1 /* $NetBSD: sysv_ipc.c,v 1.43 2024/10/09 16:27:28 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 1.43 2024/10/09 16:27:28 christos Exp $"); 34 35 #ifdef _KERNEL_OPT 36 #include "opt_sysv.h" 37 #include "opt_sysvparam.h" 38 #include "opt_compat_netbsd.h" 39 #endif 40 41 #include <sys/syscall.h> 42 #include <sys/syscallargs.h> 43 #include <sys/syscallvar.h> 44 #include <sys/param.h> 45 #include <sys/kernel.h> 46 #include <sys/proc.h> 47 #include <sys/ipc.h> 48 #ifdef SYSVMSG 49 #include <sys/msg.h> 50 #endif 51 #ifdef SYSVSEM 52 #include <sys/sem.h> 53 #endif 54 #ifdef SYSVSHM 55 #include <sys/shm.h> 56 #endif 57 #include <sys/systm.h> 58 #include <sys/kmem.h> 59 #include <sys/module.h> 60 #include <sys/mount.h> 61 #include <sys/vnode.h> 62 #include <sys/stat.h> 63 #include <sys/sysctl.h> 64 #include <sys/kauth.h> 65 #include <sys/compat_stub.h> 66 67 #include <compat/common/compat_sysv_mod.h> /* for sysctl routine vector */ 68 69 /* 70 * Values in support of System V compatible shared memory. XXX 71 * (originally located in sys/conf/param.c) 72 */ 73 #ifdef SYSVSHM 74 #if !defined(SHMMAX) && defined(SHMMAXPGS) 75 #define SHMMAX SHMMAXPGS /* shminit() performs a `*= PAGE_SIZE' */ 76 #elif !defined(SHMMAX) 77 #define SHMMAX 0 78 #endif 79 #ifndef SHMMIN 80 #define SHMMIN 1 81 #endif 82 #ifndef SHMMNI 83 #define SHMMNI 128 /* <64k, see IPCID_TO_IX in ipc.h */ 84 #endif 85 #ifndef SHMSEG 86 #define SHMSEG 128 87 #endif 88 89 struct shminfo shminfo = { 90 SHMMAX, 91 SHMMIN, 92 SHMMNI, 93 SHMSEG, 94 0 95 }; 96 #endif 97 98 /* 99 * Values in support of System V compatible semaphores. 100 */ 101 #ifdef SYSVSEM 102 struct seminfo seminfo = { 103 SEMMAP, /* # of entries in semaphore map */ 104 SEMMNI, /* # of semaphore identifiers */ 105 SEMMNS, /* # of semaphores in system */ 106 SEMMNU, /* # of undo structures in system */ 107 SEMMSL, /* max # of semaphores per id */ 108 SEMOPM, /* max # of operations per semop call */ 109 SEMUME, /* max # of undo entries per process */ 110 SEMUSZ, /* size in bytes of undo structure */ 111 SEMVMX, /* semaphore maximum value */ 112 SEMAEM /* adjust on exit max value */ 113 }; 114 #endif 115 116 /* 117 * Values in support of System V compatible messages. 118 */ 119 #ifdef SYSVMSG 120 struct msginfo msginfo = { 121 MSGMAX, /* max chars in a message */ 122 MSGMNI, /* # of message queue identifiers */ 123 MSGMNB, /* max chars in a queue */ 124 MSGTQL, /* max messages in system */ 125 MSGSSZ, /* size of a message segment */ 126 /* (must be small power of 2 greater than 4) */ 127 MSGSEG /* number of message segments */ 128 }; 129 #endif 130 131 MODULE(MODULE_CLASS_EXEC, sysv_ipc, NULL); 132 133 SYSCTL_SETUP_PROTO(sysctl_ipc_setup); 134 135 static const struct syscall_package sysvipc_syscalls[] = { 136 #if defined(SYSVSHM) 137 { SYS___shmctl50, 0, (sy_call_t *)sys___shmctl50 }, 138 { SYS_shmat, 0, (sy_call_t *)sys_shmat }, 139 { SYS_shmdt, 0, (sy_call_t *)sys_shmdt }, 140 { SYS_shmget, 0, (sy_call_t *)sys_shmget }, 141 #endif /* SYSVSHM */ 142 143 #if defined(SYSVSEM) 144 { SYS_____semctl50, 0, (sy_call_t *)sys_____semctl50 }, 145 { SYS_semget, 0, (sy_call_t *)sys_semget }, 146 { SYS_semop, 0, (sy_call_t *)sys_semop }, 147 { SYS_semconfig, 0, (sy_call_t *)sys_semconfig }, 148 { SYS_semtimedop, 0, (sy_call_t *)sys_semtimedop }, 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 error = shminit(); 183 if (error != 0) 184 return error; 185 #endif 186 #ifdef SYSVSEM 187 error = seminit(); 188 if (error != 0) { 189 #ifdef SYSVSHM 190 shmfini(); 191 #endif 192 return error; 193 } 194 #endif 195 #ifdef SYSVMSG 196 error = msginit(); 197 if (error != 0) { 198 #ifdef SYSVSEM 199 semfini(); 200 #endif 201 #ifdef SYSVSHM 202 shmfini(); 203 #endif 204 return error; 205 } 206 #endif 207 break; 208 case MODULE_CMD_FINI: 209 /* 210 * Make sure no subcomponents are active. Each one 211 * tells us if it is busy, and if it was _not_ busy, 212 * we assume it has already done its own clean-up. 213 * So we might need to re-init any components that 214 * are successfully fini'd if we find one that is 215 * still busy. 216 */ 217 #ifdef SYSVSHM 218 if (shmfini()) { 219 return EBUSY; 220 } 221 #endif 222 #ifdef SYSVSEM 223 if (semfini()) { 224 #ifdef SYSVSHM 225 shminit(); 226 #endif 227 return EBUSY; 228 } 229 #endif 230 #ifdef SYSVMSG 231 if (msgfini()) { 232 #ifdef SYSVSEM 233 seminit(); 234 #endif 235 #ifdef SYSVSHM 236 shminit(); 237 #endif 238 return EBUSY; 239 } 240 #endif 241 /* Unlink the system calls. */ 242 error = syscall_disestablish(NULL, sysvipc_syscalls); 243 if (error) 244 return error; 245 246 /* Remove the kauth listener */ 247 sysvipcfini(); 248 break; 249 default: 250 return ENOTTY; 251 } 252 return error; 253 } 254 255 static kauth_listener_t sysvipc_listener = NULL; 256 257 static int 258 sysvipc_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, 259 void *arg0, void *arg1, void *arg2, void *arg3) 260 { 261 mode_t mask; 262 struct ipc_perm *perm; 263 int mode; 264 enum kauth_system_req req; 265 266 req = (enum kauth_system_req)(uintptr_t)arg0; 267 268 if (!(action == KAUTH_SYSTEM_SYSVIPC && 269 req == KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS)) 270 return KAUTH_RESULT_DEFER; 271 272 perm = arg1; 273 mode = (int)(uintptr_t)arg2; 274 275 if (mode == IPC_M) { 276 if (kauth_cred_geteuid(cred) == perm->uid || 277 kauth_cred_geteuid(cred) == perm->cuid) 278 return (KAUTH_RESULT_ALLOW); 279 return (KAUTH_RESULT_DEFER); /* EPERM */ 280 } 281 282 mask = 0; 283 284 if (kauth_cred_geteuid(cred) == perm->uid || 285 kauth_cred_geteuid(cred) == perm->cuid) { 286 if (mode & IPC_R) 287 mask |= S_IRUSR; 288 if (mode & IPC_W) 289 mask |= S_IWUSR; 290 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 291 } 292 293 if (kauth_cred_groupmember(cred, perm->gid) == 0 || 294 kauth_cred_groupmember(cred, perm->cgid) == 0) { 295 if (mode & IPC_R) 296 mask |= S_IRGRP; 297 if (mode & IPC_W) 298 mask |= S_IWGRP; 299 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 300 } 301 302 if (mode & IPC_R) 303 mask |= S_IROTH; 304 if (mode & IPC_W) 305 mask |= S_IWOTH; 306 return ((perm->mode & mask) == mask ? KAUTH_RESULT_ALLOW : KAUTH_RESULT_DEFER /* EACCES */); 307 } 308 309 /* 310 * Check for ipc permission 311 */ 312 313 int 314 ipcperm(kauth_cred_t cred, struct ipc_perm *perm, int mode) 315 { 316 int error; 317 318 error = kauth_authorize_system(cred, KAUTH_SYSTEM_SYSVIPC, 319 KAUTH_REQ_SYSTEM_SYSVIPC_BYPASS, perm, KAUTH_ARG(mode), NULL); 320 if (error == 0) 321 return (0); 322 323 /* Adjust EPERM and EACCES errors until there's a better way to do this. */ 324 if (mode != IPC_M) 325 error = EACCES; 326 327 return error; 328 } 329 330 void 331 sysvipcfini(void) 332 { 333 334 KASSERT(sysvipc_listener != NULL); 335 kauth_unlisten_scope(sysvipc_listener); 336 sysvipc_listener = NULL; 337 } 338 339 void 340 sysvipcinit(void) 341 { 342 343 KASSERT(sysvipc_listener == NULL); 344 345 sysvipc_listener = kauth_listen_scope(KAUTH_SCOPE_SYSTEM, 346 sysvipc_listener_cb, NULL); 347 } 348 349 static int 350 stub_sysvipc50_sysctl(SYSCTLFN_ARGS) 351 { 352 return EPASSTHROUGH; 353 } 354 355 static int 356 sysctl_kern_sysvipc(SYSCTLFN_ARGS) 357 { 358 void *where = oldp; 359 size_t sz, *sizep = oldlenp; 360 #ifdef SYSVMSG 361 struct msg_sysctl_info *msgsi = NULL; 362 #endif 363 #ifdef SYSVSEM 364 struct sem_sysctl_info *semsi = NULL; 365 #endif 366 #ifdef SYSVSHM 367 struct shm_sysctl_info *shmsi = NULL; 368 #endif 369 size_t infosize, dssize, tsize, buflen; 370 void *bf = NULL; 371 char *start; 372 int32_t nds; 373 int i, error, ret; 374 375 /* 376 * If present, call the compat sysctl() code. If it handles the request 377 * completely (either success or error), return. Otherwise fallthrough 378 * to the non-compat sysctl code. 379 */ 380 381 MODULE_HOOK_CALL(sysvipc_sysctl_50_hook, (SYSCTLFN_CALL(rnode)), 382 stub_sysvipc50_sysctl(SYSCTLFN_CALL(rnode)), error); 383 if (error != EPASSTHROUGH) 384 return error; 385 386 if (namelen != 1) 387 return EINVAL; 388 389 start = where; 390 buflen = *sizep; 391 392 switch (*name) { 393 case KERN_SYSVIPC_MSG_INFO: 394 #ifdef SYSVMSG 395 infosize = sizeof(msgsi->msginfo); 396 nds = msginfo.msgmni; 397 dssize = sizeof(msgsi->msgids[0]); 398 break; 399 #else 400 return EINVAL; 401 #endif 402 case KERN_SYSVIPC_SEM_INFO: 403 #ifdef SYSVSEM 404 infosize = sizeof(semsi->seminfo); 405 nds = seminfo.semmni; 406 dssize = sizeof(semsi->semids[0]); 407 break; 408 #else 409 return EINVAL; 410 #endif 411 case KERN_SYSVIPC_SHM_INFO: 412 #ifdef SYSVSHM 413 infosize = sizeof(shmsi->shminfo); 414 nds = shminfo.shmmni; 415 dssize = sizeof(shmsi->shmids[0]); 416 break; 417 #else 418 return EINVAL; 419 #endif 420 default: 421 return EINVAL; 422 } 423 /* 424 * Round infosize to 64 bit boundary if requesting more than just 425 * the info structure or getting the total data size. 426 */ 427 if (where == NULL || *sizep > infosize) 428 infosize = roundup(infosize, sizeof(quad_t)); 429 tsize = infosize + nds * dssize; 430 431 /* Return just the total size required. */ 432 if (where == NULL) { 433 *sizep = tsize; 434 return 0; 435 } 436 437 /* Not enough room for even the info struct. */ 438 if (buflen < infosize) { 439 *sizep = 0; 440 return ENOMEM; 441 } 442 sz = uimin(tsize, buflen); 443 bf = kmem_zalloc(sz, KM_SLEEP); 444 445 switch (*name) { 446 #ifdef SYSVMSG 447 case KERN_SYSVIPC_MSG_INFO: 448 msgsi = (struct msg_sysctl_info *)bf; 449 msgsi->msginfo = msginfo; 450 break; 451 #endif 452 #ifdef SYSVSEM 453 case KERN_SYSVIPC_SEM_INFO: 454 semsi = (struct sem_sysctl_info *)bf; 455 semsi->seminfo = seminfo; 456 break; 457 #endif 458 #ifdef SYSVSHM 459 case KERN_SYSVIPC_SHM_INFO: 460 shmsi = (struct shm_sysctl_info *)bf; 461 shmsi->shminfo = shminfo; 462 break; 463 #endif 464 } 465 buflen -= infosize; 466 467 ret = 0; 468 if (buflen > 0) { 469 /* Fill in the IPC data structures. */ 470 for (i = 0; i < nds; i++) { 471 if (buflen < dssize) { 472 ret = ENOMEM; 473 break; 474 } 475 switch (*name) { 476 #ifdef SYSVMSG 477 case KERN_SYSVIPC_MSG_INFO: 478 mutex_enter(&msgmutex); 479 SYSCTL_FILL_MSG(msqs[i].msq_u, msgsi->msgids[i]); 480 mutex_exit(&msgmutex); 481 break; 482 #endif 483 #ifdef SYSVSEM 484 case KERN_SYSVIPC_SEM_INFO: 485 SYSCTL_FILL_SEM(sema[i], semsi->semids[i]); 486 break; 487 #endif 488 #ifdef SYSVSHM 489 case KERN_SYSVIPC_SHM_INFO: 490 SYSCTL_FILL_SHM(shmsegs[i], shmsi->shmids[i]); 491 break; 492 #endif 493 } 494 buflen -= dssize; 495 } 496 } 497 *sizep -= buflen; 498 error = copyout(bf, start, *sizep); 499 /* If copyout succeeded, use return code set earlier. */ 500 if (error == 0) 501 error = ret; 502 if (bf) 503 kmem_free(bf, sz); 504 return error; 505 } 506 507 SYSCTL_SETUP(sysctl_ipc_setup, "sysctl kern.ipc subtree setup") 508 { 509 510 sysctl_createv(clog, 0, NULL, NULL, 511 CTLFLAG_PERMANENT, 512 CTLTYPE_NODE, "ipc", 513 SYSCTL_DESCR("SysV IPC options"), 514 NULL, 0, NULL, 0, 515 CTL_KERN, KERN_SYSVIPC, CTL_EOL); 516 517 sysctl_createv(clog, 0, NULL, NULL, 518 CTLFLAG_PERMANENT, 519 CTLTYPE_STRUCT, "sysvipc_info", 520 SYSCTL_DESCR("System V style IPC information"), 521 sysctl_kern_sysvipc, 0, NULL, 0, 522 CTL_KERN, KERN_SYSVIPC, KERN_SYSVIPC_INFO, CTL_EOL); 523 } 524
Indexes created Sat Sep 20 22:09:52 GMT 2025