bsd/sys/cprotect.h

   1 /*
   2  * Copyright (c) 2009 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 #ifndef _SYS_CPROTECT_H_
  30 #define _SYS_CPROTECT_H_
  31
  32 #ifdef __cplusplus
  33 extern "C" {
  34 #endif
  35
  36 #if KERNEL_PRIVATE
  37
  38 #include <sys/cdefs.h>
  39 #include <sys/content_protection.h>
  40 #include <sys/kernel_types.h>
  41 #include <crypto/aes.h>
  42
  43 #define CP_IV_KEYSIZE 20                        /* 16x8 = 128, but SHA1 pushes 20 bytes so keep space for that */
  44 #define CP_MAX_KEYSIZE 32               /* 8x4 = 32, 32x8 = 256 */
  45 #define CP_MAX_WRAPPEDKEYSIZE  128      /* The size of the largest allowed key */
  46 #define CP_INITIAL_WRAPPEDKEYSIZE 40
  47 #define CP_V2_WRAPPEDKEYSIZE 40         /* Size of the wrapped key in a v2 EA */
  48
  49 /* lock events from AppleKeyStore */
  50 #define CP_LOCKED_STATE 0               /* Device is locked */
  51 #define CP_UNLOCKED_STATE 1             /* Device is unlocked */
  52
  53 #define CP_LOCKED_KEYCHAIN 0
  54 #define CP_UNLOCKED_KEYCHAIN 1
  55
  56 /* For struct cprotect: cp_flags */
  57 #define CP_NEEDS_KEYS           0x1             /* File needs persistent keys */
  58 #define CP_KEY_FLUSHED          0x2             /* File's unwrapped key has been purged from memory */
  59 #define CP_NO_XATTR                     0x4             /* Key info has not been saved as EA to the FS */
  60 #define CP_OFF_IV_ENABLED       0x8             /* Only go down relative IV route if this flag is set */
  61
  62 #define CP_RELOCATION_INFLIGHT 0x10     /* File with offset IVs is in the process of being relocated. */
  63
  64 /* Content Protection VNOP Operation flags */
  65 #define CP_READ_ACCESS  0x1
  66 #define CP_WRITE_ACCESS 0x2
  67
  68 #define CONTENT_PROTECTION_XATTR_NAME   "com.apple.system.cprotect"
  69 #define CP_NEW_MAJOR_VERS 4
  70 #define CP_PREV_MAJOR_VERS 2
  71 #define CP_MINOR_VERS 0
  72
  73 typedef struct cprotect *cprotect_t;
  74 typedef struct cp_wrap_func *cp_wrap_func_t;
  75 typedef struct cp_global_state *cp_global_state_t;
  76 typedef struct cp_xattr *cp_xattr_t;
  77
  78 typedef struct cnode * cnode_ptr_t;
  79 //forward declare the struct.
  80 struct hfsmount;
  81
  82 /* The wrappers are invoked by the AKS kext */
  83 typedef int wrapper_t(uint32_t properties, uint64_t file_id, void *key_bytes, size_t key_length, void *wrapped_data, size_t *wrapped_length);
  84 typedef int unwrapper_t(uint32_t properties, void *wrapped_data, size_t wrapped_data_length, void *key_bytes, size_t *key_length);
  85
  86 /*
  87  * Runtime-only structure containing the content protection status
  88  * for the given file.  This is contained within the cnode
  89  * This is passed down to IOStorageFamily via the bufattr struct
  90  *
  91  ******************************************************
  92  * Some Key calculation information for offset based IV
  93  ******************************************************
  94  * Kf  = original 256 bit per file key
  95  * Kiv = SHA1(Kf), use full Kf, but truncate Kiv to 128 bits
  96  * Kiv can be cached in the cprotect, so it only has to be calculated once for the file init
  97  *
  98  * IVb = Encrypt(Kiv, offset)
  99  *
 100  */
 101 struct cprotect {
 102         uint32_t        cp_flags;
 103         uint32_t        cp_pclass;
 104         aes_encrypt_ctx cp_cache_iv_ctx;
 105         uint32_t        cp_cache_key_len;
 106         uint8_t         cp_cache_key[CP_MAX_KEYSIZE];
 107         uint32_t        cp_persistent_key_len;
 108         uint8_t         cp_persistent_key[];
 109 };
 110
 111 struct cp_wrap_func {
 112         wrapper_t       *wrapper;
 113         unwrapper_t     *unwrapper;
 114 };
 115
 116 struct cp_global_state {
 117         uint8_t wrap_functions_set;
 118         uint8_t lock_state;
 119         u_int16_t reserved;
 120 };
 121
 122 /*
 123  * On-disk structure written as the per-file EA payload
 124  * All on-disk multi-byte fields for the CP XATTR must be stored
 125  * little-endian on-disk.  This means they must be endian swapped to
 126  * L.E on getxattr() and converted to LE on setxattr().
 127  */
 128 struct cp_xattr_v2 {
 129         u_int16_t xattr_major_version;
 130         u_int16_t xattr_minor_version;
 131         u_int32_t flags;
 132         u_int32_t persistent_class;
 133         u_int32_t key_size;
 134         uint8_t   persistent_key[CP_V2_WRAPPEDKEYSIZE];
 135 };
 136
 137 struct cp_xattr_v4 {
 138         u_int16_t xattr_major_version;
 139         u_int16_t xattr_minor_version;
 140         u_int32_t flags;
 141         u_int32_t persistent_class;
 142         u_int32_t key_size;
 143         u_int32_t reserved1;
 144         u_int32_t reserved2;
 145         u_int32_t reserved3;
 146         u_int32_t reserved4;
 147         u_int32_t reserved5;
 148         uint8_t   persistent_key[CP_MAX_WRAPPEDKEYSIZE];
 149 };
 150
 151 /* Same is true for the root EA, all fields must be written little endian. */
 152 struct cp_root_xattr {
 153         u_int16_t major_version;
 154         u_int16_t minor_version;
 155         u_int64_t flags;
 156         u_int32_t reserved1;
 157         u_int32_t reserved2;
 158         u_int32_t reserved3;
 159         u_int32_t reserved4;
 160 };
 161
 162
 163 /*
 164  * Functions to check the status of a CP and to query
 165  * the containing filesystem to see if it is supported.
 166  */
 167 int cp_vnode_getclass(vnode_t, int *);
 168 int cp_vnode_setclass(vnode_t, uint32_t);
 169 int cp_vnode_transcode(vnode_t);
 170
 171 int cp_key_store_action(int);
 172 int cp_register_wraps(cp_wrap_func_t);
 173
 174 int cp_entry_init(cnode_ptr_t, struct mount *);
 175 int cp_entry_create_keys(struct cprotect **entry_ptr, struct cnode *dcp, struct hfsmount *hfsmp,
 176                 uint32_t input_class, uint32_t fileid, mode_t cmode);
 177 int cp_entry_gentempkeys(struct cprotect **entry_ptr, struct hfsmount *hfsmp);
 178 void cp_entry_destroy(struct cprotect **entry_ptr);
 179
 180 cnode_ptr_t cp_get_protected_cnode(vnode_t);
 181 int cp_handle_vnop(vnode_t, int, int);
 182 int cp_fs_protected (mount_t);
 183 int cp_getrootxattr (struct hfsmount *hfsmp, struct cp_root_xattr *outxattr);
 184 int cp_setrootxattr (struct hfsmount *hfsmp, struct cp_root_xattr *newxattr);
 185 int cp_setxattr(struct cnode *cp, struct cprotect *entry, struct hfsmount *hfsmp, uint32_t fileid, int options);
 186 int cp_update_mkb (struct cprotect *entry, uint32_t fileid);
 187 int cp_handle_relocate (cnode_ptr_t cp, struct hfsmount *hfsmp);
 188 int cp_handle_open(struct vnode *vp, int mode);
 189 int cp_get_root_major_vers (struct vnode *vp, uint32_t *level);
 190
 191 #if 0
 192 int cp_isdevice_locked (void);
 193 #endif
 194
 195 #endif  /* KERNEL_PRIVATE */
 196
 197 #ifdef __cplusplus
 198 };
 199 #endif
 200
 201 #endif /* !_SYS_CPROTECT_H_ */