osfmk/ipc/ipc_object.h

   1 /*
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  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_rt.h>
  76
  77 #include <mach/kern_return.h>
  78 #include <mach/message.h>
  79 #include <kern/locks.h>
  80 #include <kern/macro_help.h>
  81 #include <kern/assert.h>
  82 #include <kern/zalloc.h>
  83 #include <ipc/ipc_types.h>
  84 #include <libkern/OSAtomic.h>
  85
  86 typedef natural_t ipc_object_refs_t;    /* for ipc/ipc_object.h         */
  87 typedef natural_t ipc_object_bits_t;
  88 typedef natural_t ipc_object_type_t;
  89
  90 /*
  91  * The ipc_object is used to both tag and reference count these two data
  92  * structures, and (Noto Bene!) pointers to either of these or the
  93  * ipc_object at the head of these are freely cast back and forth; hence
  94  * the ipc_object MUST BE FIRST in the ipc_common_data.
  95  *
  96  * If the RPC implementation enabled user-mode code to use kernel-level
  97  * data structures (as ours used to), this peculiar structuring would
  98  * avoid having anything in user code depend on the kernel configuration
  99  * (with which lock size varies).
 100  */
 101 struct ipc_object {
 102         ipc_object_bits_t io_bits;
 103         ipc_object_refs_t io_references;
 104         lck_spin_t      io_lock_data;
 105 };
 106
 107 /*
 108  * If another object type needs to participate in io_kotype()-based
 109  * dispatching, it must include a stub structure as the first
 110  * element
 111  */
 112 struct ipc_object_header {
 113         ipc_object_bits_t io_bits;
 114 #ifdef __LP64__
 115         natural_t         io_padding; /* pad to natural boundary */
 116 #endif
 117 };
 118
 119 /*
 120  * Legacy defines.  Should use IPC_OBJECT_NULL, etc...
 121  */
 122 #define IO_NULL                 ((ipc_object_t) 0)
 123 #define IO_DEAD                 ((ipc_object_t) ~0UL)
 124 #define IO_VALID(io)            (((io) != IO_NULL) && ((io) != IO_DEAD))
 125
 126 /*
 127  *      IPC steals the high-order bits from the kotype to use
 128  *      for its own purposes.  This allows IPC to record facts
 129  *      about ports that aren't otherwise obvious from the
 130  *      existing port fields.  In particular, IPC can optionally
 131  *      mark a port for no more senders detection.  Any change
 132  *      to IO_BITS_PORT_INFO must be coordinated with bitfield
 133  *      definitions in ipc_port.h.
 134  */
 135 #define IO_BITS_PORT_INFO       0x0000f000      /* stupid port tricks */
 136 #define IO_BITS_KOTYPE          0x00000fff      /* used by the object */
 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
 145 #define io_makebits(active, otype, kotype)      \
 146         (((active) ? IO_BITS_ACTIVE : 0) | ((otype) << 16) | (kotype))
 147
 148 /*
 149  * Object types: ports, port sets, kernel-loaded ports
 150  */
 151 #define IOT_PORT                0
 152 #define IOT_PORT_SET            1
 153 #define IOT_NUMBER              2               /* number of types used */
 154
 155 extern zone_t ipc_object_zones[IOT_NUMBER];
 156
 157 #define io_alloc(otype)         \
 158                 ((ipc_object_t) zalloc(ipc_object_zones[(otype)]))
 159
 160 extern void     io_free(
 161                         unsigned int    otype,
 162                         ipc_object_t    object);
 163
 164 /*
 165  * Here we depend on the ipc_object being first within the kernel struct
 166  * (ipc_port and ipc_pset).
 167  */
 168 #define io_lock_init(io) \
 169         lck_spin_init(&(io)->io_lock_data, &ipc_lck_grp, &ipc_lck_attr)
 170 #define io_lock_destroy(io) \
 171         lck_spin_destroy(&(io)->io_lock_data, &ipc_lck_grp)
 172 #define io_lock(io) \
 173         lck_spin_lock(&(io)->io_lock_data)
 174 #define io_lock_try(io) \
 175         lck_spin_try_lock(&(io)->io_lock_data)
 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 #define _VOLATILE_ volatile
 182
 183 /* Sanity check the ref count.  If it is 0, we may be doubly zfreeing.
 184  * If it is larger than max int, it has been corrupted or leaked,
 185  * probably by being modified into an address (this is architecture
 186  * dependent, but it's safe to assume there cannot really be max int
 187  * references unless some code is leaking the io_reference without leaking
 188  * object). Saturate the io_reference on release kernel if it reaches
 189  * max int to avoid use after free.
 190  *
 191  * NOTE: The 0 test alone will not catch double zfreeing of ipc_port
 192  * structs, because the io_references field is the first word of the struct,
 193  * and zfree modifies that to point to the next free zone element.
 194  */
 195 #define IO_MAX_REFERENCES                                               \
 196         (unsigned)(~0 ^ (1 << (sizeof(int)*BYTE_SIZE - 1)))
 197
 198 static inline void
 199 io_reference(ipc_object_t io) {
 200         ipc_object_refs_t new_io_references;
 201         ipc_object_refs_t old_io_references;
 202
 203         assert((io)->io_references > 0 &&
 204             (io)->io_references < IO_MAX_REFERENCES);
 205
 206         do {
 207                 old_io_references = (io)->io_references;
 208                 new_io_references = old_io_references + 1;
 209                 if (old_io_references == IO_MAX_REFERENCES) {
 210                         break;
 211                 }
 212         } while (OSCompareAndSwap(old_io_references, new_io_references,
 213                         &((io)->io_references)) == FALSE);
 214 }
 215
 216
 217 static inline void
 218 io_release(ipc_object_t io) {
 219         ipc_object_refs_t new_io_references;
 220         ipc_object_refs_t old_io_references;
 221
 222         assert((io)->io_references > 0 &&
 223             (io)->io_references < IO_MAX_REFERENCES);
 224
 225         do {
 226                 old_io_references = (io)->io_references;
 227                 new_io_references = old_io_references - 1;
 228                 if (old_io_references == IO_MAX_REFERENCES) {
 229                         break;
 230                 }
 231         } while (OSCompareAndSwap(old_io_references, new_io_references,
 232                         &((io)->io_references)) == FALSE);
 233
 234         /* If we just removed the last reference count */
 235         if (1 == old_io_references) {
 236                 /* Free the object */
 237                 io_free(io_otype((io)), (io));
 238         }
 239 }
 240
 241 /*
 242  * Retrieve a label for use in a kernel call that takes a security
 243  * label as a parameter. If necessary, io_getlabel acquires internal
 244  * (not io_lock) locks, and io_unlocklabel releases them.
 245  */
 246
 247 struct label;
 248 extern struct label *io_getlabel (ipc_object_t obj);
 249 #define io_unlocklabel(obj)
 250
 251 /*
 252  * Exported interfaces
 253  */
 254
 255 /* Take a reference to an object */
 256 extern void ipc_object_reference(
 257         ipc_object_t    object);
 258
 259 /* Release a reference to an object */
 260 extern void ipc_object_release(
 261         ipc_object_t    object);
 262
 263 /* Look up an object in a space */
 264 extern kern_return_t ipc_object_translate(
 265         ipc_space_t             space,
 266         mach_port_name_t        name,
 267         mach_port_right_t       right,
 268         ipc_object_t            *objectp);
 269
 270 /* Look up two objects in a space, locking them in the order described */
 271 extern kern_return_t ipc_object_translate_two(
 272         ipc_space_t             space,
 273         mach_port_name_t        name1,
 274         mach_port_right_t       right1,
 275         ipc_object_t            *objectp1,
 276         mach_port_name_t        name2,
 277         mach_port_right_t       right2,
 278         ipc_object_t            *objectp2);
 279
 280 /* Allocate a dead-name entry */
 281 extern kern_return_t
 282 ipc_object_alloc_dead(
 283         ipc_space_t             space,
 284         mach_port_name_t        *namep);
 285
 286 /*  Allocate a dead-name entry, with a specific name */
 287 extern kern_return_t ipc_object_alloc_dead_name(
 288         ipc_space_t             space,
 289         mach_port_name_t        name);
 290
 291 /* Allocate an object */
 292 extern kern_return_t ipc_object_alloc(
 293         ipc_space_t             space,
 294         ipc_object_type_t       otype,
 295         mach_port_type_t        type,
 296         mach_port_urefs_t       urefs,
 297         mach_port_name_t        *namep,
 298         ipc_object_t            *objectp);
 299
 300 /* Allocate an object, with a specific name */
 301 extern kern_return_t ipc_object_alloc_name(
 302         ipc_space_t             space,
 303         ipc_object_type_t       otype,
 304         mach_port_type_t        type,
 305         mach_port_urefs_t       urefs,
 306         mach_port_name_t        name,
 307         ipc_object_t            *objectp);
 308
 309 /* Convert a send type name to a received type name */
 310 extern mach_msg_type_name_t ipc_object_copyin_type(
 311         mach_msg_type_name_t    msgt_name);
 312
 313 /* Copyin a capability from a space */
 314 extern kern_return_t ipc_object_copyin(
 315         ipc_space_t             space,
 316         mach_port_name_t        name,
 317         mach_msg_type_name_t    msgt_name,
 318         ipc_object_t            *objectp);
 319
 320 /* Copyin a naked capability from the kernel */
 321 extern void ipc_object_copyin_from_kernel(
 322         ipc_object_t            object,
 323         mach_msg_type_name_t    msgt_name);
 324
 325 /* Destroy a naked capability */
 326 extern void ipc_object_destroy(
 327         ipc_object_t            object,
 328         mach_msg_type_name_t    msgt_name);
 329
 330 /* Destroy a naked destination capability */
 331 extern void ipc_object_destroy_dest(
 332         ipc_object_t            object,
 333         mach_msg_type_name_t    msgt_name);
 334
 335 /* Copyout a capability, placing it into a space */
 336 extern kern_return_t ipc_object_copyout(
 337         ipc_space_t             space,
 338         ipc_object_t            object,
 339         mach_msg_type_name_t    msgt_name,
 340         boolean_t               overflow,
 341         mach_port_name_t        *namep);
 342
 343 /* Copyout a capability with a name, placing it into a space */
 344 extern kern_return_t ipc_object_copyout_name(
 345         ipc_space_t             space,
 346         ipc_object_t            object,
 347         mach_msg_type_name_t    msgt_name,
 348         boolean_t               overflow,
 349         mach_port_name_t        name);
 350
 351 /* Translate/consume the destination right of a message */
 352 extern void ipc_object_copyout_dest(
 353         ipc_space_t             space,
 354         ipc_object_t            object,
 355         mach_msg_type_name_t    msgt_name,
 356         mach_port_name_t        *namep);
 357
 358 /* Rename an entry in a space */
 359 extern kern_return_t ipc_object_rename(
 360         ipc_space_t             space,
 361         mach_port_name_t        oname,
 362         mach_port_name_t        nname);
 363
 364 #endif  /* _IPC_IPC_OBJECT_H_ */