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/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          0x000007ff      /* used by the object */
 135 #define IO_BITS_KOBJECT         0x00000800      /* port belongs to a kobject */
 136 #define IO_BITS_OTYPE           0x7fff0000      /* determines a zone */
 137 #define IO_BITS_ACTIVE          0x80000000      /* is object alive? */
 138
 139 #define io_active(io)           (((io)->io_bits & IO_BITS_ACTIVE) != 0)
 140
 141 #define io_otype(io)            (((io)->io_bits & IO_BITS_OTYPE) >> 16)
 142 #define io_kotype(io)           ((io)->io_bits & IO_BITS_KOTYPE)
 143 #define io_is_kobject(io)       (((io)->io_bits & IO_BITS_KOBJECT) != IKOT_NONE)
 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 extern lck_grp_t        ipc_lck_grp;
 157
 158 #define io_alloc(otype)         \
 159                 ((ipc_object_t) zalloc(ipc_object_zones[(otype)]))
 160
 161 extern void     io_free(
 162         unsigned int    otype,
 163         ipc_object_t    object);
 164
 165 /*
 166  * Here we depend on the ipc_object being first within the kernel struct
 167  * (ipc_port and ipc_pset).
 168  */
 169 #define io_lock_init(io) \
 170         lck_spin_init(&(io)->io_lock_data, &ipc_lck_grp, &ipc_lck_attr)
 171 #define io_lock_destroy(io) \
 172         lck_spin_destroy(&(io)->io_lock_data, &ipc_lck_grp)
 173 #define io_lock_held(io) \
 174         LCK_SPIN_ASSERT(&(io)->io_lock_data, LCK_ASSERT_OWNED)
 175 #define io_lock_held_kdp(io) \
 176         kdp_lck_spin_is_acquired(&(io)->io_lock_data)
 177 #define io_unlock(io) \
 178         lck_spin_unlock(&(io)->io_lock_data)
 179
 180 extern void io_lock(
 181         ipc_object_t io);
 182 extern boolean_t io_lock_try(
 183         ipc_object_t io);
 184
 185 #define _VOLATILE_ volatile
 186
 187 /* Sanity check the ref count.  If it is 0, we may be doubly zfreeing.
 188  * If it is larger than max int, it has been corrupted or leaked,
 189  * probably by being modified into an address (this is architecture
 190  * dependent, but it's safe to assume there cannot really be max int
 191  * references unless some code is leaking the io_reference without leaking
 192  * object). Saturate the io_reference on release kernel if it reaches
 193  * max int to avoid use after free.
 194  *
 195  * NOTE: The 0 test alone will not catch double zfreeing of ipc_port
 196  * structs, because the io_references field is the first word of the struct,
 197  * and zfree modifies that to point to the next free zone element.
 198  */
 199 #define IO_MAX_REFERENCES                                               \
 200         (unsigned)(~0 ^ (1U << (sizeof(int)*BYTE_SIZE - 1)))
 201
 202 static inline void
 203 io_reference(ipc_object_t io)
 204 {
 205         ipc_object_refs_t new_io_references;
 206         ipc_object_refs_t old_io_references;
 207
 208         if ((io)->io_references == 0 ||
 209             (io)->io_references >= IO_MAX_REFERENCES) {
 210                 panic("%s: reference count %u is invalid\n", __func__, (io)->io_references);
 211         }
 212
 213         do {
 214                 old_io_references = (io)->io_references;
 215                 new_io_references = old_io_references + 1;
 216                 if (old_io_references == IO_MAX_REFERENCES) {
 217                         break;
 218                 }
 219         } while (OSCompareAndSwap(old_io_references, new_io_references,
 220             &((io)->io_references)) == FALSE);
 221 }
 222
 223
 224 static inline void
 225 io_release(ipc_object_t io)
 226 {
 227         ipc_object_refs_t new_io_references;
 228         ipc_object_refs_t old_io_references;
 229
 230         if ((io)->io_references == 0 ||
 231             (io)->io_references >= IO_MAX_REFERENCES) {
 232                 panic("%s: reference count %u is invalid\n", __func__, (io)->io_references);
 233         }
 234
 235         do {
 236                 old_io_references = (io)->io_references;
 237                 new_io_references = old_io_references - 1;
 238                 if (old_io_references == IO_MAX_REFERENCES) {
 239                         break;
 240                 }
 241         } while (OSCompareAndSwap(old_io_references, new_io_references,
 242             &((io)->io_references)) == FALSE);
 243
 244         /* If we just removed the last reference count */
 245         if (1 == old_io_references) {
 246                 /* Free the object */
 247                 io_free(io_otype((io)), (io));
 248         }
 249 }
 250
 251 /*
 252  * Retrieve a label for use in a kernel call that takes a security
 253  * label as a parameter. If necessary, io_getlabel acquires internal
 254  * (not io_lock) locks, and io_unlocklabel releases them.
 255  */
 256
 257 struct label;
 258 extern struct label *io_getlabel(ipc_object_t obj);
 259 #define io_unlocklabel(obj)
 260
 261 /*
 262  * Exported interfaces
 263  */
 264
 265 /* Take a reference to an object */
 266 extern void ipc_object_reference(
 267         ipc_object_t    object);
 268
 269 /* Release a reference to an object */
 270 extern void ipc_object_release(
 271         ipc_object_t    object);
 272
 273 /* Look up an object in a space */
 274 extern kern_return_t ipc_object_translate(
 275         ipc_space_t             space,
 276         mach_port_name_t        name,
 277         mach_port_right_t       right,
 278         ipc_object_t            *objectp);
 279
 280 /* Look up two objects in a space, locking them in the order described */
 281 extern kern_return_t ipc_object_translate_two(
 282         ipc_space_t             space,
 283         mach_port_name_t        name1,
 284         mach_port_right_t       right1,
 285         ipc_object_t            *objectp1,
 286         mach_port_name_t        name2,
 287         mach_port_right_t       right2,
 288         ipc_object_t            *objectp2);
 289
 290 /* Validate an object as belonging to the correct zone */
 291 extern void ipc_object_validate(
 292         ipc_object_t object);
 293
 294 /* Allocate a dead-name entry */
 295 extern kern_return_t
 296 ipc_object_alloc_dead(
 297         ipc_space_t             space,
 298         mach_port_name_t        *namep);
 299
 300 /*  Allocate a dead-name entry, with a specific name */
 301 extern kern_return_t ipc_object_alloc_dead_name(
 302         ipc_space_t             space,
 303         mach_port_name_t        name);
 304
 305 /* Allocate an object */
 306 extern kern_return_t ipc_object_alloc(
 307         ipc_space_t             space,
 308         ipc_object_type_t       otype,
 309         mach_port_type_t        type,
 310         mach_port_urefs_t       urefs,
 311         mach_port_name_t        *namep,
 312         ipc_object_t            *objectp);
 313
 314 /* Allocate an object, with a specific name */
 315 extern kern_return_t ipc_object_alloc_name(
 316         ipc_space_t             space,
 317         ipc_object_type_t       otype,
 318         mach_port_type_t        type,
 319         mach_port_urefs_t       urefs,
 320         mach_port_name_t        name,
 321         ipc_object_t            *objectp);
 322
 323 /* Convert a send type name to a received type name */
 324 extern mach_msg_type_name_t ipc_object_copyin_type(
 325         mach_msg_type_name_t    msgt_name);
 326
 327 /* Copyin a capability from a space */
 328 extern kern_return_t ipc_object_copyin(
 329         ipc_space_t             space,
 330         mach_port_name_t        name,
 331         mach_msg_type_name_t    msgt_name,
 332         ipc_object_t            *objectp,
 333         mach_port_context_t     context,
 334         mach_msg_guard_flags_t  *guard_flags,
 335         uint32_t                kmsg_flags);
 336
 337 /* Copyin a naked capability from the kernel */
 338 extern void ipc_object_copyin_from_kernel(
 339         ipc_object_t            object,
 340         mach_msg_type_name_t    msgt_name);
 341
 342 /* Destroy a naked capability */
 343 extern void ipc_object_destroy(
 344         ipc_object_t            object,
 345         mach_msg_type_name_t    msgt_name);
 346
 347 /* Destroy a naked destination capability */
 348 extern void ipc_object_destroy_dest(
 349         ipc_object_t            object,
 350         mach_msg_type_name_t    msgt_name);
 351
 352 /* Insert a send right into an object already in the current space */
 353 extern kern_return_t ipc_object_insert_send_right(
 354         ipc_space_t             space,
 355         mach_port_name_t        name,
 356         mach_msg_type_name_t    msgt_name);
 357
 358 /* Copyout a capability, placing it into a space */
 359 extern kern_return_t ipc_object_copyout(
 360         ipc_space_t             space,
 361         ipc_object_t            object,
 362         mach_msg_type_name_t    msgt_name,
 363         mach_port_context_t     *context,
 364         mach_msg_guard_flags_t  *guard_flags,
 365         mach_port_name_t        *namep);
 366
 367 /* Copyout a capability with a name, placing it into a space */
 368 extern kern_return_t ipc_object_copyout_name(
 369         ipc_space_t             space,
 370         ipc_object_t            object,
 371         mach_msg_type_name_t    msgt_name,
 372         mach_port_name_t        name);
 373
 374 /* Translate/consume the destination right of a message */
 375 extern void ipc_object_copyout_dest(
 376         ipc_space_t             space,
 377         ipc_object_t            object,
 378         mach_msg_type_name_t    msgt_name,
 379         mach_port_name_t        *namep);
 380
 381 #endif  /* _IPC_IPC_OBJECT_H_ */