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 /**
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), pad_len,
54 offset_in_page(p), block, GFP_NOFS);
55 if (err) {
56 ubifs_err(c, "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, "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 dlen, offset_in_page(&dn->data),
80 block);
81 if (err) {
82 ubifs_err(c, "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
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