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/*
* linux/fs/f2fs/f2fs_crypto.h
*
* Copied from linux/fs/ext4/ext4_crypto.h
*
* Copyright (C) 2015, Google, Inc.
*
* This contains encryption header content for f2fs
*
* Written by Michael Halcrow, 2015.
* Modified by Jaegeuk Kim, 2015.
*/
#ifndef _F2FS_CRYPTO_H
#define _F2FS_CRYPTO_H
#include <linux/fs.h>
#define F2FS_KEY_DESCRIPTOR_SIZE 8
/* Policy provided via an ioctl on the topmost directory */
struct f2fs_encryption_policy {
char version;
char contents_encryption_mode;
char filenames_encryption_mode;
char flags;
char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
} __attribute__((__packed__));
#define F2FS_ENCRYPTION_CONTEXT_FORMAT_V1 1
#define F2FS_KEY_DERIVATION_NONCE_SIZE 16
#define F2FS_POLICY_FLAGS_PAD_4 0x00
#define F2FS_POLICY_FLAGS_PAD_8 0x01
#define F2FS_POLICY_FLAGS_PAD_16 0x02
#define F2FS_POLICY_FLAGS_PAD_32 0x03
#define F2FS_POLICY_FLAGS_PAD_MASK 0x03
#define F2FS_POLICY_FLAGS_VALID 0x03
/**
* 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 f2fs_encryption_context {
char format;
char contents_encryption_mode;
char filenames_encryption_mode;
char flags;
char master_key_descriptor[F2FS_KEY_DESCRIPTOR_SIZE];
char nonce[F2FS_KEY_DERIVATION_NONCE_SIZE];
} __attribute__((__packed__));
/* Encryption parameters */
#define F2FS_XTS_TWEAK_SIZE 16
#define F2FS_AES_128_ECB_KEY_SIZE 16
#define F2FS_AES_256_GCM_KEY_SIZE 32
#define F2FS_AES_256_CBC_KEY_SIZE 32
#define F2FS_AES_256_CTS_KEY_SIZE 32
#define F2FS_AES_256_XTS_KEY_SIZE 64
#define F2FS_MAX_KEY_SIZE 64
#define F2FS_KEY_DESC_PREFIX "f2fs:"
#define F2FS_KEY_DESC_PREFIX_SIZE 5
struct f2fs_encryption_key {
__u32 mode;
char raw[F2FS_MAX_KEY_SIZE];
__u32 size;
} __attribute__((__packed__));
struct f2fs_crypt_info {
char ci_data_mode;
char ci_filename_mode;
char ci_flags;
struct crypto_ablkcipher *ci_ctfm;
struct key *ci_keyring_key;
char ci_master_key[F2FS_KEY_DESCRIPTOR_SIZE];
};
#define F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
#define F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL 0x00000002
#define F2FS_WRITE_PATH_FL 0x00000004
struct f2fs_crypto_ctx {
union {
struct {
struct page *bounce_page; /* Ciphertext page */
struct page *control_page; /* Original page */
} w;
struct {
struct bio *bio;
struct work_struct work;
} r;
struct list_head free_list; /* Free list */
};
char flags; /* Flags */
};
struct f2fs_completion_result {
struct completion completion;
int res;
};
#define DECLARE_F2FS_COMPLETION_RESULT(ecr) \
struct f2fs_completion_result ecr = { \
COMPLETION_INITIALIZER((ecr).completion), 0 }
static inline int f2fs_encryption_key_size(int mode)
{
switch (mode) {
case F2FS_ENCRYPTION_MODE_AES_256_XTS:
return F2FS_AES_256_XTS_KEY_SIZE;
case F2FS_ENCRYPTION_MODE_AES_256_GCM:
return F2FS_AES_256_GCM_KEY_SIZE;
case F2FS_ENCRYPTION_MODE_AES_256_CBC:
return F2FS_AES_256_CBC_KEY_SIZE;
case F2FS_ENCRYPTION_MODE_AES_256_CTS:
return F2FS_AES_256_CTS_KEY_SIZE;
default:
BUG();
}
return 0;
}
#define F2FS_FNAME_NUM_SCATTER_ENTRIES 4
#define F2FS_CRYPTO_BLOCK_SIZE 16
#define F2FS_FNAME_CRYPTO_DIGEST_SIZE 32
/**
* For encrypted symlinks, the ciphertext length is stored at the beginning
* of the string in little-endian format.
*/
struct f2fs_encrypted_symlink_data {
__le16 len;
char encrypted_path[1];
} __attribute__((__packed__));
/**
* This function is used to calculate the disk space required to
* store a filename of length l in encrypted symlink format.
*/
static inline u32 encrypted_symlink_data_len(u32 l)
{
return (l + sizeof(struct f2fs_encrypted_symlink_data) - 1);
}
#endif /* _F2FS_CRYPTO_H */
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