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(host: inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT, |
7 | buf: ctx, size: 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(host: inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT, |
19 | value: ctx, size: len, flags: 0, check_lock: false); |
20 | } |
21 | |
22 | static bool ubifs_crypt_empty_dir(struct inode *inode) |
23 | { |
24 | return ubifs_check_dir_empty(dir: inode) == 0; |
25 | } |
26 | |
27 | /** |
28 | * ubifs_encrypt - Encrypt data. |
29 | * @inode: inode which refers to the data node |
30 | * @dn: data node to encrypt |
31 | * @in_len: length of data to be compressed |
32 | * @out_len: allocated memory size for the data area of @dn |
33 | * @block: logical block number of the block |
34 | * |
35 | * This function encrypt a possibly-compressed data in the data node. |
36 | * The encrypted data length will store in @out_len. |
37 | */ |
38 | int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn, |
39 | unsigned int in_len, unsigned int *out_len, int block) |
40 | { |
41 | struct ubifs_info *c = inode->i_sb->s_fs_info; |
42 | void *p = &dn->data; |
43 | unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE); |
44 | int err; |
45 | |
46 | ubifs_assert(c, pad_len <= *out_len); |
47 | dn->compr_size = cpu_to_le16(in_len); |
48 | |
49 | /* pad to full block cipher length */ |
50 | if (pad_len != in_len) |
51 | memset(p + in_len, 0, pad_len - in_len); |
52 | |
53 | err = fscrypt_encrypt_block_inplace(inode, virt_to_page(p), len: pad_len, |
54 | offset_in_page(p), lblk_num: block, GFP_NOFS); |
55 | if (err) { |
56 | ubifs_err(c, fmt: "fscrypt_encrypt_block_inplace() failed: %d" , err); |
57 | return err; |
58 | } |
59 | *out_len = pad_len; |
60 | |
61 | return 0; |
62 | } |
63 | |
64 | int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn, |
65 | unsigned int *out_len, int block) |
66 | { |
67 | struct ubifs_info *c = inode->i_sb->s_fs_info; |
68 | int err; |
69 | unsigned int clen = le16_to_cpu(dn->compr_size); |
70 | unsigned int dlen = *out_len; |
71 | |
72 | if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) { |
73 | ubifs_err(c, fmt: "bad compr_size: %i" , clen); |
74 | return -EINVAL; |
75 | } |
76 | |
77 | ubifs_assert(c, dlen <= UBIFS_BLOCK_SIZE); |
78 | err = fscrypt_decrypt_block_inplace(inode, virt_to_page(&dn->data), |
79 | len: dlen, offset_in_page(&dn->data), |
80 | lblk_num: block); |
81 | if (err) { |
82 | ubifs_err(c, fmt: "fscrypt_decrypt_block_inplace() failed: %d" , err); |
83 | return err; |
84 | } |
85 | *out_len = clen; |
86 | |
87 | return 0; |
88 | } |
89 | |
90 | const struct fscrypt_operations ubifs_crypt_operations = { |
91 | .legacy_key_prefix = "ubifs:" , |
92 | .get_context = ubifs_crypt_get_context, |
93 | .set_context = ubifs_crypt_set_context, |
94 | .empty_dir = ubifs_crypt_empty_dir, |
95 | }; |
96 | |