1// SPDX-License-Identifier: GPL-2.0
 2#include "ubifs.h"
 3
 4static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
 5{
 6	return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
 7			       ctx, len);
 8}
 9
10static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
11				   size_t len, void *fs_data)
12{
13	/*
14	 * Creating an encryption context is done unlocked since we
15	 * operate on a new inode which is not visible to other users
16	 * at this point. So, no need to check whether inode is locked.
17	 */
18	return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
19			       ctx, len, 0, false);
20}
21
22static bool ubifs_crypt_empty_dir(struct inode *inode)
23{
24	return ubifs_check_dir_empty(inode) == 0;
25}
26
27static unsigned int ubifs_crypt_max_namelen(struct inode *inode)
28{
29	if (S_ISLNK(inode->i_mode))
30		return UBIFS_MAX_INO_DATA;
31	else
32		return UBIFS_MAX_NLEN;
33}
34
35int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
36		  unsigned int in_len, unsigned int *out_len, int block)
37{
38	struct ubifs_info *c = inode->i_sb->s_fs_info;
39	void *p = &dn->data;
40	struct page *ret;
41	unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
42
43	ubifs_assert(pad_len <= *out_len);
44	dn->compr_size = cpu_to_le16(in_len);
45
46	/* pad to full block cipher length */
47	if (pad_len != in_len)
48		memset(p + in_len, 0, pad_len - in_len);
49
50	ret = fscrypt_encrypt_page(inode, virt_to_page(&dn->data), pad_len,
51			offset_in_page(&dn->data), block, GFP_NOFS);
52	if (IS_ERR(ret)) {
53		ubifs_err(c, "fscrypt_encrypt_page failed: %ld", PTR_ERR(ret));
54		return PTR_ERR(ret);
55	}
56	*out_len = pad_len;
57
58	return 0;
59}
60
61int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
62		  unsigned int *out_len, int block)
63{
64	struct ubifs_info *c = inode->i_sb->s_fs_info;
65	int err;
66	unsigned int clen = le16_to_cpu(dn->compr_size);
67	unsigned int dlen = *out_len;
68
69	if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
70		ubifs_err(c, "bad compr_size: %i", clen);
71		return -EINVAL;
72	}
73
74	ubifs_assert(dlen <= UBIFS_BLOCK_SIZE);
75	err = fscrypt_decrypt_page(inode, virt_to_page(&dn->data), dlen,
76			offset_in_page(&dn->data), block);
77	if (err) {
78		ubifs_err(c, "fscrypt_decrypt_page failed: %i", err);
79		return err;
80	}
81	*out_len = clen;
82
83	return 0;
84}
85
86const struct fscrypt_operations ubifs_crypt_operations = {
87	.flags			= FS_CFLG_OWN_PAGES,
88	.key_prefix		= "ubifs:",
89	.get_context		= ubifs_crypt_get_context,
90	.set_context		= ubifs_crypt_set_context,
91	.empty_dir		= ubifs_crypt_empty_dir,
92	.max_namelen		= ubifs_crypt_max_namelen,
93};