1 /* 2 * linux/ipc/shm.c 3 * Copyright (C) 1992, 1993 Krishna Balasubramanian 4 * Many improvements/fixes by Bruno Haible. 5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994. 6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli. 7 * 8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com> 9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de> 10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr> 11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com> 12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com> 13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com> 14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com> 15 * 16 * support for audit of ipc object properties and permission changes 17 * Dustin Kirkland <dustin.kirkland@us.ibm.com> 18 * 19 * namespaces support 20 * OpenVZ, SWsoft Inc. 21 * Pavel Emelianov <xemul@openvz.org> 22 */ 23 24 #include <linux/slab.h> 25 #include <linux/mm.h> 26 #include <linux/hugetlb.h> 27 #include <linux/shm.h> 28 #include <linux/init.h> 29 #include <linux/file.h> 30 #include <linux/mman.h> 31 #include <linux/shmem_fs.h> 32 #include <linux/security.h> 33 #include <linux/syscalls.h> 34 #include <linux/audit.h> 35 #include <linux/capability.h> 36 #include <linux/ptrace.h> 37 #include <linux/seq_file.h> 38 #include <linux/mutex.h> 39 #include <linux/nsproxy.h> 40 #include <linux/mount.h> 41 42 #include <asm/uaccess.h> 43 44 #include "util.h" 45 46 struct shm_file_data { 47 int id; 48 struct ipc_namespace *ns; 49 struct file *file; 50 const struct vm_operations_struct *vm_ops; 51 }; 52 53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) 54 55 static const struct file_operations shm_file_operations; 56 static struct vm_operations_struct shm_vm_ops; 57 58 static struct ipc_ids init_shm_ids; 59 60 #define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS])) 61 62 #define shm_lock(ns, id) \ 63 ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id)) 64 #define shm_unlock(shp) \ 65 ipc_unlock(&(shp)->shm_perm) 66 #define shm_get(ns, id) \ 67 ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id)) 68 #define shm_buildid(ns, id, seq) \ 69 ipc_buildid(&shm_ids(ns), id, seq) 70 71 static int newseg (struct ipc_namespace *ns, key_t key, 72 int shmflg, size_t size); 73 static void shm_open(struct vm_area_struct *vma); 74 static void shm_close(struct vm_area_struct *vma); 75 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); 76 #ifdef CONFIG_PROC_FS 77 static int sysvipc_shm_proc_show(struct seq_file *s, void *it); 78 #endif 79 80 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) 81 { 82 ns->ids[IPC_SHM_IDS] = ids; 83 ns->shm_ctlmax = SHMMAX; 84 ns->shm_ctlall = SHMALL; 85 ns->shm_ctlmni = SHMMNI; 86 ns->shm_tot = 0; 87 ipc_init_ids(ids, 1); 88 } 89 90 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp) 91 { 92 if (shp->shm_nattch){ 93 shp->shm_perm.mode |= SHM_DEST; 94 /* Do not find it any more */ 95 shp->shm_perm.key = IPC_PRIVATE; 96 shm_unlock(shp); 97 } else 98 shm_destroy(ns, shp); 99 } 100 101 int shm_init_ns(struct ipc_namespace *ns) 102 { 103 struct ipc_ids *ids; 104 105 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL); 106 if (ids == NULL) 107 return -ENOMEM; 108 109 __shm_init_ns(ns, ids); 110 return 0; 111 } 112 113 void shm_exit_ns(struct ipc_namespace *ns) 114 { 115 int i; 116 struct shmid_kernel *shp; 117 118 mutex_lock(&shm_ids(ns).mutex); 119 for (i = 0; i <= shm_ids(ns).max_id; i++) { 120 shp = shm_lock(ns, i); 121 if (shp == NULL) 122 continue; 123 124 do_shm_rmid(ns, shp); 125 } 126 mutex_unlock(&shm_ids(ns).mutex); 127 128 ipc_fini_ids(ns->ids[IPC_SHM_IDS]); 129 kfree(ns->ids[IPC_SHM_IDS]); 130 ns->ids[IPC_SHM_IDS] = NULL; 131 } 132 133 void __init shm_init (void) 134 { 135 __shm_init_ns(&init_ipc_ns, &init_shm_ids); 136 ipc_init_proc_interface("sysvipc/shm", 137 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", 138 IPC_SHM_IDS, sysvipc_shm_proc_show); 139 } 140 141 static inline int shm_checkid(struct ipc_namespace *ns, 142 struct shmid_kernel *s, int id) 143 { 144 if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id)) 145 return -EIDRM; 146 return 0; 147 } 148 149 static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id) 150 { 151 return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id); 152 } 153 154 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp) 155 { 156 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); 157 } 158 159 160 161 /* This is called by fork, once for every shm attach. */ 162 static void shm_open(struct vm_area_struct *vma) 163 { 164 struct file *file = vma->vm_file; 165 struct shm_file_data *sfd = shm_file_data(file); 166 struct shmid_kernel *shp; 167 168 shp = shm_lock(sfd->ns, sfd->id); 169 BUG_ON(!shp); 170 shp->shm_atim = get_seconds(); 171 shp->shm_lprid = current->tgid; 172 shp->shm_nattch++; 173 shm_unlock(shp); 174 } 175 176 /* 177 * shm_destroy - free the struct shmid_kernel 178 * 179 * @shp: struct to free 180 * 181 * It has to be called with shp and shm_ids.mutex locked, 182 * but returns with shp unlocked and freed. 183 */ 184 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) 185 { 186 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; 187 shm_rmid(ns, shp->id); 188 shm_unlock(shp); 189 if (!is_file_hugepages(shp->shm_file)) 190 shmem_lock(shp->shm_file, 0, shp->mlock_user); 191 else 192 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, 193 shp->mlock_user); 194 fput (shp->shm_file); 195 security_shm_free(shp); 196 ipc_rcu_putref(shp); 197 } 198 199 /* 200 * remove the attach descriptor vma. 201 * free memory for segment if it is marked destroyed. 202 * The descriptor has already been removed from the current->mm->mmap list 203 * and will later be kfree()d. 204 */ 205 static void shm_close(struct vm_area_struct *vma) 206 { 207 struct file * file = vma->vm_file; 208 struct shm_file_data *sfd = shm_file_data(file); 209 struct shmid_kernel *shp; 210 struct ipc_namespace *ns = sfd->ns; 211 212 mutex_lock(&shm_ids(ns).mutex); 213 /* remove from the list of attaches of the shm segment */ 214 shp = shm_lock(ns, sfd->id); 215 BUG_ON(!shp); 216 shp->shm_lprid = current->tgid; 217 shp->shm_dtim = get_seconds(); 218 shp->shm_nattch--; 219 if(shp->shm_nattch == 0 && 220 shp->shm_perm.mode & SHM_DEST) 221 shm_destroy(ns, shp); 222 else 223 shm_unlock(shp); 224 mutex_unlock(&shm_ids(ns).mutex); 225 } 226 227 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 228 { 229 struct file *file = vma->vm_file; 230 struct shm_file_data *sfd = shm_file_data(file); 231 232 return sfd->vm_ops->fault(vma, vmf); 233 } 234 235 #ifdef CONFIG_NUMA 236 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) 237 { 238 struct file *file = vma->vm_file; 239 struct shm_file_data *sfd = shm_file_data(file); 240 int err = 0; 241 if (sfd->vm_ops->set_policy) 242 err = sfd->vm_ops->set_policy(vma, new); 243 return err; 244 } 245 246 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, 247 unsigned long addr) 248 { 249 struct file *file = vma->vm_file; 250 struct shm_file_data *sfd = shm_file_data(file); 251 struct mempolicy *pol = NULL; 252 253 if (sfd->vm_ops->get_policy) 254 pol = sfd->vm_ops->get_policy(vma, addr); 255 else if (vma->vm_policy) 256 pol = vma->vm_policy; 257 else 258 pol = current->mempolicy; 259 return pol; 260 } 261 #endif 262 263 static int shm_mmap(struct file * file, struct vm_area_struct * vma) 264 { 265 struct shm_file_data *sfd = shm_file_data(file); 266 int ret; 267 268 ret = sfd->file->f_op->mmap(sfd->file, vma); 269 if (ret != 0) 270 return ret; 271 sfd->vm_ops = vma->vm_ops; 272 #ifdef CONFIG_MMU 273 BUG_ON(!sfd->vm_ops->fault); 274 #endif 275 vma->vm_ops = &shm_vm_ops; 276 shm_open(vma); 277 278 return ret; 279 } 280 281 static int shm_release(struct inode *ino, struct file *file) 282 { 283 struct shm_file_data *sfd = shm_file_data(file); 284 285 put_ipc_ns(sfd->ns); 286 shm_file_data(file) = NULL; 287 kfree(sfd); 288 return 0; 289 } 290 291 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync) 292 { 293 int (*fsync) (struct file *, struct dentry *, int datasync); 294 struct shm_file_data *sfd = shm_file_data(file); 295 int ret = -EINVAL; 296 297 fsync = sfd->file->f_op->fsync; 298 if (fsync) 299 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync); 300 return ret; 301 } 302 303 static unsigned long shm_get_unmapped_area(struct file *file, 304 unsigned long addr, unsigned long len, unsigned long pgoff, 305 unsigned long flags) 306 { 307 struct shm_file_data *sfd = shm_file_data(file); 308 return get_unmapped_area(sfd->file, addr, len, pgoff, flags); 309 } 310 311 int is_file_shm_hugepages(struct file *file) 312 { 313 int ret = 0; 314 315 if (file->f_op == &shm_file_operations) { 316 struct shm_file_data *sfd; 317 sfd = shm_file_data(file); 318 ret = is_file_hugepages(sfd->file); 319 } 320 return ret; 321 } 322 323 static const struct file_operations shm_file_operations = { 324 .mmap = shm_mmap, 325 .fsync = shm_fsync, 326 .release = shm_release, 327 .get_unmapped_area = shm_get_unmapped_area, 328 }; 329 330 static struct vm_operations_struct shm_vm_ops = { 331 .open = shm_open, /* callback for a new vm-area open */ 332 .close = shm_close, /* callback for when the vm-area is released */ 333 .fault = shm_fault, 334 #if defined(CONFIG_NUMA) 335 .set_policy = shm_set_policy, 336 .get_policy = shm_get_policy, 337 #endif 338 }; 339 340 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size) 341 { 342 int error; 343 struct shmid_kernel *shp; 344 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; 345 struct file * file; 346 char name[13]; 347 int id; 348 349 if (size < SHMMIN || size > ns->shm_ctlmax) 350 return -EINVAL; 351 352 if (ns->shm_tot + numpages > ns->shm_ctlall) 353 return -ENOSPC; 354 355 shp = ipc_rcu_alloc(sizeof(*shp)); 356 if (!shp) 357 return -ENOMEM; 358 359 shp->shm_perm.key = key; 360 shp->shm_perm.mode = (shmflg & S_IRWXUGO); 361 shp->mlock_user = NULL; 362 363 shp->shm_perm.security = NULL; 364 error = security_shm_alloc(shp); 365 if (error) { 366 ipc_rcu_putref(shp); 367 return error; 368 } 369 370 sprintf (name, "SYSV%08x", key); 371 if (shmflg & SHM_HUGETLB) { 372 /* hugetlb_file_setup takes care of mlock user accounting */ 373 file = hugetlb_file_setup(name, size); 374 shp->mlock_user = current->user; 375 } else { 376 int acctflag = VM_ACCOUNT; 377 /* 378 * Do not allow no accounting for OVERCOMMIT_NEVER, even 379 * if it's asked for. 380 */ 381 if ((shmflg & SHM_NORESERVE) && 382 sysctl_overcommit_memory != OVERCOMMIT_NEVER) 383 acctflag = 0; 384 file = shmem_file_setup(name, size, acctflag); 385 } 386 error = PTR_ERR(file); 387 if (IS_ERR(file)) 388 goto no_file; 389 390 error = -ENOSPC; 391 id = shm_addid(ns, shp); 392 if(id == -1) 393 goto no_id; 394 395 shp->shm_cprid = current->tgid; 396 shp->shm_lprid = 0; 397 shp->shm_atim = shp->shm_dtim = 0; 398 shp->shm_ctim = get_seconds(); 399 shp->shm_segsz = size; 400 shp->shm_nattch = 0; 401 shp->id = shm_buildid(ns, id, shp->shm_perm.seq); 402 shp->shm_file = file; 403 /* 404 * shmid gets reported as "inode#" in /proc/pid/maps. 405 * proc-ps tools use this. Changing this will break them. 406 */ 407 file->f_dentry->d_inode->i_ino = shp->id; 408 409 ns->shm_tot += numpages; 410 shm_unlock(shp); 411 return shp->id; 412 413 no_id: 414 fput(file); 415 no_file: 416 security_shm_free(shp); 417 ipc_rcu_putref(shp); 418 return error; 419 } 420 421 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) 422 { 423 struct shmid_kernel *shp; 424 int err, id = 0; 425 struct ipc_namespace *ns; 426 427 ns = current->nsproxy->ipc_ns; 428 429 mutex_lock(&shm_ids(ns).mutex); 430 if (key == IPC_PRIVATE) { 431 err = newseg(ns, key, shmflg, size); 432 } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) { 433 if (!(shmflg & IPC_CREAT)) 434 err = -ENOENT; 435 else 436 err = newseg(ns, key, shmflg, size); 437 } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) { 438 err = -EEXIST; 439 } else { 440 shp = shm_lock(ns, id); 441 BUG_ON(shp==NULL); 442 if (shp->shm_segsz < size) 443 err = -EINVAL; 444 else if (ipcperms(&shp->shm_perm, shmflg)) 445 err = -EACCES; 446 else { 447 int shmid = shm_buildid(ns, id, shp->shm_perm.seq); 448 err = security_shm_associate(shp, shmflg); 449 if (!err) 450 err = shmid; 451 } 452 shm_unlock(shp); 453 } 454 mutex_unlock(&shm_ids(ns).mutex); 455 456 return err; 457 } 458 459 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) 460 { 461 switch(version) { 462 case IPC_64: 463 return copy_to_user(buf, in, sizeof(*in)); 464 case IPC_OLD: 465 { 466 struct shmid_ds out; 467 468 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); 469 out.shm_segsz = in->shm_segsz; 470 out.shm_atime = in->shm_atime; 471 out.shm_dtime = in->shm_dtime; 472 out.shm_ctime = in->shm_ctime; 473 out.shm_cpid = in->shm_cpid; 474 out.shm_lpid = in->shm_lpid; 475 out.shm_nattch = in->shm_nattch; 476 477 return copy_to_user(buf, &out, sizeof(out)); 478 } 479 default: 480 return -EINVAL; 481 } 482 } 483 484 struct shm_setbuf { 485 uid_t uid; 486 gid_t gid; 487 mode_t mode; 488 }; 489 490 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version) 491 { 492 switch(version) { 493 case IPC_64: 494 { 495 struct shmid64_ds tbuf; 496 497 if (copy_from_user(&tbuf, buf, sizeof(tbuf))) 498 return -EFAULT; 499 500 out->uid = tbuf.shm_perm.uid; 501 out->gid = tbuf.shm_perm.gid; 502 out->mode = tbuf.shm_perm.mode; 503 504 return 0; 505 } 506 case IPC_OLD: 507 { 508 struct shmid_ds tbuf_old; 509 510 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) 511 return -EFAULT; 512 513 out->uid = tbuf_old.shm_perm.uid; 514 out->gid = tbuf_old.shm_perm.gid; 515 out->mode = tbuf_old.shm_perm.mode; 516 517 return 0; 518 } 519 default: 520 return -EINVAL; 521 } 522 } 523 524 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) 525 { 526 switch(version) { 527 case IPC_64: 528 return copy_to_user(buf, in, sizeof(*in)); 529 case IPC_OLD: 530 { 531 struct shminfo out; 532 533 if(in->shmmax > INT_MAX) 534 out.shmmax = INT_MAX; 535 else 536 out.shmmax = (int)in->shmmax; 537 538 out.shmmin = in->shmmin; 539 out.shmmni = in->shmmni; 540 out.shmseg = in->shmseg; 541 out.shmall = in->shmall; 542 543 return copy_to_user(buf, &out, sizeof(out)); 544 } 545 default: 546 return -EINVAL; 547 } 548 } 549 550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, 551 unsigned long *swp) 552 { 553 int i; 554 555 *rss = 0; 556 *swp = 0; 557 558 for (i = 0; i <= shm_ids(ns).max_id; i++) { 559 struct shmid_kernel *shp; 560 struct inode *inode; 561 562 shp = shm_get(ns, i); 563 if(!shp) 564 continue; 565 566 inode = shp->shm_file->f_path.dentry->d_inode; 567 568 if (is_file_hugepages(shp->shm_file)) { 569 struct address_space *mapping = inode->i_mapping; 570 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages; 571 } else { 572 struct shmem_inode_info *info = SHMEM_I(inode); 573 spin_lock(&info->lock); 574 *rss += inode->i_mapping->nrpages; 575 *swp += info->swapped; 576 spin_unlock(&info->lock); 577 } 578 } 579 } 580 581 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) 582 { 583 struct shm_setbuf setbuf; 584 struct shmid_kernel *shp; 585 int err, version; 586 struct ipc_namespace *ns; 587 588 if (cmd < 0 || shmid < 0) { 589 err = -EINVAL; 590 goto out; 591 } 592 593 version = ipc_parse_version(&cmd); 594 ns = current->nsproxy->ipc_ns; 595 596 switch (cmd) { /* replace with proc interface ? */ 597 case IPC_INFO: 598 { 599 struct shminfo64 shminfo; 600 601 err = security_shm_shmctl(NULL, cmd); 602 if (err) 603 return err; 604 605 memset(&shminfo,0,sizeof(shminfo)); 606 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; 607 shminfo.shmmax = ns->shm_ctlmax; 608 shminfo.shmall = ns->shm_ctlall; 609 610 shminfo.shmmin = SHMMIN; 611 if(copy_shminfo_to_user (buf, &shminfo, version)) 612 return -EFAULT; 613 /* reading a integer is always atomic */ 614 err= shm_ids(ns).max_id; 615 if(err<0) 616 err = 0; 617 goto out; 618 } 619 case SHM_INFO: 620 { 621 struct shm_info shm_info; 622 623 err = security_shm_shmctl(NULL, cmd); 624 if (err) 625 return err; 626 627 memset(&shm_info,0,sizeof(shm_info)); 628 mutex_lock(&shm_ids(ns).mutex); 629 shm_info.used_ids = shm_ids(ns).in_use; 630 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); 631 shm_info.shm_tot = ns->shm_tot; 632 shm_info.swap_attempts = 0; 633 shm_info.swap_successes = 0; 634 err = shm_ids(ns).max_id; 635 mutex_unlock(&shm_ids(ns).mutex); 636 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { 637 err = -EFAULT; 638 goto out; 639 } 640 641 err = err < 0 ? 0 : err; 642 goto out; 643 } 644 case SHM_STAT: 645 case IPC_STAT: 646 { 647 struct shmid64_ds tbuf; 648 int result; 649 memset(&tbuf, 0, sizeof(tbuf)); 650 shp = shm_lock(ns, shmid); 651 if(shp==NULL) { 652 err = -EINVAL; 653 goto out; 654 } else if(cmd==SHM_STAT) { 655 err = -EINVAL; 656 if (shmid > shm_ids(ns).max_id) 657 goto out_unlock; 658 result = shm_buildid(ns, shmid, shp->shm_perm.seq); 659 } else { 660 err = shm_checkid(ns, shp,shmid); 661 if(err) 662 goto out_unlock; 663 result = 0; 664 } 665 err=-EACCES; 666 if (ipcperms (&shp->shm_perm, S_IRUGO)) 667 goto out_unlock; 668 err = security_shm_shmctl(shp, cmd); 669 if (err) 670 goto out_unlock; 671 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); 672 tbuf.shm_segsz = shp->shm_segsz; 673 tbuf.shm_atime = shp->shm_atim; 674 tbuf.shm_dtime = shp->shm_dtim; 675 tbuf.shm_ctime = shp->shm_ctim; 676 tbuf.shm_cpid = shp->shm_cprid; 677 tbuf.shm_lpid = shp->shm_lprid; 678 tbuf.shm_nattch = shp->shm_nattch; 679 shm_unlock(shp); 680 if(copy_shmid_to_user (buf, &tbuf, version)) 681 err = -EFAULT; 682 else 683 err = result; 684 goto out; 685 } 686 case SHM_LOCK: 687 case SHM_UNLOCK: 688 { 689 shp = shm_lock(ns, shmid); 690 if(shp==NULL) { 691 err = -EINVAL; 692 goto out; 693 } 694 err = shm_checkid(ns, shp,shmid); 695 if(err) 696 goto out_unlock; 697 698 err = audit_ipc_obj(&(shp->shm_perm)); 699 if (err) 700 goto out_unlock; 701 702 if (!capable(CAP_IPC_LOCK)) { 703 err = -EPERM; 704 if (current->euid != shp->shm_perm.uid && 705 current->euid != shp->shm_perm.cuid) 706 goto out_unlock; 707 if (cmd == SHM_LOCK && 708 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) 709 goto out_unlock; 710 } 711 712 err = security_shm_shmctl(shp, cmd); 713 if (err) 714 goto out_unlock; 715 716 if(cmd==SHM_LOCK) { 717 struct user_struct * user = current->user; 718 if (!is_file_hugepages(shp->shm_file)) { 719 err = shmem_lock(shp->shm_file, 1, user); 720 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ 721 shp->shm_perm.mode |= SHM_LOCKED; 722 shp->mlock_user = user; 723 } 724 } 725 } else if (!is_file_hugepages(shp->shm_file)) { 726 shmem_lock(shp->shm_file, 0, shp->mlock_user); 727 shp->shm_perm.mode &= ~SHM_LOCKED; 728 shp->mlock_user = NULL; 729 } 730 shm_unlock(shp); 731 goto out; 732 } 733 case IPC_RMID: 734 { 735 /* 736 * We cannot simply remove the file. The SVID states 737 * that the block remains until the last person 738 * detaches from it, then is deleted. A shmat() on 739 * an RMID segment is legal in older Linux and if 740 * we change it apps break... 741 * 742 * Instead we set a destroyed flag, and then blow 743 * the name away when the usage hits zero. 744 */ 745 mutex_lock(&shm_ids(ns).mutex); 746 shp = shm_lock(ns, shmid); 747 err = -EINVAL; 748 if (shp == NULL) 749 goto out_up; 750 err = shm_checkid(ns, shp, shmid); 751 if(err) 752 goto out_unlock_up; 753 754 err = audit_ipc_obj(&(shp->shm_perm)); 755 if (err) 756 goto out_unlock_up; 757 758 if (current->euid != shp->shm_perm.uid && 759 current->euid != shp->shm_perm.cuid && 760 !capable(CAP_SYS_ADMIN)) { 761 err=-EPERM; 762 goto out_unlock_up; 763 } 764 765 err = security_shm_shmctl(shp, cmd); 766 if (err) 767 goto out_unlock_up; 768 769 do_shm_rmid(ns, shp); 770 mutex_unlock(&shm_ids(ns).mutex); 771 goto out; 772 } 773 774 case IPC_SET: 775 { 776 if (copy_shmid_from_user (&setbuf, buf, version)) { 777 err = -EFAULT; 778 goto out; 779 } 780 mutex_lock(&shm_ids(ns).mutex); 781 shp = shm_lock(ns, shmid); 782 err=-EINVAL; 783 if(shp==NULL) 784 goto out_up; 785 err = shm_checkid(ns, shp,shmid); 786 if(err) 787 goto out_unlock_up; 788 err = audit_ipc_obj(&(shp->shm_perm)); 789 if (err) 790 goto out_unlock_up; 791 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode); 792 if (err) 793 goto out_unlock_up; 794 err=-EPERM; 795 if (current->euid != shp->shm_perm.uid && 796 current->euid != shp->shm_perm.cuid && 797 !capable(CAP_SYS_ADMIN)) { 798 goto out_unlock_up; 799 } 800 801 err = security_shm_shmctl(shp, cmd); 802 if (err) 803 goto out_unlock_up; 804 805 shp->shm_perm.uid = setbuf.uid; 806 shp->shm_perm.gid = setbuf.gid; 807 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO) 808 | (setbuf.mode & S_IRWXUGO); 809 shp->shm_ctim = get_seconds(); 810 break; 811 } 812 813 default: 814 err = -EINVAL; 815 goto out; 816 } 817 818 err = 0; 819 out_unlock_up: 820 shm_unlock(shp); 821 out_up: 822 mutex_unlock(&shm_ids(ns).mutex); 823 goto out; 824 out_unlock: 825 shm_unlock(shp); 826 out: 827 return err; 828 } 829 830 /* 831 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. 832 * 833 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The 834 * "raddr" thing points to kernel space, and there has to be a wrapper around 835 * this. 836 */ 837 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) 838 { 839 struct shmid_kernel *shp; 840 unsigned long addr; 841 unsigned long size; 842 struct file * file; 843 int err; 844 unsigned long flags; 845 unsigned long prot; 846 int acc_mode; 847 unsigned long user_addr; 848 struct ipc_namespace *ns; 849 struct shm_file_data *sfd; 850 struct path path; 851 mode_t f_mode; 852 853 err = -EINVAL; 854 if (shmid < 0) 855 goto out; 856 else if ((addr = (ulong)shmaddr)) { 857 if (addr & (SHMLBA-1)) { 858 if (shmflg & SHM_RND) 859 addr &= ~(SHMLBA-1); /* round down */ 860 else 861 #ifndef __ARCH_FORCE_SHMLBA 862 if (addr & ~PAGE_MASK) 863 #endif 864 goto out; 865 } 866 flags = MAP_SHARED | MAP_FIXED; 867 } else { 868 if ((shmflg & SHM_REMAP)) 869 goto out; 870 871 flags = MAP_SHARED; 872 } 873 874 if (shmflg & SHM_RDONLY) { 875 prot = PROT_READ; 876 acc_mode = S_IRUGO; 877 f_mode = FMODE_READ; 878 } else { 879 prot = PROT_READ | PROT_WRITE; 880 acc_mode = S_IRUGO | S_IWUGO; 881 f_mode = FMODE_READ | FMODE_WRITE; 882 } 883 if (shmflg & SHM_EXEC) { 884 prot |= PROT_EXEC; 885 acc_mode |= S_IXUGO; 886 } 887 888 /* 889 * We cannot rely on the fs check since SYSV IPC does have an 890 * additional creator id... 891 */ 892 ns = current->nsproxy->ipc_ns; 893 shp = shm_lock(ns, shmid); 894 if(shp == NULL) 895 goto out; 896 897 err = shm_checkid(ns, shp,shmid); 898 if (err) 899 goto out_unlock; 900 901 err = -EACCES; 902 if (ipcperms(&shp->shm_perm, acc_mode)) 903 goto out_unlock; 904 905 err = security_shm_shmat(shp, shmaddr, shmflg); 906 if (err) 907 goto out_unlock; 908 909 path.dentry = dget(shp->shm_file->f_path.dentry); 910 path.mnt = mntget(shp->shm_file->f_path.mnt); 911 shp->shm_nattch++; 912 size = i_size_read(path.dentry->d_inode); 913 shm_unlock(shp); 914 915 err = -ENOMEM; 916 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); 917 if (!sfd) 918 goto out_put_path; 919 920 err = -ENOMEM; 921 file = get_empty_filp(); 922 if (!file) 923 goto out_free; 924 925 file->f_op = &shm_file_operations; 926 file->private_data = sfd; 927 file->f_path = path; 928 file->f_mapping = shp->shm_file->f_mapping; 929 file->f_mode = f_mode; 930 sfd->id = shp->id; 931 sfd->ns = get_ipc_ns(ns); 932 sfd->file = shp->shm_file; 933 sfd->vm_ops = NULL; 934 935 down_write(¤t->mm->mmap_sem); 936 if (addr && !(shmflg & SHM_REMAP)) { 937 err = -EINVAL; 938 if (find_vma_intersection(current->mm, addr, addr + size)) 939 goto invalid; 940 /* 941 * If shm segment goes below stack, make sure there is some 942 * space left for the stack to grow (at least 4 pages). 943 */ 944 if (addr < current->mm->start_stack && 945 addr > current->mm->start_stack - size - PAGE_SIZE * 5) 946 goto invalid; 947 } 948 949 user_addr = do_mmap (file, addr, size, prot, flags, 0); 950 *raddr = user_addr; 951 err = 0; 952 if (IS_ERR_VALUE(user_addr)) 953 err = (long)user_addr; 954 invalid: 955 up_write(¤t->mm->mmap_sem); 956 957 fput(file); 958 959 out_nattch: 960 mutex_lock(&shm_ids(ns).mutex); 961 shp = shm_lock(ns, shmid); 962 BUG_ON(!shp); 963 shp->shm_nattch--; 964 if(shp->shm_nattch == 0 && 965 shp->shm_perm.mode & SHM_DEST) 966 shm_destroy(ns, shp); 967 else 968 shm_unlock(shp); 969 mutex_unlock(&shm_ids(ns).mutex); 970 971 out: 972 return err; 973 974 out_unlock: 975 shm_unlock(shp); 976 goto out; 977 978 out_free: 979 kfree(sfd); 980 out_put_path: 981 dput(path.dentry); 982 mntput(path.mnt); 983 goto out_nattch; 984 } 985 986 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) 987 { 988 unsigned long ret; 989 long err; 990 991 err = do_shmat(shmid, shmaddr, shmflg, &ret); 992 if (err) 993 return err; 994 force_successful_syscall_return(); 995 return (long)ret; 996 } 997 998 /* 999 * detach and kill segment if marked destroyed. 1000 * The work is done in shm_close. 1001 */ 1002 asmlinkage long sys_shmdt(char __user *shmaddr) 1003 { 1004 struct mm_struct *mm = current->mm; 1005 struct vm_area_struct *vma, *next; 1006 unsigned long addr = (unsigned long)shmaddr; 1007 loff_t size = 0; 1008 int retval = -EINVAL; 1009 1010 if (addr & ~PAGE_MASK) 1011 return retval; 1012 1013 down_write(&mm->mmap_sem); 1014 1015 /* 1016 * This function tries to be smart and unmap shm segments that 1017 * were modified by partial mlock or munmap calls: 1018 * - It first determines the size of the shm segment that should be 1019 * unmapped: It searches for a vma that is backed by shm and that 1020 * started at address shmaddr. It records it's size and then unmaps 1021 * it. 1022 * - Then it unmaps all shm vmas that started at shmaddr and that 1023 * are within the initially determined size. 1024 * Errors from do_munmap are ignored: the function only fails if 1025 * it's called with invalid parameters or if it's called to unmap 1026 * a part of a vma. Both calls in this function are for full vmas, 1027 * the parameters are directly copied from the vma itself and always 1028 * valid - therefore do_munmap cannot fail. (famous last words?) 1029 */ 1030 /* 1031 * If it had been mremap()'d, the starting address would not 1032 * match the usual checks anyway. So assume all vma's are 1033 * above the starting address given. 1034 */ 1035 vma = find_vma(mm, addr); 1036 1037 while (vma) { 1038 next = vma->vm_next; 1039 1040 /* 1041 * Check if the starting address would match, i.e. it's 1042 * a fragment created by mprotect() and/or munmap(), or it 1043 * otherwise it starts at this address with no hassles. 1044 */ 1045 if ((vma->vm_ops == &shm_vm_ops) && 1046 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { 1047 1048 1049 size = vma->vm_file->f_path.dentry->d_inode->i_size; 1050 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); 1051 /* 1052 * We discovered the size of the shm segment, so 1053 * break out of here and fall through to the next 1054 * loop that uses the size information to stop 1055 * searching for matching vma's. 1056 */ 1057 retval = 0; 1058 vma = next; 1059 break; 1060 } 1061 vma = next; 1062 } 1063 1064 /* 1065 * We need look no further than the maximum address a fragment 1066 * could possibly have landed at. Also cast things to loff_t to 1067 * prevent overflows and make comparisions vs. equal-width types. 1068 */ 1069 size = PAGE_ALIGN(size); 1070 while (vma && (loff_t)(vma->vm_end - addr) <= size) { 1071 next = vma->vm_next; 1072 1073 /* finding a matching vma now does not alter retval */ 1074 if ((vma->vm_ops == &shm_vm_ops) && 1075 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) 1076 1077 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); 1078 vma = next; 1079 } 1080 1081 up_write(&mm->mmap_sem); 1082 return retval; 1083 } 1084 1085 #ifdef CONFIG_PROC_FS 1086 static int sysvipc_shm_proc_show(struct seq_file *s, void *it) 1087 { 1088 struct shmid_kernel *shp = it; 1089 char *format; 1090 1091 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" 1092 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" 1093 1094 if (sizeof(size_t) <= sizeof(int)) 1095 format = SMALL_STRING; 1096 else 1097 format = BIG_STRING; 1098 return seq_printf(s, format, 1099 shp->shm_perm.key, 1100 shp->id, 1101 shp->shm_perm.mode, 1102 shp->shm_segsz, 1103 shp->shm_cprid, 1104 shp->shm_lprid, 1105 shp->shm_nattch, 1106 shp->shm_perm.uid, 1107 shp->shm_perm.gid, 1108 shp->shm_perm.cuid, 1109 shp->shm_perm.cgid, 1110 shp->shm_atim, 1111 shp->shm_dtim, 1112 shp->shm_ctim); 1113 } 1114 #endif 1115