sysv_ipc.c revision 1.32.16.6
1 /* $NetBSD: sysv_ipc.c,v 1.32.16.6 2018/10/15 22:06:16 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 1.32.16.6 2018/10/15 22:06:16 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 #ifdef _MODULE 171 /* Set up the common sysctl tree */ 172 sysctl_ipc_setup(&sysctl_sysvipc_clog); 173 #endif 174 175 /* Link the system calls */ 176 error = syscall_establish(NULL, sysvipc_syscalls); 177 if (error) 178 sysvipcfini(); 179 180 /* 181 * Initialize each sub-component, including their 182 * sysctl data 183 */ 184 #ifdef SYSVSHM 185 shminit(&sysctl_sysvipc_clog); 186 #endif 187 #ifdef SYSVSEM 188 seminit(&sysctl_sysvipc_clog); 189 #endif 190 #ifdef SYSVMSG 191 msginit(&sysctl_sysvipc_clog); 192 #endif 193 break; 194 case MODULE_CMD_FINI: 195 /* 196 * Make sure no subcomponents are active. Each one 197 * tells us if it is busy, and if it was _not_ busy, 198 * we assume it has already done its own clean-up. 199 * So we might need to re-init any components that 200 * are successfully fini'd if we find one that is 201 * still busy. 202 */ 203 #ifdef SYSVSHM 204 if (shmfini()) { 205 return EBUSY; 206 } 207 #endif 208 #ifdef SYSVSEM 209 if (semfini()) { 210 #ifdef SYSVSHM 211 shminit(NULL); 212 #endif 213 return EBUSY; 214 } 215 #endif 216 #ifdef SYSVMSG 217 if (msgfini()) { 218 #ifdef SYSVSEM 219 seminit(NULL); 220 #endif 221 #ifdef SYSVSHM 222 shminit(NULL); 223 #endif 224 return EBUSY; 225 } 226 #endif 227 228 /* Unlink the system calls. */ 229 error = syscall_disestablish(NULL, sysvipc_syscalls); 230 if (error) 231 return error; 232 233 #ifdef _MODULE 234 /* Remove the sysctl sub-trees */ 235 sysctl_teardown(&sysctl_sysvipc_clog); 236 #endif 237 238 /* Remove the kauth listener */ 239 sysvipcfini(); 240 break; 241 default: 242 return ENOTTY; 243 } 244 return error; 245 } 246 247 static kauth_listener_t sysvipc_listener = NULL; 248 249 static int 250 sysvipc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 251 void *arg0, void *arg1, void *arg2, void *arg3) 252 { 253 mode_t mask; 254 int ismember = 0; 255 struct ipc_perm *perm; 256 int mode; 257 enum kauth_system_req req; 258 259 req = (enum kauth_system_req)arg0; 260 261 if (!(action == KAUTH_SYSTEM_SYSVIPC && 262 req == KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS)) 263 return KAUTH_RESULT_DEFER; 264 265 perm = arg1; 266 mode = (int)(uintptr_t)arg2; 267 268 if (mode == IPC_M) { 269 if (kauth_cred_geteuid(cred) == perm->uid || 270 kauth_cred_geteuid(cred) == perm->cuid) 271 return (KAUTH_RESULT_ALLOW); 272 return (KAUTH_RESULT_DEFER); /* EPERM */ 273 } 274 275 mask = 0; 276 277 if (kauth_cred_geteuid(cred) == perm->uid || 278 kauth_cred_geteuid(cred) == perm->cuid) { 279 if (mode & IPC_R) 280 mask |= S_IRUSR; 281 if (mode & IPC_W) 282 mask |= S_IWUSR; 283 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 284 } 285 286 if (kauth_cred_getegid(cred) == perm->gid || 287 (kauth_cred_ismember_gid(cred, perm->gid, &ismember) == 0 && ismember) || 288 kauth_cred_getegid(cred) == perm->cgid || 289 (kauth_cred_ismember_gid(cred, perm->cgid, &ismember) == 0 && ismember)) { 290 if (mode & IPC_R) 291 mask |= S_IRGRP; 292 if (mode & IPC_W) 293 mask |= S_IWGRP; 294 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 295 } 296 297 if (mode & IPC_R) 298 mask |= S_IROTH; 299 if (mode & IPC_W) 300 mask |= S_IWOTH; 301 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 302 } 303 304 /* 305 * Check for ipc permission 306 */ 307 308 int 309 ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode) 310 { 311 int error; 312 313 error = kauth_authorize_system(cred, KAUTH_SYSTEM_SYSVIPC, 314 KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS, perm, KAUTH_ARG(mode), NULL); 315 if (error == 0) 316 return (0); 317 318 /* Adjust EPERM and EACCES errors until there's a better way to do this. */ 319 if (mode != IPC_M) 320 error = EACCES; 321 322 return error; 323 } 324 325 void 326 sysvipcfini(void) 327 { 328 329 KASSERT(sysvipc_listener != NULL); 330 kauth_unlisten_scope(sysvipc_listener); 331 sysvipc_listener = NULL; 332 } 333 334 void 335 sysvipcinit(void) 336 { 337 338 KASSERT(sysvipc_listener == NULL); 339 340 sysvipc_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 341 sysvipc_listener_cb, NULL); 342 } 343 344 static int 345 stub_sysvipc50_sysctl(SYSCTLFN_ARGS) 346 { 347 return EPASSTHROUGH; 348 } 349 350 MODULE_CALL_HOOK_DECL(sysvipc50_sysctl_hook, f, (SYSCTLFN_PROTO)); 351 MODULE_CALL_HOOK(sysvipc50_sysctl_hook, f, (SYSCTLFN_ARGS), 352 (SYSCTLFN_CALL(rnode)), stub_sysvipc50_sysctl(SYSCTLFN_CALL(rnode))); 353 354 static int 355 sysctl_kern_sysvipc(SYSCTLFN_ARGS) 356 { 357 void *where = oldp; 358 size_t sz, *sizep = oldlenp; 359 #ifdef SYSVMSG 360 struct msg_sysctl_info *msgsi = NULL; 361 #endif 362 #ifdef SYSVSEM 363 struct sem_sysctl_info *semsi = NULL; 364 #endif 365 #ifdef SYSVSHM 366 struct shm_sysctl_info *shmsi = NULL; 367 #endif 368 size_t infosize, dssize, tsize, buflen; 369 void *bf = NULL; 370 char *start; 371 int32_t nds; 372 int i, error, ret; 373 374 /* 375 * If present, call the compat sysctl() code. If it handles the request 376 * completely (either success or error), return. Otherwise fallthrough 377 * to the non-compat sysctl code. 378 */ 379 380 error = sysvipc50_sysctl_hook_f_call(SYSCTLFN_CALL(rnode)); 381 if (error != EPASSTHROUGH) 382 return error; 383 384 if (namelen != 1) 385 return EINVAL; 386 387 start = where; 388 buflen = *sizep; 389 390 switch (*name) { 391 case KERN_SYSVIPC_MSG_INFO: 392 #ifdef SYSVMSG 393 infosize = sizeof(msgsi->msginfo); 394 nds = msginfo.msgmni; 395 dssize = sizeof(msgsi->msgids[0]); 396 break; 397 #else 398 return EINVAL; 399 #endif 400 case KERN_SYSVIPC_SEM_INFO: 401 #ifdef SYSVSEM 402 infosize = sizeof(semsi->seminfo); 403 nds = seminfo.semmni; 404 dssize = sizeof(semsi->semids[0]); 405 break; 406 #else 407 return EINVAL; 408 #endif 409 case KERN_SYSVIPC_SHM_INFO: 410 #ifdef SYSVSHM 411 infosize = sizeof(shmsi->shminfo); 412 nds = shminfo.shmmni; 413 dssize = sizeof(shmsi->shmids[0]); 414 break; 415 #else 416 return EINVAL; 417 #endif 418 default: 419 return EINVAL; 420 } 421 /* 422 * Round infosize to 64 bit boundary if requesting more than just 423 * the info structure or getting the total data size. 424 */ 425 if (where == NULL || *sizep > infosize) 426 infosize = roundup(infosize, sizeof(quad_t)); 427 tsize = infosize + nds * dssize; 428 429 /* Return just the total size required. */ 430 if (where == NULL) { 431 *sizep = tsize; 432 return 0; 433 } 434 435 /* Not enough room for even the info struct. */ 436 if (buflen < infosize) { 437 *sizep = 0; 438 return ENOMEM; 439 } 440 sz = uimin(tsize, buflen); 441 bf = kmem_zalloc(sz, KM_SLEEP); 442 443 switch (*name) { 444 #ifdef SYSVMSG 445 case KERN_SYSVIPC_MSG_INFO: 446 msgsi = (struct msg_sysctl_info *)bf; 447 msgsi->msginfo = msginfo; 448 break; 449 #endif 450 #ifdef SYSVSEM 451 case KERN_SYSVIPC_SEM_INFO: 452 semsi = (struct sem_sysctl_info *)bf; 453 semsi->seminfo = seminfo; 454 break; 455 #endif 456 #ifdef SYSVSHM 457 case KERN_SYSVIPC_SHM_INFO: 458 shmsi = (struct shm_sysctl_info *)bf; 459 shmsi->shminfo = shminfo; 460 break; 461 #endif 462 } 463 buflen -= infosize; 464 465 ret = 0; 466 if (buflen > 0) { 467 /* Fill in the IPC data structures. */ 468 for (i = 0; i < nds; i++) { 469 if (buflen < dssize) { 470 ret = ENOMEM; 471 break; 472 } 473 switch (*name) { 474 #ifdef SYSVMSG 475 case KERN_SYSVIPC_MSG_INFO: 476 mutex_enter(&msgmutex); 477 SYSCTL_FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]); 478 mutex_exit(&msgmutex); 479 break; 480 #endif 481 #ifdef SYSVSEM 482 case KERN_SYSVIPC_SEM_INFO: 483 SYSCTL_FILL_SEM(sema[i], semsi->semids[i]); 484 break; 485 #endif 486 #ifdef SYSVSHM 487 case KERN_SYSVIPC_SHM_INFO: 488 SYSCTL_FILL_SHM(shmsegs[i], shmsi->shmids[i]); 489 break; 490 #endif 491 } 492 buflen -= dssize; 493 } 494 } 495 *sizep -= buflen; 496 error = copyout(bf, start, *sizep); 497 /* If copyout succeeded, use return code set earlier. */ 498 if (error == 0) 499 error = ret; 500 if (bf) 501 kmem_free(bf, sz); 502 return error; 503 } 504 505 SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup") 506 { 507 508 sysctl_createv(clog, 0, NULL, NULL, 509 CTLFLAG_PERMANENT, 510 CTLTYPE_NODE, "ipc", 511 SYSCTL_DESCR("SysV IPC options"), 512 NULL, 0, NULL, 0, 513 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 514 515 sysctl_createv(clog, 0, NULL, NULL, 516 CTLFLAG_PERMANENT, 517 CTLTYPE_STRUCT, "sysvipc_info", 518 SYSCTL_DESCR("System V style IPC information"), 519 sysctl_kern_sysvipc, 0, NULL, 0, 520 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_INFO, CTL_EOL); 521 } 522
Indexes created Wed Sep 24 15:09:51 GMT 2025