| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 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 | |
| 15 | #define __FS_HAS_ENCRYPTION 1 |
| 16 | #include <linux/fscrypt.h> |
| 17 | #include <crypto/hash.h> |
| 18 | |
| 19 | /* Encryption parameters */ |
| 20 | #define FS_IV_SIZE 16 |
| 21 | #define FS_KEY_DERIVATION_NONCE_SIZE 16 |
| 22 | |
| 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; |
| 39 | u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE]; |
| 40 | u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE]; |
| 41 | } __packed; |
| 42 | |
| 43 | #define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1 |
| 44 | |
| 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 | |
| 54 | /* |
| 55 | * A pointer to this structure is stored in the file system's in-core |
| 56 | * representation of an inode. |
| 57 | */ |
| 58 | struct fscrypt_info { |
| 59 | u8 ci_data_mode; |
| 60 | u8 ci_filename_mode; |
| 61 | u8 ci_flags; |
| 62 | struct crypto_skcipher *ci_ctfm; |
| 63 | struct crypto_cipher *ci_essiv_tfm; |
| 64 | u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; |
| 65 | }; |
| 66 | |
| 67 | typedef enum { |
| 68 | FS_DECRYPT = 0, |
| 69 | FS_ENCRYPT, |
| 70 | } fscrypt_direction_t; |
| 71 | |
| 72 | #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 |
| 73 | #define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002 |
| 74 | |
| 75 | static inline bool fscrypt_valid_enc_modes(u32 contents_mode, |
| 76 | u32 filenames_mode) |
| 77 | { |
| 78 | if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC && |
| 79 | filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS) |
| 80 | return true; |
| 81 | |
| 82 | if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS && |
| 83 | filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS) |
| 84 | return true; |
| 85 | |
| 86 | return false; |
| 87 | } |
| 88 | |
| 89 | /* crypto.c */ |
| 90 | extern struct kmem_cache *fscrypt_info_cachep; |
| 91 | extern int fscrypt_initialize(unsigned int cop_flags); |
| 92 | extern int fscrypt_do_page_crypto(const struct inode *inode, |
| 93 | fscrypt_direction_t rw, u64 lblk_num, |
| 94 | struct page *src_page, |
| 95 | struct page *dest_page, |
| 96 | unsigned int len, unsigned int offs, |
| 97 | gfp_t gfp_flags); |
| 98 | extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, |
| 99 | gfp_t gfp_flags); |
| 100 | extern const struct dentry_operations fscrypt_d_ops; |
| 101 | |
| 102 | extern void __printf(3, 4) __cold |
| 103 | fscrypt_msg(struct super_block *sb, const char *level, const char *fmt, ...); |
| 104 | |
| 105 | #define fscrypt_warn(sb, fmt, ...) \ |
| 106 | fscrypt_msg(sb, KERN_WARNING, fmt, ##__VA_ARGS__) |
| 107 | #define fscrypt_err(sb, fmt, ...) \ |
| 108 | fscrypt_msg(sb, KERN_ERR, fmt, ##__VA_ARGS__) |
| 109 | |
| 110 | /* fname.c */ |
| 111 | extern int fname_encrypt(struct inode *inode, const struct qstr *iname, |
| 112 | u8 *out, unsigned int olen); |
| 113 | extern bool fscrypt_fname_encrypted_size(const struct inode *inode, |
| 114 | u32 orig_len, u32 max_len, |
| 115 | u32 *encrypted_len_ret); |
| 116 | |
| 117 | /* keyinfo.c */ |
| 118 | extern void __exit fscrypt_essiv_cleanup(void); |
| 119 | |
| 120 | #endif /* _FSCRYPT_PRIVATE_H */ |