[linux-block.git] / fs / crypto / fscrypt_private.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * fscrypt_private.h
 *
 * Copyright (C) 2015, Google, Inc.
 *
 * This contains encryption key functions.
 *
 * Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
 */

#ifndef _FSCRYPT_PRIVATE_H
#define _FSCRYPT_PRIVATE_H

#define __FS_HAS_ENCRYPTION 1
#include <linux/fscrypt.h>
#include <crypto/hash.h>

/* Encryption parameters */
#define FS_IV_SIZE			16
#define FS_AES_128_ECB_KEY_SIZE		16
#define FS_AES_128_CBC_KEY_SIZE		16
#define FS_AES_128_CTS_KEY_SIZE		16
#define FS_AES_256_GCM_KEY_SIZE		32
#define FS_AES_256_CBC_KEY_SIZE		32
#define FS_AES_256_CTS_KEY_SIZE		32
#define FS_AES_256_XTS_KEY_SIZE		64

#define FS_KEY_DERIVATION_NONCE_SIZE		16

/**
 * Encryption context for inode
 *
 * Protector format:
 *  1 byte: Protector format (1 = this version)
 *  1 byte: File contents encryption mode
 *  1 byte: File names encryption mode
 *  1 byte: Flags
 *  8 bytes: Master Key descriptor
 *  16 bytes: Encryption Key derivation nonce
 */
struct fscrypt_context {
	u8 format;
	u8 contents_encryption_mode;
	u8 filenames_encryption_mode;
	u8 flags;
	u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
} __packed;

#define FS_ENCRYPTION_CONTEXT_FORMAT_V1		1

/**
 * For encrypted symlinks, the ciphertext length is stored at the beginning
 * of the string in little-endian format.
 */
struct fscrypt_symlink_data {
	__le16 len;
	char encrypted_path[1];
} __packed;

/*
 * A pointer to this structure is stored in the file system's in-core
 * representation of an inode.
 */
struct fscrypt_info {
	u8 ci_data_mode;
	u8 ci_filename_mode;
	u8 ci_flags;
	struct crypto_skcipher *ci_ctfm;
	struct crypto_cipher *ci_essiv_tfm;
	u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
};

typedef enum {
	FS_DECRYPT = 0,
	FS_ENCRYPT,
} fscrypt_direction_t;

#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL		0x00000001
#define FS_CTX_HAS_BOUNCE_BUFFER_FL		0x00000002

static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
					   u32 filenames_mode)
{
	if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
	    filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
		return true;

	if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
	    filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
		return true;

	return false;
}

/* crypto.c */
extern struct kmem_cache *fscrypt_info_cachep;
extern int fscrypt_initialize(unsigned int cop_flags);
extern struct workqueue_struct *fscrypt_read_workqueue;
extern int fscrypt_do_page_crypto(const struct inode *inode,
				  fscrypt_direction_t rw, u64 lblk_num,
				  struct page *src_page,
				  struct page *dest_page,
				  unsigned int len, unsigned int offs,
				  gfp_t gfp_flags);
extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
					      gfp_t gfp_flags);

/* fname.c */
extern int fname_encrypt(struct inode *inode, const struct qstr *iname,
			 u8 *out, unsigned int olen);
extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
					 u32 orig_len, u32 max_len,
					 u32 *encrypted_len_ret);

/* keyinfo.c */
extern void __exit fscrypt_essiv_cleanup(void);

#endif /* _FSCRYPT_PRIVATE_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
3325bea5 TT	2	/*
	3	* fscrypt_private.h
	4	*
	5	* Copyright (C) 2015, Google, Inc.
	6	*
	7	* This contains encryption key functions.
	8	*
	9	* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
	10	*/
	11
	12	#ifndef _FSCRYPT_PRIVATE_H
	13	#define _FSCRYPT_PRIVATE_H
	14
734f0d24 DC	15	#define __FS_HAS_ENCRYPTION 1
734f0d24 DC	16	#include <linux/fscrypt.h>
b7e7cf7a	17	#include <crypto/hash.h>
3325bea5	18
cc4e0df0	19	/* Encryption parameters */
b7e7cf7a	20	#define FS_IV_SIZE 16
cc4e0df0	21	#define FS_AES_128_ECB_KEY_SIZE 16
b7e7cf7a DW	22	#define FS_AES_128_CBC_KEY_SIZE 16
b7e7cf7a DW	23	#define FS_AES_128_CTS_KEY_SIZE 16
cc4e0df0 TT	24	#define FS_AES_256_GCM_KEY_SIZE 32
	25	#define FS_AES_256_CBC_KEY_SIZE 32
	26	#define FS_AES_256_CTS_KEY_SIZE 32
	27	#define FS_AES_256_XTS_KEY_SIZE 64
cc4e0df0 TT	28
	29	#define FS_KEY_DERIVATION_NONCE_SIZE 16
	30
	31	/**
	32	* Encryption context for inode
	33	*
	34	* Protector format:
	35	* 1 byte: Protector format (1 = this version)
	36	* 1 byte: File contents encryption mode
	37	* 1 byte: File names encryption mode
	38	* 1 byte: Flags
	39	* 8 bytes: Master Key descriptor
	40	* 16 bytes: Encryption Key derivation nonce
	41	*/
	42	struct fscrypt_context {
	43	u8 format;
	44	u8 contents_encryption_mode;
	45	u8 filenames_encryption_mode;
	46	u8 flags;
	47	u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
	48	u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
	49	} __packed;
	50
	51	#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
	52
0eaab5b1 EB	53	/**
	54	* For encrypted symlinks, the ciphertext length is stored at the beginning
	55	* of the string in little-endian format.
	56	*/
	57	struct fscrypt_symlink_data {
	58	__le16 len;
	59	char encrypted_path[1];
	60	} __packed;
	61
cc4e0df0 TT	62	/*
	63	* A pointer to this structure is stored in the file system's in-core
	64	* representation of an inode.
	65	*/
	66	struct fscrypt_info {
	67	u8 ci_data_mode;
	68	u8 ci_filename_mode;
	69	u8 ci_flags;
	70	struct crypto_skcipher *ci_ctfm;
b7e7cf7a	71	struct crypto_cipher *ci_essiv_tfm;
cc4e0df0 TT	72	u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
	73	};
	74
58ae7468 RW	75	typedef enum {
	76	FS_DECRYPT = 0,
	77	FS_ENCRYPT,
	78	} fscrypt_direction_t;
	79
cc4e0df0	80	#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
6a34e4d2	81	#define FS_CTX_HAS_BOUNCE_BUFFER_FL 0x00000002
cc4e0df0	82
bb8179e5 EB	83	static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
	84	u32 filenames_mode)
	85	{
	86	if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
	87	filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
	88	return true;
	89
	90	if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
	91	filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
	92	return true;
	93
	94	return false;
	95	}
	96
b98701df	97	/* crypto.c */
e4de782a	98	extern struct kmem_cache *fscrypt_info_cachep;
58ae7468 RW	99	extern int fscrypt_initialize(unsigned int cop_flags);
	100	extern struct workqueue_struct *fscrypt_read_workqueue;
	101	extern int fscrypt_do_page_crypto(const struct inode *inode,
	102	fscrypt_direction_t rw, u64 lblk_num,
	103	struct page *src_page,
	104	struct page *dest_page,
	105	unsigned int len, unsigned int offs,
	106	gfp_t gfp_flags);
	107	extern struct page fscrypt_alloc_bounce_page(struct fscrypt_ctx ctx,
	108	gfp_t gfp_flags);
b98701df	109
76e81d6d	110	/* fname.c */
50c961de EB	111	extern int fname_encrypt(struct inode inode, const struct qstr iname,
50c961de EB	112	u8 *out, unsigned int olen);
b9db0b4a EB	113	extern bool fscrypt_fname_encrypted_size(const struct inode *inode,
	114	u32 orig_len, u32 max_len,
	115	u32 *encrypted_len_ret);
76e81d6d	116
b7e7cf7a DW	117	/* keyinfo.c */
	118	extern void __exit fscrypt_essiv_cleanup(void);
	119
3325bea5	120	#endif /* _FSCRYPT_PRIVATE_H */