cprotect.h   [plain text]

/*
 * Copyright (c) 2009-2014 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */

#ifndef _SYS_CPROTECT_H_
#define	_SYS_CPROTECT_H_

#if KERNEL_PRIVATE

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/buf.h>
#include <sys/kdebug.h>
#include <crypto/aes.h>
#include <stdbool.h>

__BEGIN_DECLS

#define CP_CODE(code) FSDBG_CODE(DBG_CONTENT_PROT, code)
/* 
 * Class DBG_FSYSTEM == 0x03
 * Subclass DBG_CONTENT_PROT == 0xCF
 * These debug codes are of the form 0x03CFzzzz
 */

enum {
	CPDBG_OFFSET_IO = CP_CODE(0),	/* 0x03CF0000 */
};

/* normally the debug events are no-ops */
#define CP_DEBUG(x,a,b,c,d,e) do {} while (0);

/* dev kernels only! */
#if !SECURE_KERNEL 

/* KDEBUG events used by content protection subsystem */
#if 0
#undef CP_DEBUG
#define CP_DEBUG KERNEL_DEBUG_CONSTANT
#endif

#endif

#define CP_MAX_WRAPPEDKEYSIZE     128	/* The size of the largest allowed key */

/* lock events from AppleKeyStore */
#define CP_LOCKED_STATE           0 	/* Device is locked */
#define CP_UNLOCKED_STATE         1 	/* Device is unlocked */

#define CP_MAX_STATE			  1 	/* uint8_t ; maximum # of states is 255 */

typedef struct cprotect *cprotect_t;
typedef struct cp_wrap_func *cp_wrap_func_t;
typedef struct cpx *cpx_t;

/* Structures passed between HFS and AKS kext */
typedef struct {
	void     *key;
	unsigned key_len;
	void     *iv_key;
	unsigned iv_key_len;
	uint32_t flags;
} cp_raw_key_s;

typedef cp_raw_key_s* cp_raw_key_t;

typedef struct {
	void     *key;
	unsigned key_len;
	uint32_t dp_class;
} cp_wrapped_key_s;

typedef cp_wrapped_key_s* cp_wrapped_key_t;

typedef uint16_t cp_key_revision_t;

typedef struct {
	ino64_t				inode;
	uint32_t			volume;
	pid_t				pid;
	uid_t				uid;
	cp_key_revision_t	key_revision;
} cp_cred_s;

typedef cp_cred_s* cp_cred_t;

/* The wrappers are invoked on the AKS kext */
typedef int unwrapper_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_raw_key_t key_out);
typedef int rewrapper_t(cp_cred_t access, uint32_t dp_class, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);
typedef int new_key_t(cp_cred_t access, uint32_t dp_class, cp_raw_key_t key_out, cp_wrapped_key_t wrapped_key_out);
typedef int invalidater_t(cp_cred_t access); /* invalidates keys */
typedef int backup_key_t(cp_cred_t access, const cp_wrapped_key_t wrapped_key_in, cp_wrapped_key_t wrapped_key_out);


/* 
 * Flags for Interaction between AKS / Kernel 
 * These are twiddled via the input/output structs in the above
 * wrapper/unwrapper functions.
 */
#define CP_RAW_KEY_WRAPPEDKEY	0x00000001

/*
 * Function prototypes for kexts to interface with our internal cprotect
 * fields;  cpx provides opacity and allows us to modify behavior internally
 * without requiring kext changes.
 */
cpx_t cpx_alloc(size_t key_size);
void cpx_free(cpx_t);
__attribute__((const)) size_t cpx_size(size_t key_size);
__attribute__((pure)) bool cpx_is_sep_wrapped_key(const struct cpx *);
void cpx_set_is_sep_wrapped_key(struct cpx *, bool);
__attribute__((pure)) bool cpx_use_offset_for_iv(const struct cpx *);
void cpx_set_use_offset_for_iv(struct cpx *, bool);
__attribute__((pure)) uint16_t cpx_key_len(const struct cpx *);
void cpx_set_key_len(struct cpx *, uint16_t key_len);
__attribute__((pure)) void *cpx_key(const struct cpx *);
aes_encrypt_ctx *cpx_iv_aes_ctx(struct cpx *);

/* Structure to store pointers for AKS functions */
struct cp_wrap_func {
	new_key_t       *new_key;
	unwrapper_t     *unwrapper;
	rewrapper_t     *rewrapper;
	invalidater_t	*invalidater;
	backup_key_t	*backup_key;
};

int cp_key_store_action(int);
int cp_register_wraps(cp_wrap_func_t);

#ifdef BSD_KERNEL_PRIVATE

/*
 * Declarations that are not exported from the kernel but are used by
 * VFS to call into the implementation (i.e. HFS) should be here.
 */

/* Content Protection VNOP Operation flags */
#define CP_READ_ACCESS            0x1
#define CP_WRITE_ACCESS           0x2

/*
 * Functions to check the status of a CP and to query
 * the containing filesystem to see if it is supported.
 */
struct vnode;
struct hfsmount;

int cp_vnode_getclass(struct vnode *, int *);
int cp_vnode_setclass(struct vnode *, uint32_t);
int cp_vnode_transcode(struct vnode * vp, void *key, unsigned *len);

int cp_handle_vnop(struct vnode *, int, int);
int cp_handle_open(struct vnode *vp, int mode);
int cp_get_root_major_vers (struct vnode *vp, uint32_t *level);
int cp_get_default_level (struct vnode *vp, uint32_t *level);
int cp_is_valid_class (int isdir, int32_t protectionclass);
int cp_set_trimmed(struct hfsmount *hfsmp);
int cp_set_rewrapped(struct hfsmount *hfsmp);
int cp_flop_generation (struct hfsmount *hfsmp);

#endif /* BSD_KERNEL_PRIVATE */

__END_DECLS

#endif /* KERNEL_PRIVATE */
#endif /* !_SYS_CPROTECT_H_ */