Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 2 | /* |
| 3 | * fscrypt_private.h |
| 4 | * |
| 5 | * Copyright (C) 2015, Google, Inc. |
| 6 | * |
Eric Biggers | 3ec4f2a6 | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 7 | * Originally written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar. |
| 8 | * Heavily modified since then. |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 9 | */ |
| 10 | |
| 11 | #ifndef _FSCRYPT_PRIVATE_H |
| 12 | #define _FSCRYPT_PRIVATE_H |
| 13 | |
Dave Chinner | 734f0d2 | 2017-10-09 12:15:34 -0700 | [diff] [blame] | 14 | #include <linux/fscrypt.h> |
Daniel Walter | b7e7cf7 | 2017-06-19 09:27:58 +0200 | [diff] [blame] | 15 | #include <crypto/hash.h> |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 16 | |
Eric Biggers | 22d94f4 | 2019-08-04 19:35:46 -0700 | [diff] [blame^] | 17 | #define CONST_STRLEN(str) (sizeof(str) - 1) |
| 18 | |
Eric Biggers | 11b8818 | 2018-04-30 15:51:46 -0700 | [diff] [blame] | 19 | #define FS_KEY_DERIVATION_NONCE_SIZE 16 |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 20 | |
Eric Biggers | 22d94f4 | 2019-08-04 19:35:46 -0700 | [diff] [blame^] | 21 | #define FSCRYPT_MIN_KEY_SIZE 16 |
| 22 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 23 | /** |
| 24 | * Encryption context for inode |
| 25 | * |
| 26 | * Protector format: |
| 27 | * 1 byte: Protector format (1 = this version) |
| 28 | * 1 byte: File contents encryption mode |
| 29 | * 1 byte: File names encryption mode |
| 30 | * 1 byte: Flags |
| 31 | * 8 bytes: Master Key descriptor |
| 32 | * 16 bytes: Encryption Key derivation nonce |
| 33 | */ |
| 34 | struct fscrypt_context { |
| 35 | u8 format; |
| 36 | u8 contents_encryption_mode; |
| 37 | u8 filenames_encryption_mode; |
| 38 | u8 flags; |
Eric Biggers | 3b6df59 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 39 | u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 40 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
| 41 | } __packed; |
| 42 | |
| 43 | #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 |
| 44 | |
Eric Biggers | 0eaab5b | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 45 | /** |
| 46 | * For encrypted symlinks, the ciphertext length is stored at the beginning |
| 47 | * of the string in little-endian format. |
| 48 | */ |
| 49 | struct fscrypt_symlink_data { |
| 50 | __le16 len; |
| 51 | char encrypted_path[1]; |
| 52 | } __packed; |
| 53 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 54 | /* |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 55 | * fscrypt_info - the "encryption key" for an inode |
| 56 | * |
| 57 | * When an encrypted file's key is made available, an instance of this struct is |
| 58 | * allocated and stored in ->i_crypt_info. Once created, it remains until the |
| 59 | * inode is evicted. |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 60 | */ |
| 61 | struct fscrypt_info { |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 62 | |
| 63 | /* The actual crypto transform used for encryption and decryption */ |
| 64 | struct crypto_skcipher *ci_ctfm; |
| 65 | |
| 66 | /* |
| 67 | * Cipher for ESSIV IV generation. Only set for CBC contents |
| 68 | * encryption, otherwise is NULL. |
| 69 | */ |
| 70 | struct crypto_cipher *ci_essiv_tfm; |
| 71 | |
| 72 | /* |
| 73 | * Encryption mode used for this inode. It corresponds to either |
| 74 | * ci_data_mode or ci_filename_mode, depending on the inode type. |
| 75 | */ |
| 76 | struct fscrypt_mode *ci_mode; |
| 77 | |
Eric Biggers | 59dc6a8 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 78 | /* Back-pointer to the inode */ |
| 79 | struct inode *ci_inode; |
| 80 | |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 81 | /* |
Eric Biggers | a828daa | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 82 | * If non-NULL, then encryption is done using the master key directly |
| 83 | * and ci_ctfm will equal ci_direct_key->dk_ctfm. |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 84 | */ |
Eric Biggers | a828daa | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 85 | struct fscrypt_direct_key *ci_direct_key; |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 86 | |
| 87 | /* fields from the fscrypt_context */ |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 88 | u8 ci_data_mode; |
| 89 | u8 ci_filename_mode; |
| 90 | u8 ci_flags; |
Eric Biggers | 3b6df59 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 91 | u8 ci_master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 92 | u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 93 | }; |
| 94 | |
Richard Weinberger | 58ae746 | 2016-12-19 12:25:32 +0100 | [diff] [blame] | 95 | typedef enum { |
| 96 | FS_DECRYPT = 0, |
| 97 | FS_ENCRYPT, |
| 98 | } fscrypt_direction_t; |
| 99 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 100 | #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 101 | |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 102 | static inline bool fscrypt_valid_enc_modes(u32 contents_mode, |
| 103 | u32 filenames_mode) |
| 104 | { |
Eric Biggers | 3b6df59 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 105 | if (contents_mode == FSCRYPT_MODE_AES_128_CBC && |
| 106 | filenames_mode == FSCRYPT_MODE_AES_128_CTS) |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 107 | return true; |
| 108 | |
Eric Biggers | 3b6df59 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 109 | if (contents_mode == FSCRYPT_MODE_AES_256_XTS && |
| 110 | filenames_mode == FSCRYPT_MODE_AES_256_CTS) |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 111 | return true; |
| 112 | |
Eric Biggers | 3b6df59 | 2019-08-04 19:35:44 -0700 | [diff] [blame] | 113 | if (contents_mode == FSCRYPT_MODE_ADIANTUM && |
| 114 | filenames_mode == FSCRYPT_MODE_ADIANTUM) |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 115 | return true; |
| 116 | |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 117 | return false; |
| 118 | } |
| 119 | |
Theodore Ts'o | b98701df | 2016-11-26 20:43:09 -0500 | [diff] [blame] | 120 | /* crypto.c */ |
Eric Biggers | e4de782 | 2018-01-05 10:44:54 -0800 | [diff] [blame] | 121 | extern struct kmem_cache *fscrypt_info_cachep; |
Richard Weinberger | 58ae746 | 2016-12-19 12:25:32 +0100 | [diff] [blame] | 122 | extern int fscrypt_initialize(unsigned int cop_flags); |
Eric Biggers | f47fcbb | 2019-05-20 09:29:41 -0700 | [diff] [blame] | 123 | extern int fscrypt_crypt_block(const struct inode *inode, |
| 124 | fscrypt_direction_t rw, u64 lblk_num, |
| 125 | struct page *src_page, struct page *dest_page, |
| 126 | unsigned int len, unsigned int offs, |
| 127 | gfp_t gfp_flags); |
Eric Biggers | d2d0727 | 2019-05-20 09:29:39 -0700 | [diff] [blame] | 128 | extern struct page *fscrypt_alloc_bounce_page(gfp_t gfp_flags); |
Eric Biggers | 5422202 | 2018-04-30 15:51:36 -0700 | [diff] [blame] | 129 | extern const struct dentry_operations fscrypt_d_ops; |
Theodore Ts'o | b98701df | 2016-11-26 20:43:09 -0500 | [diff] [blame] | 130 | |
Eric Biggers | 544d08f | 2018-04-30 15:51:47 -0700 | [diff] [blame] | 131 | extern void __printf(3, 4) __cold |
Eric Biggers | 886da8b | 2019-07-24 11:07:58 -0700 | [diff] [blame] | 132 | fscrypt_msg(const struct inode *inode, const char *level, const char *fmt, ...); |
Eric Biggers | 544d08f | 2018-04-30 15:51:47 -0700 | [diff] [blame] | 133 | |
Eric Biggers | 886da8b | 2019-07-24 11:07:58 -0700 | [diff] [blame] | 134 | #define fscrypt_warn(inode, fmt, ...) \ |
| 135 | fscrypt_msg((inode), KERN_WARNING, fmt, ##__VA_ARGS__) |
| 136 | #define fscrypt_err(inode, fmt, ...) \ |
| 137 | fscrypt_msg((inode), KERN_ERR, fmt, ##__VA_ARGS__) |
Eric Biggers | 544d08f | 2018-04-30 15:51:47 -0700 | [diff] [blame] | 138 | |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 139 | #define FSCRYPT_MAX_IV_SIZE 32 |
| 140 | |
| 141 | union fscrypt_iv { |
| 142 | struct { |
| 143 | /* logical block number within the file */ |
| 144 | __le64 lblk_num; |
| 145 | |
| 146 | /* per-file nonce; only set in DIRECT_KEY mode */ |
| 147 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
| 148 | }; |
| 149 | u8 raw[FSCRYPT_MAX_IV_SIZE]; |
| 150 | }; |
| 151 | |
| 152 | void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, |
| 153 | const struct fscrypt_info *ci); |
| 154 | |
Eric Biggers | 76e81d6 | 2018-01-05 10:45:01 -0800 | [diff] [blame] | 155 | /* fname.c */ |
Eric Biggers | 50c961d | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 156 | extern int fname_encrypt(struct inode *inode, const struct qstr *iname, |
| 157 | u8 *out, unsigned int olen); |
Eric Biggers | b9db0b4 | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 158 | extern bool fscrypt_fname_encrypted_size(const struct inode *inode, |
| 159 | u32 orig_len, u32 max_len, |
| 160 | u32 *encrypted_len_ret); |
Eric Biggers | 76e81d6 | 2018-01-05 10:45:01 -0800 | [diff] [blame] | 161 | |
Eric Biggers | 22d94f4 | 2019-08-04 19:35:46 -0700 | [diff] [blame^] | 162 | /* keyring.c */ |
| 163 | |
| 164 | /* |
| 165 | * fscrypt_master_key_secret - secret key material of an in-use master key |
| 166 | */ |
| 167 | struct fscrypt_master_key_secret { |
| 168 | |
| 169 | /* Size of the raw key in bytes */ |
| 170 | u32 size; |
| 171 | |
| 172 | /* The raw key */ |
| 173 | u8 raw[FSCRYPT_MAX_KEY_SIZE]; |
| 174 | |
| 175 | } __randomize_layout; |
| 176 | |
| 177 | /* |
| 178 | * fscrypt_master_key - an in-use master key |
| 179 | * |
| 180 | * This represents a master encryption key which has been added to the |
| 181 | * filesystem and can be used to "unlock" the encrypted files which were |
| 182 | * encrypted with it. |
| 183 | */ |
| 184 | struct fscrypt_master_key { |
| 185 | |
| 186 | /* The secret key material */ |
| 187 | struct fscrypt_master_key_secret mk_secret; |
| 188 | |
| 189 | /* Arbitrary key descriptor which was assigned by userspace */ |
| 190 | struct fscrypt_key_specifier mk_spec; |
| 191 | |
| 192 | } __randomize_layout; |
| 193 | |
| 194 | static inline const char *master_key_spec_type( |
| 195 | const struct fscrypt_key_specifier *spec) |
| 196 | { |
| 197 | switch (spec->type) { |
| 198 | case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: |
| 199 | return "descriptor"; |
| 200 | } |
| 201 | return "[unknown]"; |
| 202 | } |
| 203 | |
| 204 | static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec) |
| 205 | { |
| 206 | switch (spec->type) { |
| 207 | case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: |
| 208 | return FSCRYPT_KEY_DESCRIPTOR_SIZE; |
| 209 | } |
| 210 | return 0; |
| 211 | } |
| 212 | |
| 213 | extern struct key * |
| 214 | fscrypt_find_master_key(struct super_block *sb, |
| 215 | const struct fscrypt_key_specifier *mk_spec); |
| 216 | |
| 217 | extern int __init fscrypt_init_keyring(void); |
| 218 | |
Eric Biggers | feed825 | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 219 | /* keysetup.c */ |
Eric Biggers | 8094c3c | 2019-01-06 08:36:21 -0500 | [diff] [blame] | 220 | |
| 221 | struct fscrypt_mode { |
| 222 | const char *friendly_name; |
| 223 | const char *cipher_str; |
| 224 | int keysize; |
| 225 | int ivsize; |
| 226 | bool logged_impl_name; |
| 227 | bool needs_essiv; |
| 228 | }; |
| 229 | |
Eric Biggers | 3ec4f2a6 | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 230 | static inline bool |
| 231 | fscrypt_mode_supports_direct_key(const struct fscrypt_mode *mode) |
| 232 | { |
| 233 | return mode->ivsize >= offsetofend(union fscrypt_iv, nonce); |
| 234 | } |
| 235 | |
Eric Biggers | 0109ce76 | 2019-08-04 19:35:45 -0700 | [diff] [blame] | 236 | extern struct crypto_skcipher * |
| 237 | fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key, |
| 238 | const struct inode *inode); |
| 239 | |
| 240 | extern int fscrypt_set_derived_key(struct fscrypt_info *ci, |
| 241 | const u8 *derived_key); |
| 242 | |
| 243 | /* keysetup_v1.c */ |
| 244 | |
| 245 | extern void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); |
| 246 | |
| 247 | extern int fscrypt_setup_v1_file_key(struct fscrypt_info *ci, |
| 248 | const u8 *raw_master_key); |
| 249 | |
| 250 | extern int fscrypt_setup_v1_file_key_via_subscribed_keyrings( |
| 251 | struct fscrypt_info *ci); |
| 252 | |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 253 | #endif /* _FSCRYPT_PRIVATE_H */ |