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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/types.h>
12 
13 /* Encryption policy flags */
14 #define FSCRYPT_POLICY_FLAGS_PAD_4		0x00
15 #define FSCRYPT_POLICY_FLAGS_PAD_8		0x01
16 #define FSCRYPT_POLICY_FLAGS_PAD_16		0x02
17 #define FSCRYPT_POLICY_FLAGS_PAD_32		0x03
18 #define FSCRYPT_POLICY_FLAGS_PAD_MASK		0x03
19 #define FSCRYPT_POLICY_FLAG_DIRECT_KEY		0x04
20 #define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64	0x08
21 #define FSCRYPT_POLICY_FLAGS_VALID		0x0F
22 
23 /* Encryption algorithms */
24 #define FSCRYPT_MODE_AES_256_XTS		1
25 #define FSCRYPT_MODE_AES_256_CTS		4
26 #define FSCRYPT_MODE_AES_128_CBC		5
27 #define FSCRYPT_MODE_AES_128_CTS		6
28 #define FSCRYPT_MODE_ADIANTUM			9
29 #define __FSCRYPT_MODE_MAX			9
30 
31 /*
32  * Legacy policy version; ad-hoc KDF and no key verification.
33  * For new encrypted directories, use fscrypt_policy_v2 instead.
34  *
35  * Careful: the .version field for this is actually 0, not 1.
36  */
37 #define FSCRYPT_POLICY_V1		0
38 #define FSCRYPT_KEY_DESCRIPTOR_SIZE	8
39 struct fscrypt_policy_v1 {
40 	__u8 version;
41 	__u8 contents_encryption_mode;
42 	__u8 filenames_encryption_mode;
43 	__u8 flags;
44 	__u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
45 };
46 #define fscrypt_policy	fscrypt_policy_v1
47 
48 /*
49  * Process-subscribed "logon" key description prefix and payload format.
50  * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
51  */
52 #define FSCRYPT_KEY_DESC_PREFIX		"fscrypt:"
53 #define FSCRYPT_KEY_DESC_PREFIX_SIZE	8
54 #define FSCRYPT_MAX_KEY_SIZE		64
55 struct fscrypt_key {
56 	__u32 mode;
57 	__u8 raw[FSCRYPT_MAX_KEY_SIZE];
58 	__u32 size;
59 };
60 
61 /*
62  * New policy version with HKDF and key verification (recommended).
63  */
64 #define FSCRYPT_POLICY_V2		2
65 #define FSCRYPT_KEY_IDENTIFIER_SIZE	16
66 struct fscrypt_policy_v2 {
67 	__u8 version;
68 	__u8 contents_encryption_mode;
69 	__u8 filenames_encryption_mode;
70 	__u8 flags;
71 	__u8 __reserved[4];
72 	__u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
73 };
74 
75 /* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
76 struct fscrypt_get_policy_ex_arg {
77 	__u64 policy_size; /* input/output */
78 	union {
79 		__u8 version;
80 		struct fscrypt_policy_v1 v1;
81 		struct fscrypt_policy_v2 v2;
82 	} policy; /* output */
83 };
84 
85 /*
86  * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
87  * matching fscrypt_policy_v1::master_key_descriptor.
88  */
89 #define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR	1
90 
91 /*
92  * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
93  * calculates as a cryptographic hash of the key itself,
94  * matching fscrypt_policy_v2::master_key_identifier.
95  */
96 #define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER	2
97 
98 /*
99  * Specifies a key, either for v1 or v2 policies.  This doesn't contain the
100  * actual key itself; this is just the "name" of the key.
101  */
102 struct fscrypt_key_specifier {
103 	__u32 type;	/* one of FSCRYPT_KEY_SPEC_TYPE_* */
104 	__u32 __reserved;
105 	union {
106 		__u8 __reserved[32]; /* reserve some extra space */
107 		__u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
108 		__u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
109 	} u;
110 };
111 
112 /* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
113 struct fscrypt_add_key_arg {
114 	struct fscrypt_key_specifier key_spec;
115 	__u32 raw_size;
116 	__u32 __reserved[8];
117 	/* N.B.: "temporary" flag, not reserved upstream */
118 #define __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED		0x00000001
119 	__u32 __flags;
120 	__u8 raw[];
121 };
122 
123 /* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
124 struct fscrypt_remove_key_arg {
125 	struct fscrypt_key_specifier key_spec;
126 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY	0x00000001
127 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS	0x00000002
128 	__u32 removal_status_flags;	/* output */
129 	__u32 __reserved[5];
130 };
131 
132 /* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
133 struct fscrypt_get_key_status_arg {
134 	/* input */
135 	struct fscrypt_key_specifier key_spec;
136 	__u32 __reserved[6];
137 
138 	/* output */
139 #define FSCRYPT_KEY_STATUS_ABSENT		1
140 #define FSCRYPT_KEY_STATUS_PRESENT		2
141 #define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED	3
142 	__u32 status;
143 #define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
144 	__u32 status_flags;
145 	__u32 user_count;
146 	__u32 __out_reserved[13];
147 };
148 
149 #define FS_IOC_SET_ENCRYPTION_POLICY		_IOR('f', 19, struct fscrypt_policy)
150 #define FS_IOC_GET_ENCRYPTION_PWSALT		_IOW('f', 20, __u8[16])
151 #define FS_IOC_GET_ENCRYPTION_POLICY		_IOW('f', 21, struct fscrypt_policy)
152 #define FS_IOC_GET_ENCRYPTION_POLICY_EX		_IOWR('f', 22, __u8[9]) /* size + version */
153 #define FS_IOC_ADD_ENCRYPTION_KEY		_IOWR('f', 23, struct fscrypt_add_key_arg)
154 #define FS_IOC_REMOVE_ENCRYPTION_KEY		_IOWR('f', 24, struct fscrypt_remove_key_arg)
155 #define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS	_IOWR('f', 25, struct fscrypt_remove_key_arg)
156 #define FS_IOC_GET_ENCRYPTION_KEY_STATUS	_IOWR('f', 26, struct fscrypt_get_key_status_arg)
157 
158 /**********************************************************************/
159 
160 /* old names; don't add anything new here! */
161 #ifndef __KERNEL__
162 #define FS_KEY_DESCRIPTOR_SIZE		FSCRYPT_KEY_DESCRIPTOR_SIZE
163 #define FS_POLICY_FLAGS_PAD_4		FSCRYPT_POLICY_FLAGS_PAD_4
164 #define FS_POLICY_FLAGS_PAD_8		FSCRYPT_POLICY_FLAGS_PAD_8
165 #define FS_POLICY_FLAGS_PAD_16		FSCRYPT_POLICY_FLAGS_PAD_16
166 #define FS_POLICY_FLAGS_PAD_32		FSCRYPT_POLICY_FLAGS_PAD_32
167 #define FS_POLICY_FLAGS_PAD_MASK	FSCRYPT_POLICY_FLAGS_PAD_MASK
168 #define FS_POLICY_FLAG_DIRECT_KEY	FSCRYPT_POLICY_FLAG_DIRECT_KEY
169 #define FS_POLICY_FLAGS_VALID		FSCRYPT_POLICY_FLAGS_VALID
170 #define FS_ENCRYPTION_MODE_INVALID	0	/* never used */
171 #define FS_ENCRYPTION_MODE_AES_256_XTS	FSCRYPT_MODE_AES_256_XTS
172 #define FS_ENCRYPTION_MODE_AES_256_GCM	2	/* never used */
173 #define FS_ENCRYPTION_MODE_AES_256_CBC	3	/* never used */
174 #define FS_ENCRYPTION_MODE_AES_256_CTS	FSCRYPT_MODE_AES_256_CTS
175 #define FS_ENCRYPTION_MODE_AES_128_CBC	FSCRYPT_MODE_AES_128_CBC
176 #define FS_ENCRYPTION_MODE_AES_128_CTS	FSCRYPT_MODE_AES_128_CTS
177 #define FS_ENCRYPTION_MODE_SPECK128_256_XTS	7	/* removed */
178 #define FS_ENCRYPTION_MODE_SPECK128_256_CTS	8	/* removed */
179 #define FS_ENCRYPTION_MODE_ADIANTUM	FSCRYPT_MODE_ADIANTUM
180 #define FS_KEY_DESC_PREFIX		FSCRYPT_KEY_DESC_PREFIX
181 #define FS_KEY_DESC_PREFIX_SIZE		FSCRYPT_KEY_DESC_PREFIX_SIZE
182 #define FS_MAX_KEY_SIZE			FSCRYPT_MAX_KEY_SIZE
183 #endif /* !__KERNEL__ */
184 
185 #endif /* _UAPI_LINUX_FSCRYPT_H */
186