1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
|
/*
* fs/crypto/hooks.c
*
* Encryption hooks for higher-level filesystem operations.
*/
#include <linux/ratelimit.h>
#include "fscrypt_private.h"
/**
* fscrypt_file_open - prepare to open a possibly-encrypted regular file
* @inode: the inode being opened
* @filp: the struct file being set up
*
* Currently, an encrypted regular file can only be opened if its encryption key
* is available; access to the raw encrypted contents is not supported.
* Therefore, we first set up the inode's encryption key (if not already done)
* and return an error if it's unavailable.
*
* We also verify that if the parent directory (from the path via which the file
* is being opened) is encrypted, then the inode being opened uses the same
* encryption policy. This is needed as part of the enforcement that all files
* in an encrypted directory tree use the same encryption policy, as a
* protection against certain types of offline attacks. Note that this check is
* needed even when opening an *unencrypted* file, since it's forbidden to have
* an unencrypted file in an encrypted directory.
*
* Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
*/
int fscrypt_file_open(struct inode *inode, struct file *filp)
{
int err;
struct dentry *dir;
err = fscrypt_require_key(inode);
if (err)
return err;
dir = dget_parent(file_dentry(filp));
if (IS_ENCRYPTED(d_inode(dir)) &&
!fscrypt_has_permitted_context(d_inode(dir), inode)) {
pr_warn_ratelimited("fscrypt: inconsistent encryption contexts: %lu/%lu",
d_inode(dir)->i_ino, inode->i_ino);
err = -EPERM;
}
dput(dir);
return err;
}
EXPORT_SYMBOL_GPL(fscrypt_file_open);
int __fscrypt_prepare_link(struct inode *inode, struct inode *dir)
{
int err;
err = fscrypt_require_key(dir);
if (err)
return err;
if (!fscrypt_has_permitted_context(dir, inode))
return -EPERM;
return 0;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_link);
int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
int err;
err = fscrypt_require_key(old_dir);
if (err)
return err;
err = fscrypt_require_key(new_dir);
if (err)
return err;
if (old_dir != new_dir) {
if (IS_ENCRYPTED(new_dir) &&
!fscrypt_has_permitted_context(new_dir,
d_inode(old_dentry)))
return -EPERM;
if ((flags & RENAME_EXCHANGE) &&
IS_ENCRYPTED(old_dir) &&
!fscrypt_has_permitted_context(old_dir,
d_inode(new_dentry)))
return -EPERM;
}
return 0;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename);
int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry)
{
int err = fscrypt_get_encryption_info(dir);
if (err)
return err;
if (fscrypt_has_encryption_key(dir)) {
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
spin_unlock(&dentry->d_lock);
}
d_set_d_op(dentry, &fscrypt_d_ops);
return 0;
}
EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
|
