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
  16 #define FS_FNAME_CRYPTO_DIGEST_SIZE     32
  17
  18 /* Encryption parameters */
  19 #define FS_XTS_TWEAK_SIZE               16
  20 #define FS_AES_128_ECB_KEY_SIZE         16
  21 #define FS_AES_256_GCM_KEY_SIZE         32
  22 #define FS_AES_256_CBC_KEY_SIZE         32
  23 #define FS_AES_256_CTS_KEY_SIZE         32
  24 #define FS_AES_256_XTS_KEY_SIZE         64
  25 #define FS_MAX_KEY_SIZE                 64
  26
  27 #define FS_KEY_DESC_PREFIX              "fscrypt:"
  28 #define FS_KEY_DESC_PREFIX_SIZE         8
  29
  30 #define FS_KEY_DERIVATION_NONCE_SIZE            16
  31
  32 /**
  33  * Encryption context for inode
  34  *
  35  * Protector format:
  36  *  1 byte: Protector format (1 = this version)
  37  *  1 byte: File contents encryption mode
  38  *  1 byte: File names encryption mode
  39  *  1 byte: Flags
  40  *  8 bytes: Master Key descriptor
  41  *  16 bytes: Encryption Key derivation nonce
  42  */
  43 struct fscrypt_context {
  44         u8 format;
  45         u8 contents_encryption_mode;
  46         u8 filenames_encryption_mode;
  47         u8 flags;
  48         u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
  49         u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
  50 } __packed;
  51
  52 #define FS_ENCRYPTION_CONTEXT_FORMAT_V1         1
  53
  54 /* This is passed in from userspace into the kernel keyring */
  55 struct fscrypt_key {
  56         u32 mode;
  57         u8 raw[FS_MAX_KEY_SIZE];
  58         u32 size;
  59 } __packed;
  60
  61 /*
  62  * A pointer to this structure is stored in the file system's in-core
  63  * representation of an inode.
  64  */
  65 struct fscrypt_info {
  66         u8 ci_data_mode;
  67         u8 ci_filename_mode;
  68         u8 ci_flags;
  69         struct crypto_skcipher *ci_ctfm;
  70         struct key *ci_keyring_key;
  71         u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
  72 };
  73
  74 typedef enum {
  75         FS_DECRYPT = 0,
  76         FS_ENCRYPT,
  77 } fscrypt_direction_t;
  78
  79 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL         0x00000001
  80 #define FS_CTX_HAS_BOUNCE_BUFFER_FL             0x00000002
  81
  82 struct fscrypt_completion_result {
  83         struct completion completion;
  84         int res;
  85 };
  86
  87 #define DECLARE_FS_COMPLETION_RESULT(ecr) \
  88         struct fscrypt_completion_result ecr = { \
  89                 COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 }
  90
  91
  92 /* crypto.c */
  93 extern int fscrypt_initialize(unsigned int cop_flags);
  94 extern struct workqueue_struct *fscrypt_read_workqueue;
  95 extern int fscrypt_do_page_crypto(const struct inode *inode,
  96                                   fscrypt_direction_t rw, u64 lblk_num,
  97                                   struct page *src_page,
  98                                   struct page *dest_page,
  99                                   unsigned int len, unsigned int offs,
 100                                   gfp_t gfp_flags);
 101 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
 102                                               gfp_t gfp_flags);
 103
 104 /* keyinfo.c */
 105 extern int fscrypt_get_crypt_info(struct inode *);
 106
 107 #endif /* _FSCRYPT_PRIVATE_H */