LXR linux/include/uapi/linux/fscrypt.h

   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
  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_ADIANTUM                   9
  30/* If adding a mode number > 9, update FSCRYPT_MODE_MAX in fscrypt_private.h */
  31
  32/*
  33 * Legacy policy version; ad-hoc KDF and no key verification.
  34 * For new encrypted directories, use fscrypt_policy_v2 instead.
  35 *
  36 * Careful: the .version field for this is actually 0, not 1.
  37 */
  38#define FSCRYPT_POLICY_V1               0
  39#define FSCRYPT_KEY_DESCRIPTOR_SIZE     8
  40struct fscrypt_policy_v1 {
  41        __u8 version;
  42        __u8 contents_encryption_mode;
  43        __u8 filenames_encryption_mode;
  44        __u8 flags;
  45        __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
  46};
  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
  55struct 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
  66struct 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 */
  76struct 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 */
 102struct 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/*
 113 * Payload of Linux keyring key of type "fscrypt-provisioning", referenced by
 114 * fscrypt_add_key_arg::key_id as an alternative to fscrypt_add_key_arg::raw.
 115 */
 116struct fscrypt_provisioning_key_payload {
 117        __u32 type;
 118        __u32 __reserved;
 119        __u8 raw[];
 120};
 121
 122/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */
 123struct fscrypt_add_key_arg {
 124        struct fscrypt_key_specifier key_spec;
 125        __u32 raw_size;
 126        __u32 key_id;
 127        __u32 __reserved[8];
 128        __u8 raw[];
 129};
 130
 131/* Struct passed to FS_IOC_REMOVE_ENCRYPTION_KEY */
 132struct fscrypt_remove_key_arg {
 133        struct fscrypt_key_specifier key_spec;
 134#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_FILES_BUSY      0x00000001
 135#define FSCRYPT_KEY_REMOVAL_STATUS_FLAG_OTHER_USERS     0x00000002
 136        __u32 removal_status_flags;     /* output */
 137        __u32 __reserved[5];
 138};
 139
 140/* Struct passed to FS_IOC_GET_ENCRYPTION_KEY_STATUS */
 141struct fscrypt_get_key_status_arg {
 142        /* input */
 143        struct fscrypt_key_specifier key_spec;
 144        __u32 __reserved[6];
 145
 146        /* output */
 147#define FSCRYPT_KEY_STATUS_ABSENT               1
 148#define FSCRYPT_KEY_STATUS_PRESENT              2
 149#define FSCRYPT_KEY_STATUS_INCOMPLETELY_REMOVED 3
 150        __u32 status;
 151#define FSCRYPT_KEY_STATUS_FLAG_ADDED_BY_SELF   0x00000001
 152        __u32 status_flags;
 153        __u32 user_count;
 154        __u32 __out_reserved[13];
 155};
 156
 157#define FS_IOC_SET_ENCRYPTION_POLICY            _IOR('f', 19, struct fscrypt_policy_v1)
 158#define FS_IOC_GET_ENCRYPTION_PWSALT            _IOW('f', 20, __u8[16])
 159#define FS_IOC_GET_ENCRYPTION_POLICY            _IOW('f', 21, struct fscrypt_policy_v1)
 160#define FS_IOC_GET_ENCRYPTION_POLICY_EX         _IOWR('f', 22, __u8[9]) /* size + version */
 161#define FS_IOC_ADD_ENCRYPTION_KEY               _IOWR('f', 23, struct fscrypt_add_key_arg)
 162#define FS_IOC_REMOVE_ENCRYPTION_KEY            _IOWR('f', 24, struct fscrypt_remove_key_arg)
 163#define FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS  _IOWR('f', 25, struct fscrypt_remove_key_arg)
 164#define FS_IOC_GET_ENCRYPTION_KEY_STATUS        _IOWR('f', 26, struct fscrypt_get_key_status_arg)
 165#define FS_IOC_GET_ENCRYPTION_NONCE             _IOR('f', 27, __u8[16])
 166
 167/**********************************************************************/
 168
 169/* old names; don't add anything new here! */
 170#ifndef __KERNEL__
 171#define fscrypt_policy                  fscrypt_policy_v1
 172#define FS_KEY_DESCRIPTOR_SIZE          FSCRYPT_KEY_DESCRIPTOR_SIZE
 173#define FS_POLICY_FLAGS_PAD_4           FSCRYPT_POLICY_FLAGS_PAD_4
 174#define FS_POLICY_FLAGS_PAD_8           FSCRYPT_POLICY_FLAGS_PAD_8
 175#define FS_POLICY_FLAGS_PAD_16          FSCRYPT_POLICY_FLAGS_PAD_16
 176#define FS_POLICY_FLAGS_PAD_32          FSCRYPT_POLICY_FLAGS_PAD_32
 177#define FS_POLICY_FLAGS_PAD_MASK        FSCRYPT_POLICY_FLAGS_PAD_MASK
 178#define FS_POLICY_FLAG_DIRECT_KEY       FSCRYPT_POLICY_FLAG_DIRECT_KEY
 179#define FS_POLICY_FLAGS_VALID           0x07    /* contains old flags only */
 180#define FS_ENCRYPTION_MODE_INVALID      0       /* never used */
 181#define FS_ENCRYPTION_MODE_AES_256_XTS  FSCRYPT_MODE_AES_256_XTS
 182#define FS_ENCRYPTION_MODE_AES_256_GCM  2       /* never used */
 183#define FS_ENCRYPTION_MODE_AES_256_CBC  3       /* never used */
 184#define FS_ENCRYPTION_MODE_AES_256_CTS  FSCRYPT_MODE_AES_256_CTS
 185#define FS_ENCRYPTION_MODE_AES_128_CBC  FSCRYPT_MODE_AES_128_CBC
 186#define FS_ENCRYPTION_MODE_AES_128_CTS  FSCRYPT_MODE_AES_128_CTS
 187#define FS_ENCRYPTION_MODE_SPECK128_256_XTS     7       /* removed */
 188#define FS_ENCRYPTION_MODE_SPECK128_256_CTS     8       /* removed */
 189#define FS_ENCRYPTION_MODE_ADIANTUM     FSCRYPT_MODE_ADIANTUM
 190#define FS_KEY_DESC_PREFIX              FSCRYPT_KEY_DESC_PREFIX
 191#define FS_KEY_DESC_PREFIX_SIZE         FSCRYPT_KEY_DESC_PREFIX_SIZE
 192#define FS_MAX_KEY_SIZE                 FSCRYPT_MAX_KEY_SIZE
 193#endif /* !__KERNEL__ */
 194
 195#endif /* _UAPI_LINUX_FSCRYPT_H */
 196