sysv_ipc.c revision 1.34
1 /* $NetBSD: sysv_ipc.c,v 1.34 2019/01/10 22:02:16 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1998, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Charles M. Hannum. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: sysv_ipc.c,v 1.34 2019/01/10 22:02:16 christos Exp $"); 34 35 #ifdef _KERNEL_OPT 36 #include "opt_sysv.h" 37 #include "opt_compat_netbsd.h" 38 #endif 39 40 #include <sys/syscall.h> 41 #include <sys/syscallargs.h> 42 #include <sys/syscallvar.h> 43 #include <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/proc.h> 46 #include <sys/ipc.h> 47 #ifdef SYSVMSG 48 #include <sys/msg.h> 49 #endif 50 #ifdef SYSVSEM 51 #include <sys/sem.h> 52 #endif 53 #ifdef SYSVSHM 54 #include <sys/shm.h> 55 #endif 56 #include <sys/systm.h> 57 #include <sys/kmem.h> 58 #include <sys/module.h> 59 #include <sys/mount.h> 60 #include <sys/vnode.h> 61 #include <sys/stat.h> 62 #include <sys/sysctl.h> 63 #include <sys/kauth.h> 64 65 /* 66 * Values in support of System V compatible shared memory. XXX 67 * (originally located in sys/conf/param.c) 68 */ 69 #ifdef SYSVSHM 70 #if !defined(SHMMAX) && defined(SHMMAXPGS) 71 #define SHMMAX SHMMAXPGS /* shminit() performs a `*= PAGE_SIZE' */ 72 #elif !defined(SHMMAX) 73 #define SHMMAX 0 74 #endif 75 #ifndef SHMMIN 76 #define SHMMIN 1 77 #endif 78 #ifndef SHMMNI 79 #define SHMMNI 128 /* <64k, see IPCID_TO_IX in ipc.h */ 80 #endif 81 #ifndef SHMSEG 82 #define SHMSEG 128 83 #endif 84 85 struct shminfo shminfo = { 86 SHMMAX, 87 SHMMIN, 88 SHMMNI, 89 SHMSEG, 90 0 91 }; 92 #endif 93 94 /* 95 * Values in support of System V compatible semaphores. 96 */ 97 #ifdef SYSVSEM 98 struct seminfo seminfo = { 99 SEMMAP, /* # of entries in semaphore map */ 100 SEMMNI, /* # of semaphore identifiers */ 101 SEMMNS, /* # of semaphores in system */ 102 SEMMNU, /* # of undo structures in system */ 103 SEMMSL, /* max # of semaphores per id */ 104 SEMOPM, /* max # of operations per semop call */ 105 SEMUME, /* max # of undo entries per process */ 106 SEMUSZ, /* size in bytes of undo structure */ 107 SEMVMX, /* semaphore maximum value */ 108 SEMAEM /* adjust on exit max value */ 109 }; 110 #endif 111 112 /* 113 * Values in support of System V compatible messages. 114 */ 115 #ifdef SYSVMSG 116 struct msginfo msginfo = { 117 MSGMAX, /* max chars in a message */ 118 MSGMNI, /* # of message queue identifiers */ 119 MSGMNB, /* max chars in a queue */ 120 MSGTQL, /* max messages in system */ 121 MSGSSZ, /* size of a message segment */ 122 /* (must be small power of 2 greater than 4) */ 123 MSGSEG /* number of message segments */ 124 }; 125 #endif 126 127 #if defined(COMPAT_50) 128 int sysctl_kern_sysvipc50(SYSCTLFN_PROTO); 129 #endif 130 131 MODULE(MODULE_CLASS_EXEC, sysv_ipc, NULL); 132 133 SYSCTL_SETUP_PROTO(sysctl_ipc_setup); 134 135 static struct sysctllog *sysctl_sysvipc_clog = NULL; 136 137 static const struct syscall_package sysvipc_syscalls[] = { 138 #if defined(SYSVSHM) 139 { SYS___shmctl50, 0, (sy_call_t *)sys___shmctl50 }, 140 { SYS_shmat, 0, (sy_call_t *)sys_shmat }, 141 { SYS_shmdt, 0, (sy_call_t *)sys_shmdt }, 142 { SYS_shmget, 0, (sy_call_t *)sys_shmget }, 143 #if defined(COMPAT_10) && !defined(_LP64) 144 { SYS_compat_10_oshmsys, 0, (sy_call_t *)compat_10_sys_shmsys }, 145 #endif 146 #if defined(COMPAT_14) 147 { SYS_compat_14_shmctl, 0, (sy_call_t *)compat_14_sys_shmctl }, 148 #endif 149 #if defined(COMPAT_50) 150 { SYS_compat_50___shmctl13, 0, (sy_call_t *)compat_50_sys___shmctl13 }, 151 #endif 152 #endif /* SYSVSHM */ 153 154 #if defined(SYSVSEM) 155 { SYS_____semctl50, 0, (sy_call_t *)sys_____semctl50 }, 156 { SYS_semget, 0, (sy_call_t *)sys_semget }, 157 { SYS_semop, 0, (sy_call_t *)sys_semop }, 158 { SYS_semconfig, 0, (sy_call_t *)sys_semconfig }, 159 #if defined(COMPAT_10) && !defined(_LP64) 160 { SYS_compat_10_osemsys, 0, (sy_call_t *)compat_10_sys_semsys }, 161 #endif 162 #if defined(COMPAT_14) 163 { SYS_compat_14___semctl, 0, (sy_call_t *)compat_14_sys___semctl }, 164 #endif 165 #if defined(COMPAT_50) 166 { SYS_compat_50_____semctl13, 0, (sy_call_t *)compat_50_sys_____semctl13 }, 167 #endif 168 #endif /* SYSVSEM */ 169 170 #if defined(SYSVMSG) 171 { SYS___msgctl50, 0, (sy_call_t *)sys___msgctl50 }, 172 { SYS_msgget, 0, (sy_call_t *)sys_msgget }, 173 { SYS_msgsnd, 0, (sy_call_t *)sys_msgsnd }, 174 { SYS_msgrcv, 0, (sy_call_t *)sys_msgrcv }, 175 #if defined(COMPAT_10) && !defined(_LP64) 176 { SYS_compat_10_omsgsys, 0, (sy_call_t *)compat_10_sys_msgsys }, 177 #endif 178 #if defined(COMPAT_14) 179 { SYS_compat_14_msgctl, 0, (sy_call_t *)compat_14_sys_msgctl }, 180 #endif 181 #if defined(COMPAT_50) 182 { SYS_compat_50___msgctl13, 0, (sy_call_t *)compat_50_sys___msgctl13 }, 183 #endif 184 #endif /* SYSVMSG */ 185 { 0, 0, NULL } 186 }; 187 188 static int 189 sysv_ipc_modcmd(modcmd_t cmd, void *arg) 190 { 191 int error = 0; 192 193 switch (cmd) { 194 case MODULE_CMD_INIT: 195 /* Set up the kauth listener */ 196 sysvipcinit(); 197 198 /* Link the system calls */ 199 error = syscall_establish(NULL, sysvipc_syscalls); 200 if (error) { 201 sysvipcfini(); 202 return error; 203 } 204 205 /* 206 * Initialize each sub-component, including their 207 * sysctl data 208 */ 209 #ifdef SYSVSHM 210 shminit(&sysctl_sysvipc_clog); 211 #endif 212 #ifdef SYSVSEM 213 seminit(&sysctl_sysvipc_clog); 214 #endif 215 #ifdef SYSVMSG 216 msginit(&sysctl_sysvipc_clog); 217 #endif 218 219 #ifdef _MODULE 220 /* Set up the common sysctl tree */ 221 sysctl_ipc_setup(&sysctl_sysvipc_clog); 222 #endif 223 break; 224 case MODULE_CMD_FINI: 225 /* 226 * Make sure no subcomponents are active. Each one 227 * tells us if it is busy, and if it was _not_ busy, 228 * we assume it has already done its own clean-up. 229 * So we might need to re-init any components that 230 * are successfully fini'd if we find one that is 231 * still busy. 232 */ 233 #ifdef SYSVSHM 234 if (shmfini()) { 235 return EBUSY; 236 } 237 #endif 238 #ifdef SYSVSEM 239 if (semfini()) { 240 #ifdef SYSVSHM 241 shminit(NULL); 242 #endif 243 return EBUSY; 244 } 245 #endif 246 #ifdef SYSVMSG 247 if (msgfini()) { 248 #ifdef SYSVSEM 249 seminit(NULL); 250 #endif 251 #ifdef SYSVSHM 252 shminit(NULL); 253 #endif 254 return EBUSY; 255 } 256 #endif 257 258 #ifdef _MODULE 259 /* Remove the sysctl sub-trees */ 260 sysctl_teardown(&sysctl_sysvipc_clog); 261 #endif 262 263 /* Unlink the system calls. */ 264 error = syscall_disestablish(NULL, sysvipc_syscalls); 265 if (error) 266 return error; 267 268 /* Remove the kauth listener */ 269 sysvipcfini(); 270 break; 271 default: 272 return ENOTTY; 273 } 274 return error; 275 } 276 277 static kauth_listener_t sysvipc_listener = NULL; 278 279 static int 280 sysvipc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 281 void *arg0, void *arg1, void *arg2, void *arg3) 282 { 283 mode_t mask; 284 int ismember = 0; 285 struct ipc_perm *perm; 286 int mode; 287 enum kauth_system_req req; 288 289 req = (enum kauth_system_req)arg0; 290 291 if (!(action == KAUTH_SYSTEM_SYSVIPC && 292 req == KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS)) 293 return KAUTH_RESULT_DEFER; 294 295 perm = arg1; 296 mode = (int)(uintptr_t)arg2; 297 298 if (mode == IPC_M) { 299 if (kauth_cred_geteuid(cred) == perm->uid || 300 kauth_cred_geteuid(cred) == perm->cuid) 301 return (KAUTH_RESULT_ALLOW); 302 return (KAUTH_RESULT_DEFER); /* EPERM */ 303 } 304 305 mask = 0; 306 307 if (kauth_cred_geteuid(cred) == perm->uid || 308 kauth_cred_geteuid(cred) == perm->cuid) { 309 if (mode & IPC_R) 310 mask |= S_IRUSR; 311 if (mode & IPC_W) 312 mask |= S_IWUSR; 313 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 314 } 315 316 if (kauth_cred_getegid(cred) == perm->gid || 317 (kauth_cred_ismember_gid(cred, perm->gid, &ismember) == 0 && ismember) || 318 kauth_cred_getegid(cred) == perm->cgid || 319 (kauth_cred_ismember_gid(cred, perm->cgid, &ismember) == 0 && ismember)) { 320 if (mode & IPC_R) 321 mask |= S_IRGRP; 322 if (mode & IPC_W) 323 mask |= S_IWGRP; 324 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 325 } 326 327 if (mode & IPC_R) 328 mask |= S_IROTH; 329 if (mode & IPC_W) 330 mask |= S_IWOTH; 331 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 332 } 333 334 /* 335 * Check for ipc permission 336 */ 337 338 int 339 ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode) 340 { 341 int error; 342 343 error = kauth_authorize_system(cred, KAUTH_SYSTEM_SYSVIPC, 344 KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS, perm, KAUTH_ARG(mode), NULL); 345 if (error == 0) 346 return (0); 347 348 /* Adjust EPERM and EACCES errors until there's a better way to do this. */ 349 if (mode != IPC_M) 350 error = EACCES; 351 352 return error; 353 } 354 355 void 356 sysvipcfini(void) 357 { 358 359 KASSERT(sysvipc_listener != NULL); 360 kauth_unlisten_scope(sysvipc_listener); 361 sysvipc_listener = NULL; 362 } 363 364 void 365 sysvipcinit(void) 366 { 367 368 KASSERT(sysvipc_listener == NULL); 369 370 sysvipc_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 371 sysvipc_listener_cb, NULL); 372 } 373 374 static int 375 sysctl_kern_sysvipc(SYSCTLFN_ARGS) 376 { 377 void *where = oldp; 378 size_t sz, *sizep = oldlenp; 379 #ifdef SYSVMSG 380 struct msg_sysctl_info *msgsi = NULL; 381 #endif 382 #ifdef SYSVSEM 383 struct sem_sysctl_info *semsi = NULL; 384 #endif 385 #ifdef SYSVSHM 386 struct shm_sysctl_info *shmsi = NULL; 387 #endif 388 size_t infosize, dssize, tsize, buflen; 389 void *bf = NULL; 390 char *start; 391 int32_t nds; 392 int i, error, ret; 393 394 /* 395 * If present, call the compat sysctl() code. If it handles the request 396 * completely (either success or error), return. Otherwise fallthrough 397 * to the non-compat sysctl code. 398 */ 399 400 #if defined(COMPAT_50) 401 error = sysctl_kern_sysvipc50(SYSCTLFN_CALL(rnode)); 402 if (error != EPASSTHROUGH) 403 return error; 404 #endif 405 406 if (namelen != 1) 407 return EINVAL; 408 409 start = where; 410 buflen = *sizep; 411 412 switch (*name) { 413 case KERN_SYSVIPC_MSG_INFO: 414 #ifdef SYSVMSG 415 infosize = sizeof(msgsi->msginfo); 416 nds = msginfo.msgmni; 417 dssize = sizeof(msgsi->msgids[0]); 418 break; 419 #else 420 return EINVAL; 421 #endif 422 case KERN_SYSVIPC_SEM_INFO: 423 #ifdef SYSVSEM 424 infosize = sizeof(semsi->seminfo); 425 nds = seminfo.semmni; 426 dssize = sizeof(semsi->semids[0]); 427 break; 428 #else 429 return EINVAL; 430 #endif 431 case KERN_SYSVIPC_SHM_INFO: 432 #ifdef SYSVSHM 433 infosize = sizeof(shmsi->shminfo); 434 nds = shminfo.shmmni; 435 dssize = sizeof(shmsi->shmids[0]); 436 break; 437 #else 438 return EINVAL; 439 #endif 440 default: 441 return EINVAL; 442 } 443 /* 444 * Round infosize to 64 bit boundary if requesting more than just 445 * the info structure or getting the total data size. 446 */ 447 if (where == NULL || *sizep > infosize) 448 infosize = roundup(infosize, sizeof(quad_t)); 449 tsize = infosize + nds * dssize; 450 451 /* Return just the total size required. */ 452 if (where == NULL) { 453 *sizep = tsize; 454 return 0; 455 } 456 457 /* Not enough room for even the info struct. */ 458 if (buflen < infosize) { 459 *sizep = 0; 460 return ENOMEM; 461 } 462 sz = uimin(tsize, buflen); 463 bf = kmem_zalloc(sz, KM_SLEEP); 464 465 switch (*name) { 466 #ifdef SYSVMSG 467 case KERN_SYSVIPC_MSG_INFO: 468 msgsi = (struct msg_sysctl_info *)bf; 469 msgsi->msginfo = msginfo; 470 break; 471 #endif 472 #ifdef SYSVSEM 473 case KERN_SYSVIPC_SEM_INFO: 474 semsi = (struct sem_sysctl_info *)bf; 475 semsi->seminfo = seminfo; 476 break; 477 #endif 478 #ifdef SYSVSHM 479 case KERN_SYSVIPC_SHM_INFO: 480 shmsi = (struct shm_sysctl_info *)bf; 481 shmsi->shminfo = shminfo; 482 break; 483 #endif 484 } 485 buflen -= infosize; 486 487 ret = 0; 488 if (buflen > 0) { 489 /* Fill in the IPC data structures. */ 490 for (i = 0; i < nds; i++) { 491 if (buflen < dssize) { 492 ret = ENOMEM; 493 break; 494 } 495 switch (*name) { 496 #ifdef SYSVMSG 497 case KERN_SYSVIPC_MSG_INFO: 498 mutex_enter(&msgmutex); 499 SYSCTL_FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]); 500 mutex_exit(&msgmutex); 501 break; 502 #endif 503 #ifdef SYSVSEM 504 case KERN_SYSVIPC_SEM_INFO: 505 SYSCTL_FILL_SEM(sema[i], semsi->semids[i]); 506 break; 507 #endif 508 #ifdef SYSVSHM 509 case KERN_SYSVIPC_SHM_INFO: 510 SYSCTL_FILL_SHM(shmsegs[i], shmsi->shmids[i]); 511 break; 512 #endif 513 } 514 buflen -= dssize; 515 } 516 } 517 *sizep -= buflen; 518 error = copyout(bf, start, *sizep); 519 /* If copyout succeeded, use return code set earlier. */ 520 if (error == 0) 521 error = ret; 522 if (bf) 523 kmem_free(bf, sz); 524 return error; 525 } 526 527 SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup") 528 { 529 530 sysctl_createv(clog, 0, NULL, NULL, 531 CTLFLAG_PERMANENT, 532 CTLTYPE_NODE, "ipc", 533 SYSCTL_DESCR("SysV IPC options"), 534 NULL, 0, NULL, 0, 535 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 536 537 sysctl_createv(clog, 0, NULL, NULL, 538 CTLFLAG_PERMANENT, 539 CTLTYPE_STRUCT, "sysvipc_info", 540 SYSCTL_DESCR("System V style IPC information"), 541 sysctl_kern_sysvipc, 0, NULL, 0, 542 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_INFO, CTL_EOL); 543 } 544
Indexes created Wed Sep 24 15:09:51 GMT 2025