/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
/*
 * fscrypt user API
 *
 * These ioctls can be used on filesystems that support fscrypt.  See the
 * "User API" section of Documentation/filesystems/fscrypt.rst.
 */
#ifndef _UAPI_LINUX_FSCRYPT_H
#define _UAPI_LINUX_FSCRYPT_H

#include <linux/ioctl.h>
#include <linux/types.h>

/* Encryption policy flags */
#define FSCRYPT_POLICY_FLAGS_PAD_4              0x00
#define FSCRYPT_POLICY_FLAGS_PAD_8              0x01
#define FSCRYPT_POLICY_FLAGS_PAD_16             0x02
#define FSCRYPT_POLICY_FLAGS_PAD_32             0x03
#define FSCRYPT_POLICY_FLAGS_PAD_MASK           0x03
#define FSCRYPT_POLICY_FLAG_DIRECT_KEY          0x04
#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64      0x08
#define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32      0x10

/* Encryption algorithms */
#define FSCRYPT_MODE_AES_256_XTS                1
#define FSCRYPT_MODE_AES_256_CTS                4
#define FSCRYPT_MODE_AES_128_CBC                5
#define FSCRYPT_MODE_AES_128_CTS                6
#define FSCRYPT_MODE_SM4_XTS                    7
#define FSCRYPT_MODE_SM4_CTS                    8
#define FSCRYPT_MODE_ADIANTUM                   9
#define FSCRYPT_MODE_AES_256_HCTR2              10
/* If adding a mode number > 10, update FSCRYPT_MODE_MAX in fscrypt_private.h */

/*
 * Legacy policy version; ad-hoc KDF and no key verification.
 * For new encrypted directories, use fscrypt_policy_v2 instead.
 *
 * Careful: the .version field for this is actually 0, not 1.
 */
#define FSCRYPT_POLICY_V1               0
#define FSCRYPT_KEY_DESCRIPTOR_SIZE     8
struct fscrypt_policy_v1 {
        __u8 version;
        __u8 contents_encryption_mode;
        __u8 filenames_encryption_mode;
        __u8 flags;
        __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};

/*
 * Process-subscribed "logon" key description prefix and payload format.
 * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead.
 */
#define FSCRYPT_KEY_DESC_PREFIX         "fscrypt:"
#define FSCRYPT_KEY_DESC_PREFIX_SIZE    8
#define FSCRYPT_MAX_KEY_SIZE            64
struct fscrypt_key {
        __u32 mode;
        __u8 raw[FSCRYPT_MAX_KEY_SIZE];
        __u32 size;
};

/*
 * New policy version with HKDF and key verification (recommended).
 */
#define FSCRYPT_POLICY_V2               2
#define FSCRYPT_KEY_IDENTIFIER_SIZE     16
struct fscrypt_policy_v2 {
        __u8 version;
        __u8 contents_encryption_mode;
        __u8 filenames_encryption_mode;
        __u8 flags;
        __u8 log2_data_unit_size;
        __u8 __reserved[3];
        __u8 master_key_identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
};

/* Struct passed to FS_IOC_GET_ENCRYPTION_POLICY_EX */
struct fscrypt_get_policy_ex_arg {
        __u64 policy_size; /* input/output */
        union {
                __u8 version;
                struct fscrypt_policy_v1 v1;
                struct fscrypt_policy_v2 v2;
        } policy; /* output */
};

/*
 * v1 policy keys are specified by an arbitrary 8-byte key "descriptor",
 * matching fscrypt_policy_v1::master_key_descriptor.
 */
#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR        1

/*
 * v2 policy keys are specified by a 16-byte key "identifier" which the kernel
 * calculates as a cryptographic hash of the key itself,
 * matching fscrypt_policy_v2::master_key_identifier.
 */
#define FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER        2

/*
 * Specifies a key, either for v1 or v2 policies.  This doesn't contain the
 * actual key itself; this is just the "name" of the key.
 */
struct fscrypt_key_specifier {
        __u32 type;     /* one of FSCRYPT_KEY_SPEC_TYPE_* */
        __u32 __reserved;
        union {
                __u8 __reserved[32]; /* reserve some extra space */
                __u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
                __u8 identifier[FSCRYPT_KEY_IDENTIFIER_SIZE];
        } u;
};

/*
 * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by
 * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw.
 */
struct fscrypt_provisioning_key_payload {
        __u32 type;
        __u32 flags;
        __u8 raw[];
};

/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
struct fscrypt_add_key_arg {
        struct fscrypt_key_specifier key_spec;
        __u32 raw_size;
        __u32 key_id;
#define FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED 0x00000001
        __u32 flags;
        __u32 __reserved[7];
        __u8 raw[];
};

/* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
struct fscrypt_remove_key_arg {
        struct fscrypt_key_specifier key_spec;
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY      0x00000001
#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS     0x00000002
        __u32 removal_status_flags;     /* output */
        __u32 __reserved[5];
};

/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
struct fscrypt_get_key_status_arg {
        /* input */
        struct fscrypt_key_specifier key_spec;
        __u32 __reserved[6];

        /* output */
#define FSCRYPT_KEY_STATUS_ABSENT               1
#define FSCRYPT_KEY_STATUS_PRESENT              2
#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
        __u32 status;
#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
        __u32 status_flags;
        __u32 user_count;
        __u32 __out_reserved[13];
};

#define FS_IOC_SET_ENCRYPTION_POLICY            _IOR('f', 19, struct fscrypt_policy_v1)
#define FS_IOC_GET_ENCRYPTION_PWSALT            _IOW('f', 20, __u8[16])
#define FS_IOC_GET_ENCRYPTION_POLICY            _IOW('f', 21, struct fscrypt_policy_v1)
#define FS_IOC_GET_ENCRYPTION_POLICY_EX         _IOWR('f', 22, __u8[9]) /* size + version */
#define FS_IOC_ADD_ENCRYPTION_KEY               _IOWR('f', 23, struct fscrypt_add_key_arg)
#define FS_IOC_REMOVE_ENCRYPTION_KEY            _IOWR('f', 24, struct fscrypt_remove_key_arg)
#define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS  _IOWR('f', 25, struct fscrypt_remove_key_arg)
#define FS_IOC_GET_ENCRYPTION_KEY_STATUS        _IOWR('f', 26, struct fscrypt_get_key_status_arg)
#define FS_IOC_GET_ENCRYPTION_NONCE             _IOR('f', 27, __u8[16])

/**********************************************************************/

/* old names; don't add anything new here! */
#ifndef __KERNEL__
#define fscrypt_policy                  fscrypt_policy_v1
#define FS_KEY_DESCRIPTOR_SIZE          FSCRYPT_KEY_DESCRIPTOR_SIZE
#define FS_POLICY_FLAGS_PAD_4           FSCRYPT_POLICY_FLAGS_PAD_4
#define FS_POLICY_FLAGS_PAD_8           FSCRYPT_POLICY_FLAGS_PAD_8
#define FS_POLICY_FLAGS_PAD_16          FSCRYPT_POLICY_FLAGS_PAD_16
#define FS_POLICY_FLAGS_PAD_32          FSCRYPT_POLICY_FLAGS_PAD_32
#define FS_POLICY_FLAGS_PAD_MASK        FSCRYPT_POLICY_FLAGS_PAD_MASK
#define FS_POLICY_FLAG_DIRECT_KEY       FSCRYPT_POLICY_FLAG_DIRECT_KEY
#define FS_POLICY_FLAGS_VALID           0x07    /* contains old flags only */
#define FS_ENCRYPTION_MODE_INVALID      0       /* never used */
#define FS_ENCRYPTION_MODE_AES_256_XTS  FSCRYPT_MODE_AES_256_XTS
#define FS_ENCRYPTION_MODE_AES_256_GCM  2       /* never used */
#define FS_ENCRYPTION_MODE_AES_256_CBC  3       /* never used */
#define FS_ENCRYPTION_MODE_AES_256_CTS  FSCRYPT_MODE_AES_256_CTS
#define FS_ENCRYPTION_MODE_AES_128_CBC  FSCRYPT_MODE_AES_128_CBC
#define FS_ENCRYPTION_MODE_AES_128_CTS  FSCRYPT_MODE_AES_128_CTS
#define FS_ENCRYPTION_MODE_ADIANTUM     FSCRYPT_MODE_ADIANTUM
#define FS_KEY_DESC_PREFIX              FSCRYPT_KEY_DESC_PREFIX
#define FS_KEY_DESC_PREFIX_SIZE         FSCRYPT_KEY_DESC_PREFIX_SIZE
#define FS_MAX_KEY_SIZE                 FSCRYPT_MAX_KEY_SIZE
#endif /* !__KERNEL__ */

#endif /* _UAPI_LINUX_FSCRYPT_H */