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linux-next/fs/ubifs/crypto.c
Eric Biggers a5d431eff2 fscrypt: make fscrypt_operations.key_prefix a string
There was an unnecessary amount of complexity around requesting the
filesystem-specific key prefix.  It was unclear why; perhaps it was
envisioned that different instances of the same filesystem type could
use different key prefixes, or that key prefixes could be binary.
However, neither of those things were implemented or really make sense
at all.  So simplify the code by making key_prefix a const char *.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2017-01-08 01:03:41 -05:00

89 lines
2.3 KiB
C

#include "ubifs.h"
static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
{
return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
ctx, len);
}
static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
size_t len, void *fs_data)
{
return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
ctx, len, 0);
}
static bool ubifs_crypt_empty_dir(struct inode *inode)
{
return ubifs_check_dir_empty(inode) == 0;
}
static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
{
if (S_ISLNK(inode->i_mode))
return UBIFS_MAX_INO_DATA;
else
return UBIFS_MAX_NLEN;
}
int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
unsigned int in_len, unsigned int *out_len, int block)
{
struct ubifs_info *c = inode->i_sb->s_fs_info;
void *p = &dn->data;
struct page *ret;
unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
ubifs_assert(pad_len <= *out_len);
dn->compr_size = cpu_to_le16(in_len);
/* pad to full block cipher length */
if (pad_len != in_len)
memset(p + in_len, 0, pad_len - in_len);
ret = fscrypt_encrypt_page(inode, virt_to_page(&dn->data), pad_len,
offset_in_page(&dn->data), block, GFP_NOFS);
if (IS_ERR(ret)) {
ubifs_err(c, "fscrypt_encrypt_page failed: %ld", PTR_ERR(ret));
return PTR_ERR(ret);
}
*out_len = pad_len;
return 0;
}
int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
unsigned int *out_len, int block)
{
struct ubifs_info *c = inode->i_sb->s_fs_info;
int err;
unsigned int clen = le16_to_cpu(dn->compr_size);
unsigned int dlen = *out_len;
if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
ubifs_err(c, "bad compr_size: %i", clen);
return -EINVAL;
}
ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
err = fscrypt_decrypt_page(inode, virt_to_page(&dn->data), dlen,
offset_in_page(&dn->data), block);
if (err) {
ubifs_err(c, "fscrypt_decrypt_page failed: %i", err);
return err;
}
*out_len = clen;
return 0;
}
struct fscrypt_operations ubifs_crypt_operations = {
.flags = FS_CFLG_OWN_PAGES,
.key_prefix = "ubifs:",
.get_context = ubifs_crypt_get_context,
.set_context = ubifs_crypt_set_context,
.is_encrypted = __ubifs_crypt_is_encrypted,
.empty_dir = ubifs_crypt_empty_dir,
.max_namelen = ubifs_crypt_max_namelen,
};