Michael Halcrow | 9bd8212 | 2015-04-11 07:48:01 -0400 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/ext4/ext4_crypto.h |
| 3 | * |
| 4 | * Copyright (C) 2015, Google, Inc. |
| 5 | * |
| 6 | * This contains encryption header content for ext4 |
| 7 | * |
| 8 | * Written by Michael Halcrow, 2015. |
| 9 | */ |
| 10 | |
| 11 | #ifndef _EXT4_CRYPTO_H |
| 12 | #define _EXT4_CRYPTO_H |
| 13 | |
| 14 | #include <linux/fs.h> |
| 15 | |
| 16 | #define EXT4_KEY_DESCRIPTOR_SIZE 8 |
| 17 | |
| 18 | /* Policy provided via an ioctl on the topmost directory */ |
| 19 | struct ext4_encryption_policy { |
| 20 | char version; |
| 21 | char contents_encryption_mode; |
| 22 | char filenames_encryption_mode; |
| 23 | char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE]; |
| 24 | } __attribute__((__packed__)); |
| 25 | |
| 26 | #define EXT4_ENCRYPTION_CONTEXT_FORMAT_V1 1 |
| 27 | #define EXT4_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: Reserved |
| 37 | * 8 bytes: Master Key descriptor |
| 38 | * 16 bytes: Encryption Key derivation nonce |
| 39 | */ |
| 40 | struct ext4_encryption_context { |
| 41 | char format; |
| 42 | char contents_encryption_mode; |
| 43 | char filenames_encryption_mode; |
| 44 | char reserved; |
| 45 | char master_key_descriptor[EXT4_KEY_DESCRIPTOR_SIZE]; |
| 46 | char nonce[EXT4_KEY_DERIVATION_NONCE_SIZE]; |
| 47 | } __attribute__((__packed__)); |
| 48 | |
Michael Halcrow | b30ab0e | 2015-04-12 00:43:56 -0400 | [diff] [blame] | 49 | /* Encryption parameters */ |
| 50 | #define EXT4_XTS_TWEAK_SIZE 16 |
| 51 | #define EXT4_AES_128_ECB_KEY_SIZE 16 |
| 52 | #define EXT4_AES_256_GCM_KEY_SIZE 32 |
| 53 | #define EXT4_AES_256_CBC_KEY_SIZE 32 |
| 54 | #define EXT4_AES_256_CTS_KEY_SIZE 32 |
| 55 | #define EXT4_AES_256_XTS_KEY_SIZE 64 |
| 56 | #define EXT4_MAX_KEY_SIZE 64 |
| 57 | |
Michael Halcrow | 88bd6cc | 2015-04-12 00:55:06 -0400 | [diff] [blame^] | 58 | #define EXT4_KEY_DESC_PREFIX "ext4:" |
| 59 | #define EXT4_KEY_DESC_PREFIX_SIZE 5 |
| 60 | |
Michael Halcrow | b30ab0e | 2015-04-12 00:43:56 -0400 | [diff] [blame] | 61 | struct ext4_encryption_key { |
| 62 | uint32_t mode; |
| 63 | char raw[EXT4_MAX_KEY_SIZE]; |
| 64 | uint32_t size; |
| 65 | }; |
| 66 | |
| 67 | #define EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001 |
| 68 | #define EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL 0x00000002 |
| 69 | |
| 70 | struct ext4_crypto_ctx { |
| 71 | struct crypto_tfm *tfm; /* Crypto API context */ |
| 72 | struct page *bounce_page; /* Ciphertext page on write path */ |
| 73 | struct page *control_page; /* Original page on write path */ |
| 74 | struct bio *bio; /* The bio for this context */ |
| 75 | struct work_struct work; /* Work queue for read complete path */ |
| 76 | struct list_head free_list; /* Free list */ |
| 77 | int flags; /* Flags */ |
| 78 | int mode; /* Encryption mode for tfm */ |
| 79 | }; |
| 80 | |
| 81 | struct ext4_completion_result { |
| 82 | struct completion completion; |
| 83 | int res; |
| 84 | }; |
| 85 | |
| 86 | #define DECLARE_EXT4_COMPLETION_RESULT(ecr) \ |
| 87 | struct ext4_completion_result ecr = { \ |
| 88 | COMPLETION_INITIALIZER((ecr).completion), 0 } |
| 89 | |
| 90 | static inline int ext4_encryption_key_size(int mode) |
| 91 | { |
| 92 | switch (mode) { |
| 93 | case EXT4_ENCRYPTION_MODE_AES_256_XTS: |
| 94 | return EXT4_AES_256_XTS_KEY_SIZE; |
| 95 | case EXT4_ENCRYPTION_MODE_AES_256_GCM: |
| 96 | return EXT4_AES_256_GCM_KEY_SIZE; |
| 97 | case EXT4_ENCRYPTION_MODE_AES_256_CBC: |
| 98 | return EXT4_AES_256_CBC_KEY_SIZE; |
| 99 | case EXT4_ENCRYPTION_MODE_AES_256_CTS: |
| 100 | return EXT4_AES_256_CTS_KEY_SIZE; |
| 101 | default: |
| 102 | BUG(); |
| 103 | } |
| 104 | return 0; |
| 105 | } |
| 106 | |
Michael Halcrow | 9bd8212 | 2015-04-11 07:48:01 -0400 | [diff] [blame] | 107 | #endif /* _EXT4_CRYPTO_H */ |