osfmk/ipc/ipc_object.h

   1 /*
   2  * Copyright (c) 2000-2007 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  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  * NOTICE: This file was modified by McAfee Research in 2004 to introduce
  58  * support for mandatory and extensible security protections.  This notice
  59  * is included in support of clause 2.2 (b) of the Apple Public License,
  60  * Version 2.0.
  61  */
  62 /*
  63  */
  64 /*
  65  *      File:   ipc/ipc_object.h
  66  *      Author: Rich Draves
  67  *      Date:   1989
  68  *
  69  *      Definitions for IPC objects, for which tasks have capabilities.
  70  */
  71
  72 #ifndef _IPC_IPC_OBJECT_H_
  73 #define _IPC_IPC_OBJECT_H_
  74
  75 #include <mach/kern_return.h>
  76 #include <mach/message.h>
  77 #include <kern/locks.h>
  78 #include <kern/macro_help.h>
  79 #include <kern/assert.h>
  80 #include <kern/zalloc.h>
  81 #include <ipc/ipc_types.h>
  82 #include <libkern/OSAtomic.h>
  83
  84 typedef natural_t ipc_object_refs_t;    /* for ipc/ipc_object.h         */
  85 typedef natural_t ipc_object_bits_t;
  86 typedef natural_t ipc_object_type_t;
  87
  88 /*
  89  * The ipc_object is used to both tag and reference count these two data
  90  * structures, and (Noto Bene!) pointers to either of these or the
  91  * ipc_object at the head of these are freely cast back and forth; hence
  92  * the ipc_object MUST BE FIRST in the ipc_common_data.
  93  *
  94  * If the RPC implementation enabled user-mode code to use kernel-level
  95  * data structures (as ours used to), this peculiar structuring would
  96  * avoid having anything in user code depend on the kernel configuration
  97  * (with which lock size varies).
  98  */
  99 struct ipc_object {
 100         ipc_object_bits_t io_bits;
 101         ipc_object_refs_t io_references;
 102         lck_spin_t        io_lock_data;
 103 } __attribute__((aligned(8)));
 104
 105 /*
 106  * If another object type needs to participate in io_kotype()-based
 107  * dispatching, it must include a stub structure as the first
 108  * element
 109  */
 110 struct ipc_object_header {
 111         ipc_object_bits_t io_bits;
 112 #ifdef __LP64__
 113         natural_t         io_padding; /* pad to natural boundary */
 114 #endif
 115 };
 116
 117 /*
 118  * Legacy defines.  Should use IPC_OBJECT_NULL, etc...
 119  */
 120 #define IO_NULL                 ((ipc_object_t) 0)
 121 #define IO_DEAD                 ((ipc_object_t) ~0UL)
 122 #define IO_VALID(io)            (((io) != IO_NULL) && ((io) != IO_DEAD))
 123
 124 /*
 125  *      IPC steals the high-order bits from the kotype to use
 126  *      for its own purposes.  This allows IPC to record facts
 127  *      about ports that aren't otherwise obvious from the
 128  *      existing port fields.  In particular, IPC can optionally
 129  *      mark a port for no more senders detection.  Any change
 130  *      to IO_BITS_PORT_INFO must be coordinated with bitfield
 131  *      definitions in ipc_port.h.
 132  */
 133 #define IO_BITS_PORT_INFO       0x0000f000      /* stupid port tricks */
 134 #define IO_BITS_KOTYPE          0x000003ff      /* used by the object */
 135 #define IO_BITS_KOBJECT         0x00000800      /* port belongs to a kobject */
 136 #define IO_BITS_KOLABEL         0x00000400      /* The kobject has a label */
 137 #define IO_BITS_OTYPE           0x7fff0000      /* determines a zone */
 138 #define IO_BITS_ACTIVE          0x80000000      /* is object alive? */
 139
 140 #define io_active(io)           (((io)->io_bits & IO_BITS_ACTIVE) != 0)
 141
 142 #define io_otype(io)            (((io)->io_bits & IO_BITS_OTYPE) >> 16)
 143 #define io_kotype(io)           ((io)->io_bits & IO_BITS_KOTYPE)
 144 #define io_is_kobject(io)       (((io)->io_bits & IO_BITS_KOBJECT) != IKOT_NONE)
 145 #define io_is_kolabeled(io)     (((io)->io_bits & IO_BITS_KOLABEL) != 0)
 146 #define io_makebits(active, otype, kotype)      \
 147         (((active) ? IO_BITS_ACTIVE : 0) | ((otype) << 16) | (kotype))
 148
 149 /*
 150  * Object types: ports, port sets, kernel-loaded ports
 151  */
 152 #define IOT_PORT                0
 153 #define IOT_PORT_SET            1
 154 #define IOT_NUMBER              2               /* number of types used */
 155
 156 extern zone_t ipc_object_zones[IOT_NUMBER];
 157 extern lck_grp_t        ipc_lck_grp;
 158
 159 #define io_alloc(otype)         \
 160                 ((ipc_object_t) zalloc(ipc_object_zones[(otype)]))
 161
 162 extern void     io_free(
 163         unsigned int    otype,
 164         ipc_object_t    object);
 165
 166 /*
 167  * Here we depend on the ipc_object being first within the kernel struct
 168  * (ipc_port and ipc_pset).
 169  */
 170 #define io_lock_init(io) \
 171         lck_spin_init(&(io)->io_lock_data, &ipc_lck_grp, &ipc_lck_attr)
 172 #define io_lock_destroy(io) \
 173         lck_spin_destroy(&(io)->io_lock_data, &ipc_lck_grp)
 174 #define io_lock_held(io) \
 175         LCK_SPIN_ASSERT(&(io)->io_lock_data, LCK_ASSERT_OWNED)
 176 #define io_lock_held_kdp(io) \
 177         kdp_lck_spin_is_acquired(&(io)->io_lock_data)
 178 #define io_unlock(io) \
 179         lck_spin_unlock(&(io)->io_lock_data)
 180
 181 extern void io_lock(
 182         ipc_object_t io);
 183 extern boolean_t io_lock_try(
 184         ipc_object_t io);
 185
 186 #define _VOLATILE_ volatile
 187
 188 /* Sanity check the ref count.  If it is 0, we may be doubly zfreeing.
 189  * If it is larger than max int, it has been corrupted or leaked,
 190  * probably by being modified into an address (this is architecture
 191  * dependent, but it's safe to assume there cannot really be max int
 192  * references unless some code is leaking the io_reference without leaking
 193  * object). Saturate the io_reference on release kernel if it reaches
 194  * max int to avoid use after free.
 195  *
 196  * NOTE: The 0 test alone will not catch double zfreeing of ipc_port
 197  * structs, because the io_references field is the first word of the struct,
 198  * and zfree modifies that to point to the next free zone element.
 199  */
 200 #define IO_MAX_REFERENCES                                               \
 201         (unsigned)(~0U ^ (1U << (sizeof(int)*BYTE_SIZE - 1)))
 202
 203 static inline void
 204 io_reference(ipc_object_t io)
 205 {
 206         ipc_object_refs_t new_io_references;
 207         ipc_object_refs_t old_io_references;
 208
 209         if ((io)->io_references == 0 ||
 210             (io)->io_references >= IO_MAX_REFERENCES) {
 211                 panic("%s: reference count %u is invalid\n", __func__, (io)->io_references);
 212         }
 213
 214         do {
 215                 old_io_references = (io)->io_references;
 216                 new_io_references = old_io_references + 1;
 217                 if (old_io_references == IO_MAX_REFERENCES) {
 218                         break;
 219                 }
 220         } while (OSCompareAndSwap(old_io_references, new_io_references,
 221             &((io)->io_references)) == FALSE);
 222 }
 223
 224
 225 static inline void
 226 io_release(ipc_object_t io)
 227 {
 228         ipc_object_refs_t new_io_references;
 229         ipc_object_refs_t old_io_references;
 230
 231         if ((io)->io_references == 0 ||
 232             (io)->io_references >= IO_MAX_REFERENCES) {
 233                 panic("%s: reference count %u is invalid\n", __func__, (io)->io_references);
 234         }
 235
 236         do {
 237                 old_io_references = (io)->io_references;
 238                 new_io_references = old_io_references - 1;
 239                 if (old_io_references == IO_MAX_REFERENCES) {
 240                         break;
 241                 }
 242         } while (OSCompareAndSwap(old_io_references, new_io_references,
 243             &((io)->io_references)) == FALSE);
 244
 245         /* If we just removed the last reference count */
 246         if (1 == old_io_references) {
 247                 /* Free the object */
 248                 io_free(io_otype((io)), (io));
 249         }
 250 }
 251
 252 /*
 253  * Retrieve a label for use in a kernel call that takes a security
 254  * label as a parameter. If necessary, io_getlabel acquires internal
 255  * (not io_lock) locks, and io_unlocklabel releases them.
 256  */
 257
 258 struct label;
 259 extern struct label *io_getlabel(ipc_object_t obj);
 260 #define io_unlocklabel(obj)
 261
 262 /*
 263  * Exported interfaces
 264  */
 265
 266 /* Take a reference to an object */
 267 extern void ipc_object_reference(
 268         ipc_object_t    object);
 269
 270 /* Release a reference to an object */
 271 extern void ipc_object_release(
 272         ipc_object_t    object);
 273
 274 /* Look up an object in a space */
 275 extern kern_return_t ipc_object_translate(
 276         ipc_space_t             space,
 277         mach_port_name_t        name,
 278         mach_port_right_t       right,
 279         ipc_object_t            *objectp);
 280
 281 /* Look up two objects in a space, locking them in the order described */
 282 extern kern_return_t ipc_object_translate_two(
 283         ipc_space_t             space,
 284         mach_port_name_t        name1,
 285         mach_port_right_t       right1,
 286         ipc_object_t            *objectp1,
 287         mach_port_name_t        name2,
 288         mach_port_right_t       right2,
 289         ipc_object_t            *objectp2);
 290
 291 /* Validate an object as belonging to the correct zone */
 292 extern void ipc_object_validate(
 293         ipc_object_t object);
 294
 295 /* Allocate a dead-name entry */
 296 extern kern_return_t
 297 ipc_object_alloc_dead(
 298         ipc_space_t             space,
 299         mach_port_name_t        *namep);
 300
 301 /*  Allocate a dead-name entry, with a specific name */
 302 extern kern_return_t ipc_object_alloc_dead_name(
 303         ipc_space_t             space,
 304         mach_port_name_t        name);
 305
 306 /* Allocate an object */
 307 extern kern_return_t ipc_object_alloc(
 308         ipc_space_t             space,
 309         ipc_object_type_t       otype,
 310         mach_port_type_t        type,
 311         mach_port_urefs_t       urefs,
 312         mach_port_name_t        *namep,
 313         ipc_object_t            *objectp);
 314
 315 /* Allocate an object, with a specific name */
 316 extern kern_return_t ipc_object_alloc_name(
 317         ipc_space_t             space,
 318         ipc_object_type_t       otype,
 319         mach_port_type_t        type,
 320         mach_port_urefs_t       urefs,
 321         mach_port_name_t        name,
 322         ipc_object_t            *objectp);
 323
 324 /* Convert a send type name to a received type name */
 325 extern mach_msg_type_name_t ipc_object_copyin_type(
 326         mach_msg_type_name_t    msgt_name);
 327
 328 /* Copyin a capability from a space */
 329 extern kern_return_t ipc_object_copyin(
 330         ipc_space_t             space,
 331         mach_port_name_t        name,
 332         mach_msg_type_name_t    msgt_name,
 333         ipc_object_t            *objectp,
 334         mach_port_context_t     context,
 335         mach_msg_guard_flags_t  *guard_flags,
 336         uint16_t                kmsg_flags);
 337
 338 /* Copyin a naked capability from the kernel */
 339 extern void ipc_object_copyin_from_kernel(
 340         ipc_object_t            object,
 341         mach_msg_type_name_t    msgt_name);
 342
 343 /* Destroy a naked capability */
 344 extern void ipc_object_destroy(
 345         ipc_object_t            object,
 346         mach_msg_type_name_t    msgt_name);
 347
 348 /* Destroy a naked destination capability */
 349 extern void ipc_object_destroy_dest(
 350         ipc_object_t            object,
 351         mach_msg_type_name_t    msgt_name);
 352
 353 /* Insert a send right into an object already in the current space */
 354 extern kern_return_t ipc_object_insert_send_right(
 355         ipc_space_t             space,
 356         mach_port_name_t        name,
 357         mach_msg_type_name_t    msgt_name);
 358
 359 /* Copyout a capability, placing it into a space */
 360 extern kern_return_t ipc_object_copyout(
 361         ipc_space_t             space,
 362         ipc_object_t            object,
 363         mach_msg_type_name_t    msgt_name,
 364         mach_port_context_t     *context,
 365         mach_msg_guard_flags_t  *guard_flags,
 366         mach_port_name_t        *namep);
 367
 368 /* Copyout a capability with a name, placing it into a space */
 369 extern kern_return_t ipc_object_copyout_name(
 370         ipc_space_t             space,
 371         ipc_object_t            object,
 372         mach_msg_type_name_t    msgt_name,
 373         mach_port_name_t        name);
 374
 375 /* Translate/consume the destination right of a message */
 376 extern void ipc_object_copyout_dest(
 377         ipc_space_t             space,
 378         ipc_object_t            object,
 379         mach_msg_type_name_t    msgt_name,
 380         mach_port_name_t        *namep);
 381
 382 #endif  /* _IPC_IPC_OBJECT_H_ */