ipc/shm.c

   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 const 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_rmid_forced = 0;
  78         ns->shm_tot = 0;
  79         ipc_init_ids(&shm_ids(ns));
  80 }
  81
  82 /*
  83  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  84  * Only shm_ids.rw_mutex remains locked on exit.
  85  */
  86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
  87 {
  88         struct shmid_kernel *shp;
  89         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
  90
  91         if (shp->shm_nattch){
  92                 shp->shm_perm.mode |= SHM_DEST;
  93                 /* Do not find it any more */
  94                 shp->shm_perm.key = IPC_PRIVATE;
  95                 shm_unlock(shp);
  96         } else
  97                 shm_destroy(ns, shp);
  98 }
  99
 100 #ifdef CONFIG_IPC_NS
 101 void shm_exit_ns(struct ipc_namespace *ns)
 102 {
 103         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
 104         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
 105 }
 106 #endif
 107
 108 static int __init ipc_ns_init(void)
 109 {
 110         shm_init_ns(&init_ipc_ns);
 111         return 0;
 112 }
 113
 114 pure_initcall(ipc_ns_init);
 115
 116 void __init shm_init (void)
 117 {
 118         ipc_init_proc_interface("sysvipc/shm",
 119 #if BITS_PER_LONG <= 32
 120                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
 121 #else
 122                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
 123 #endif
 124                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 125 }
 126
 127 /*
 128  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 129  * is not necessarily held.
 130  */
 131 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 132 {
 133         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 134
 135         if (IS_ERR(ipcp))
 136                 return (struct shmid_kernel *)ipcp;
 137
 138         return container_of(ipcp, struct shmid_kernel, shm_perm);
 139 }
 140
 141 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
 142 {
 143         rcu_read_lock();
 144         spin_lock(&ipcp->shm_perm.lock);
 145 }
 146
 147 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 148                                                 int id)
 149 {
 150         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 151
 152         if (IS_ERR(ipcp))
 153                 return (struct shmid_kernel *)ipcp;
 154
 155         return container_of(ipcp, struct shmid_kernel, shm_perm);
 156 }
 157
 158 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 159 {
 160         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 161 }
 162
 163
 164 /* This is called by fork, once for every shm attach. */
 165 static void shm_open(struct vm_area_struct *vma)
 166 {
 167         struct file *file = vma->vm_file;
 168         struct shm_file_data *sfd = shm_file_data(file);
 169         struct shmid_kernel *shp;
 170
 171         shp = shm_lock(sfd->ns, sfd->id);
 172         BUG_ON(IS_ERR(shp));
 173         shp->shm_atim = get_seconds();
 174         shp->shm_lprid = task_tgid_vnr(current);
 175         shp->shm_nattch++;
 176         shm_unlock(shp);
 177 }
 178
 179 /*
 180  * shm_destroy - free the struct shmid_kernel
 181  *
 182  * @ns: namespace
 183  * @shp: struct to free
 184  *
 185  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 186  * but returns with shp unlocked and freed.
 187  */
 188 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 189 {
 190         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 191         shm_rmid(ns, shp);
 192         shm_unlock(shp);
 193         if (!is_file_hugepages(shp->shm_file))
 194                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 195         else if (shp->mlock_user)
 196                 user_shm_unlock(file_inode(shp->shm_file)->i_size,
 197                                                 shp->mlock_user);
 198         fput (shp->shm_file);
 199         security_shm_free(shp);
 200         ipc_rcu_putref(shp);
 201 }
 202
 203 /*
 204  * shm_may_destroy - identifies whether shm segment should be destroyed now
 205  *
 206  * Returns true if and only if there are no active users of the segment and
 207  * one of the following is true:
 208  *
 209  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
 210  *
 211  * 2) sysctl kernel.shm_rmid_forced is set to 1.
 212  */
 213 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 214 {
 215         return (shp->shm_nattch == 0) &&
 216                (ns->shm_rmid_forced ||
 217                 (shp->shm_perm.mode & SHM_DEST));
 218 }
 219
 220 /*
 221  * remove the attach descriptor vma.
 222  * free memory for segment if it is marked destroyed.
 223  * The descriptor has already been removed from the current->mm->mmap list
 224  * and will later be kfree()d.
 225  */
 226 static void shm_close(struct vm_area_struct *vma)
 227 {
 228         struct file * file = vma->vm_file;
 229         struct shm_file_data *sfd = shm_file_data(file);
 230         struct shmid_kernel *shp;
 231         struct ipc_namespace *ns = sfd->ns;
 232
 233         down_write(&shm_ids(ns).rw_mutex);
 234         /* remove from the list of attaches of the shm segment */
 235         shp = shm_lock(ns, sfd->id);
 236         BUG_ON(IS_ERR(shp));
 237         shp->shm_lprid = task_tgid_vnr(current);
 238         shp->shm_dtim = get_seconds();
 239         shp->shm_nattch--;
 240         if (shm_may_destroy(ns, shp))
 241                 shm_destroy(ns, shp);
 242         else
 243                 shm_unlock(shp);
 244         up_write(&shm_ids(ns).rw_mutex);
 245 }
 246
 247 /* Called with ns->shm_ids(ns).rw_mutex locked */
 248 static int shm_try_destroy_current(int id, void *p, void *data)
 249 {
 250         struct ipc_namespace *ns = data;
 251         struct kern_ipc_perm *ipcp = p;
 252         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 253
 254         if (shp->shm_creator != current)
 255                 return 0;
 256
 257         /*
 258          * Mark it as orphaned to destroy the segment when
 259          * kernel.shm_rmid_forced is changed.
 260          * It is noop if the following shm_may_destroy() returns true.
 261          */
 262         shp->shm_creator = NULL;
 263
 264         /*
 265          * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
 266          * is not set, it shouldn't be deleted here.
 267          */
 268         if (!ns->shm_rmid_forced)
 269                 return 0;
 270
 271         if (shm_may_destroy(ns, shp)) {
 272                 shm_lock_by_ptr(shp);
 273                 shm_destroy(ns, shp);
 274         }
 275         return 0;
 276 }
 277
 278 /* Called with ns->shm_ids(ns).rw_mutex locked */
 279 static int shm_try_destroy_orphaned(int id, void *p, void *data)
 280 {
 281         struct ipc_namespace *ns = data;
 282         struct kern_ipc_perm *ipcp = p;
 283         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 284
 285         /*
 286          * We want to destroy segments without users and with already
 287          * exit'ed originating process.
 288          *
 289          * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
 290          */
 291         if (shp->shm_creator != NULL)
 292                 return 0;
 293
 294         if (shm_may_destroy(ns, shp)) {
 295                 shm_lock_by_ptr(shp);
 296                 shm_destroy(ns, shp);
 297         }
 298         return 0;
 299 }
 300
 301 void shm_destroy_orphaned(struct ipc_namespace *ns)
 302 {
 303         down_write(&shm_ids(ns).rw_mutex);
 304         if (shm_ids(ns).in_use)
 305                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
 306         up_write(&shm_ids(ns).rw_mutex);
 307 }
 308
 309
 310 void exit_shm(struct task_struct *task)
 311 {
 312         struct ipc_namespace *ns = task->nsproxy->ipc_ns;
 313
 314         if (shm_ids(ns).in_use == 0)
 315                 return;
 316
 317         /* Destroy all already created segments, but not mapped yet */
 318         down_write(&shm_ids(ns).rw_mutex);
 319         if (shm_ids(ns).in_use)
 320                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
 321         up_write(&shm_ids(ns).rw_mutex);
 322 }
 323
 324 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 325 {
 326         struct file *file = vma->vm_file;
 327         struct shm_file_data *sfd = shm_file_data(file);
 328
 329         return sfd->vm_ops->fault(vma, vmf);
 330 }
 331
 332 #ifdef CONFIG_NUMA
 333 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 334 {
 335         struct file *file = vma->vm_file;
 336         struct shm_file_data *sfd = shm_file_data(file);
 337         int err = 0;
 338         if (sfd->vm_ops->set_policy)
 339                 err = sfd->vm_ops->set_policy(vma, new);
 340         return err;
 341 }
 342
 343 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 344                                         unsigned long addr)
 345 {
 346         struct file *file = vma->vm_file;
 347         struct shm_file_data *sfd = shm_file_data(file);
 348         struct mempolicy *pol = NULL;
 349
 350         if (sfd->vm_ops->get_policy)
 351                 pol = sfd->vm_ops->get_policy(vma, addr);
 352         else if (vma->vm_policy)
 353                 pol = vma->vm_policy;
 354
 355         return pol;
 356 }
 357 #endif
 358
 359 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 360 {
 361         struct shm_file_data *sfd = shm_file_data(file);
 362         int ret;
 363
 364         ret = sfd->file->f_op->mmap(sfd->file, vma);
 365         if (ret != 0)
 366                 return ret;
 367         sfd->vm_ops = vma->vm_ops;
 368 #ifdef CONFIG_MMU
 369         BUG_ON(!sfd->vm_ops->fault);
 370 #endif
 371         vma->vm_ops = &shm_vm_ops;
 372         shm_open(vma);
 373
 374         return ret;
 375 }
 376
 377 static int shm_release(struct inode *ino, struct file *file)
 378 {
 379         struct shm_file_data *sfd = shm_file_data(file);
 380
 381         put_ipc_ns(sfd->ns);
 382         shm_file_data(file) = NULL;
 383         kfree(sfd);
 384         return 0;
 385 }
 386
 387 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 388 {
 389         struct shm_file_data *sfd = shm_file_data(file);
 390
 391         if (!sfd->file->f_op->fsync)
 392                 return -EINVAL;
 393         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
 394 }
 395
 396 static long shm_fallocate(struct file *file, int mode, loff_t offset,
 397                           loff_t len)
 398 {
 399         struct shm_file_data *sfd = shm_file_data(file);
 400
 401         if (!sfd->file->f_op->fallocate)
 402                 return -EOPNOTSUPP;
 403         return sfd->file->f_op->fallocate(file, mode, offset, len);
 404 }
 405
 406 static unsigned long shm_get_unmapped_area(struct file *file,
 407         unsigned long addr, unsigned long len, unsigned long pgoff,
 408         unsigned long flags)
 409 {
 410         struct shm_file_data *sfd = shm_file_data(file);
 411         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
 412                                                 pgoff, flags);
 413 }
 414
 415 static const struct file_operations shm_file_operations = {
 416         .mmap           = shm_mmap,
 417         .fsync          = shm_fsync,
 418         .release        = shm_release,
 419 #ifndef CONFIG_MMU
 420         .get_unmapped_area      = shm_get_unmapped_area,
 421 #endif
 422         .llseek         = noop_llseek,
 423         .fallocate      = shm_fallocate,
 424 };
 425
 426 static const struct file_operations shm_file_operations_huge = {
 427         .mmap           = shm_mmap,
 428         .fsync          = shm_fsync,
 429         .release        = shm_release,
 430         .get_unmapped_area      = shm_get_unmapped_area,
 431         .llseek         = noop_llseek,
 432         .fallocate      = shm_fallocate,
 433 };
 434
 435 int is_file_shm_hugepages(struct file *file)
 436 {
 437         return file->f_op == &shm_file_operations_huge;
 438 }
 439
 440 static const struct vm_operations_struct shm_vm_ops = {
 441         .open   = shm_open,     /* callback for a new vm-area open */
 442         .close  = shm_close,    /* callback for when the vm-area is released */
 443         .fault  = shm_fault,
 444 #if defined(CONFIG_NUMA)
 445         .set_policy = shm_set_policy,
 446         .get_policy = shm_get_policy,
 447 #endif
 448 };
 449
 450 /**
 451  * newseg - Create a new shared memory segment
 452  * @ns: namespace
 453  * @params: ptr to the structure that contains key, size and shmflg
 454  *
 455  * Called with shm_ids.rw_mutex held as a writer.
 456  */
 457
 458 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 459 {
 460         key_t key = params->key;
 461         int shmflg = params->flg;
 462         size_t size = params->u.size;
 463         int error;
 464         struct shmid_kernel *shp;
 465         size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 466         struct file * file;
 467         char name[13];
 468         int id;
 469         vm_flags_t acctflag = 0;
 470
 471         if (size < SHMMIN || size > ns->shm_ctlmax)
 472                 return -EINVAL;
 473
 474         if (ns->shm_tot + numpages > ns->shm_ctlall)
 475                 return -ENOSPC;
 476
 477         shp = ipc_rcu_alloc(sizeof(*shp));
 478         if (!shp)
 479                 return -ENOMEM;
 480
 481         shp->shm_perm.key = key;
 482         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 483         shp->mlock_user = NULL;
 484
 485         shp->shm_perm.security = NULL;
 486         error = security_shm_alloc(shp);
 487         if (error) {
 488                 ipc_rcu_putref(shp);
 489                 return error;
 490         }
 491
 492         sprintf (name, "SYSV%08x", key);
 493         if (shmflg & SHM_HUGETLB) {
 494                 struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
 495                                                 & SHM_HUGE_MASK);
 496                 size_t hugesize;
 497
 498                 if (!hs) {
 499                         error = -EINVAL;
 500                         goto no_file;
 501                 }
 502                 hugesize = ALIGN(size, huge_page_size(hs));
 503
 504                 /* hugetlb_file_setup applies strict accounting */
 505                 if (shmflg & SHM_NORESERVE)
 506                         acctflag = VM_NORESERVE;
 507                 file = hugetlb_file_setup(name, hugesize, acctflag,
 508                                   &shp->mlock_user, HUGETLB_SHMFS_INODE,
 509                                 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
 510         } else {
 511                 /*
 512                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 513                  * if it's asked for.
 514                  */
 515                 if  ((shmflg & SHM_NORESERVE) &&
 516                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 517                         acctflag = VM_NORESERVE;
 518                 file = shmem_file_setup(name, size, acctflag);
 519         }
 520         error = PTR_ERR(file);
 521         if (IS_ERR(file))
 522                 goto no_file;
 523
 524         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 525         if (id < 0) {
 526                 error = id;
 527                 goto no_id;
 528         }
 529
 530         shp->shm_cprid = task_tgid_vnr(current);
 531         shp->shm_lprid = 0;
 532         shp->shm_atim = shp->shm_dtim = 0;
 533         shp->shm_ctim = get_seconds();
 534         shp->shm_segsz = size;
 535         shp->shm_nattch = 0;
 536         shp->shm_file = file;
 537         shp->shm_creator = current;
 538         /*
 539          * shmid gets reported as "inode#" in /proc/pid/maps.
 540          * proc-ps tools use this. Changing this will break them.
 541          */
 542         file_inode(file)->i_ino = shp->shm_perm.id;
 543
 544         ns->shm_tot += numpages;
 545         error = shp->shm_perm.id;
 546         shm_unlock(shp);
 547         return error;
 548
 549 no_id:
 550         if (is_file_hugepages(file) && shp->mlock_user)
 551                 user_shm_unlock(size, shp->mlock_user);
 552         fput(file);
 553 no_file:
 554         security_shm_free(shp);
 555         ipc_rcu_putref(shp);
 556         return error;
 557 }
 558
 559 /*
 560  * Called with shm_ids.rw_mutex and ipcp locked.
 561  */
 562 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 563 {
 564         struct shmid_kernel *shp;
 565
 566         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 567         return security_shm_associate(shp, shmflg);
 568 }
 569
 570 /*
 571  * Called with shm_ids.rw_mutex and ipcp locked.
 572  */
 573 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 574                                 struct ipc_params *params)
 575 {
 576         struct shmid_kernel *shp;
 577
 578         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 579         if (shp->shm_segsz < params->u.size)
 580                 return -EINVAL;
 581
 582         return 0;
 583 }
 584
 585 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
 586 {
 587         struct ipc_namespace *ns;
 588         struct ipc_ops shm_ops;
 589         struct ipc_params shm_params;
 590
 591         ns = current->nsproxy->ipc_ns;
 592
 593         shm_ops.getnew = newseg;
 594         shm_ops.associate = shm_security;
 595         shm_ops.more_checks = shm_more_checks;
 596
 597         shm_params.key = key;
 598         shm_params.flg = shmflg;
 599         shm_params.u.size = size;
 600
 601         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 602 }
 603
 604 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 605 {
 606         switch(version) {
 607         case IPC_64:
 608                 return copy_to_user(buf, in, sizeof(*in));
 609         case IPC_OLD:
 610             {
 611                 struct shmid_ds out;
 612
 613                 memset(&out, 0, sizeof(out));
 614                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 615                 out.shm_segsz   = in->shm_segsz;
 616                 out.shm_atime   = in->shm_atime;
 617                 out.shm_dtime   = in->shm_dtime;
 618                 out.shm_ctime   = in->shm_ctime;
 619                 out.shm_cpid    = in->shm_cpid;
 620                 out.shm_lpid    = in->shm_lpid;
 621                 out.shm_nattch  = in->shm_nattch;
 622
 623                 return copy_to_user(buf, &out, sizeof(out));
 624             }
 625         default:
 626                 return -EINVAL;
 627         }
 628 }
 629
 630 static inline unsigned long
 631 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 632 {
 633         switch(version) {
 634         case IPC_64:
 635                 if (copy_from_user(out, buf, sizeof(*out)))
 636                         return -EFAULT;
 637                 return 0;
 638         case IPC_OLD:
 639             {
 640                 struct shmid_ds tbuf_old;
 641
 642                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 643                         return -EFAULT;
 644
 645                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
 646                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
 647                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
 648
 649                 return 0;
 650             }
 651         default:
 652                 return -EINVAL;
 653         }
 654 }
 655
 656 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 657 {
 658         switch(version) {
 659         case IPC_64:
 660                 return copy_to_user(buf, in, sizeof(*in));
 661         case IPC_OLD:
 662             {
 663                 struct shminfo out;
 664
 665                 if(in->shmmax > INT_MAX)
 666                         out.shmmax = INT_MAX;
 667                 else
 668                         out.shmmax = (int)in->shmmax;
 669
 670                 out.shmmin      = in->shmmin;
 671                 out.shmmni      = in->shmmni;
 672                 out.shmseg      = in->shmseg;
 673                 out.shmall      = in->shmall;
 674
 675                 return copy_to_user(buf, &out, sizeof(out));
 676             }
 677         default:
 678                 return -EINVAL;
 679         }
 680 }
 681
 682 /*
 683  * Calculate and add used RSS and swap pages of a shm.
 684  * Called with shm_ids.rw_mutex held as a reader
 685  */
 686 static void shm_add_rss_swap(struct shmid_kernel *shp,
 687         unsigned long *rss_add, unsigned long *swp_add)
 688 {
 689         struct inode *inode;
 690
 691         inode = file_inode(shp->shm_file);
 692
 693         if (is_file_hugepages(shp->shm_file)) {
 694                 struct address_space *mapping = inode->i_mapping;
 695                 struct hstate *h = hstate_file(shp->shm_file);
 696                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
 697         } else {
 698 #ifdef CONFIG_SHMEM
 699                 struct shmem_inode_info *info = SHMEM_I(inode);
 700                 spin_lock(&info->lock);
 701                 *rss_add += inode->i_mapping->nrpages;
 702                 *swp_add += info->swapped;
 703                 spin_unlock(&info->lock);
 704 #else
 705                 *rss_add += inode->i_mapping->nrpages;
 706 #endif
 707         }
 708 }
 709
 710 /*
 711  * Called with shm_ids.rw_mutex held as a reader
 712  */
 713 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 714                 unsigned long *swp)
 715 {
 716         int next_id;
 717         int total, in_use;
 718
 719         *rss = 0;
 720         *swp = 0;
 721
 722         in_use = shm_ids(ns).in_use;
 723
 724         for (total = 0, next_id = 0; total < in_use; next_id++) {
 725                 struct kern_ipc_perm *ipc;
 726                 struct shmid_kernel *shp;
 727
 728                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 729                 if (ipc == NULL)
 730                         continue;
 731                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
 732
 733                 shm_add_rss_swap(shp, rss, swp);
 734
 735                 total++;
 736         }
 737 }
 738
 739 /*
 740  * This function handles some shmctl commands which require the rw_mutex
 741  * to be held in write mode.
 742  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 743  */
 744 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 745                        struct shmid_ds __user *buf, int version)
 746 {
 747         struct kern_ipc_perm *ipcp;
 748         struct shmid64_ds shmid64;
 749         struct shmid_kernel *shp;
 750         int err;
 751
 752         if (cmd == IPC_SET) {
 753                 if (copy_shmid_from_user(&shmid64, buf, version))
 754                         return -EFAULT;
 755         }
 756
 757         ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
 758                                &shmid64.shm_perm, 0);
 759         if (IS_ERR(ipcp))
 760                 return PTR_ERR(ipcp);
 761
 762         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 763
 764         err = security_shm_shmctl(shp, cmd);
 765         if (err)
 766                 goto out_unlock;
 767         switch (cmd) {
 768         case IPC_RMID:
 769                 do_shm_rmid(ns, ipcp);
 770                 goto out_up;
 771         case IPC_SET:
 772                 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
 773                 if (err)
 774                         goto out_unlock;
 775                 shp->shm_ctim = get_seconds();
 776                 break;
 777         default:
 778                 err = -EINVAL;
 779         }
 780 out_unlock:
 781         shm_unlock(shp);
 782 out_up:
 783         up_write(&shm_ids(ns).rw_mutex);
 784         return err;
 785 }
 786
 787 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
 788 {
 789         struct shmid_kernel *shp;
 790         int err, version;
 791         struct ipc_namespace *ns;
 792
 793         if (cmd < 0 || shmid < 0) {
 794                 err = -EINVAL;
 795                 goto out;
 796         }
 797
 798         version = ipc_parse_version(&cmd);
 799         ns = current->nsproxy->ipc_ns;
 800
 801         switch (cmd) { /* replace with proc interface ? */
 802         case IPC_INFO:
 803         {
 804                 struct shminfo64 shminfo;
 805
 806                 err = security_shm_shmctl(NULL, cmd);
 807                 if (err)
 808                         return err;
 809
 810                 memset(&shminfo, 0, sizeof(shminfo));
 811                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 812                 shminfo.shmmax = ns->shm_ctlmax;
 813                 shminfo.shmall = ns->shm_ctlall;
 814
 815                 shminfo.shmmin = SHMMIN;
 816                 if(copy_shminfo_to_user (buf, &shminfo, version))
 817                         return -EFAULT;
 818
 819                 down_read(&shm_ids(ns).rw_mutex);
 820                 err = ipc_get_maxid(&shm_ids(ns));
 821                 up_read(&shm_ids(ns).rw_mutex);
 822
 823                 if(err<0)
 824                         err = 0;
 825                 goto out;
 826         }
 827         case SHM_INFO:
 828         {
 829                 struct shm_info shm_info;
 830
 831                 err = security_shm_shmctl(NULL, cmd);
 832                 if (err)
 833                         return err;
 834
 835                 memset(&shm_info, 0, sizeof(shm_info));
 836                 down_read(&shm_ids(ns).rw_mutex);
 837                 shm_info.used_ids = shm_ids(ns).in_use;
 838                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 839                 shm_info.shm_tot = ns->shm_tot;
 840                 shm_info.swap_attempts = 0;
 841                 shm_info.swap_successes = 0;
 842                 err = ipc_get_maxid(&shm_ids(ns));
 843                 up_read(&shm_ids(ns).rw_mutex);
 844                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
 845                         err = -EFAULT;
 846                         goto out;
 847                 }
 848
 849                 err = err < 0 ? 0 : err;
 850                 goto out;
 851         }
 852         case SHM_STAT:
 853         case IPC_STAT:
 854         {
 855                 struct shmid64_ds tbuf;
 856                 int result;
 857
 858                 if (cmd == SHM_STAT) {
 859                         shp = shm_lock(ns, shmid);
 860                         if (IS_ERR(shp)) {
 861                                 err = PTR_ERR(shp);
 862                                 goto out;
 863                         }
 864                         result = shp->shm_perm.id;
 865                 } else {
 866                         shp = shm_lock_check(ns, shmid);
 867                         if (IS_ERR(shp)) {
 868                                 err = PTR_ERR(shp);
 869                                 goto out;
 870                         }
 871                         result = 0;
 872                 }
 873                 err = -EACCES;
 874                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
 875                         goto out_unlock;
 876                 err = security_shm_shmctl(shp, cmd);
 877                 if (err)
 878                         goto out_unlock;
 879                 memset(&tbuf, 0, sizeof(tbuf));
 880                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 881                 tbuf.shm_segsz  = shp->shm_segsz;
 882                 tbuf.shm_atime  = shp->shm_atim;
 883                 tbuf.shm_dtime  = shp->shm_dtim;
 884                 tbuf.shm_ctime  = shp->shm_ctim;
 885                 tbuf.shm_cpid   = shp->shm_cprid;
 886                 tbuf.shm_lpid   = shp->shm_lprid;
 887                 tbuf.shm_nattch = shp->shm_nattch;
 888                 shm_unlock(shp);
 889                 if(copy_shmid_to_user (buf, &tbuf, version))
 890                         err = -EFAULT;
 891                 else
 892                         err = result;
 893                 goto out;
 894         }
 895         case SHM_LOCK:
 896         case SHM_UNLOCK:
 897         {
 898                 struct file *shm_file;
 899
 900                 shp = shm_lock_check(ns, shmid);
 901                 if (IS_ERR(shp)) {
 902                         err = PTR_ERR(shp);
 903                         goto out;
 904                 }
 905
 906                 audit_ipc_obj(&(shp->shm_perm));
 907
 908                 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
 909                         kuid_t euid = current_euid();
 910                         err = -EPERM;
 911                         if (!uid_eq(euid, shp->shm_perm.uid) &&
 912                             !uid_eq(euid, shp->shm_perm.cuid))
 913                                 goto out_unlock;
 914                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
 915                                 goto out_unlock;
 916                 }
 917
 918                 err = security_shm_shmctl(shp, cmd);
 919                 if (err)
 920                         goto out_unlock;
 921
 922                 shm_file = shp->shm_file;
 923                 if (is_file_hugepages(shm_file))
 924                         goto out_unlock;
 925
 926                 if (cmd == SHM_LOCK) {
 927                         struct user_struct *user = current_user();
 928                         err = shmem_lock(shm_file, 1, user);
 929                         if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
 930                                 shp->shm_perm.mode |= SHM_LOCKED;
 931                                 shp->mlock_user = user;
 932                         }
 933                         goto out_unlock;
 934                 }
 935
 936                 /* SHM_UNLOCK */
 937                 if (!(shp->shm_perm.mode & SHM_LOCKED))
 938                         goto out_unlock;
 939                 shmem_lock(shm_file, 0, shp->mlock_user);
 940                 shp->shm_perm.mode &= ~SHM_LOCKED;
 941                 shp->mlock_user = NULL;
 942                 get_file(shm_file);
 943                 shm_unlock(shp);
 944                 shmem_unlock_mapping(shm_file->f_mapping);
 945                 fput(shm_file);
 946                 goto out;
 947         }
 948         case IPC_RMID:
 949         case IPC_SET:
 950                 err = shmctl_down(ns, shmid, cmd, buf, version);
 951                 return err;
 952         default:
 953                 return -EINVAL;
 954         }
 955
 956 out_unlock:
 957         shm_unlock(shp);
 958 out:
 959         return err;
 960 }
 961
 962 /*
 963  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 964  *
 965  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 966  * "raddr" thing points to kernel space, and there has to be a wrapper around
 967  * this.
 968  */
 969 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
 970               unsigned long shmlba)
 971 {
 972         struct shmid_kernel *shp;
 973         unsigned long addr;
 974         unsigned long size;
 975         struct file * file;
 976         int    err;
 977         unsigned long flags;
 978         unsigned long prot;
 979         int acc_mode;
 980         struct ipc_namespace *ns;
 981         struct shm_file_data *sfd;
 982         struct path path;
 983         fmode_t f_mode;
 984         unsigned long populate = 0;
 985
 986         err = -EINVAL;
 987         if (shmid < 0)
 988                 goto out;
 989         else if ((addr = (ulong)shmaddr)) {
 990                 if (addr & (shmlba - 1)) {
 991                         if (shmflg & SHM_RND)
 992                                 addr &= ~(shmlba - 1);     /* round down */
 993                         else
 994 #ifndef __ARCH_FORCE_SHMLBA
 995                                 if (addr & ~PAGE_MASK)
 996 #endif
 997                                         goto out;
 998                 }
 999                 flags = MAP_SHARED | MAP_FIXED;
1000         } else {
1001                 if ((shmflg & SHM_REMAP))
1002                         goto out;
1003
1004                 flags = MAP_SHARED;
1005         }
1006
1007         if (shmflg & SHM_RDONLY) {
1008                 prot = PROT_READ;
1009                 acc_mode = S_IRUGO;
1010                 f_mode = FMODE_READ;
1011         } else {
1012                 prot = PROT_READ | PROT_WRITE;
1013                 acc_mode = S_IRUGO | S_IWUGO;
1014                 f_mode = FMODE_READ | FMODE_WRITE;
1015         }
1016         if (shmflg & SHM_EXEC) {
1017                 prot |= PROT_EXEC;
1018                 acc_mode |= S_IXUGO;
1019         }
1020
1021         /*
1022          * We cannot rely on the fs check since SYSV IPC does have an
1023          * additional creator id...
1024          */
1025         ns = current->nsproxy->ipc_ns;
1026         shp = shm_lock_check(ns, shmid);
1027         if (IS_ERR(shp)) {
1028                 err = PTR_ERR(shp);
1029                 goto out;
1030         }
1031
1032         err = -EACCES;
1033         if (ipcperms(ns, &shp->shm_perm, acc_mode))
1034                 goto out_unlock;
1035
1036         err = security_shm_shmat(shp, shmaddr, shmflg);
1037         if (err)
1038                 goto out_unlock;
1039
1040         path = shp->shm_file->f_path;
1041         path_get(&path);
1042         shp->shm_nattch++;
1043         size = i_size_read(path.dentry->d_inode);
1044         shm_unlock(shp);
1045
1046         err = -ENOMEM;
1047         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1048         if (!sfd)
1049                 goto out_put_dentry;
1050
1051         file = alloc_file(&path, f_mode,
1052                           is_file_hugepages(shp->shm_file) ?
1053                                 &shm_file_operations_huge :
1054                                 &shm_file_operations);
1055         err = PTR_ERR(file);
1056         if (IS_ERR(file))
1057                 goto out_free;
1058
1059         file->private_data = sfd;
1060         file->f_mapping = shp->shm_file->f_mapping;
1061         sfd->id = shp->shm_perm.id;
1062         sfd->ns = get_ipc_ns(ns);
1063         sfd->file = shp->shm_file;
1064         sfd->vm_ops = NULL;
1065
1066         err = security_mmap_file(file, prot, flags);
1067         if (err)
1068                 goto out_fput;
1069
1070         down_write(&current->mm->mmap_sem);
1071         if (addr && !(shmflg & SHM_REMAP)) {
1072                 err = -EINVAL;
1073                 if (find_vma_intersection(current->mm, addr, addr + size))
1074                         goto invalid;
1075                 /*
1076                  * If shm segment goes below stack, make sure there is some
1077                  * space left for the stack to grow (at least 4 pages).
1078                  */
1079                 if (addr < current->mm->start_stack &&
1080                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1081                         goto invalid;
1082         }
1083
1084         addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1085         *raddr = addr;
1086         err = 0;
1087         if (IS_ERR_VALUE(addr))
1088                 err = (long)addr;
1089 invalid:
1090         up_write(&current->mm->mmap_sem);
1091         if (populate)
1092                 mm_populate(addr, populate);
1093
1094 out_fput:
1095         fput(file);
1096
1097 out_nattch:
1098         down_write(&shm_ids(ns).rw_mutex);
1099         shp = shm_lock(ns, shmid);
1100         BUG_ON(IS_ERR(shp));
1101         shp->shm_nattch--;
1102         if (shm_may_destroy(ns, shp))
1103                 shm_destroy(ns, shp);
1104         else
1105                 shm_unlock(shp);
1106         up_write(&shm_ids(ns).rw_mutex);
1107
1108 out:
1109         return err;
1110
1111 out_unlock:
1112         shm_unlock(shp);
1113         goto out;
1114
1115 out_free:
1116         kfree(sfd);
1117 out_put_dentry:
1118         path_put(&path);
1119         goto out_nattch;
1120 }
1121
1122 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1123 {
1124         unsigned long ret;
1125         long err;
1126
1127         err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1128         if (err)
1129                 return err;
1130         force_successful_syscall_return();
1131         return (long)ret;
1132 }
1133
1134 /*
1135  * detach and kill segment if marked destroyed.
1136  * The work is done in shm_close.
1137  */
1138 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1139 {
1140         struct mm_struct *mm = current->mm;
1141         struct vm_area_struct *vma;
1142         unsigned long addr = (unsigned long)shmaddr;
1143         int retval = -EINVAL;
1144 #ifdef CONFIG_MMU
1145         loff_t size = 0;
1146         struct vm_area_struct *next;
1147 #endif
1148
1149         if (addr & ~PAGE_MASK)
1150                 return retval;
1151
1152         down_write(&mm->mmap_sem);
1153
1154         /*
1155          * This function tries to be smart and unmap shm segments that
1156          * were modified by partial mlock or munmap calls:
1157          * - It first determines the size of the shm segment that should be
1158          *   unmapped: It searches for a vma that is backed by shm and that
1159          *   started at address shmaddr. It records it's size and then unmaps
1160          *   it.
1161          * - Then it unmaps all shm vmas that started at shmaddr and that
1162          *   are within the initially determined size.
1163          * Errors from do_munmap are ignored: the function only fails if
1164          * it's called with invalid parameters or if it's called to unmap
1165          * a part of a vma. Both calls in this function are for full vmas,
1166          * the parameters are directly copied from the vma itself and always
1167          * valid - therefore do_munmap cannot fail. (famous last words?)
1168          */
1169         /*
1170          * If it had been mremap()'d, the starting address would not
1171          * match the usual checks anyway. So assume all vma's are
1172          * above the starting address given.
1173          */
1174         vma = find_vma(mm, addr);
1175
1176 #ifdef CONFIG_MMU
1177         while (vma) {
1178                 next = vma->vm_next;
1179
1180                 /*
1181                  * Check if the starting address would match, i.e. it's
1182                  * a fragment created by mprotect() and/or munmap(), or it
1183                  * otherwise it starts at this address with no hassles.
1184                  */
1185                 if ((vma->vm_ops == &shm_vm_ops) &&
1186                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1187
1188
1189                         size = file_inode(vma->vm_file)->i_size;
1190                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1191                         /*
1192                          * We discovered the size of the shm segment, so
1193                          * break out of here and fall through to the next
1194                          * loop that uses the size information to stop
1195                          * searching for matching vma's.
1196                          */
1197                         retval = 0;
1198                         vma = next;
1199                         break;
1200                 }
1201                 vma = next;
1202         }
1203
1204         /*
1205          * We need look no further than the maximum address a fragment
1206          * could possibly have landed at. Also cast things to loff_t to
1207          * prevent overflows and make comparisons vs. equal-width types.
1208          */
1209         size = PAGE_ALIGN(size);
1210         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1211                 next = vma->vm_next;
1212
1213                 /* finding a matching vma now does not alter retval */
1214                 if ((vma->vm_ops == &shm_vm_ops) &&
1215                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1216
1217                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1218                 vma = next;
1219         }
1220
1221 #else /* CONFIG_MMU */
1222         /* under NOMMU conditions, the exact address to be destroyed must be
1223          * given */
1224         retval = -EINVAL;
1225         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1226                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1227                 retval = 0;
1228         }
1229
1230 #endif
1231
1232         up_write(&mm->mmap_sem);
1233         return retval;
1234 }
1235
1236 #ifdef CONFIG_PROC_FS
1237 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1238 {
1239         struct user_namespace *user_ns = seq_user_ns(s);
1240         struct shmid_kernel *shp = it;
1241         unsigned long rss = 0, swp = 0;
1242
1243         shm_add_rss_swap(shp, &rss, &swp);
1244
1245 #if BITS_PER_LONG <= 32
1246 #define SIZE_SPEC "%10lu"
1247 #else
1248 #define SIZE_SPEC "%21lu"
1249 #endif
1250
1251         return seq_printf(s,
1252                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1253                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1254                           SIZE_SPEC " " SIZE_SPEC "\n",
1255                           shp->shm_perm.key,
1256                           shp->shm_perm.id,
1257                           shp->shm_perm.mode,
1258                           shp->shm_segsz,
1259                           shp->shm_cprid,
1260                           shp->shm_lprid,
1261                           shp->shm_nattch,
1262                           from_kuid_munged(user_ns, shp->shm_perm.uid),
1263                           from_kgid_munged(user_ns, shp->shm_perm.gid),
1264                           from_kuid_munged(user_ns, shp->shm_perm.cuid),
1265                           from_kgid_munged(user_ns, shp->shm_perm.cgid),
1266                           shp->shm_atim,
1267                           shp->shm_dtim,
1268                           shp->shm_ctim,
1269                           rss * PAGE_SIZE,
1270                           swp * PAGE_SIZE);
1271 }
1272 #endif