sysv_ipc.c revision 1.35
1 /* $NetBSD: sysv_ipc.c,v 1.35 2019/01/27 02:08:43 pgoyette 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 1.35 2019/01/27 02:08:43 pgoyette 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 #include <sys/compat_stub.h> 65 66 #include <compat/common/compat_sysv_mod.h> /* for sysctl routine vector */ 67 68 /* 69 * Values in support of System V compatible shared memory. XXX 70 * (originally located in sys/conf/param.c) 71 */ 72 #ifdef SYSVSHM 73 #if !defined(SHMMAX) && defined(SHMMAXPGS) 74 #define SHMMAX SHMMAXPGS /* shminit() performs a `*= PAGE_SIZE' */ 75 #elif !defined(SHMMAX) 76 #define SHMMAX 0 77 #endif 78 #ifndef SHMMIN 79 #define SHMMIN 1 80 #endif 81 #ifndef SHMMNI 82 #define SHMMNI 128 /* <64k, see IPCID_TO_IX in ipc.h */ 83 #endif 84 #ifndef SHMSEG 85 #define SHMSEG 128 86 #endif 87 88 struct shminfo shminfo = { 89 SHMMAX, 90 SHMMIN, 91 SHMMNI, 92 SHMSEG, 93 0 94 }; 95 #endif 96 97 /* 98 * Values in support of System V compatible semaphores. 99 */ 100 #ifdef SYSVSEM 101 struct seminfo seminfo = { 102 SEMMAP, /* # of entries in semaphore map */ 103 SEMMNI, /* # of semaphore identifiers */ 104 SEMMNS, /* # of semaphores in system */ 105 SEMMNU, /* # of undo structures in system */ 106 SEMMSL, /* max # of semaphores per id */ 107 SEMOPM, /* max # of operations per semop call */ 108 SEMUME, /* max # of undo entries per process */ 109 SEMUSZ, /* size in bytes of undo structure */ 110 SEMVMX, /* semaphore maximum value */ 111 SEMAEM /* adjust on exit max value */ 112 }; 113 #endif 114 115 /* 116 * Values in support of System V compatible messages. 117 */ 118 #ifdef SYSVMSG 119 struct msginfo msginfo = { 120 MSGMAX, /* max chars in a message */ 121 MSGMNI, /* # of message queue identifiers */ 122 MSGMNB, /* max chars in a queue */ 123 MSGTQL, /* max messages in system */ 124 MSGSSZ, /* size of a message segment */ 125 /* (must be small power of 2 greater than 4) */ 126 MSGSEG /* number of message segments */ 127 }; 128 #endif 129 130 MODULE(MODULE_CLASS_EXEC, sysv_ipc, NULL); 131 132 SYSCTL_SETUP_PROTO(sysctl_ipc_setup); 133 134 static struct sysctllog *sysctl_sysvipc_clog = NULL; 135 136 static const struct syscall_package sysvipc_syscalls[] = { 137 #if defined(SYSVSHM) 138 { SYS___shmctl50, 0, (sy_call_t *)sys___shmctl50 }, 139 { SYS_shmat, 0, (sy_call_t *)sys_shmat }, 140 { SYS_shmdt, 0, (sy_call_t *)sys_shmdt }, 141 { SYS_shmget, 0, (sy_call_t *)sys_shmget }, 142 #endif /* SYSVSHM */ 143 144 #if defined(SYSVSEM) 145 { SYS_____semctl50, 0, (sy_call_t *)sys_____semctl50 }, 146 { SYS_semget, 0, (sy_call_t *)sys_semget }, 147 { SYS_semop, 0, (sy_call_t *)sys_semop }, 148 { SYS_semconfig, 0, (sy_call_t *)sys_semconfig }, 149 #endif /* SYSVSEM */ 150 151 #if defined(SYSVMSG) 152 { SYS___msgctl50, 0, (sy_call_t *)sys___msgctl50 }, 153 { SYS_msgget, 0, (sy_call_t *)sys_msgget }, 154 { SYS_msgsnd, 0, (sy_call_t *)sys_msgsnd }, 155 { SYS_msgrcv, 0, (sy_call_t *)sys_msgrcv }, 156 #endif /* SYSVMSG */ 157 { 0, 0, NULL } 158 }; 159 160 static int 161 sysv_ipc_modcmd(modcmd_t cmd, void *arg) 162 { 163 int error = 0; 164 165 switch (cmd) { 166 case MODULE_CMD_INIT: 167 /* Set up the kauth listener */ 168 sysvipcinit(); 169 170 /* Link the system calls */ 171 error = syscall_establish(NULL, sysvipc_syscalls); 172 if (error) { 173 sysvipcfini(); 174 return error; 175 } 176 177 /* 178 * Initialize each sub-component, including their 179 * sysctl data 180 */ 181 #ifdef SYSVSHM 182 shminit(&sysctl_sysvipc_clog); 183 #endif 184 #ifdef SYSVSEM 185 seminit(&sysctl_sysvipc_clog); 186 #endif 187 #ifdef SYSVMSG 188 msginit(&sysctl_sysvipc_clog); 189 #endif 190 191 #ifdef _MODULE 192 /* Set up the common sysctl tree */ 193 sysctl_ipc_setup(&sysctl_sysvipc_clog); 194 #endif 195 break; 196 case MODULE_CMD_FINI: 197 /* 198 * Make sure no subcomponents are active. Each one 199 * tells us if it is busy, and if it was _not_ busy, 200 * we assume it has already done its own clean-up. 201 * So we might need to re-init any components that 202 * are successfully fini'd if we find one that is 203 * still busy. 204 */ 205 #ifdef SYSVSHM 206 if (shmfini()) { 207 return EBUSY; 208 } 209 #endif 210 #ifdef SYSVSEM 211 if (semfini()) { 212 #ifdef SYSVSHM 213 shminit(NULL); 214 #endif 215 return EBUSY; 216 } 217 #endif 218 #ifdef SYSVMSG 219 if (msgfini()) { 220 #ifdef SYSVSEM 221 seminit(NULL); 222 #endif 223 #ifdef SYSVSHM 224 shminit(NULL); 225 #endif 226 return EBUSY; 227 } 228 #endif 229 230 #ifdef _MODULE 231 /* Remove the sysctl sub-trees */ 232 sysctl_teardown(&sysctl_sysvipc_clog); 233 #endif 234 235 /* Unlink the system calls. */ 236 error = syscall_disestablish(NULL, sysvipc_syscalls); 237 if (error) 238 return error; 239 240 /* Remove the kauth listener */ 241 sysvipcfini(); 242 break; 243 default: 244 return ENOTTY; 245 } 246 return error; 247 } 248 249 static kauth_listener_t sysvipc_listener = NULL; 250 251 static int 252 sysvipc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 253 void *arg0, void *arg1, void *arg2, void *arg3) 254 { 255 mode_t mask; 256 int ismember = 0; 257 struct ipc_perm *perm; 258 int mode; 259 enum kauth_system_req req; 260 261 req = (enum kauth_system_req)arg0; 262 263 if (!(action == KAUTH_SYSTEM_SYSVIPC && 264 req == KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS)) 265 return KAUTH_RESULT_DEFER; 266 267 perm = arg1; 268 mode = (int)(uintptr_t)arg2; 269 270 if (mode == IPC_M) { 271 if (kauth_cred_geteuid(cred) == perm->uid || 272 kauth_cred_geteuid(cred) == perm->cuid) 273 return (KAUTH_RESULT_ALLOW); 274 return (KAUTH_RESULT_DEFER); /* EPERM */ 275 } 276 277 mask = 0; 278 279 if (kauth_cred_geteuid(cred) == perm->uid || 280 kauth_cred_geteuid(cred) == perm->cuid) { 281 if (mode & IPC_R) 282 mask |= S_IRUSR; 283 if (mode & IPC_W) 284 mask |= S_IWUSR; 285 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 286 } 287 288 if (kauth_cred_getegid(cred) == perm->gid || 289 (kauth_cred_ismember_gid(cred, perm->gid, &ismember) == 0 && ismember) || 290 kauth_cred_getegid(cred) == perm->cgid || 291 (kauth_cred_ismember_gid(cred, perm->cgid, &ismember) == 0 && ismember)) { 292 if (mode & IPC_R) 293 mask |= S_IRGRP; 294 if (mode & IPC_W) 295 mask |= S_IWGRP; 296 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 297 } 298 299 if (mode & IPC_R) 300 mask |= S_IROTH; 301 if (mode & IPC_W) 302 mask |= S_IWOTH; 303 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 304 } 305 306 /* 307 * Check for ipc permission 308 */ 309 310 int 311 ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode) 312 { 313 int error; 314 315 error = kauth_authorize_system(cred, KAUTH_SYSTEM_SYSVIPC, 316 KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS, perm, KAUTH_ARG(mode), NULL); 317 if (error == 0) 318 return (0); 319 320 /* Adjust EPERM and EACCES errors until there's a better way to do this. */ 321 if (mode != IPC_M) 322 error = EACCES; 323 324 return error; 325 } 326 327 void 328 sysvipcfini(void) 329 { 330 331 KASSERT(sysvipc_listener != NULL); 332 kauth_unlisten_scope(sysvipc_listener); 333 sysvipc_listener = NULL; 334 } 335 336 void 337 sysvipcinit(void) 338 { 339 340 KASSERT(sysvipc_listener == NULL); 341 342 sysvipc_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 343 sysvipc_listener_cb, NULL); 344 } 345 346 static int 347 stub_sysvipc50_sysctl(SYSCTLFN_ARGS) 348 { 349 return EPASSTHROUGH; 350 } 351 352 static int 353 sysctl_kern_sysvipc(SYSCTLFN_ARGS) 354 { 355 void *where = oldp; 356 size_t sz, *sizep = oldlenp; 357 #ifdef SYSVMSG 358 struct msg_sysctl_info *msgsi = NULL; 359 #endif 360 #ifdef SYSVSEM 361 struct sem_sysctl_info *semsi = NULL; 362 #endif 363 #ifdef SYSVSHM 364 struct shm_sysctl_info *shmsi = NULL; 365 #endif 366 size_t infosize, dssize, tsize, buflen; 367 void *bf = NULL; 368 char *start; 369 int32_t nds; 370 int i, error, ret; 371 372 /* 373 * If present, call the compat sysctl() code. If it handles the request 374 * completely (either success or error), return. Otherwise fallthrough 375 * to the non-compat sysctl code. 376 */ 377 378 MODULE_CALL_HOOK(sysvipc50_sysctl_hook, (SYSCTLFN_CALL(rnode)), 379 stub_sysvipc50_sysctl(SYSCTLFN_CALL(rnode)), error); 380 if (error != EPASSTHROUGH) 381 return error; 382 383 if (namelen != 1) 384 return EINVAL; 385 386 start = where; 387 buflen = *sizep; 388 389 switch (*name) { 390 case KERN_SYSVIPC_MSG_INFO: 391 #ifdef SYSVMSG 392 infosize = sizeof(msgsi->msginfo); 393 nds = msginfo.msgmni; 394 dssize = sizeof(msgsi->msgids[0]); 395 break; 396 #else 397 return EINVAL; 398 #endif 399 case KERN_SYSVIPC_SEM_INFO: 400 #ifdef SYSVSEM 401 infosize = sizeof(semsi->seminfo); 402 nds = seminfo.semmni; 403 dssize = sizeof(semsi->semids[0]); 404 break; 405 #else 406 return EINVAL; 407 #endif 408 case KERN_SYSVIPC_SHM_INFO: 409 #ifdef SYSVSHM 410 infosize = sizeof(shmsi->shminfo); 411 nds = shminfo.shmmni; 412 dssize = sizeof(shmsi->shmids[0]); 413 break; 414 #else 415 return EINVAL; 416 #endif 417 default: 418 return EINVAL; 419 } 420 /* 421 * Round infosize to 64 bit boundary if requesting more than just 422 * the info structure or getting the total data size. 423 */ 424 if (where == NULL || *sizep > infosize) 425 infosize = roundup(infosize, sizeof(quad_t)); 426 tsize = infosize + nds * dssize; 427 428 /* Return just the total size required. */ 429 if (where == NULL) { 430 *sizep = tsize; 431 return 0; 432 } 433 434 /* Not enough room for even the info struct. */ 435 if (buflen < infosize) { 436 *sizep = 0; 437 return ENOMEM; 438 } 439 sz = uimin(tsize, buflen); 440 bf = kmem_zalloc(sz, KM_SLEEP); 441 442 switch (*name) { 443 #ifdef SYSVMSG 444 case KERN_SYSVIPC_MSG_INFO: 445 msgsi = (struct msg_sysctl_info *)bf; 446 msgsi->msginfo = msginfo; 447 break; 448 #endif 449 #ifdef SYSVSEM 450 case KERN_SYSVIPC_SEM_INFO: 451 semsi = (struct sem_sysctl_info *)bf; 452 semsi->seminfo = seminfo; 453 break; 454 #endif 455 #ifdef SYSVSHM 456 case KERN_SYSVIPC_SHM_INFO: 457 shmsi = (struct shm_sysctl_info *)bf; 458 shmsi->shminfo = shminfo; 459 break; 460 #endif 461 } 462 buflen -= infosize; 463 464 ret = 0; 465 if (buflen > 0) { 466 /* Fill in the IPC data structures. */ 467 for (i = 0; i < nds; i++) { 468 if (buflen < dssize) { 469 ret = ENOMEM; 470 break; 471 } 472 switch (*name) { 473 #ifdef SYSVMSG 474 case KERN_SYSVIPC_MSG_INFO: 475 mutex_enter(&msgmutex); 476 SYSCTL_FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]); 477 mutex_exit(&msgmutex); 478 break; 479 #endif 480 #ifdef SYSVSEM 481 case KERN_SYSVIPC_SEM_INFO: 482 SYSCTL_FILL_SEM(sema[i], semsi->semids[i]); 483 break; 484 #endif 485 #ifdef SYSVSHM 486 case KERN_SYSVIPC_SHM_INFO: 487 SYSCTL_FILL_SHM(shmsegs[i], shmsi->shmids[i]); 488 break; 489 #endif 490 } 491 buflen -= dssize; 492 } 493 } 494 *sizep -= buflen; 495 error = copyout(bf, start, *sizep); 496 /* If copyout succeeded, use return code set earlier. */ 497 if (error == 0) 498 error = ret; 499 if (bf) 500 kmem_free(bf, sz); 501 return error; 502 } 503 504 SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup") 505 { 506 507 sysctl_createv(clog, 0, NULL, NULL, 508 CTLFLAG_PERMANENT, 509 CTLTYPE_NODE, "ipc", 510 SYSCTL_DESCR("SysV IPC options"), 511 NULL, 0, NULL, 0, 512 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 513 514 sysctl_createv(clog, 0, NULL, NULL, 515 CTLFLAG_PERMANENT, 516 CTLTYPE_STRUCT, "sysvipc_info", 517 SYSCTL_DESCR("System V style IPC information"), 518 sysctl_kern_sysvipc, 0, NULL, 0, 519 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_INFO, CTL_EOL); 520 } 521
Indexes created Wed Sep 24 22:09:59 GMT 2025