uapi/linux/fscrypt.h

0001 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
0002 /*
0003  * fscrypt user API
0004  *
0005  * These ioctls can be used on filesystems that support fscrypt.  See the
0006  * "User API" section of Documentation/filesystems/fscrypt.rst.
0007  */
0008 #ifndef _UAPI_LINUX_FSCRYPT_H
0009 #define _UAPI_LINUX_FSCRYPT_H
0010
0011 #include <linux/ioctl.h>
0012 #include <linux/types.h>
0013
0014 /* Encryption policy flags */
0015 #define FSCRYPT_POLICY_FLAGS_PAD_4      0x00
0016 #define FSCRYPT_POLICY_FLAGS_PAD_8      0x01
0017 #define FSCRYPT_POLICY_FLAGS_PAD_16     0x02
0018 #define FSCRYPT_POLICY_FLAGS_PAD_32     0x03
0019 #define FSCRYPT_POLICY_FLAGS_PAD_MASK       0x03
0020 #define FSCRYPT_POLICY_FLAG_DIRECT_KEY      0x04
0021 #define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64  0x08
0022 #define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32  0x10
0023
0024 /* Encryption algorithms */
0025 #define FSCRYPT_MODE_AES_256_XTS        1
0026 #define FSCRYPT_MODE_AES_256_CTS        4
0027 #define FSCRYPT_MODE_AES_128_CBC        5
0028 #define FSCRYPT_MODE_AES_128_CTS        6
0029 #define FSCRYPT_MODE_ADIANTUM           9
0030 #define FSCRYPT_MODE_AES_256_HCTR2      10
0031 /* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */
0032
0033 /*
0034  * Legacy policy version; ad-hoc KDF and no key verification.
0035  * For new encrypted directories, use fscrypt_policy_v2 instead.
0036  *
0037  * Careful: the .version field for this is actually 0, not 1.
0038  */
0039 #define FSCRYPT_POLICY_V1       0
0040 #define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
0041 struct fscrypt_policy_v1 {
0042     __u8 version;
0043     __u8 contents_encryption_mode;
0044     __u8 filenames_encryption_mode;
0045     __u8 flags;
0046     __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
0047 };
0048
0049 /*
0050  * Process-subscribed "logon" key description prefix and payload format.
0051  * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
0052  */
0053 #define FSCRYPT_KEY_DESC_PREFIX     "fscrypt:"
0054 #define FSCRYPT_KEY_DESC_PREFIX_SIZE    8
0055 #define FSCRYPT_MAX_KEY_SIZE        64
0056 struct fscrypt_key {
0057     __u32 mode;
0058     __u8 raw[FSCRYPT_MAX_KEY_SIZE];
0059     __u32 size;
0060 };
0061
0062 /*
0063  * New policy version with HKDF and key verification (recommended).
0064  */
0065 #define FSCRYPT_POLICY_V2       2
0066 #define FSCRYPT_KEY_IDENTIFIER_SIZE 16
0067 struct fscrypt_policy_v2 {
0068     __u8 version;
0069     __u8 contents_encryption_mode;
0070     __u8 filenames_encryption_mode;
0071     __u8 flags;
0072     __u8 __reserved[4];
0073     __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
0074 };
0075
0076 /* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
0077 struct fscrypt_get_policy_ex_arg {
0078     __u64 policy_size; /* input/output */
0079     union {
0080         __u8 version;
0081         struct fscrypt_policy_v1 v1;
0082         struct fscrypt_policy_v2 v2;
0083     } policy; /* output */
0084 };
0085
0086 /*
0087  * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
0088  * matching fscrypt_policy_v1::master_key_descriptor.
0089  */
0090 #define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR    1
0091
0092 /*
0093  * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
0094  * calculates as a cryptographic hash of the key itself,
0095  * matching fscrypt_policy_v2::master_key_identifier.
0096  */
0097 #define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER    2
0098
0099 /*
0100  * Specifies a key, either for v1 or v2 policies.  This doesn't contain the
0101  * actual key itself; this is just the "name" of the key.
0102  */
0103 struct fscrypt_key_specifier {
0104     __u32 type; /* one of FSCRYPT_KEY_SPEC_TYPE_* */
0105     __u32 __reserved;
0106     union {
0107         __u8 __reserved[32]; /* reserve some extra space */
0108         __u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
0109         __u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
0110     } u;
0111 };
0112
0113 /*
0114  * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by
0115  * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw.
0116  */
0117 struct fscrypt_provisioning_key_payload {
0118     __u32 type;
0119     __u32 __reserved;
0120     __u8 raw[];
0121 };
0122
0123 /* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
0124 struct fscrypt_add_key_arg {
0125     struct fscrypt_key_specifier key_spec;
0126     __u32 raw_size;
0127     __u32 key_id;
0128     __u32 __reserved[8];
0129     __u8 raw[];
0130 };
0131
0132 /* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
0133 struct fscrypt_remove_key_arg {
0134     struct fscrypt_key_specifier key_spec;
0135 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY  0x00000001
0136 #define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS 0x00000002
0137     __u32 removal_status_flags; /* output */
0138     __u32 __reserved[5];
0139 };
0140
0141 /* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
0142 struct fscrypt_get_key_status_arg {
0143     /* input */
0144     struct fscrypt_key_specifier key_spec;
0145     __u32 __reserved[6];
0146
0147     /* output */
0148 #define FSCRYPT_KEY_STATUS_ABSENT       1
0149 #define FSCRYPT_KEY_STATUS_PRESENT      2
0150 #define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
0151     __u32 status;
0152 #define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
0153     __u32 status_flags;
0154     __u32 user_count;
0155     __u32 __out_reserved[13];
0156 };
0157
0158 #define FS_IOC_SET_ENCRYPTION_POLICY        _IOR('f', 19, struct fscrypt_policy_v1)
0159 #define FS_IOC_GET_ENCRYPTION_PWSALT        _IOW('f', 20, __u8[16])
0160 #define FS_IOC_GET_ENCRYPTION_POLICY        _IOW('f', 21, struct fscrypt_policy_v1)
0161 #define FS_IOC_GET_ENCRYPTION_POLICY_EX     _IOWR('f', 22, __u8[9]) /* size + version */
0162 #define FS_IOC_ADD_ENCRYPTION_KEY       _IOWR('f', 23, struct fscrypt_add_key_arg)
0163 #define FS_IOC_REMOVE_ENCRYPTION_KEY        _IOWR('f', 24, struct fscrypt_remove_key_arg)
0164 #define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS  _IOWR('f', 25, struct fscrypt_remove_key_arg)
0165 #define FS_IOC_GET_ENCRYPTION_KEY_STATUS    _IOWR('f', 26, struct fscrypt_get_key_status_arg)
0166 #define FS_IOC_GET_ENCRYPTION_NONCE     _IOR('f', 27, __u8[16])
0167
0168 /**********************************************************************/
0169
0170 /* old names; don't add anything new here! */
0171 #ifndef __KERNEL__
0172 #define fscrypt_policy          fscrypt_policy_v1
0173 #define FS_KEY_DESCRIPTOR_SIZE      FSCRYPT_KEY_DESCRIPTOR_SIZE
0174 #define FS_POLICY_FLAGS_PAD_4       FSCRYPT_POLICY_FLAGS_PAD_4
0175 #define FS_POLICY_FLAGS_PAD_8       FSCRYPT_POLICY_FLAGS_PAD_8
0176 #define FS_POLICY_FLAGS_PAD_16      FSCRYPT_POLICY_FLAGS_PAD_16
0177 #define FS_POLICY_FLAGS_PAD_32      FSCRYPT_POLICY_FLAGS_PAD_32
0178 #define FS_POLICY_FLAGS_PAD_MASK    FSCRYPT_POLICY_FLAGS_PAD_MASK
0179 #define FS_POLICY_FLAG_DIRECT_KEY   FSCRYPT_POLICY_FLAG_DIRECT_KEY
0180 #define FS_POLICY_FLAGS_VALID       0x07    /* contains old flags only */
0181 #define FS_ENCRYPTION_MODE_INVALID  0   /* never used */
0182 #define FS_ENCRYPTION_MODE_AES_256_XTS  FSCRYPT_MODE_AES_256_XTS
0183 #define FS_ENCRYPTION_MODE_AES_256_GCM  2   /* never used */
0184 #define FS_ENCRYPTION_MODE_AES_256_CBC  3   /* never used */
0185 #define FS_ENCRYPTION_MODE_AES_256_CTS  FSCRYPT_MODE_AES_256_CTS
0186 #define FS_ENCRYPTION_MODE_AES_128_CBC  FSCRYPT_MODE_AES_128_CBC
0187 #define FS_ENCRYPTION_MODE_AES_128_CTS  FSCRYPT_MODE_AES_128_CTS
0188 #define FS_ENCRYPTION_MODE_SPECK128_256_XTS 7   /* removed */
0189 #define FS_ENCRYPTION_MODE_SPECK128_256_CTS 8   /* removed */
0190 #define FS_ENCRYPTION_MODE_ADIANTUM FSCRYPT_MODE_ADIANTUM
0191 #define FS_KEY_DESC_PREFIX      FSCRYPT_KEY_DESC_PREFIX
0192 #define FS_KEY_DESC_PREFIX_SIZE     FSCRYPT_KEY_DESC_PREFIX_SIZE
0193 #define FS_MAX_KEY_SIZE         FSCRYPT_MAX_KEY_SIZE
0194 #endif /* !__KERNEL__ */
0195
0196 #endif /* _UAPI_LINUX_FSCRYPT_H */