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