fs/crypto/fscrypt_private.h

   1 /*
   2  * fscrypt_private.h
   3  *
   4  * Copyright (C) 2015, Google, Inc.
   5  *
   6  * This contains encryption key functions.
   7  *
   8  * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
   9  */
  10
  11 #ifndef _FSCRYPT_PRIVATE_H
  12 #define _FSCRYPT_PRIVATE_H
  13
  14 #include <linux/fscrypt_supp.h>
  15 #include <crypto/hash.h>
  16
  17 /* Encryption parameters */
  18 #define FS_IV_SIZE                      16
  19 #define FS_AES_128_ECB_KEY_SIZE         16
  20 #define FS_AES_128_CBC_KEY_SIZE         16
  21 #define FS_AES_128_CTS_KEY_SIZE         16
  22 #define FS_AES_256_GCM_KEY_SIZE         32
  23 #define FS_AES_256_CBC_KEY_SIZE         32
  24 #define FS_AES_256_CTS_KEY_SIZE         32
  25 #define FS_AES_256_XTS_KEY_SIZE         64
  26
  27 #define FS_KEY_DERIVATION_NONCE_SIZE            16
  28
  29 /**
  30  * Encryption context for inode
  31  *
  32  * Protector format:
  33  *  1 byte: Protector format (1 = this version)
  34  *  1 byte: File contents encryption mode
  35  *  1 byte: File names encryption mode
  36  *  1 byte: Flags
  37  *  8 bytes: Master Key descriptor
  38  *  16 bytes: Encryption Key derivation nonce
  39  */
  40 struct fscrypt_context {
  41         u8 format;
  42         u8 contents_encryption_mode;
  43         u8 filenames_encryption_mode;
  44         u8 flags;
  45         u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
  46         u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
  47 } __packed;
  48
  49 #define FS_ENCRYPTION_CONTEXT_FORMAT_V1         1
  50
  51 /*
  52  * A pointer to this structure is stored in the file system's in-core
  53  * representation of an inode.
  54  */
  55 struct fscrypt_info {
  56         u8 ci_data_mode;
  57         u8 ci_filename_mode;
  58         u8 ci_flags;
  59         struct crypto_skcipher *ci_ctfm;
  60         struct crypto_cipher *ci_essiv_tfm;
  61         u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
  62 };
  63
  64 typedef enum {
  65         FS_DECRYPT = 0,
  66         FS_ENCRYPT,
  67 } fscrypt_direction_t;
  68
  69 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL         0x00000001
  70 #define FS_CTX_HAS_BOUNCE_BUFFER_FL             0x00000002
  71
  72 struct fscrypt_completion_result {
  73         struct completion completion;
  74         int res;
  75 };
  76
  77 #define DECLARE_FS_COMPLETION_RESULT(ecr) \
  78         struct fscrypt_completion_result ecr = { \
  79                 COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 }
  80
  81
  82 /* crypto.c */
  83 extern int fscrypt_initialize(unsigned int cop_flags);
  84 extern struct workqueue_struct *fscrypt_read_workqueue;
  85 extern int fscrypt_do_page_crypto(const struct inode *inode,
  86                                   fscrypt_direction_t rw, u64 lblk_num,
  87                                   struct page *src_page,
  88                                   struct page *dest_page,
  89                                   unsigned int len, unsigned int offs,
  90                                   gfp_t gfp_flags);
  91 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
  92                                               gfp_t gfp_flags);
  93
  94 /* keyinfo.c */
  95 extern void __exit fscrypt_essiv_cleanup(void);
  96
  97 #endif /* _FSCRYPT_PRIVATE_H */