fs/crypto/fscrypt_private.h

   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_AES_128_ECB_KEY_SIZE         16
  22 #define FS_AES_128_CBC_KEY_SIZE         16
  23 #define FS_AES_128_CTS_KEY_SIZE         16
  24 #define FS_AES_256_GCM_KEY_SIZE         32
  25 #define FS_AES_256_CBC_KEY_SIZE         32
  26 #define FS_AES_256_CTS_KEY_SIZE         32
  27 #define FS_AES_256_XTS_KEY_SIZE         64
  28
  29 #define FS_KEY_DERIVATION_NONCE_SIZE            16
  30
  31 /**
  32  * Encryption context for inode
  33  *
  34  * Protector format:
  35  *  1 byte: Protector format (1 = this version)
  36  *  1 byte: File contents encryption mode
  37  *  1 byte: File names encryption mode
  38  *  1 byte: Flags
  39  *  8 bytes: Master Key descriptor
  40  *  16 bytes: Encryption Key derivation nonce
  41  */
  42 struct fscrypt_context {
  43         u8 format;
  44         u8 contents_encryption_mode;
  45         u8 filenames_encryption_mode;
  46         u8 flags;
  47         u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
  48         u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
  49 } __packed;
  50
  51 #define FS_ENCRYPTION_CONTEXT_FORMAT_V1         1
  52
  53 /*
  54  * A pointer to this structure is stored in the file system's in-core
  55  * representation of an inode.
  56  */
  57 struct fscrypt_info {
  58         u8 ci_data_mode;
  59         u8 ci_filename_mode;
  60         u8 ci_flags;
  61         struct crypto_skcipher *ci_ctfm;
  62         struct crypto_cipher *ci_essiv_tfm;
  63         u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
  64 };
  65
  66 typedef enum {
  67         FS_DECRYPT = 0,
  68         FS_ENCRYPT,
  69 } fscrypt_direction_t;
  70
  71 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL         0x00000001
  72 #define FS_CTX_HAS_BOUNCE_BUFFER_FL             0x00000002
  73
  74 /* crypto.c */
  75 extern int fscrypt_initialize(unsigned int cop_flags);
  76 extern struct workqueue_struct *fscrypt_read_workqueue;
  77 extern int fscrypt_do_page_crypto(const struct inode *inode,
  78                                   fscrypt_direction_t rw, u64 lblk_num,
  79                                   struct page *src_page,
  80                                   struct page *dest_page,
  81                                   unsigned int len, unsigned int offs,
  82                                   gfp_t gfp_flags);
  83 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
  84                                               gfp_t gfp_flags);
  85
  86 /* keyinfo.c */
  87 extern void __exit fscrypt_essiv_cleanup(void);
  88
  89 #endif /* _FSCRYPT_PRIVATE_H */