guarded.h   [plain text]

/*
 * Copyright (c) 2018 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
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 */

#ifndef _SYS_GUARDED_H_
#define _SYS_GUARDED_H_

#include <sys/types.h>
#include <sys/cdefs.h>

#include <sys/_types/_iovec_t.h>
#ifdef PRIVATE

__BEGIN_DECLS

#if !defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE)

#ifndef _GUARDID_T
#define _GUARDID_T
typedef __uint64_t guardid_t;
#endif /* _GUARDID_T */

#if !defined(KERNEL)
extern int guarded_open_np(const char *path,
    const guardid_t *guard, u_int guardflags, int flags, ...);
extern int guarded_open_dprotected_np(const char *path,
    const guardid_t *guard, u_int guardflags, int flags,
    int dpclass, int dpflags, ...);
extern int guarded_kqueue_np(const guardid_t *guard, u_int guardflags);
extern int guarded_close_np(int fd, const guardid_t *guard);
extern int change_fdguard_np(int fd, const guardid_t *guard, u_int guardflags,
    const guardid_t *nguard, u_int nguardflags, int *fdflagsp);
extern ssize_t guarded_write_np(int fd, const guardid_t *guard, const void *buf, size_t nbyte);
extern ssize_t guarded_pwrite_np(int fd, const guardid_t *guard, const void *buf, size_t nbyte, off_t offset);
extern ssize_t guarded_writev_np(int fd, const guardid_t *guard, const struct iovec *iovp, int iovcnt);
#endif /* KERNEL */

#ifndef GUARD_TYPE_FD
/* temporary source compat: use <kern/exc_guard.h> instead */
#define GUARD_TYPE_FD           0x2
#endif

/*
 * File descriptor guard flavors.
 */

/*
 * Forbid close(2), and the implicit close() that a dup2(2) may do.
 * Forces close-on-fork to be set immutably too.
 */
#define GUARD_CLOSE             (1u << 0)

/*
 * Forbid dup(2), dup2(2), and fcntl(2) subcodes F_DUPFD, F_DUPFD_CLOEXEC
 * on a guarded fd. Also forbids open's of a guarded fd via /dev/fd/
 * (an implicit dup.)
 */
#define GUARD_DUP               (1u << 1)

/*
 * Forbid sending a guarded fd via a socket
 */
#define GUARD_SOCKET_IPC        (1u << 2)

/*
 * Forbid creating a fileport from a guarded fd
 */
#define GUARD_FILEPORT          (1u << 3)

/*
 * Forbid writes on a guarded fd
 */
#define GUARD_WRITE             (1u << 4)

/*
 * Violating a guard results in an error (EPERM), and potentially
 * an exception with one or more of the following bits set.
 */
enum guard_fd_exception_codes {
	kGUARD_EXC_CLOSE        = 1u << 0,      /* close of a guarded fd */
	kGUARD_EXC_DUP          = 1u << 1,      /* dup of a guarded fd */
	kGUARD_EXC_NOCLOEXEC    = 1u << 2,      /* clear close-on-exec */
	kGUARD_EXC_SOCKET_IPC   = 1u << 3,      /* sendmsg of a guarded fd */
	kGUARD_EXC_FILEPORT     = 1u << 4,      /* fileport_makeport .. */
	kGUARD_EXC_MISMATCH     = 1u << 5,      /* wrong guard for guarded fd */
	kGUARD_EXC_WRITE        = 1u << 6       /* write on a guarded fd */
};

/*
 * Experimental guarded vnode support
 */
#define VNG_RENAME_TO           (1u << 0)
#define VNG_RENAME_FROM         (1u << 1)
#define VNG_UNLINK              (1u << 2)
#define VNG_WRITE_OTHER         (1u << 3)
#define VNG_TRUNC_OTHER         (1u << 4)
#define VNG_LINK                (1u << 5)
#define VNG_EXCHDATA            (1u << 6)

#define VNG_ALL \
	(VNG_RENAME_TO | VNG_RENAME_FROM | VNG_UNLINK | VNG_LINK | \
	 VNG_WRITE_OTHER | VNG_TRUNC_OTHER | VNG_EXCHDATA)

struct vnguard_set {
	int vns_fd;
	unsigned vns_attrs;
	guardid_t vns_guard;
};

struct vnguard_getattr {
	int vga_fd;             /* in */
	unsigned vga_attrs;     /* out */
	guardid_t vga_guard;    /* in */
};

#define VNG_SYSC_PING           0
#define VNG_SYSC_SET_GUARD      1
#define VNG_SYSC_GET_ATTR       2

#define VNG_POLICY_NAME         "vnguard"

/*
 * Violating a guard may result in an error (EPERM), and potentially
 * an exception with one or more of the following bits set.
 */
enum guard_vn_exception_codes {
	kGUARD_EXC_RENAME_TO    = VNG_RENAME_TO,
	kGUARD_EXC_RENAME_FROM  = VNG_RENAME_FROM,
	kGUARD_EXC_UNLINK       = VNG_UNLINK,
	kGUARD_EXC_WRITE_OTHER  = VNG_WRITE_OTHER,
	kGUARD_EXC_TRUNC_OTHER  = VNG_TRUNC_OTHER,
	kGUARD_EXC_LINK         = VNG_LINK,
	kGUARD_EXC_EXCHDATA     = VNG_EXCHDATA,
};

/* Guard violation behaviors: not all combinations make sense */

#define kVNG_POLICY_LOGMSG      (1u << 0)
#define kVNG_POLICY_EPERM       (1u << 1)
#define kVNG_POLICY_EXC         (1u << 2)
#define kVNG_POLICY_EXC_CORPSE  (1u << 3)
#define kVNG_POLICY_SIGKILL     (1u << 4)
#define kVNG_POLICY_UPRINTMSG   (1u << 5)

#if defined(KERNEL)
extern int vnguard_exceptions_active(void);
extern void vnguard_policy_init(void);
#endif /* KERNEL */

#endif /* (!_POSIX_C_SOURCE || _DARWIN_C_SOURCE) */

__END_DECLS

#endif /* PRIVATE */

#endif /* !_SYS_GUARDED_H_ */