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 u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; 71 }; 72 73 typedef enum { 74 FS_DECRYPT = 0, 75 FS_ENCRYPT, 76 } fscrypt_direction_t; 77 78 #define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 79 #define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002 80 81 struct fscrypt_completion_result { 82 struct completion completion; 83 int res; 84 }; 85 86 #define DECLARE_FS_COMPLETION_RESULT(ecr) \ 87 struct fscrypt_completion_result ecr = { \ 88 COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 } 89 90 91 /* crypto.c */ 92 extern int fscrypt_initialize(unsigned int cop_flags); 93 extern struct workqueue_struct *fscrypt_read_workqueue; 94 extern int fscrypt_do_page_crypto(const struct inode *inode, 95 fscrypt_direction_t rw, u64 lblk_num, 96 struct page *src_page, 97 struct page *dest_page, 98 unsigned int len, unsigned int offs, 99 gfp_t gfp_flags); 100 extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, 101 gfp_t gfp_flags); 102 103 #endif /* _FSCRYPT_PRIVATE_H */ 104