1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2/*
3 * fscrypt user API
4 *
5 * These ioctls can be used on filesystems that support fscrypt. See the
6 * "User API" section of Documentation/filesystems/fscrypt.rst.
7 */
8#ifndef _LINUX_FSCRYPT_H
9#define _LINUX_FSCRYPT_H
10
11#include <linux/ioctl.h>
12#include <linux/types.h>
13
14/* Encryption policy flags */
15#define FSCRYPT_POLICY_FLAGS_PAD_4 0x00
16#define FSCRYPT_POLICY_FLAGS_PAD_8 0x01
17#define FSCRYPT_POLICY_FLAGS_PAD_16 0x02
18#define FSCRYPT_POLICY_FLAGS_PAD_32 0x03
19#define FSCRYPT_POLICY_FLAGS_PAD_MASK 0x03
20#define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04
21#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 0x08
22#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32 0x10
23
24/* Encryption algorithms */
25#define FSCRYPT_MODE_AES_256_XTS 1
26#define FSCRYPT_MODE_AES_256_CTS 4
27#define FSCRYPT_MODE_AES_128_CBC 5
28#define FSCRYPT_MODE_AES_128_CTS 6
29#define FSCRYPT_MODE_SM4_XTS 7
30#define FSCRYPT_MODE_SM4_CTS 8
31#define FSCRYPT_MODE_ADIANTUM 9
32#define FSCRYPT_MODE_AES_256_HCTR2 10
33/* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */
34
35/*
36 * Legacy policy version; ad-hoc KDF and no key verification.
37 * For new encrypted directories, use fscrypt_policy_v2 instead.
38 *
39 * Careful: the .version field for this is actually 0, not 1.
40 */
41#define FSCRYPT_POLICY_V1 0
42#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
43struct fscrypt_policy_v1 {
44 __u8 version;
45 __u8 contents_encryption_mode;
46 __u8 filenames_encryption_mode;
47 __u8 flags;
48 __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
49};
50
51/*
52 * Process-subscribed "logon" key description prefix and payload format.
53 * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
54 */
55#define FSCRYPT_KEY_DESC_PREFIX "fscrypt:"
56#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8
57#define FSCRYPT_MAX_KEY_SIZE 64
58struct fscrypt_key {
59 __u32 mode;
60 __u8 raw[FSCRYPT_MAX_KEY_SIZE];
61 __u32 size;
62};
63
64/*
65 * New policy version with HKDF and key verification (recommended).
66 */
67#define FSCRYPT_POLICY_V2 2
68#define FSCRYPT_KEY_IDENTIFIER_SIZE 16
69struct fscrypt_policy_v2 {
70 __u8 version;
71 __u8 contents_encryption_mode;
72 __u8 filenames_encryption_mode;
73 __u8 flags;
74 __u8 log2_data_unit_size;
75 __u8 __reserved[3];
76 __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
77};
78
79/* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
80struct fscrypt_get_policy_ex_arg {
81 __u64 policy_size; /* input/output */
82 union {
83 __u8 version;
84 struct fscrypt_policy_v1 v1;
85 struct fscrypt_policy_v2 v2;
86 } policy; /* output */
87};
88
89/*
90 * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
91 * matching fscrypt_policy_v1::master_key_descriptor.
92 */
93#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR 1
94
95/*
96 * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
97 * calculates as a cryptographic hash of the key itself,
98 * matching fscrypt_policy_v2::master_key_identifier.
99 */
100#define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER 2
101
102/*
103 * Specifies a key, either for v1 or v2 policies. This doesn't contain the
104 * actual key itself; this is just the "name" of the key.
105 */
106struct fscrypt_key_specifier {
107 __u32 type; /* one of FSCRYPT_KEY_SPEC_TYPE_* */
108 __u32 __reserved;
109 union {
110 __u8 __reserved[32]; /* reserve some extra space */
111 __u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
112 __u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
113 } u;
114};
115
116/*
117 * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by
118 * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw.
119 */
120struct fscrypt_provisioning_key_payload {
121 __u32 type;
122 __u32 __reserved;
123 __u8 raw[];
124};
125
126/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
127struct fscrypt_add_key_arg {
128 struct fscrypt_key_specifier key_spec;
129 __u32 raw_size;
130 __u32 key_id;
131 __u32 __reserved[8];
132 __u8 raw[];
133};
134
135/* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
136struct fscrypt_remove_key_arg {
137 struct fscrypt_key_specifier key_spec;
138#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY 0x00000001
139#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS 0x00000002
140 __u32 removal_status_flags; /* output */
141 __u32 __reserved[5];
142};
143
144/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
145struct fscrypt_get_key_status_arg {
146 /* input */
147 struct fscrypt_key_specifier key_spec;
148 __u32 __reserved[6];
149
150 /* output */
151#define FSCRYPT_KEY_STATUS_ABSENT 1
152#define FSCRYPT_KEY_STATUS_PRESENT 2
153#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
154 __u32 status;
155#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF 0x00000001
156 __u32 status_flags;
157 __u32 user_count;
158 __u32 __out_reserved[13];
159};
160
161#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy_v1)
162#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16])
163#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy_v1)
164#define FS_IOC_GET_ENCRYPTION_POLICY_EX _IOWR('f', 22, __u8[9]) /* size + version */
165#define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg)
166#define FS_IOC_REMOVE_ENCRYPTION_KEY _IOWR('f', 24, struct fscrypt_remove_key_arg)
167#define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS _IOWR('f', 25, struct fscrypt_remove_key_arg)
168#define FS_IOC_GET_ENCRYPTION_KEY_STATUS _IOWR('f', 26, struct fscrypt_get_key_status_arg)
169#define FS_IOC_GET_ENCRYPTION_NONCE _IOR('f', 27, __u8[16])
170
171/**********************************************************************/
172
173/* old names; don't add anything new here! */
174#define fscrypt_policy fscrypt_policy_v1
175#define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE
176#define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4
177#define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8
178#define FS_POLICY_FLAGS_PAD_16 FSCRYPT_POLICY_FLAGS_PAD_16
179#define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32
180#define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK
181#define FS_POLICY_FLAG_DIRECT_KEY FSCRYPT_POLICY_FLAG_DIRECT_KEY
182#define FS_POLICY_FLAGS_VALID 0x07 /* contains old flags only */
183#define FS_ENCRYPTION_MODE_INVALID 0 /* never used */
184#define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS
185#define FS_ENCRYPTION_MODE_AES_256_GCM 2 /* never used */
186#define FS_ENCRYPTION_MODE_AES_256_CBC 3 /* never used */
187#define FS_ENCRYPTION_MODE_AES_256_CTS FSCRYPT_MODE_AES_256_CTS
188#define FS_ENCRYPTION_MODE_AES_128_CBC FSCRYPT_MODE_AES_128_CBC
189#define FS_ENCRYPTION_MODE_AES_128_CTS FSCRYPT_MODE_AES_128_CTS
190#define FS_ENCRYPTION_MODE_ADIANTUM FSCRYPT_MODE_ADIANTUM
191#define FS_KEY_DESC_PREFIX FSCRYPT_KEY_DESC_PREFIX
192#define FS_KEY_DESC_PREFIX_SIZE FSCRYPT_KEY_DESC_PREFIX_SIZE
193#define FS_MAX_KEY_SIZE FSCRYPT_MAX_KEY_SIZE
194
195#endif /* _LINUX_FSCRYPT_H */
196