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 | * |
| 7 | * This contains encryption key functions. |
| 8 | * |
| 9 | * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015. |
| 10 | */ |
| 11 | |
| 12 | #ifndef _FSCRYPT_PRIVATE_H |
| 13 | #define _FSCRYPT_PRIVATE_H |
| 14 | |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 15 | #ifndef __FS_HAS_ENCRYPTION |
Dave Chinner | 734f0d2 | 2017-10-09 12:15:34 -0700 | [diff] [blame] | 16 | #define __FS_HAS_ENCRYPTION 1 |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 17 | #endif |
Dave Chinner | 734f0d2 | 2017-10-09 12:15:34 -0700 | [diff] [blame] | 18 | #include <linux/fscrypt.h> |
Daniel Walter | b7e7cf7 | 2017-06-19 09:27:58 +0200 | [diff] [blame] | 19 | #include <crypto/hash.h> |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 20 | #include <linux/pfk.h> |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 21 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 22 | /* Encryption parameters */ |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 23 | |
| 24 | #define FS_AES_128_ECB_KEY_SIZE 16 |
| 25 | #define FS_AES_128_CBC_KEY_SIZE 16 |
| 26 | #define FS_AES_128_CTS_KEY_SIZE 16 |
| 27 | #define FS_AES_256_GCM_KEY_SIZE 32 |
| 28 | #define FS_AES_256_CBC_KEY_SIZE 32 |
| 29 | #define FS_AES_256_CTS_KEY_SIZE 32 |
| 30 | #define FS_AES_256_XTS_KEY_SIZE 64 |
| 31 | |
Eric Biggers | 11b8818 | 2018-04-30 15:51:46 -0700 | [diff] [blame] | 32 | #define FS_KEY_DERIVATION_NONCE_SIZE 16 |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 33 | |
| 34 | /** |
| 35 | * Encryption context for inode |
| 36 | * |
| 37 | * Protector format: |
| 38 | * 1 byte: Protector format (1 = this version) |
| 39 | * 1 byte: File contents encryption mode |
| 40 | * 1 byte: File names encryption mode |
| 41 | * 1 byte: Flags |
| 42 | * 8 bytes: Master Key descriptor |
| 43 | * 16 bytes: Encryption Key derivation nonce |
| 44 | */ |
| 45 | struct fscrypt_context { |
| 46 | u8 format; |
| 47 | u8 contents_encryption_mode; |
| 48 | u8 filenames_encryption_mode; |
| 49 | u8 flags; |
| 50 | u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; |
| 51 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
| 52 | } __packed; |
| 53 | |
| 54 | #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 |
| 55 | |
Eric Biggers | 0eaab5b | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 56 | /** |
| 57 | * For encrypted symlinks, the ciphertext length is stored at the beginning |
| 58 | * of the string in little-endian format. |
| 59 | */ |
| 60 | struct fscrypt_symlink_data { |
| 61 | __le16 len; |
| 62 | char encrypted_path[1]; |
| 63 | } __packed; |
| 64 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 65 | /* |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 66 | * fscrypt_info - the "encryption key" for an inode |
| 67 | * |
| 68 | * When an encrypted file's key is made available, an instance of this struct is |
| 69 | * allocated and stored in ->i_crypt_info. Once created, it remains until the |
| 70 | * inode is evicted. |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 71 | */ |
| 72 | struct fscrypt_info { |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 73 | |
| 74 | /* The actual crypto transform used for encryption and decryption */ |
| 75 | struct crypto_skcipher *ci_ctfm; |
| 76 | |
| 77 | /* |
| 78 | * Cipher for ESSIV IV generation. Only set for CBC contents |
| 79 | * encryption, otherwise is NULL. |
| 80 | */ |
| 81 | struct crypto_cipher *ci_essiv_tfm; |
| 82 | |
| 83 | /* |
| 84 | * Encryption mode used for this inode. It corresponds to either |
| 85 | * ci_data_mode or ci_filename_mode, depending on the inode type. |
| 86 | */ |
| 87 | struct fscrypt_mode *ci_mode; |
| 88 | |
| 89 | /* |
| 90 | * If non-NULL, then this inode uses a master key directly rather than a |
| 91 | * derived key, and ci_ctfm will equal ci_master_key->mk_ctfm. |
| 92 | * Otherwise, this inode uses a derived key. |
| 93 | */ |
| 94 | struct fscrypt_master_key *ci_master_key; |
| 95 | |
| 96 | /* fields from the fscrypt_context */ |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 97 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 98 | u8 ci_data_mode; |
| 99 | u8 ci_filename_mode; |
| 100 | u8 ci_flags; |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 101 | u8 ci_master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; |
| 102 | u8 ci_nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 103 | u8 ci_raw_key[FS_MAX_KEY_SIZE]; |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 104 | }; |
| 105 | |
Richard Weinberger | 58ae746 | 2016-12-19 12:25:32 +0100 | [diff] [blame] | 106 | typedef enum { |
| 107 | FS_DECRYPT = 0, |
| 108 | FS_ENCRYPT, |
| 109 | } fscrypt_direction_t; |
| 110 | |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 111 | #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 |
David Gstir | 6a34e4d | 2016-12-06 23:53:58 +0100 | [diff] [blame] | 112 | #define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002 |
Theodore Ts'o | cc4e0df | 2016-11-26 22:05:18 -0500 | [diff] [blame] | 113 | |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 114 | static inline bool fscrypt_valid_enc_modes(u32 contents_mode, |
| 115 | u32 filenames_mode) |
| 116 | { |
| 117 | if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC && |
| 118 | filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS) |
| 119 | return true; |
| 120 | |
| 121 | if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS && |
| 122 | filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS) |
| 123 | return true; |
| 124 | |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 125 | if (contents_mode == FS_ENCRYPTION_MODE_ADIANTUM && |
| 126 | filenames_mode == FS_ENCRYPTION_MODE_ADIANTUM) |
| 127 | return true; |
| 128 | |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 129 | if (contents_mode == FS_ENCRYPTION_MODE_PRIVATE && |
| 130 | filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS) |
| 131 | return true; |
| 132 | |
Eric Biggers | bb8179e | 2018-01-05 10:44:58 -0800 | [diff] [blame] | 133 | return false; |
| 134 | } |
| 135 | |
Theodore Ts'o | b98701df | 2016-11-26 20:43:09 -0500 | [diff] [blame] | 136 | /* crypto.c */ |
Eric Biggers | e4de782 | 2018-01-05 10:44:54 -0800 | [diff] [blame] | 137 | extern struct kmem_cache *fscrypt_info_cachep; |
Richard Weinberger | 58ae746 | 2016-12-19 12:25:32 +0100 | [diff] [blame] | 138 | extern int fscrypt_initialize(unsigned int cop_flags); |
Richard Weinberger | 58ae746 | 2016-12-19 12:25:32 +0100 | [diff] [blame] | 139 | extern int fscrypt_do_page_crypto(const struct inode *inode, |
| 140 | fscrypt_direction_t rw, u64 lblk_num, |
| 141 | struct page *src_page, |
| 142 | struct page *dest_page, |
| 143 | unsigned int len, unsigned int offs, |
| 144 | gfp_t gfp_flags); |
| 145 | extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, |
| 146 | gfp_t gfp_flags); |
Eric Biggers | 5422202 | 2018-04-30 15:51:36 -0700 | [diff] [blame] | 147 | extern const struct dentry_operations fscrypt_d_ops; |
Theodore Ts'o | b98701df | 2016-11-26 20:43:09 -0500 | [diff] [blame] | 148 | |
Eric Biggers | 544d08f | 2018-04-30 15:51:47 -0700 | [diff] [blame] | 149 | extern void __printf(3, 4) __cold |
| 150 | fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...); |
| 151 | |
| 152 | #define fscrypt_warn(sb, fmt, ...) \ |
| 153 | fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__) |
| 154 | #define fscrypt_err(sb, fmt, ...) \ |
| 155 | fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__) |
| 156 | |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 157 | #define FSCRYPT_MAX_IV_SIZE 32 |
| 158 | |
| 159 | union fscrypt_iv { |
| 160 | struct { |
| 161 | /* logical block number within the file */ |
| 162 | __le64 lblk_num; |
| 163 | |
| 164 | /* per-file nonce; only set in DIRECT_KEY mode */ |
| 165 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
| 166 | }; |
| 167 | u8 raw[FSCRYPT_MAX_IV_SIZE]; |
| 168 | }; |
| 169 | |
| 170 | void fscrypt_generate_iv(union fscrypt_iv *iv, u64 lblk_num, |
| 171 | const struct fscrypt_info *ci); |
| 172 | |
Eric Biggers | 76e81d6 | 2018-01-05 10:45:01 -0800 | [diff] [blame] | 173 | /* fname.c */ |
Eric Biggers | 50c961d | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 174 | extern int fname_encrypt(struct inode *inode, const struct qstr *iname, |
| 175 | u8 *out, unsigned int olen); |
Eric Biggers | b9db0b4 | 2018-01-11 23:30:08 -0500 | [diff] [blame] | 176 | extern bool fscrypt_fname_encrypted_size(const struct inode *inode, |
| 177 | u32 orig_len, u32 max_len, |
| 178 | u32 *encrypted_len_ret); |
Eric Biggers | 76e81d6 | 2018-01-05 10:45:01 -0800 | [diff] [blame] | 179 | |
Daniel Walter | b7e7cf7 | 2017-06-19 09:27:58 +0200 | [diff] [blame] | 180 | /* keyinfo.c */ |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 181 | |
| 182 | struct fscrypt_mode { |
| 183 | const char *friendly_name; |
| 184 | const char *cipher_str; |
| 185 | int keysize; |
| 186 | int ivsize; |
| 187 | bool logged_impl_name; |
| 188 | bool needs_essiv; |
Zhen Kong | ee7bdc6 | 2019-03-14 10:55:19 -0700 | [diff] [blame^] | 189 | bool inline_encryption; |
Eric Biggers | 78d7a79 | 2018-11-26 11:27:37 -0800 | [diff] [blame] | 190 | }; |
| 191 | |
Daniel Walter | b7e7cf7 | 2017-06-19 09:27:58 +0200 | [diff] [blame] | 192 | extern void __exit fscrypt_essiv_cleanup(void); |
| 193 | |
Theodore Ts'o | 3325bea | 2016-11-26 20:32:46 -0500 | [diff] [blame] | 194 | #endif /* _FSCRYPT_PRIVATE_H */ |