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 _UAPI_LINUX_FSCRYPT_H
9 #define _UAPI_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 #define FSCRYPT_POLICY_FLAGS_VALID		0x1F
24 
25 /* Encryption algorithms */
26 #define FSCRYPT_MODE_AES_256_XTS		1
27 #define FSCRYPT_MODE_AES_256_CTS		4
28 #define FSCRYPT_MODE_AES_128_CBC		5
29 #define FSCRYPT_MODE_AES_128_CTS		6
30 #define FSCRYPT_MODE_ADIANTUM			9
31 #define __FSCRYPT_MODE_MAX			9
32 
33 /*
34  * Legacy policy version; ad-hoc KDF and no key verification.
35  * For new encrypted directories, use fscrypt_policy_v2 instead.
36  *
37  * Careful: the .version field for this is actually 0, not 1.
38  */
39 #define FSCRYPT_POLICY_V1		0
40 #define FSCRYPT_KEY_DESCRIPTOR_SIZE	8
41 struct fscrypt_policy_v1 {
42 	__u8 version;
43 	__u8 contents_encryption_mode;
44 	__u8 filenames_encryption_mode;
45 	__u8 flags;
46 	__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
47 };
48 
49 /*
50  * Process-subscribed "logon" key description prefix and payload format.
51  * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
52  */
53 #define FSCRYPT_KEY_DESC_PREFIX		"fscrypt:"
54 #define FSCRYPT_KEY_DESC_PREFIX_SIZE	8
55 #define FSCRYPT_MAX_KEY_SIZE		64
56 struct fscrypt_key {
57 	__u32 mode;
58 	__u8 raw[FSCRYPT_MAX_KEY_SIZE];
59 	__u32 size;
60 };
61 
62 /*
63  * New policy version with HKDF and key verification (recommended).
64  */
65 #define FSCRYPT_POLICY_V2		2
66 #define FSCRYPT_KEY_IDENTIFIER_SIZE	16
67 struct fscrypt_policy_v2 {
68 	__u8 version;
69 	__u8 contents_encryption_mode;
70 	__u8 filenames_encryption_mode;
71 	__u8 flags;
72 	__u8 __reserved[4];
73 	__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
74 };
75 
76 /* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
77 struct fscrypt_get_policy_ex_arg {
78 	__u64 policy_size; /* input/output */
79 	union {
80 		__u8 version;
81 		struct fscrypt_policy_v1 v1;
82 		struct fscrypt_policy_v2 v2;
83 	} policy; /* output */
84 };
85 
86 /*
87  * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
88  * matching fscrypt_policy_v1::master_key_descriptor.
89  */
90 #define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR	1
91 
92 /*
93  * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
94  * calculates as a cryptographic hash of the key itself,
95  * matching fscrypt_policy_v2::master_key_identifier.
96  */
97 #define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER	2
98 
99 /*
100  * Specifies a key, either for v1 or v2 policies.  This doesn't contain the
101  * actual key itself; this is just the "name" of the key.
102  */
103 struct fscrypt_key_specifier {
104 	__u32 type;	/* one of FSCRYPT_KEY_SPEC_TYPE_* */
105 	__u32 __reserved;
106 	union {
107 		__u8 __reserved[32]; /* reserve some extra space */
108 		__u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
109 		__u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
110 	} u;
111 };
112 
113 /*
114  * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by
115  * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw.
116  */
117 struct fscrypt_provisioning_key_payload {
118 	__u32 type;
119 	__u32 __reserved;
120 	__u8 raw[];
121 };
122 
123 /* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
124 struct fscrypt_add_key_arg {
125 	struct fscrypt_key_specifier key_spec;
126 	__u32 raw_size;
127 	__u32 key_id;
128 	__u32 __reserved[8];
129 	__u8 raw[];
130 };
131 
132 /* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
133 struct fscrypt_remove_key_arg {
134 	struct fscrypt_key_specifier key_spec;
135 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY	0x00000001
136 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS	0x00000002
137 	__u32 removal_status_flags;	/* output */
138 	__u32 __reserved[5];
139 };
140 
141 /* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
142 struct fscrypt_get_key_status_arg {
143 	/* input */
144 	struct fscrypt_key_specifier key_spec;
145 	__u32 __reserved[6];
146 
147 	/* output */
148 #define FSCRYPT_KEY_STATUS_ABSENT		1
149 #define FSCRYPT_KEY_STATUS_PRESENT		2
150 #define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED	3
151 	__u32 status;
152 #define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
153 	__u32 status_flags;
154 	__u32 user_count;
155 	__u32 __out_reserved[13];
156 };
157 
158 #define FS_IOC_SET_ENCRYPTION_POLICY		_IOR('f', 19, struct fscrypt_policy_v1)
159 #define FS_IOC_GET_ENCRYPTION_PWSALT		_IOW('f', 20, __u8[16])
160 #define FS_IOC_GET_ENCRYPTION_POLICY		_IOW('f', 21, struct fscrypt_policy_v1)
161 #define FS_IOC_GET_ENCRYPTION_POLICY_EX		_IOWR('f', 22, __u8[9]) /* size + version */
162 #define FS_IOC_ADD_ENCRYPTION_KEY		_IOWR('f', 23, struct fscrypt_add_key_arg)
163 #define FS_IOC_REMOVE_ENCRYPTION_KEY		_IOWR('f', 24, struct fscrypt_remove_key_arg)
164 #define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS	_IOWR('f', 25, struct fscrypt_remove_key_arg)
165 #define FS_IOC_GET_ENCRYPTION_KEY_STATUS	_IOWR('f', 26, struct fscrypt_get_key_status_arg)
166 #define FS_IOC_GET_ENCRYPTION_NONCE		_IOR('f', 27, __u8[16])
167 
168 /**********************************************************************/
169 
170 /* old names; don't add anything new here! */
171 #ifndef __KERNEL__
172 #define fscrypt_policy			fscrypt_policy_v1
173 #define FS_KEY_DESCRIPTOR_SIZE		FSCRYPT_KEY_DESCRIPTOR_SIZE
174 #define FS_POLICY_FLAGS_PAD_4		FSCRYPT_POLICY_FLAGS_PAD_4
175 #define FS_POLICY_FLAGS_PAD_8		FSCRYPT_POLICY_FLAGS_PAD_8
176 #define FS_POLICY_FLAGS_PAD_16		FSCRYPT_POLICY_FLAGS_PAD_16
177 #define FS_POLICY_FLAGS_PAD_32		FSCRYPT_POLICY_FLAGS_PAD_32
178 #define FS_POLICY_FLAGS_PAD_MASK	FSCRYPT_POLICY_FLAGS_PAD_MASK
179 #define FS_POLICY_FLAG_DIRECT_KEY	FSCRYPT_POLICY_FLAG_DIRECT_KEY
180 #define FS_POLICY_FLAGS_VALID		FSCRYPT_POLICY_FLAGS_VALID
181 #define FS_ENCRYPTION_MODE_INVALID	0	/* never used */
182 #define FS_ENCRYPTION_MODE_AES_256_XTS	FSCRYPT_MODE_AES_256_XTS
183 #define FS_ENCRYPTION_MODE_AES_256_GCM	2	/* never used */
184 #define FS_ENCRYPTION_MODE_AES_256_CBC	3	/* never used */
185 #define FS_ENCRYPTION_MODE_AES_256_CTS	FSCRYPT_MODE_AES_256_CTS
186 #define FS_ENCRYPTION_MODE_AES_128_CBC	FSCRYPT_MODE_AES_128_CBC
187 #define FS_ENCRYPTION_MODE_AES_128_CTS	FSCRYPT_MODE_AES_128_CTS
188 #define FS_ENCRYPTION_MODE_SPECK128_256_XTS	7	/* removed */
189 #define FS_ENCRYPTION_MODE_SPECK128_256_CTS	8	/* removed */
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 #endif /* !__KERNEL__ */
195 
196 #endif /* _UAPI_LINUX_FSCRYPT_H */
197