* Initialize a crypt_mnt_ftr structure. The keysize is |
| * defaulted to 16 bytes, and the filesystem size to 0. |
| * Presumably, at a minimum, the caller will update the |
| * filesystem size and crypto_type_name after calling this function. |
| */ |
| static int cryptfs_init_crypt_mnt_ftr(struct crypt_mnt_ftr *ftr) |
| { |
| off64_t off; |
| |
| memset(ftr, 0, sizeof(struct crypt_mnt_ftr)); |
| ftr->magic = CRYPT_MNT_MAGIC; |
| ftr->major_version = CURRENT_MAJOR_VERSION; |
| ftr->minor_version = CURRENT_MINOR_VERSION; |
| ftr->ftr_size = sizeof(struct crypt_mnt_ftr); |
| ftr->keysize = KEY_LEN_BYTES; |
| |
| switch (keymaster_check_compatibility()) { |
| case 1: |
| ftr->kdf_type = KDF_SCRYPT_KEYMASTER; |
| break; |
| |
| case 0: |
| ftr->kdf_type = KDF_SCRYPT; |
| break; |
| |
| default: |
| printf("keymaster_check_compatibility failed"); |
| return -1; |
| } |
| |
| get_device_scrypt_params(ftr); |
| |
| ftr->persist_data_size = CRYPT_PERSIST_DATA_SIZE; |
| if (get_crypt_ftr_info(NULL, &off) == 0) { |
| ftr->persist_data_offset[0] = off + CRYPT_FOOTER_TO_PERSIST_OFFSET; |
| ftr->persist_data_offset[1] = off + CRYPT_FOOTER_TO_PERSIST_OFFSET + |
| ftr->persist_data_size; |
| } |
| |
| return 0; |
| } |
| |
| /* Returns type of the password, default, pattern, pin or password. |
| */ |
| int cryptfs_get_password_type(void) |
| { |
| struct crypt_mnt_ftr crypt_ftr; |
| |
| if (get_crypt_ftr_and_key(&crypt_ftr)) { |
| printf("Error getting crypt footer and key\n"); |
| return -1; |
| } |
| |
| if (crypt_ftr.flags & CRYPT_INCONSISTENT_STATE) { |
| return -1; |
| } |
| |
| return crypt_ftr.crypt_type; |
| } |