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[mirror_ubuntu-focal-kernel.git] / fs / ubifs / crypto.c
1 // SPDX-License-Identifier: GPL-2.0
2 #include "ubifs.h"
3
4 static 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
10 static 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
22 static bool ubifs_crypt_empty_dir(struct inode *inode)
23 {
24 return ubifs_check_dir_empty(inode) == 0;
25 }
26
27 static 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
35 int 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
61 int 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
86 const 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 .is_encrypted = __ubifs_crypt_is_encrypted,
92 .empty_dir = ubifs_crypt_empty_dir,
93 .max_namelen = ubifs_crypt_max_namelen,
94 };