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/rwsem.h> 39 #include <linux/nsproxy.h> 40 #include <linux/mount.h> 41 #include <linux/ipc_namespace.h> 42 43 #include <asm/uaccess.h> 44 45 #include "util.h" 46 47 struct shm_file_data { 48 int id; 49 struct ipc_namespace *ns; 50 struct file *file; 51 const struct vm_operations_struct *vm_ops; 52 }; 53 54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) 55 56 static const struct file_operations shm_file_operations; 57 static struct vm_operations_struct shm_vm_ops; 58 59 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS]) 60 61 #define shm_unlock(shp) \ 62 ipc_unlock(&(shp)->shm_perm) 63 64 static int newseg(struct ipc_namespace *, struct ipc_params *); 65 static void shm_open(struct vm_area_struct *vma); 66 static void shm_close(struct vm_area_struct *vma); 67 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); 68 #ifdef CONFIG_PROC_FS 69 static int sysvipc_shm_proc_show(struct seq_file *s, void *it); 70 #endif 71 72 void shm_init_ns(struct ipc_namespace *ns) 73 { 74 ns->shm_ctlmax = SHMMAX; 75 ns->shm_ctlall = SHMALL; 76 ns->shm_ctlmni = SHMMNI; 77 ns->shm_tot = 0; 78 ipc_init_ids(&shm_ids(ns)); 79 } 80 81 /* 82 * Called with shm_ids.rw_mutex (writer) and the shp structure locked. 83 * Only shm_ids.rw_mutex remains locked on exit. 84 */ 85 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) 86 { 87 struct shmid_kernel *shp; 88 shp = container_of(ipcp, struct shmid_kernel, shm_perm); 89 90 if (shp->shm_nattch){ 91 shp->shm_perm.mode |= SHM_DEST; 92 /* Do not find it any more */ 93 shp->shm_perm.key = IPC_PRIVATE; 94 shm_unlock(shp); 95 } else 96 shm_destroy(ns, shp); 97 } 98 99 #ifdef CONFIG_IPC_NS 100 void shm_exit_ns(struct ipc_namespace *ns) 101 { 102 free_ipcs(ns, &shm_ids(ns), do_shm_rmid); 103 } 104 #endif 105 106 void __init shm_init (void) 107 { 108 shm_init_ns(&init_ipc_ns); 109 ipc_init_proc_interface("sysvipc/shm", 110 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", 111 IPC_SHM_IDS, sysvipc_shm_proc_show); 112 } 113 114 /* 115 * shm_lock_(check_) routines are called in the paths where the rw_mutex 116 * is not necessarily held. 117 */ 118 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) 119 { 120 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); 121 122 if (IS_ERR(ipcp)) 123 return (struct shmid_kernel *)ipcp; 124 125 return container_of(ipcp, struct shmid_kernel, shm_perm); 126 } 127 128 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns, 129 int id) 130 { 131 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id); 132 133 if (IS_ERR(ipcp)) 134 return (struct shmid_kernel *)ipcp; 135 136 return container_of(ipcp, struct shmid_kernel, shm_perm); 137 } 138 139 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) 140 { 141 ipc_rmid(&shm_ids(ns), &s->shm_perm); 142 } 143 144 145 /* This is called by fork, once for every shm attach. */ 146 static void shm_open(struct vm_area_struct *vma) 147 { 148 struct file *file = vma->vm_file; 149 struct shm_file_data *sfd = shm_file_data(file); 150 struct shmid_kernel *shp; 151 152 shp = shm_lock(sfd->ns, sfd->id); 153 BUG_ON(IS_ERR(shp)); 154 shp->shm_atim = get_seconds(); 155 shp->shm_lprid = task_tgid_vnr(current); 156 shp->shm_nattch++; 157 shm_unlock(shp); 158 } 159 160 /* 161 * shm_destroy - free the struct shmid_kernel 162 * 163 * @ns: namespace 164 * @shp: struct to free 165 * 166 * It has to be called with shp and shm_ids.rw_mutex (writer) locked, 167 * but returns with shp unlocked and freed. 168 */ 169 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) 170 { 171 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; 172 shm_rmid(ns, shp); 173 shm_unlock(shp); 174 if (!is_file_hugepages(shp->shm_file)) 175 shmem_lock(shp->shm_file, 0, shp->mlock_user); 176 else 177 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, 178 shp->mlock_user); 179 fput (shp->shm_file); 180 security_shm_free(shp); 181 ipc_rcu_putref(shp); 182 } 183 184 /* 185 * remove the attach descriptor vma. 186 * free memory for segment if it is marked destroyed. 187 * The descriptor has already been removed from the current->mm->mmap list 188 * and will later be kfree()d. 189 */ 190 static void shm_close(struct vm_area_struct *vma) 191 { 192 struct file * file = vma->vm_file; 193 struct shm_file_data *sfd = shm_file_data(file); 194 struct shmid_kernel *shp; 195 struct ipc_namespace *ns = sfd->ns; 196 197 down_write(&shm_ids(ns).rw_mutex); 198 /* remove from the list of attaches of the shm segment */ 199 shp = shm_lock(ns, sfd->id); 200 BUG_ON(IS_ERR(shp)); 201 shp->shm_lprid = task_tgid_vnr(current); 202 shp->shm_dtim = get_seconds(); 203 shp->shm_nattch--; 204 if(shp->shm_nattch == 0 && 205 shp->shm_perm.mode & SHM_DEST) 206 shm_destroy(ns, shp); 207 else 208 shm_unlock(shp); 209 up_write(&shm_ids(ns).rw_mutex); 210 } 211 212 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) 213 { 214 struct file *file = vma->vm_file; 215 struct shm_file_data *sfd = shm_file_data(file); 216 217 return sfd->vm_ops->fault(vma, vmf); 218 } 219 220 #ifdef CONFIG_NUMA 221 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) 222 { 223 struct file *file = vma->vm_file; 224 struct shm_file_data *sfd = shm_file_data(file); 225 int err = 0; 226 if (sfd->vm_ops->set_policy) 227 err = sfd->vm_ops->set_policy(vma, new); 228 return err; 229 } 230 231 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, 232 unsigned long addr) 233 { 234 struct file *file = vma->vm_file; 235 struct shm_file_data *sfd = shm_file_data(file); 236 struct mempolicy *pol = NULL; 237 238 if (sfd->vm_ops->get_policy) 239 pol = sfd->vm_ops->get_policy(vma, addr); 240 else if (vma->vm_policy) 241 pol = vma->vm_policy; 242 243 return pol; 244 } 245 #endif 246 247 static int shm_mmap(struct file * file, struct vm_area_struct * vma) 248 { 249 struct shm_file_data *sfd = shm_file_data(file); 250 int ret; 251 252 ret = sfd->file->f_op->mmap(sfd->file, vma); 253 if (ret != 0) 254 return ret; 255 sfd->vm_ops = vma->vm_ops; 256 #ifdef CONFIG_MMU 257 BUG_ON(!sfd->vm_ops->fault); 258 #endif 259 vma->vm_ops = &shm_vm_ops; 260 shm_open(vma); 261 262 return ret; 263 } 264 265 static int shm_release(struct inode *ino, struct file *file) 266 { 267 struct shm_file_data *sfd = shm_file_data(file); 268 269 put_ipc_ns(sfd->ns); 270 shm_file_data(file) = NULL; 271 kfree(sfd); 272 return 0; 273 } 274 275 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync) 276 { 277 int (*fsync) (struct file *, struct dentry *, int datasync); 278 struct shm_file_data *sfd = shm_file_data(file); 279 int ret = -EINVAL; 280 281 fsync = sfd->file->f_op->fsync; 282 if (fsync) 283 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync); 284 return ret; 285 } 286 287 static unsigned long shm_get_unmapped_area(struct file *file, 288 unsigned long addr, unsigned long len, unsigned long pgoff, 289 unsigned long flags) 290 { 291 struct shm_file_data *sfd = shm_file_data(file); 292 return get_unmapped_area(sfd->file, addr, len, pgoff, flags); 293 } 294 295 int is_file_shm_hugepages(struct file *file) 296 { 297 int ret = 0; 298 299 if (file->f_op == &shm_file_operations) { 300 struct shm_file_data *sfd; 301 sfd = shm_file_data(file); 302 ret = is_file_hugepages(sfd->file); 303 } 304 return ret; 305 } 306 307 static const struct file_operations shm_file_operations = { 308 .mmap = shm_mmap, 309 .fsync = shm_fsync, 310 .release = shm_release, 311 .get_unmapped_area = shm_get_unmapped_area, 312 }; 313 314 static struct vm_operations_struct shm_vm_ops = { 315 .open = shm_open, /* callback for a new vm-area open */ 316 .close = shm_close, /* callback for when the vm-area is released */ 317 .fault = shm_fault, 318 #if defined(CONFIG_NUMA) 319 .set_policy = shm_set_policy, 320 .get_policy = shm_get_policy, 321 #endif 322 }; 323 324 /** 325 * newseg - Create a new shared memory segment 326 * @ns: namespace 327 * @params: ptr to the structure that contains key, size and shmflg 328 * 329 * Called with shm_ids.rw_mutex held as a writer. 330 */ 331 332 static int newseg(struct ipc_namespace *ns, struct ipc_params *params) 333 { 334 key_t key = params->key; 335 int shmflg = params->flg; 336 size_t size = params->u.size; 337 int error; 338 struct shmid_kernel *shp; 339 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; 340 struct file * file; 341 char name[13]; 342 int id; 343 int acctflag = 0; 344 345 if (size < SHMMIN || size > ns->shm_ctlmax) 346 return -EINVAL; 347 348 if (ns->shm_tot + numpages > ns->shm_ctlall) 349 return -ENOSPC; 350 351 shp = ipc_rcu_alloc(sizeof(*shp)); 352 if (!shp) 353 return -ENOMEM; 354 355 shp->shm_perm.key = key; 356 shp->shm_perm.mode = (shmflg & S_IRWXUGO); 357 shp->mlock_user = NULL; 358 359 shp->shm_perm.security = NULL; 360 error = security_shm_alloc(shp); 361 if (error) { 362 ipc_rcu_putref(shp); 363 return error; 364 } 365 366 sprintf (name, "SYSV%08x", key); 367 if (shmflg & SHM_HUGETLB) { 368 /* hugetlb_file_setup applies strict accounting */ 369 if (shmflg & SHM_NORESERVE) 370 acctflag = VM_NORESERVE; 371 file = hugetlb_file_setup(name, size, acctflag); 372 shp->mlock_user = current_user(); 373 } else { 374 /* 375 * Do not allow no accounting for OVERCOMMIT_NEVER, even 376 * if it's asked for. 377 */ 378 if ((shmflg & SHM_NORESERVE) && 379 sysctl_overcommit_memory != OVERCOMMIT_NEVER) 380 acctflag = VM_NORESERVE; 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 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); 388 if (id < 0) { 389 error = id; 390 goto no_id; 391 } 392 393 shp->shm_cprid = task_tgid_vnr(current); 394 shp->shm_lprid = 0; 395 shp->shm_atim = shp->shm_dtim = 0; 396 shp->shm_ctim = get_seconds(); 397 shp->shm_segsz = size; 398 shp->shm_nattch = 0; 399 shp->shm_file = file; 400 /* 401 * shmid gets reported as "inode#" in /proc/pid/maps. 402 * proc-ps tools use this. Changing this will break them. 403 */ 404 file->f_dentry->d_inode->i_ino = shp->shm_perm.id; 405 406 ns->shm_tot += numpages; 407 error = shp->shm_perm.id; 408 shm_unlock(shp); 409 return error; 410 411 no_id: 412 fput(file); 413 no_file: 414 security_shm_free(shp); 415 ipc_rcu_putref(shp); 416 return error; 417 } 418 419 /* 420 * Called with shm_ids.rw_mutex and ipcp locked. 421 */ 422 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) 423 { 424 struct shmid_kernel *shp; 425 426 shp = container_of(ipcp, struct shmid_kernel, shm_perm); 427 return security_shm_associate(shp, shmflg); 428 } 429 430 /* 431 * Called with shm_ids.rw_mutex and ipcp locked. 432 */ 433 static inline int shm_more_checks(struct kern_ipc_perm *ipcp, 434 struct ipc_params *params) 435 { 436 struct shmid_kernel *shp; 437 438 shp = container_of(ipcp, struct shmid_kernel, shm_perm); 439 if (shp->shm_segsz < params->u.size) 440 return -EINVAL; 441 442 return 0; 443 } 444 445 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) 446 { 447 struct ipc_namespace *ns; 448 struct ipc_ops shm_ops; 449 struct ipc_params shm_params; 450 451 ns = current->nsproxy->ipc_ns; 452 453 shm_ops.getnew = newseg; 454 shm_ops.associate = shm_security; 455 shm_ops.more_checks = shm_more_checks; 456 457 shm_params.key = key; 458 shm_params.flg = shmflg; 459 shm_params.u.size = size; 460 461 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); 462 } 463 464 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) 465 { 466 switch(version) { 467 case IPC_64: 468 return copy_to_user(buf, in, sizeof(*in)); 469 case IPC_OLD: 470 { 471 struct shmid_ds out; 472 473 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); 474 out.shm_segsz = in->shm_segsz; 475 out.shm_atime = in->shm_atime; 476 out.shm_dtime = in->shm_dtime; 477 out.shm_ctime = in->shm_ctime; 478 out.shm_cpid = in->shm_cpid; 479 out.shm_lpid = in->shm_lpid; 480 out.shm_nattch = in->shm_nattch; 481 482 return copy_to_user(buf, &out, sizeof(out)); 483 } 484 default: 485 return -EINVAL; 486 } 487 } 488 489 static inline unsigned long 490 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) 491 { 492 switch(version) { 493 case IPC_64: 494 if (copy_from_user(out, buf, sizeof(*out))) 495 return -EFAULT; 496 return 0; 497 case IPC_OLD: 498 { 499 struct shmid_ds tbuf_old; 500 501 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) 502 return -EFAULT; 503 504 out->shm_perm.uid = tbuf_old.shm_perm.uid; 505 out->shm_perm.gid = tbuf_old.shm_perm.gid; 506 out->shm_perm.mode = tbuf_old.shm_perm.mode; 507 508 return 0; 509 } 510 default: 511 return -EINVAL; 512 } 513 } 514 515 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) 516 { 517 switch(version) { 518 case IPC_64: 519 return copy_to_user(buf, in, sizeof(*in)); 520 case IPC_OLD: 521 { 522 struct shminfo out; 523 524 if(in->shmmax > INT_MAX) 525 out.shmmax = INT_MAX; 526 else 527 out.shmmax = (int)in->shmmax; 528 529 out.shmmin = in->shmmin; 530 out.shmmni = in->shmmni; 531 out.shmseg = in->shmseg; 532 out.shmall = in->shmall; 533 534 return copy_to_user(buf, &out, sizeof(out)); 535 } 536 default: 537 return -EINVAL; 538 } 539 } 540 541 /* 542 * Called with shm_ids.rw_mutex held as a reader 543 */ 544 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, 545 unsigned long *swp) 546 { 547 int next_id; 548 int total, in_use; 549 550 *rss = 0; 551 *swp = 0; 552 553 in_use = shm_ids(ns).in_use; 554 555 for (total = 0, next_id = 0; total < in_use; next_id++) { 556 struct shmid_kernel *shp; 557 struct inode *inode; 558 559 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id); 560 if (shp == NULL) 561 continue; 562 563 inode = shp->shm_file->f_path.dentry->d_inode; 564 565 if (is_file_hugepages(shp->shm_file)) { 566 struct address_space *mapping = inode->i_mapping; 567 struct hstate *h = hstate_file(shp->shm_file); 568 *rss += pages_per_huge_page(h) * mapping->nrpages; 569 } else { 570 #ifdef CONFIG_SHMEM 571 struct shmem_inode_info *info = SHMEM_I(inode); 572 spin_lock(&info->lock); 573 *rss += inode->i_mapping->nrpages; 574 *swp += info->swapped; 575 spin_unlock(&info->lock); 576 #else 577 *rss += inode->i_mapping->nrpages; 578 #endif 579 } 580 581 total++; 582 } 583 } 584 585 /* 586 * This function handles some shmctl commands which require the rw_mutex 587 * to be held in write mode. 588 * NOTE: no locks must be held, the rw_mutex is taken inside this function. 589 */ 590 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, 591 struct shmid_ds __user *buf, int version) 592 { 593 struct kern_ipc_perm *ipcp; 594 struct shmid64_ds shmid64; 595 struct shmid_kernel *shp; 596 int err; 597 598 if (cmd == IPC_SET) { 599 if (copy_shmid_from_user(&shmid64, buf, version)) 600 return -EFAULT; 601 } 602 603 ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0); 604 if (IS_ERR(ipcp)) 605 return PTR_ERR(ipcp); 606 607 shp = container_of(ipcp, struct shmid_kernel, shm_perm); 608 609 err = security_shm_shmctl(shp, cmd); 610 if (err) 611 goto out_unlock; 612 switch (cmd) { 613 case IPC_RMID: 614 do_shm_rmid(ns, ipcp); 615 goto out_up; 616 case IPC_SET: 617 ipc_update_perm(&shmid64.shm_perm, ipcp); 618 shp->shm_ctim = get_seconds(); 619 break; 620 default: 621 err = -EINVAL; 622 } 623 out_unlock: 624 shm_unlock(shp); 625 out_up: 626 up_write(&shm_ids(ns).rw_mutex); 627 return err; 628 } 629 630 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) 631 { 632 struct shmid_kernel *shp; 633 int err, version; 634 struct ipc_namespace *ns; 635 636 if (cmd < 0 || shmid < 0) { 637 err = -EINVAL; 638 goto out; 639 } 640 641 version = ipc_parse_version(&cmd); 642 ns = current->nsproxy->ipc_ns; 643 644 switch (cmd) { /* replace with proc interface ? */ 645 case IPC_INFO: 646 { 647 struct shminfo64 shminfo; 648 649 err = security_shm_shmctl(NULL, cmd); 650 if (err) 651 return err; 652 653 memset(&shminfo, 0, sizeof(shminfo)); 654 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; 655 shminfo.shmmax = ns->shm_ctlmax; 656 shminfo.shmall = ns->shm_ctlall; 657 658 shminfo.shmmin = SHMMIN; 659 if(copy_shminfo_to_user (buf, &shminfo, version)) 660 return -EFAULT; 661 662 down_read(&shm_ids(ns).rw_mutex); 663 err = ipc_get_maxid(&shm_ids(ns)); 664 up_read(&shm_ids(ns).rw_mutex); 665 666 if(err<0) 667 err = 0; 668 goto out; 669 } 670 case SHM_INFO: 671 { 672 struct shm_info shm_info; 673 674 err = security_shm_shmctl(NULL, cmd); 675 if (err) 676 return err; 677 678 memset(&shm_info, 0, sizeof(shm_info)); 679 down_read(&shm_ids(ns).rw_mutex); 680 shm_info.used_ids = shm_ids(ns).in_use; 681 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); 682 shm_info.shm_tot = ns->shm_tot; 683 shm_info.swap_attempts = 0; 684 shm_info.swap_successes = 0; 685 err = ipc_get_maxid(&shm_ids(ns)); 686 up_read(&shm_ids(ns).rw_mutex); 687 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { 688 err = -EFAULT; 689 goto out; 690 } 691 692 err = err < 0 ? 0 : err; 693 goto out; 694 } 695 case SHM_STAT: 696 case IPC_STAT: 697 { 698 struct shmid64_ds tbuf; 699 int result; 700 701 if (cmd == SHM_STAT) { 702 shp = shm_lock(ns, shmid); 703 if (IS_ERR(shp)) { 704 err = PTR_ERR(shp); 705 goto out; 706 } 707 result = shp->shm_perm.id; 708 } else { 709 shp = shm_lock_check(ns, shmid); 710 if (IS_ERR(shp)) { 711 err = PTR_ERR(shp); 712 goto out; 713 } 714 result = 0; 715 } 716 err = -EACCES; 717 if (ipcperms (&shp->shm_perm, S_IRUGO)) 718 goto out_unlock; 719 err = security_shm_shmctl(shp, cmd); 720 if (err) 721 goto out_unlock; 722 memset(&tbuf, 0, sizeof(tbuf)); 723 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); 724 tbuf.shm_segsz = shp->shm_segsz; 725 tbuf.shm_atime = shp->shm_atim; 726 tbuf.shm_dtime = shp->shm_dtim; 727 tbuf.shm_ctime = shp->shm_ctim; 728 tbuf.shm_cpid = shp->shm_cprid; 729 tbuf.shm_lpid = shp->shm_lprid; 730 tbuf.shm_nattch = shp->shm_nattch; 731 shm_unlock(shp); 732 if(copy_shmid_to_user (buf, &tbuf, version)) 733 err = -EFAULT; 734 else 735 err = result; 736 goto out; 737 } 738 case SHM_LOCK: 739 case SHM_UNLOCK: 740 { 741 struct file *uninitialized_var(shm_file); 742 743 lru_add_drain_all(); /* drain pagevecs to lru lists */ 744 745 shp = shm_lock_check(ns, shmid); 746 if (IS_ERR(shp)) { 747 err = PTR_ERR(shp); 748 goto out; 749 } 750 751 audit_ipc_obj(&(shp->shm_perm)); 752 753 if (!capable(CAP_IPC_LOCK)) { 754 uid_t euid = current_euid(); 755 err = -EPERM; 756 if (euid != shp->shm_perm.uid && 757 euid != shp->shm_perm.cuid) 758 goto out_unlock; 759 if (cmd == SHM_LOCK && 760 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) 761 goto out_unlock; 762 } 763 764 err = security_shm_shmctl(shp, cmd); 765 if (err) 766 goto out_unlock; 767 768 if(cmd==SHM_LOCK) { 769 struct user_struct *user = current_user(); 770 if (!is_file_hugepages(shp->shm_file)) { 771 err = shmem_lock(shp->shm_file, 1, user); 772 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ 773 shp->shm_perm.mode |= SHM_LOCKED; 774 shp->mlock_user = user; 775 } 776 } 777 } else if (!is_file_hugepages(shp->shm_file)) { 778 shmem_lock(shp->shm_file, 0, shp->mlock_user); 779 shp->shm_perm.mode &= ~SHM_LOCKED; 780 shp->mlock_user = NULL; 781 } 782 shm_unlock(shp); 783 goto out; 784 } 785 case IPC_RMID: 786 case IPC_SET: 787 err = shmctl_down(ns, shmid, cmd, buf, version); 788 return err; 789 default: 790 return -EINVAL; 791 } 792 793 out_unlock: 794 shm_unlock(shp); 795 out: 796 return err; 797 } 798 799 /* 800 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. 801 * 802 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The 803 * "raddr" thing points to kernel space, and there has to be a wrapper around 804 * this. 805 */ 806 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) 807 { 808 struct shmid_kernel *shp; 809 unsigned long addr; 810 unsigned long size; 811 struct file * file; 812 int err; 813 unsigned long flags; 814 unsigned long prot; 815 int acc_mode; 816 unsigned long user_addr; 817 struct ipc_namespace *ns; 818 struct shm_file_data *sfd; 819 struct path path; 820 fmode_t f_mode; 821 822 err = -EINVAL; 823 if (shmid < 0) 824 goto out; 825 else if ((addr = (ulong)shmaddr)) { 826 if (addr & (SHMLBA-1)) { 827 if (shmflg & SHM_RND) 828 addr &= ~(SHMLBA-1); /* round down */ 829 else 830 #ifndef __ARCH_FORCE_SHMLBA 831 if (addr & ~PAGE_MASK) 832 #endif 833 goto out; 834 } 835 flags = MAP_SHARED | MAP_FIXED; 836 } else { 837 if ((shmflg & SHM_REMAP)) 838 goto out; 839 840 flags = MAP_SHARED; 841 } 842 843 if (shmflg & SHM_RDONLY) { 844 prot = PROT_READ; 845 acc_mode = S_IRUGO; 846 f_mode = FMODE_READ; 847 } else { 848 prot = PROT_READ | PROT_WRITE; 849 acc_mode = S_IRUGO | S_IWUGO; 850 f_mode = FMODE_READ | FMODE_WRITE; 851 } 852 if (shmflg & SHM_EXEC) { 853 prot |= PROT_EXEC; 854 acc_mode |= S_IXUGO; 855 } 856 857 /* 858 * We cannot rely on the fs check since SYSV IPC does have an 859 * additional creator id... 860 */ 861 ns = current->nsproxy->ipc_ns; 862 shp = shm_lock_check(ns, shmid); 863 if (IS_ERR(shp)) { 864 err = PTR_ERR(shp); 865 goto out; 866 } 867 868 err = -EACCES; 869 if (ipcperms(&shp->shm_perm, acc_mode)) 870 goto out_unlock; 871 872 err = security_shm_shmat(shp, shmaddr, shmflg); 873 if (err) 874 goto out_unlock; 875 876 path.dentry = dget(shp->shm_file->f_path.dentry); 877 path.mnt = shp->shm_file->f_path.mnt; 878 shp->shm_nattch++; 879 size = i_size_read(path.dentry->d_inode); 880 shm_unlock(shp); 881 882 err = -ENOMEM; 883 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); 884 if (!sfd) 885 goto out_put_dentry; 886 887 file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations); 888 if (!file) 889 goto out_free; 890 891 file->private_data = sfd; 892 file->f_mapping = shp->shm_file->f_mapping; 893 sfd->id = shp->shm_perm.id; 894 sfd->ns = get_ipc_ns(ns); 895 sfd->file = shp->shm_file; 896 sfd->vm_ops = NULL; 897 898 down_write(¤t->mm->mmap_sem); 899 if (addr && !(shmflg & SHM_REMAP)) { 900 err = -EINVAL; 901 if (find_vma_intersection(current->mm, addr, addr + size)) 902 goto invalid; 903 /* 904 * If shm segment goes below stack, make sure there is some 905 * space left for the stack to grow (at least 4 pages). 906 */ 907 if (addr < current->mm->start_stack && 908 addr > current->mm->start_stack - size - PAGE_SIZE * 5) 909 goto invalid; 910 } 911 912 user_addr = do_mmap (file, addr, size, prot, flags, 0); 913 *raddr = user_addr; 914 err = 0; 915 if (IS_ERR_VALUE(user_addr)) 916 err = (long)user_addr; 917 invalid: 918 up_write(¤t->mm->mmap_sem); 919 920 fput(file); 921 922 out_nattch: 923 down_write(&shm_ids(ns).rw_mutex); 924 shp = shm_lock(ns, shmid); 925 BUG_ON(IS_ERR(shp)); 926 shp->shm_nattch--; 927 if(shp->shm_nattch == 0 && 928 shp->shm_perm.mode & SHM_DEST) 929 shm_destroy(ns, shp); 930 else 931 shm_unlock(shp); 932 up_write(&shm_ids(ns).rw_mutex); 933 934 out: 935 return err; 936 937 out_unlock: 938 shm_unlock(shp); 939 goto out; 940 941 out_free: 942 kfree(sfd); 943 out_put_dentry: 944 dput(path.dentry); 945 goto out_nattch; 946 } 947 948 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) 949 { 950 unsigned long ret; 951 long err; 952 953 err = do_shmat(shmid, shmaddr, shmflg, &ret); 954 if (err) 955 return err; 956 force_successful_syscall_return(); 957 return (long)ret; 958 } 959 960 /* 961 * detach and kill segment if marked destroyed. 962 * The work is done in shm_close. 963 */ 964 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) 965 { 966 struct mm_struct *mm = current->mm; 967 struct vm_area_struct *vma, *next; 968 unsigned long addr = (unsigned long)shmaddr; 969 loff_t size = 0; 970 int retval = -EINVAL; 971 972 if (addr & ~PAGE_MASK) 973 return retval; 974 975 down_write(&mm->mmap_sem); 976 977 /* 978 * This function tries to be smart and unmap shm segments that 979 * were modified by partial mlock or munmap calls: 980 * - It first determines the size of the shm segment that should be 981 * unmapped: It searches for a vma that is backed by shm and that 982 * started at address shmaddr. It records it's size and then unmaps 983 * it. 984 * - Then it unmaps all shm vmas that started at shmaddr and that 985 * are within the initially determined size. 986 * Errors from do_munmap are ignored: the function only fails if 987 * it's called with invalid parameters or if it's called to unmap 988 * a part of a vma. Both calls in this function are for full vmas, 989 * the parameters are directly copied from the vma itself and always 990 * valid - therefore do_munmap cannot fail. (famous last words?) 991 */ 992 /* 993 * If it had been mremap()'d, the starting address would not 994 * match the usual checks anyway. So assume all vma's are 995 * above the starting address given. 996 */ 997 vma = find_vma(mm, addr); 998 999 #ifdef CONFIG_MMU 1000 while (vma) { 1001 next = vma->vm_next; 1002 1003 /* 1004 * Check if the starting address would match, i.e. it's 1005 * a fragment created by mprotect() and/or munmap(), or it 1006 * otherwise it starts at this address with no hassles. 1007 */ 1008 if ((vma->vm_ops == &shm_vm_ops) && 1009 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { 1010 1011 1012 size = vma->vm_file->f_path.dentry->d_inode->i_size; 1013 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); 1014 /* 1015 * We discovered the size of the shm segment, so 1016 * break out of here and fall through to the next 1017 * loop that uses the size information to stop 1018 * searching for matching vma's. 1019 */ 1020 retval = 0; 1021 vma = next; 1022 break; 1023 } 1024 vma = next; 1025 } 1026 1027 /* 1028 * We need look no further than the maximum address a fragment 1029 * could possibly have landed at. Also cast things to loff_t to 1030 * prevent overflows and make comparisions vs. equal-width types. 1031 */ 1032 size = PAGE_ALIGN(size); 1033 while (vma && (loff_t)(vma->vm_end - addr) <= size) { 1034 next = vma->vm_next; 1035 1036 /* finding a matching vma now does not alter retval */ 1037 if ((vma->vm_ops == &shm_vm_ops) && 1038 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) 1039 1040 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); 1041 vma = next; 1042 } 1043 1044 #else /* CONFIG_MMU */ 1045 /* under NOMMU conditions, the exact address to be destroyed must be 1046 * given */ 1047 retval = -EINVAL; 1048 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { 1049 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); 1050 retval = 0; 1051 } 1052 1053 #endif 1054 1055 up_write(&mm->mmap_sem); 1056 return retval; 1057 } 1058 1059 #ifdef CONFIG_PROC_FS 1060 static int sysvipc_shm_proc_show(struct seq_file *s, void *it) 1061 { 1062 struct shmid_kernel *shp = it; 1063 1064 #if BITS_PER_LONG <= 32 1065 #define SIZE_SPEC "%10lu" 1066 #else 1067 #define SIZE_SPEC "%21lu" 1068 #endif 1069 1070 return seq_printf(s, 1071 "%10d %10d %4o " SIZE_SPEC " %5u %5u " 1072 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n", 1073 shp->shm_perm.key, 1074 shp->shm_perm.id, 1075 shp->shm_perm.mode, 1076 shp->shm_segsz, 1077 shp->shm_cprid, 1078 shp->shm_lprid, 1079 shp->shm_nattch, 1080 shp->shm_perm.uid, 1081 shp->shm_perm.gid, 1082 shp->shm_perm.cuid, 1083 shp->shm_perm.cgid, 1084 shp->shm_atim, 1085 shp->shm_dtim, 1086 shp->shm_ctim); 1087 } 1088 #endif 1089