forked from Minki/linux
9c8268def6
This commit exposes the necessary constants and structures for a userspace program to pass filesystem encryption keys into the keyring. The fscrypt_key structure was already part of the kernel ABI, this change just makes it so programs no longer have to redeclare these structures (like e4crypt in e2fsprogs currently does). Note that we do not expose the other FS_*_KEY_SIZE constants as they are not necessary. Only XTS is supported for contents_encryption_mode, so currently FS_MAX_KEY_SIZE bytes of key material must always be passed to the kernel. This commit also removes __packed from fscrypt_key as it does not contain any implicit padding and does not refer to an on-disk structure. Signed-off-by: Joe Richey <joerichey@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
/*
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* fscrypt_private.h
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*
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* Copyright (C) 2015, Google, Inc.
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*
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* This contains encryption key functions.
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*
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* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
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*/
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#ifndef _FSCRYPT_PRIVATE_H
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#define _FSCRYPT_PRIVATE_H
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#include <linux/fscrypt_supp.h>
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#define FS_FNAME_CRYPTO_DIGEST_SIZE 32
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/* Encryption parameters */
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#define FS_XTS_TWEAK_SIZE 16
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#define FS_AES_128_ECB_KEY_SIZE 16
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#define FS_AES_256_GCM_KEY_SIZE 32
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#define FS_AES_256_CBC_KEY_SIZE 32
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#define FS_AES_256_CTS_KEY_SIZE 32
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#define FS_AES_256_XTS_KEY_SIZE 64
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#define FS_KEY_DERIVATION_NONCE_SIZE 16
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/**
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* Encryption context for inode
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*
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* Protector format:
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* 1 byte: Protector format (1 = this version)
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* 1 byte: File contents encryption mode
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* 1 byte: File names encryption mode
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* 1 byte: Flags
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* 8 bytes: Master Key descriptor
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* 16 bytes: Encryption Key derivation nonce
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*/
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struct fscrypt_context {
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u8 format;
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u8 contents_encryption_mode;
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u8 filenames_encryption_mode;
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u8 flags;
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u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
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u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
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} __packed;
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#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
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/*
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* A pointer to this structure is stored in the file system's in-core
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* representation of an inode.
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*/
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struct fscrypt_info {
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u8 ci_data_mode;
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u8 ci_filename_mode;
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u8 ci_flags;
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struct crypto_skcipher *ci_ctfm;
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u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
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};
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typedef enum {
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FS_DECRYPT = 0,
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FS_ENCRYPT,
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} fscrypt_direction_t;
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#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
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#define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002
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struct fscrypt_completion_result {
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struct completion completion;
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int res;
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};
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#define DECLARE_FS_COMPLETION_RESULT(ecr) \
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struct fscrypt_completion_result ecr = { \
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COMPLETION_INITIALIZER_ONSTACK((ecr).completion), 0 }
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/* crypto.c */
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extern int fscrypt_initialize(unsigned int cop_flags);
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extern struct workqueue_struct *fscrypt_read_workqueue;
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extern int fscrypt_do_page_crypto(const struct inode *inode,
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fscrypt_direction_t rw, u64 lblk_num,
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struct page *src_page,
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struct page *dest_page,
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unsigned int len, unsigned int offs,
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gfp_t gfp_flags);
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extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
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gfp_t gfp_flags);
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#endif /* _FSCRYPT_PRIVATE_H */
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