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Ken Sumrall8f869aa2010-12-03 03:47:09 -08001/*
2 * Copyright (C) 2010 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/* This structure starts 16,384 bytes before the end of a hardware
Ken Sumrall160b4d62013-04-22 12:15:39 -070018 * partition that is encrypted, or in a separate partition. It's location
19 * is specified by a property set in init.<device>.rc.
20 * The structure allocates 48 bytes for a key, but the real key size is
21 * specified in the struct. Currently, the code is hardcoded to use 128
22 * bit keys.
23 * The fields after salt are only valid in rev 1.1 and later stuctures.
Ken Sumrall8f869aa2010-12-03 03:47:09 -080024 * Obviously, the filesystem does not include the last 16 kbytes
Ken Sumrall160b4d62013-04-22 12:15:39 -070025 * of the partition if the crypt_mnt_ftr lives at the end of the
26 * partition.
Ken Sumrall8f869aa2010-12-03 03:47:09 -080027 */
28
Paul Lawrence2f32cda2015-05-05 14:28:25 -070029#include <stdbool.h>
Ken Sumrall160b4d62013-04-22 12:15:39 -070030#include <cutils/properties.h>
31
Kenny Rootc96a5f82013-06-14 12:08:28 -070032/* The current cryptfs version */
33#define CURRENT_MAJOR_VERSION 1
Paul Lawrencef4faa572014-01-29 13:31:03 -080034#define CURRENT_MINOR_VERSION 3
Kenny Rootc96a5f82013-06-14 12:08:28 -070035
Ken Sumrall8f869aa2010-12-03 03:47:09 -080036#define CRYPT_FOOTER_OFFSET 0x4000
Ken Sumrall160b4d62013-04-22 12:15:39 -070037#define CRYPT_FOOTER_TO_PERSIST_OFFSET 0x1000
38#define CRYPT_PERSIST_DATA_SIZE 0x1000
Ken Sumrall8f869aa2010-12-03 03:47:09 -080039
40#define MAX_CRYPTO_TYPE_NAME_LEN 64
41
Ken Sumrall160b4d62013-04-22 12:15:39 -070042#define MAX_KEY_LEN 48
Ken Sumralle8744072011-01-18 22:01:55 -080043#define SALT_LEN 16
Paul Lawrenced0c7b172014-08-08 14:28:10 -070044#define SCRYPT_LEN 32
Ken Sumralle8744072011-01-18 22:01:55 -080045
Ken Sumrall8f869aa2010-12-03 03:47:09 -080046/* definitions of flags in the structure below */
47#define CRYPT_MNT_KEY_UNENCRYPTED 0x1 /* The key for the partition is not encrypted. */
Paul Lawrence6bfed202014-07-28 12:47:22 -070048#define CRYPT_ENCRYPTION_IN_PROGRESS 0x2 /* Encryption partially completed,
49 encrypted_upto valid*/
50#define CRYPT_INCONSISTENT_STATE 0x4 /* Set when starting encryption, clear when
51 exit cleanly, either through success or
52 correctly marked partial encryption */
Paul Lawrence74f29f12014-08-28 15:54:10 -070053#define CRYPT_DATA_CORRUPT 0x8 /* Set when encryption is fine, but the
54 underlying volume is corrupt */
Ken Sumrall8f869aa2010-12-03 03:47:09 -080055
Paul Lawrencef4faa572014-01-29 13:31:03 -080056/* Allowed values for type in the structure below */
57#define CRYPT_TYPE_PASSWORD 0 /* master_key is encrypted with a password
58 * Must be zero to be compatible with pre-L
59 * devices where type is always password.*/
60#define CRYPT_TYPE_DEFAULT 1 /* master_key is encrypted with default
61 * password */
62#define CRYPT_TYPE_PATTERN 2 /* master_key is encrypted with a pattern */
63#define CRYPT_TYPE_PIN 3 /* master_key is encrypted with a pin */
64#define CRYPT_TYPE_MAX_TYPE 3 /* type cannot be larger than this value */
65
Ken Sumrall8f869aa2010-12-03 03:47:09 -080066#define CRYPT_MNT_MAGIC 0xD0B5B1C4
Ken Sumrall160b4d62013-04-22 12:15:39 -070067#define PERSIST_DATA_MAGIC 0xE950CD44
Ken Sumrall8f869aa2010-12-03 03:47:09 -080068
Kenny Rootc4c70f12013-06-14 12:11:38 -070069#define SCRYPT_PROP "ro.crypto.scrypt_params"
70#define SCRYPT_DEFAULTS { 15, 3, 1 }
71
72/* Key Derivation Function algorithms */
73#define KDF_PBKDF2 1
74#define KDF_SCRYPT 2
Paul Lawrencedb3730c2015-02-03 13:08:10 -080075/* Algorithms 3 & 4 deprecated before shipping outside of google, so removed */
Shawn Willdene17a9c42014-09-08 13:04:08 -060076#define KDF_SCRYPT_KEYMASTER 5
Paul Lawrence69f4ebd2014-04-14 12:17:14 -070077
78/* Maximum allowed keymaster blob size. */
79#define KEYMASTER_BLOB_SIZE 2048
Kenny Rootc4c70f12013-06-14 12:11:38 -070080
Mark Salyzyn3e971272014-01-21 13:27:04 -080081/* __le32 and __le16 defined in system/extras/ext4_utils/ext4_utils.h */
Kenny Rootc4c70f12013-06-14 12:11:38 -070082#define __le8 unsigned char
Ken Sumrall8f869aa2010-12-03 03:47:09 -080083
Adam Langley41405bb2015-01-22 16:45:28 -080084#if !defined(SHA256_DIGEST_LENGTH)
85#define SHA256_DIGEST_LENGTH 32
86#endif
87
Ken Sumrall8f869aa2010-12-03 03:47:09 -080088struct crypt_mnt_ftr {
Paul Lawrencef4faa572014-01-29 13:31:03 -080089 __le32 magic; /* See above */
Ken Sumrall8f869aa2010-12-03 03:47:09 -080090 __le16 major_version;
91 __le16 minor_version;
Paul Lawrencef4faa572014-01-29 13:31:03 -080092 __le32 ftr_size; /* in bytes, not including key following */
93 __le32 flags; /* See above */
94 __le32 keysize; /* in bytes */
95 __le32 crypt_type; /* how master_key is encrypted. Must be a
96 * CRYPT_TYPE_XXX value */
Ken Sumrall8f869aa2010-12-03 03:47:09 -080097 __le64 fs_size; /* Size of the encrypted fs, in 512 byte sectors */
98 __le32 failed_decrypt_count; /* count of # of failed attempts to decrypt and
Paul Lawrence87999172014-02-20 12:21:31 -080099 mount, set to 0 on successful mount */
Ken Sumrall8f869aa2010-12-03 03:47:09 -0800100 unsigned char crypto_type_name[MAX_CRYPTO_TYPE_NAME_LEN]; /* The type of encryption
Paul Lawrence87999172014-02-20 12:21:31 -0800101 needed to decrypt this
102 partition, null terminated */
Ken Sumrall160b4d62013-04-22 12:15:39 -0700103 __le32 spare2; /* ignored */
104 unsigned char master_key[MAX_KEY_LEN]; /* The encrypted key for decrypting the filesystem */
105 unsigned char salt[SALT_LEN]; /* The salt used for this encryption */
106 __le64 persist_data_offset[2]; /* Absolute offset to both copies of crypt_persist_data
107 * on device with that info, either the footer of the
108 * real_blkdevice or the metadata partition. */
109
110 __le32 persist_data_size; /* The number of bytes allocated to each copy of the
111 * persistent data table*/
Kenny Rootc4c70f12013-06-14 12:11:38 -0700112
113 __le8 kdf_type; /* The key derivation function used. */
114
115 /* scrypt parameters. See www.tarsnap.com/scrypt/scrypt.pdf */
116 __le8 N_factor; /* (1 << N) */
117 __le8 r_factor; /* (1 << r) */
118 __le8 p_factor; /* (1 << p) */
Paul Lawrence87999172014-02-20 12:21:31 -0800119 __le64 encrypted_upto; /* If we are in state CRYPT_ENCRYPTION_IN_PROGRESS and
120 we have to stop (e.g. power low) this is the last
121 encrypted 512 byte sector.*/
122 __le8 hash_first_block[SHA256_DIGEST_LENGTH]; /* When CRYPT_ENCRYPTION_IN_PROGRESS
123 set, hash of first block, used
124 to validate before continuing*/
Paul Lawrence69f4ebd2014-04-14 12:17:14 -0700125
Paul Lawrenced0c7b172014-08-08 14:28:10 -0700126 /* key_master key, used to sign the derived key which is then used to generate
127 * the intermediate key
Paul Lawrence69f4ebd2014-04-14 12:17:14 -0700128 * This key should be used for no other purposes! We use this key to sign unpadded
129 * data, which is acceptable but only if the key is not reused elsewhere. */
130 __le8 keymaster_blob[KEYMASTER_BLOB_SIZE];
131 __le32 keymaster_blob_size;
Paul Lawrenced0c7b172014-08-08 14:28:10 -0700132
133 /* Store scrypt of salted intermediate key. When decryption fails, we can
134 check if this matches, and if it does, we know that the problem is with the
135 drive, and there is no point in asking the user for more passwords.
136
137 Note that if any part of this structure is corrupt, this will not match and
138 we will continue to believe the user entered the wrong password. In that
139 case the only solution is for the user to enter a password enough times to
140 force a wipe.
141
142 Note also that there is no need to worry about migration. If this data is
143 wrong, we simply won't recognise a right password, and will continue to
144 prompt. On the first password change, this value will be populated and
145 then we will be OK.
146 */
147 unsigned char scrypted_intermediate_key[SCRYPT_LEN];
Ken Sumrall160b4d62013-04-22 12:15:39 -0700148};
149
150/* Persistant data that should be available before decryption.
151 * Things like airplane mode, locale and timezone are kept
152 * here and can be retrieved by the CryptKeeper UI to properly
153 * configure the phone before asking for the password
154 * This is only valid if the major and minor version above
155 * is set to 1.1 or higher.
156 *
157 * This is a 4K structure. There are 2 copies, and the code alternates
158 * writing one and then clearing the previous one. The reading
159 * code reads the first valid copy it finds, based on the magic number.
160 * The absolute offset to the first of the two copies is kept in rev 1.1
161 * and higher crypt_mnt_ftr structures.
162 */
163struct crypt_persist_entry {
164 char key[PROPERTY_KEY_MAX];
165 char val[PROPERTY_VALUE_MAX];
166};
167
168/* Should be exactly 4K in size */
169struct crypt_persist_data {
170 __le32 persist_magic;
171 __le32 persist_valid_entries;
172 __le32 persist_spare[30];
173 struct crypt_persist_entry persist_entry[0];
Ken Sumrall8f869aa2010-12-03 03:47:09 -0800174};
175
JP Abgrall502dc742013-11-01 13:06:20 -0700176#define DATA_MNT_POINT "/data"
177
Paul Lawrence74f29f12014-08-28 15:54:10 -0700178/* Return values for cryptfs_crypto_complete */
179#define CRYPTO_COMPLETE_NOT_ENCRYPTED 1
180#define CRYPTO_COMPLETE_ENCRYPTED 0
Chih-Hung Hsiehaae79382016-06-10 14:13:59 -0700181#define CRYPTO_COMPLETE_BAD_METADATA (-1)
182#define CRYPTO_COMPLETE_PARTIAL (-2)
183#define CRYPTO_COMPLETE_INCONSISTENT (-3)
184#define CRYPTO_COMPLETE_CORRUPT (-4)
Paul Lawrence74f29f12014-08-28 15:54:10 -0700185
JP Abgrall7fc1de82014-10-10 18:43:41 -0700186/* Return values for cryptfs_enable_inplace*() */
187#define ENABLE_INPLACE_OK 0
Chih-Hung Hsiehaae79382016-06-10 14:13:59 -0700188#define ENABLE_INPLACE_ERR_OTHER (-1)
189#define ENABLE_INPLACE_ERR_DEV (-2) /* crypto_blkdev issue */
JP Abgrall7fc1de82014-10-10 18:43:41 -0700190
Rubin Xu85c01f92014-10-13 12:49:54 +0100191/* Return values for cryptfs_getfield */
192#define CRYPTO_GETFIELD_OK 0
Chih-Hung Hsiehaae79382016-06-10 14:13:59 -0700193#define CRYPTO_GETFIELD_ERROR_NO_FIELD (-1)
194#define CRYPTO_GETFIELD_ERROR_OTHER (-2)
195#define CRYPTO_GETFIELD_ERROR_BUF_TOO_SMALL (-3)
Rubin Xu85c01f92014-10-13 12:49:54 +0100196
197/* Return values for cryptfs_setfield */
198#define CRYPTO_SETFIELD_OK 0
Chih-Hung Hsiehaae79382016-06-10 14:13:59 -0700199#define CRYPTO_SETFIELD_ERROR_OTHER (-1)
200#define CRYPTO_SETFIELD_ERROR_FIELD_TOO_LONG (-2)
201#define CRYPTO_SETFIELD_ERROR_VALUE_TOO_LONG (-3)
Rubin Xu85c01f92014-10-13 12:49:54 +0100202
203/* Return values for persist_del_key */
204#define PERSIST_DEL_KEY_OK 0
Chih-Hung Hsiehaae79382016-06-10 14:13:59 -0700205#define PERSIST_DEL_KEY_ERROR_OTHER (-1)
206#define PERSIST_DEL_KEY_ERROR_NO_FIELD (-2)
Rubin Xu85c01f92014-10-13 12:49:54 +0100207
Ken Sumrall8f869aa2010-12-03 03:47:09 -0800208#ifdef __cplusplus
209extern "C" {
210#endif
Kenny Rootc4c70f12013-06-14 12:11:38 -0700211
Paul Lawrence2f32cda2015-05-05 14:28:25 -0700212 int wait_and_unmount(const char *mountpoint, bool kill);
213
Paul Lawrence69f4ebd2014-04-14 12:17:14 -0700214 typedef int (*kdf_func)(const char *passwd, const unsigned char *salt,
Paul Lawrence13486032014-02-03 13:28:11 -0800215 unsigned char *ikey, void *params);
Kenny Rootc4c70f12013-06-14 12:11:38 -0700216
Ken Sumrall7f7dbaa2011-02-01 15:46:41 -0800217 int cryptfs_crypto_complete(void);
Ken Sumrall8f869aa2010-12-03 03:47:09 -0800218 int cryptfs_check_passwd(char *pw);
Ken Sumrall3ad90722011-10-04 20:38:29 -0700219 int cryptfs_verify_passwd(char *newpw);
Ken Sumrall6864b7e2011-01-14 15:20:02 -0800220 int cryptfs_restart(void);
Paul Lawrence569649f2015-09-09 12:13:00 -0700221 int cryptfs_enable(char *flag, int type, char *passwd, int no_ui);
Paul Lawrence13486032014-02-03 13:28:11 -0800222 int cryptfs_changepw(int type, const char *newpw);
Paul Lawrence569649f2015-09-09 12:13:00 -0700223 int cryptfs_enable_default(char *flag, int no_ui);
Jeff Sharkey9c484982015-03-31 10:35:33 -0700224 int cryptfs_setup_ext_volume(const char* label, const char* real_blkdev,
225 const unsigned char* key, int keysize, char* out_crypto_blkdev);
226 int cryptfs_revert_ext_volume(const char* label);
Paul Lawrence731a7a22015-04-28 22:14:15 +0000227 int cryptfs_enable_file();
Rubin Xu85c01f92014-10-13 12:49:54 +0100228 int cryptfs_getfield(const char *fieldname, char *value, int len);
229 int cryptfs_setfield(const char *fieldname, const char *value);
Paul Lawrencef4faa572014-01-29 13:31:03 -0800230 int cryptfs_mount_default_encrypted(void);
231 int cryptfs_get_password_type(void);
Paul Lawrence05335c32015-03-05 09:46:23 -0800232 const char* cryptfs_get_password(void);
Paul Lawrence399317e2014-03-10 13:20:50 -0700233 void cryptfs_clear_password(void);
Paul Lawrence731a7a22015-04-28 22:14:15 +0000234
235 // Functions for file encryption to use to inherit our encryption logic
236 int cryptfs_create_default_ftr(struct crypt_mnt_ftr* ftr, int key_length);
237 int cryptfs_get_master_key(struct crypt_mnt_ftr* ftr, const char* password,
238 unsigned char* master_key);
239 int cryptfs_set_password(struct crypt_mnt_ftr* ftr, const char* password,
240 const unsigned char* master_key);
Ken Sumrall8f869aa2010-12-03 03:47:09 -0800241#ifdef __cplusplus
242}
243#endif