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/* Copyright (c) 2018, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "fscrypt_ice.h"
extern int fscrypt_get_mode_key_size(int mode);
int fscrypt_using_hardware_encryption(const struct inode *inode)
{
struct fscrypt_info *ci = inode->i_crypt_info;
return S_ISREG(inode->i_mode) && ci &&
ci->ci_data_mode == FS_ENCRYPTION_MODE_PRIVATE;
}
EXPORT_SYMBOL(fscrypt_using_hardware_encryption);
size_t fscrypt_get_ice_encryption_key_size(const struct inode *inode)
{
struct fscrypt_info *ci = NULL;
if (inode)
ci = inode->i_crypt_info;
if (!ci)
return 0;
return fscrypt_get_mode_key_size(ci->ci_data_mode) / 2;
}
size_t fscrypt_get_ice_encryption_salt_size(const struct inode *inode)
{
struct fscrypt_info *ci = NULL;
if (inode)
ci = inode->i_crypt_info;
if (!ci)
return 0;
return fscrypt_get_mode_key_size(ci->ci_data_mode) / 2;
}
/*
* Retrieves encryption key from the inode
*/
char *fscrypt_get_ice_encryption_key(const struct inode *inode)
{
struct fscrypt_info *ci = NULL;
if (!inode)
return NULL;
ci = inode->i_crypt_info;
if (!ci)
return NULL;
return &(ci->ci_raw_key[0]);
}
/*
* Retrieves encryption salt from the inode
*/
char *fscrypt_get_ice_encryption_salt(const struct inode *inode)
{
struct fscrypt_info *ci = NULL;
int size = 0;
if (!inode)
return NULL;
ci = inode->i_crypt_info;
if (!ci)
return NULL;
size = fscrypt_get_ice_encryption_key_size(inode);
if (!size)
return NULL;
return &(ci->ci_raw_key[size]);
}
/*
* returns true if the cipher mode in inode is AES XTS
*/
int fscrypt_is_aes_xts_cipher(const struct inode *inode)
{
struct fscrypt_info *ci = inode->i_crypt_info;
if (!ci)
return 0;
return (ci->ci_data_mode == FS_ENCRYPTION_MODE_PRIVATE);
}
/*
* returns true if encryption info in both inodes is equal
*/
bool fscrypt_is_ice_encryption_info_equal(const struct inode *inode1,
const struct inode *inode2)
{
char *key1 = NULL;
char *key2 = NULL;
char *salt1 = NULL;
char *salt2 = NULL;
if (!inode1 || !inode2)
return false;
if (inode1 == inode2)
return true;
/* both do not belong to ice, so we don't care, they are equal
*for us
*/
if (!fscrypt_should_be_processed_by_ice(inode1) &&
!fscrypt_should_be_processed_by_ice(inode2))
return true;
/* one belongs to ice, the other does not -> not equal */
if (fscrypt_should_be_processed_by_ice(inode1) ^
fscrypt_should_be_processed_by_ice(inode2))
return false;
key1 = fscrypt_get_ice_encryption_key(inode1);
key2 = fscrypt_get_ice_encryption_key(inode2);
salt1 = fscrypt_get_ice_encryption_salt(inode1);
salt2 = fscrypt_get_ice_encryption_salt(inode2);
/* key and salt should not be null by this point */
if (!key1 || !key2 || !salt1 || !salt2 ||
(fscrypt_get_ice_encryption_key_size(inode1) !=
fscrypt_get_ice_encryption_key_size(inode2)) ||
(fscrypt_get_ice_encryption_salt_size(inode1) !=
fscrypt_get_ice_encryption_salt_size(inode2)))
return false;
if ((memcmp(key1, key2,
fscrypt_get_ice_encryption_key_size(inode1)) == 0) &&
(memcmp(salt1, salt2,
fscrypt_get_ice_encryption_salt_size(inode1)) == 0))
return true;
return false;
}
void fscrypt_set_ice_dun(const struct inode *inode, struct bio *bio, u64 dun)
{
if (fscrypt_should_be_processed_by_ice(inode))
bio->bi_iter.bi_dun = dun;
}
EXPORT_SYMBOL(fscrypt_set_ice_dun);
void fscrypt_set_ice_skip(struct bio *bio, int bi_crypt_skip)
{
#ifdef CONFIG_DM_DEFAULT_KEY
bio->bi_crypt_skip = bi_crypt_skip;
#endif
}
EXPORT_SYMBOL(fscrypt_set_ice_skip);
/*
* This function will be used for filesystem when deciding to merge bios.
* Basic assumption is, if inline_encryption is set, single bio has to
* guarantee consecutive LBAs as well as ino|pg->index.
*/
bool fscrypt_mergeable_bio(struct bio *bio, u64 dun, bool bio_encrypted,
int bi_crypt_skip)
{
if (!bio)
return true;
#ifdef CONFIG_DM_DEFAULT_KEY
if (bi_crypt_skip != bio->bi_crypt_skip)
return false;
#endif
/* if both of them are not encrypted, no further check is needed */
if (!bio_dun(bio) && !bio_encrypted)
return true;
/* ICE allows only consecutive iv_key stream. */
return bio_end_dun(bio, bio_sectors(bio)) == dun;
}
EXPORT_SYMBOL(fscrypt_mergeable_bio);
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