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 */ 91