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