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   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 #include <linux/ima.h>
  43
  44 #include <asm/uaccess.h>
  45
  46 #include "util.h"
  47
  48 struct shm_file_data {
  49         int id;
  50         struct ipc_namespace *ns;
  51         struct file *file;
  52         const struct vm_operations_struct *vm_ops;
  53 };
  54
  55 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  56
  57 static const struct file_operations shm_file_operations;
  58 static struct vm_operations_struct shm_vm_ops;
  59
  60 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
  61
  62 #define shm_unlock(shp)                 \
  63         ipc_unlock(&(shp)->shm_perm)
  64
  65 static int newseg(struct ipc_namespace *, struct ipc_params *);
  66 static void shm_open(struct vm_area_struct *vma);
  67 static void shm_close(struct vm_area_struct *vma);
  68 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  69 #ifdef CONFIG_PROC_FS
  70 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  71 #endif
  72
  73 void shm_init_ns(struct ipc_namespace *ns)
  74 {
  75         ns->shm_ctlmax = SHMMAX;
  76         ns->shm_ctlall = SHMALL;
  77         ns->shm_ctlmni = SHMMNI;
  78         ns->shm_tot = 0;
  79         ipc_init_ids(&ns->ids[IPC_SHM_IDS]);
  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 }
 105 #endif
 106
 107 void __init shm_init (void)
 108 {
 109         shm_init_ns(&init_ipc_ns);
 110         ipc_init_proc_interface("sysvipc/shm",
 111                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 112                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 113 }
 114
 115 /*
 116  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 117  * is not necessarily held.
 118  */
 119 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 120 {
 121         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 122
 123         if (IS_ERR(ipcp))
 124                 return (struct shmid_kernel *)ipcp;
 125
 126         return container_of(ipcp, struct shmid_kernel, shm_perm);
 127 }
 128
 129 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 130                                                 int id)
 131 {
 132         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 133
 134         if (IS_ERR(ipcp))
 135                 return (struct shmid_kernel *)ipcp;
 136
 137         return container_of(ipcp, struct shmid_kernel, shm_perm);
 138 }
 139
 140 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 141 {
 142         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 143 }
 144
 145
 146 /* This is called by fork, once for every shm attach. */
 147 static void shm_open(struct vm_area_struct *vma)
 148 {
 149         struct file *file = vma->vm_file;
 150         struct shm_file_data *sfd = shm_file_data(file);
 151         struct shmid_kernel *shp;
 152
 153         shp = shm_lock(sfd->ns, sfd->id);
 154         BUG_ON(IS_ERR(shp));
 155         shp->shm_atim = get_seconds();
 156         shp->shm_lprid = task_tgid_vnr(current);
 157         shp->shm_nattch++;
 158         shm_unlock(shp);
 159 }
 160
 161 /*
 162  * shm_destroy - free the struct shmid_kernel
 163  *
 164  * @ns: namespace
 165  * @shp: struct to free
 166  *
 167  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 168  * but returns with shp unlocked and freed.
 169  */
 170 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 171 {
 172         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 173         shm_rmid(ns, shp);
 174         shm_unlock(shp);
 175         if (!is_file_hugepages(shp->shm_file))
 176                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 177         else
 178                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 179                                                 shp->mlock_user);
 180         fput (shp->shm_file);
 181         security_shm_free(shp);
 182         ipc_rcu_putref(shp);
 183 }
 184
 185 /*
 186  * remove the attach descriptor vma.
 187  * free memory for segment if it is marked destroyed.
 188  * The descriptor has already been removed from the current->mm->mmap list
 189  * and will later be kfree()d.
 190  */
 191 static void shm_close(struct vm_area_struct *vma)
 192 {
 193         struct file * file = vma->vm_file;
 194         struct shm_file_data *sfd = shm_file_data(file);
 195         struct shmid_kernel *shp;
 196         struct ipc_namespace *ns = sfd->ns;
 197
 198         down_write(&shm_ids(ns).rw_mutex);
 199         /* remove from the list of attaches of the shm segment */
 200         shp = shm_lock(ns, sfd->id);
 201         BUG_ON(IS_ERR(shp));
 202         shp->shm_lprid = task_tgid_vnr(current);
 203         shp->shm_dtim = get_seconds();
 204         shp->shm_nattch--;
 205         if(shp->shm_nattch == 0 &&
 206            shp->shm_perm.mode & SHM_DEST)
 207                 shm_destroy(ns, shp);
 208         else
 209                 shm_unlock(shp);
 210         up_write(&shm_ids(ns).rw_mutex);
 211 }
 212
 213 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 214 {
 215         struct file *file = vma->vm_file;
 216         struct shm_file_data *sfd = shm_file_data(file);
 217
 218         return sfd->vm_ops->fault(vma, vmf);
 219 }
 220
 221 #ifdef CONFIG_NUMA
 222 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 223 {
 224         struct file *file = vma->vm_file;
 225         struct shm_file_data *sfd = shm_file_data(file);
 226         int err = 0;
 227         if (sfd->vm_ops->set_policy)
 228                 err = sfd->vm_ops->set_policy(vma, new);
 229         return err;
 230 }
 231
 232 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 233                                         unsigned long addr)
 234 {
 235         struct file *file = vma->vm_file;
 236         struct shm_file_data *sfd = shm_file_data(file);
 237         struct mempolicy *pol = NULL;
 238
 239         if (sfd->vm_ops->get_policy)
 240                 pol = sfd->vm_ops->get_policy(vma, addr);
 241         else if (vma->vm_policy)
 242                 pol = vma->vm_policy;
 243
 244         return pol;
 245 }
 246 #endif
 247
 248 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 249 {
 250         struct shm_file_data *sfd = shm_file_data(file);
 251         int ret;
 252
 253         ret = sfd->file->f_op->mmap(sfd->file, vma);
 254         if (ret != 0)
 255                 return ret;
 256         sfd->vm_ops = vma->vm_ops;
 257 #ifdef CONFIG_MMU
 258         BUG_ON(!sfd->vm_ops->fault);
 259 #endif
 260         vma->vm_ops = &shm_vm_ops;
 261         shm_open(vma);
 262
 263         return ret;
 264 }
 265
 266 static int shm_release(struct inode *ino, struct file *file)
 267 {
 268         struct shm_file_data *sfd = shm_file_data(file);
 269
 270         put_ipc_ns(sfd->ns);
 271         shm_file_data(file) = NULL;
 272         kfree(sfd);
 273         return 0;
 274 }
 275
 276 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 277 {
 278         int (*fsync) (struct file *, struct dentry *, int datasync);
 279         struct shm_file_data *sfd = shm_file_data(file);
 280         int ret = -EINVAL;
 281
 282         fsync = sfd->file->f_op->fsync;
 283         if (fsync)
 284                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 285         return ret;
 286 }
 287
 288 static unsigned long shm_get_unmapped_area(struct file *file,
 289         unsigned long addr, unsigned long len, unsigned long pgoff,
 290         unsigned long flags)
 291 {
 292         struct shm_file_data *sfd = shm_file_data(file);
 293         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 294 }
 295
 296 int is_file_shm_hugepages(struct file *file)
 297 {
 298         int ret = 0;
 299
 300         if (file->f_op == &shm_file_operations) {
 301                 struct shm_file_data *sfd;
 302                 sfd = shm_file_data(file);
 303                 ret = is_file_hugepages(sfd->file);
 304         }
 305         return ret;
 306 }
 307
 308 static const struct file_operations shm_file_operations = {
 309         .mmap           = shm_mmap,
 310         .fsync          = shm_fsync,
 311         .release        = shm_release,
 312         .get_unmapped_area      = shm_get_unmapped_area,
 313 };
 314
 315 static struct vm_operations_struct shm_vm_ops = {
 316         .open   = shm_open,     /* callback for a new vm-area open */
 317         .close  = shm_close,    /* callback for when the vm-area is released */
 318         .fault  = shm_fault,
 319 #if defined(CONFIG_NUMA)
 320         .set_policy = shm_set_policy,
 321         .get_policy = shm_get_policy,
 322 #endif
 323 };
 324
 325 /**
 326  * newseg - Create a new shared memory segment
 327  * @ns: namespace
 328  * @params: ptr to the structure that contains key, size and shmflg
 329  *
 330  * Called with shm_ids.rw_mutex held as a writer.
 331  */
 332
 333 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 334 {
 335         key_t key = params->key;
 336         int shmflg = params->flg;
 337         size_t size = params->u.size;
 338         int error;
 339         struct shmid_kernel *shp;
 340         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 341         struct file * file;
 342         char name[13];
 343         int id;
 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 takes care of mlock user accounting */
 369                 file = hugetlb_file_setup(name, 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                 file = shmem_file_setup(name, size, acctflag);
 381         }
 382         error = PTR_ERR(file);
 383         if (IS_ERR(file))
 384                 goto no_file;
 385         ima_shm_check(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 asmlinkage long sys_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                         struct shmem_inode_info *info = SHMEM_I(inode);
 571                         spin_lock(&info->lock);
 572                         *rss += inode->i_mapping->nrpages;
 573                         *swp += info->swapped;
 574                         spin_unlock(&info->lock);
 575                 }
 576
 577                 total++;
 578         }
 579 }
 580
 581 /*
 582  * This function handles some shmctl commands which require the rw_mutex
 583  * to be held in write mode.
 584  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 585  */
 586 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 587                        struct shmid_ds __user *buf, int version)
 588 {
 589         struct kern_ipc_perm *ipcp;
 590         struct shmid64_ds shmid64;
 591         struct shmid_kernel *shp;
 592         int err;
 593
 594         if (cmd == IPC_SET) {
 595                 if (copy_shmid_from_user(&shmid64, buf, version))
 596                         return -EFAULT;
 597         }
 598
 599         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
 600         if (IS_ERR(ipcp))
 601                 return PTR_ERR(ipcp);
 602
 603         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 604
 605         err = security_shm_shmctl(shp, cmd);
 606         if (err)
 607                 goto out_unlock;
 608         switch (cmd) {
 609         case IPC_RMID:
 610                 do_shm_rmid(ns, ipcp);
 611                 goto out_up;
 612         case IPC_SET:
 613                 ipc_update_perm(&shmid64.shm_perm, ipcp);
 614                 shp->shm_ctim = get_seconds();
 615                 break;
 616         default:
 617                 err = -EINVAL;
 618         }
 619 out_unlock:
 620         shm_unlock(shp);
 621 out_up:
 622         up_write(&shm_ids(ns).rw_mutex);
 623         return err;
 624 }
 625
 626 asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 627 {
 628         struct shmid_kernel *shp;
 629         int err, version;
 630         struct ipc_namespace *ns;
 631
 632         if (cmd < 0 || shmid < 0) {
 633                 err = -EINVAL;
 634                 goto out;
 635         }
 636
 637         version = ipc_parse_version(&cmd);
 638         ns = current->nsproxy->ipc_ns;
 639
 640         switch (cmd) { /* replace with proc interface ? */
 641         case IPC_INFO:
 642         {
 643                 struct shminfo64 shminfo;
 644
 645                 err = security_shm_shmctl(NULL, cmd);
 646                 if (err)
 647                         return err;
 648
 649                 memset(&shminfo,0,sizeof(shminfo));
 650                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 651                 shminfo.shmmax = ns->shm_ctlmax;
 652                 shminfo.shmall = ns->shm_ctlall;
 653
 654                 shminfo.shmmin = SHMMIN;
 655                 if(copy_shminfo_to_user (buf, &shminfo, version))
 656                         return -EFAULT;
 657
 658                 down_read(&shm_ids(ns).rw_mutex);
 659                 err = ipc_get_maxid(&shm_ids(ns));
 660                 up_read(&shm_ids(ns).rw_mutex);
 661
 662                 if(err<0)
 663                         err = 0;
 664                 goto out;
 665         }
 666         case SHM_INFO:
 667         {
 668                 struct shm_info shm_info;
 669
 670                 err = security_shm_shmctl(NULL, cmd);
 671                 if (err)
 672                         return err;
 673
 674                 memset(&shm_info,0,sizeof(shm_info));
 675                 down_read(&shm_ids(ns).rw_mutex);
 676                 shm_info.used_ids = shm_ids(ns).in_use;
 677                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 678                 shm_info.shm_tot = ns->shm_tot;
 679                 shm_info.swap_attempts = 0;
 680                 shm_info.swap_successes = 0;
 681                 err = ipc_get_maxid(&shm_ids(ns));
 682                 up_read(&shm_ids(ns).rw_mutex);
 683                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 684                         err = -EFAULT;
 685                         goto out;
 686                 }
 687
 688                 err = err < 0 ? 0 : err;
 689                 goto out;
 690         }
 691         case SHM_STAT:
 692         case IPC_STAT:
 693         {
 694                 struct shmid64_ds tbuf;
 695                 int result;
 696
 697                 if (!buf) {
 698                         err = -EFAULT;
 699                         goto out;
 700                 }
 701
 702                 if (cmd == SHM_STAT) {
 703                         shp = shm_lock(ns, shmid);
 704                         if (IS_ERR(shp)) {
 705                                 err = PTR_ERR(shp);
 706                                 goto out;
 707                         }
 708                         result = shp->shm_perm.id;
 709                 } else {
 710                         shp = shm_lock_check(ns, shmid);
 711                         if (IS_ERR(shp)) {
 712                                 err = PTR_ERR(shp);
 713                                 goto out;
 714                         }
 715                         result = 0;
 716                 }
 717                 err=-EACCES;
 718                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 719                         goto out_unlock;
 720                 err = security_shm_shmctl(shp, cmd);
 721                 if (err)
 722                         goto out_unlock;
 723                 memset(&tbuf, 0, sizeof(tbuf));
 724                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 725                 tbuf.shm_segsz  = shp->shm_segsz;
 726                 tbuf.shm_atime  = shp->shm_atim;
 727                 tbuf.shm_dtime  = shp->shm_dtim;
 728                 tbuf.shm_ctime  = shp->shm_ctim;
 729                 tbuf.shm_cpid   = shp->shm_cprid;
 730                 tbuf.shm_lpid   = shp->shm_lprid;
 731                 tbuf.shm_nattch = shp->shm_nattch;
 732                 shm_unlock(shp);
 733                 if(copy_shmid_to_user (buf, &tbuf, version))
 734                         err = -EFAULT;
 735                 else
 736                         err = result;
 737                 goto out;
 738         }
 739         case SHM_LOCK:
 740         case SHM_UNLOCK:
 741         {
 742                 struct file *uninitialized_var(shm_file);
 743
 744                 lru_add_drain_all();  /* drain pagevecs to lru lists */
 745
 746                 shp = shm_lock_check(ns, shmid);
 747                 if (IS_ERR(shp)) {
 748                         err = PTR_ERR(shp);
 749                         goto out;
 750                 }
 751
 752                 err = audit_ipc_obj(&(shp->shm_perm));
 753                 if (err)
 754                         goto out_unlock;
 755
 756                 if (!capable(CAP_IPC_LOCK)) {
 757                         uid_t euid = current_euid();
 758                         err = -EPERM;
 759                         if (euid != shp->shm_perm.uid &&
 760                             euid != shp->shm_perm.cuid)
 761                                 goto out_unlock;
 762                         if (cmd == SHM_LOCK &&
 763                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 764                                 goto out_unlock;
 765                 }
 766
 767                 err = security_shm_shmctl(shp, cmd);
 768                 if (err)
 769                         goto out_unlock;
 770
 771                 if(cmd==SHM_LOCK) {
 772                         struct user_struct *user = current_user();
 773                         if (!is_file_hugepages(shp->shm_file)) {
 774                                 err = shmem_lock(shp->shm_file, 1, user);
 775                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 776                                         shp->shm_perm.mode |= SHM_LOCKED;
 777                                         shp->mlock_user = user;
 778                                 }
 779                         }
 780                 } else if (!is_file_hugepages(shp->shm_file)) {
 781                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 782                         shp->shm_perm.mode &= ~SHM_LOCKED;
 783                         shp->mlock_user = NULL;
 784                 }
 785                 shm_unlock(shp);
 786                 goto out;
 787         }
 788         case IPC_RMID:
 789         case IPC_SET:
 790                 err = shmctl_down(ns, shmid, cmd, buf, version);
 791                 return err;
 792         default:
 793                 return -EINVAL;
 794         }
 795
 796 out_unlock:
 797         shm_unlock(shp);
 798 out:
 799         return err;
 800 }
 801
 802 /*
 803  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 804  *
 805  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 806  * "raddr" thing points to kernel space, and there has to be a wrapper around
 807  * this.
 808  */
 809 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 810 {
 811         struct shmid_kernel *shp;
 812         unsigned long addr;
 813         unsigned long size;
 814         struct file * file;
 815         int    err;
 816         unsigned long flags;
 817         unsigned long prot;
 818         int acc_mode;
 819         unsigned long user_addr;
 820         struct ipc_namespace *ns;
 821         struct shm_file_data *sfd;
 822         struct path path;
 823         fmode_t f_mode;
 824
 825         err = -EINVAL;
 826         if (shmid < 0)
 827                 goto out;
 828         else if ((addr = (ulong)shmaddr)) {
 829                 if (addr & (SHMLBA-1)) {
 830                         if (shmflg & SHM_RND)
 831                                 addr &= ~(SHMLBA-1);       /* round down */
 832                         else
 833 #ifndef __ARCH_FORCE_SHMLBA
 834                                 if (addr & ~PAGE_MASK)
 835 #endif
 836                                         goto out;
 837                 }
 838                 flags = MAP_SHARED | MAP_FIXED;
 839         } else {
 840                 if ((shmflg & SHM_REMAP))
 841                         goto out;
 842
 843                 flags = MAP_SHARED;
 844         }
 845
 846         if (shmflg & SHM_RDONLY) {
 847                 prot = PROT_READ;
 848                 acc_mode = S_IRUGO;
 849                 f_mode = FMODE_READ;
 850         } else {
 851                 prot = PROT_READ | PROT_WRITE;
 852                 acc_mode = S_IRUGO | S_IWUGO;
 853                 f_mode = FMODE_READ | FMODE_WRITE;
 854         }
 855         if (shmflg & SHM_EXEC) {
 856                 prot |= PROT_EXEC;
 857                 acc_mode |= S_IXUGO;
 858         }
 859
 860         /*
 861          * We cannot rely on the fs check since SYSV IPC does have an
 862          * additional creator id...
 863          */
 864         ns = current->nsproxy->ipc_ns;
 865         shp = shm_lock_check(ns, shmid);
 866         if (IS_ERR(shp)) {
 867                 err = PTR_ERR(shp);
 868                 goto out;
 869         }
 870
 871         err = -EACCES;
 872         if (ipcperms(&shp->shm_perm, acc_mode))
 873                 goto out_unlock;
 874
 875         err = security_shm_shmat(shp, shmaddr, shmflg);
 876         if (err)
 877                 goto out_unlock;
 878
 879         path.dentry = dget(shp->shm_file->f_path.dentry);
 880         path.mnt    = shp->shm_file->f_path.mnt;
 881         shp->shm_nattch++;
 882         size = i_size_read(path.dentry->d_inode);
 883         shm_unlock(shp);
 884
 885         err = -ENOMEM;
 886         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 887         if (!sfd)
 888                 goto out_put_dentry;
 889
 890         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 891         if (!file)
 892                 goto out_free;
 893         ima_shm_check(file);
 894
 895         file->private_data = sfd;
 896         file->f_mapping = shp->shm_file->f_mapping;
 897         sfd->id = shp->shm_perm.id;
 898         sfd->ns = get_ipc_ns(ns);
 899         sfd->file = shp->shm_file;
 900         sfd->vm_ops = NULL;
 901
 902         down_write(&current->mm->mmap_sem);
 903         if (addr && !(shmflg & SHM_REMAP)) {
 904                 err = -EINVAL;
 905                 if (find_vma_intersection(current->mm, addr, addr + size))
 906                         goto invalid;
 907                 /*
 908                  * If shm segment goes below stack, make sure there is some
 909                  * space left for the stack to grow (at least 4 pages).
 910                  */
 911                 if (addr < current->mm->start_stack &&
 912                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 913                         goto invalid;
 914         }
 915
 916         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 917         *raddr = user_addr;
 918         err = 0;
 919         if (IS_ERR_VALUE(user_addr))
 920                 err = (long)user_addr;
 921 invalid:
 922         up_write(&current->mm->mmap_sem);
 923
 924         fput(file);
 925
 926 out_nattch:
 927         down_write(&shm_ids(ns).rw_mutex);
 928         shp = shm_lock(ns, shmid);
 929         BUG_ON(IS_ERR(shp));
 930         shp->shm_nattch--;
 931         if(shp->shm_nattch == 0 &&
 932            shp->shm_perm.mode & SHM_DEST)
 933                 shm_destroy(ns, shp);
 934         else
 935                 shm_unlock(shp);
 936         up_write(&shm_ids(ns).rw_mutex);
 937
 938 out:
 939         return err;
 940
 941 out_unlock:
 942         shm_unlock(shp);
 943         goto out;
 944
 945 out_free:
 946         kfree(sfd);
 947 out_put_dentry:
 948         dput(path.dentry);
 949         goto out_nattch;
 950 }
 951
 952 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
 953 {
 954         unsigned long ret;
 955         long err;
 956
 957         err = do_shmat(shmid, shmaddr, shmflg, &ret);
 958         if (err)
 959                 return err;
 960         force_successful_syscall_return();
 961         return (long)ret;
 962 }
 963
 964 /*
 965  * detach and kill segment if marked destroyed.
 966  * The work is done in shm_close.
 967  */
 968 asmlinkage long sys_shmdt(char __user *shmaddr)
 969 {
 970         struct mm_struct *mm = current->mm;
 971         struct vm_area_struct *vma, *next;
 972         unsigned long addr = (unsigned long)shmaddr;
 973         loff_t size = 0;
 974         int retval = -EINVAL;
 975
 976         if (addr & ~PAGE_MASK)
 977                 return retval;
 978
 979         down_write(&mm->mmap_sem);
 980
 981         /*
 982          * This function tries to be smart and unmap shm segments that
 983          * were modified by partial mlock or munmap calls:
 984          * - It first determines the size of the shm segment that should be
 985          *   unmapped: It searches for a vma that is backed by shm and that
 986          *   started at address shmaddr. It records it's size and then unmaps
 987          *   it.
 988          * - Then it unmaps all shm vmas that started at shmaddr and that
 989          *   are within the initially determined size.
 990          * Errors from do_munmap are ignored: the function only fails if
 991          * it's called with invalid parameters or if it's called to unmap
 992          * a part of a vma. Both calls in this function are for full vmas,
 993          * the parameters are directly copied from the vma itself and always
 994          * valid - therefore do_munmap cannot fail. (famous last words?)
 995          */
 996         /*
 997          * If it had been mremap()'d, the starting address would not
 998          * match the usual checks anyway. So assume all vma's are
 999          * above the starting address given.
1000          */
1001         vma = find_vma(mm, addr);
1002
1003         while (vma) {
1004                 next = vma->vm_next;
1005
1006                 /*
1007                  * Check if the starting address would match, i.e. it's
1008                  * a fragment created by mprotect() and/or munmap(), or it
1009                  * otherwise it starts at this address with no hassles.
1010                  */
1011                 if ((vma->vm_ops == &shm_vm_ops) &&
1012                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1013
1014
1015                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1016                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1017                         /*
1018                          * We discovered the size of the shm segment, so
1019                          * break out of here and fall through to the next
1020                          * loop that uses the size information to stop
1021                          * searching for matching vma's.
1022                          */
1023                         retval = 0;
1024                         vma = next;
1025                         break;
1026                 }
1027                 vma = next;
1028         }
1029
1030         /*
1031          * We need look no further than the maximum address a fragment
1032          * could possibly have landed at. Also cast things to loff_t to
1033          * prevent overflows and make comparisions vs. equal-width types.
1034          */
1035         size = PAGE_ALIGN(size);
1036         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1037                 next = vma->vm_next;
1038
1039                 /* finding a matching vma now does not alter retval */
1040                 if ((vma->vm_ops == &shm_vm_ops) &&
1041                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1042
1043                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1044                 vma = next;
1045         }
1046
1047         up_write(&mm->mmap_sem);
1048         return retval;
1049 }
1050
1051 #ifdef CONFIG_PROC_FS
1052 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1053 {
1054         struct shmid_kernel *shp = it;
1055
1056 #if BITS_PER_LONG <= 32
1057 #define SIZE_SPEC "%10lu"
1058 #else
1059 #define SIZE_SPEC "%21lu"
1060 #endif
1061
1062         return seq_printf(s,
1063                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1064                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1065                           shp->shm_perm.key,
1066                           shp->shm_perm.id,
1067                           shp->shm_perm.mode,
1068                           shp->shm_segsz,
1069                           shp->shm_cprid,
1070                           shp->shm_lprid,
1071                           shp->shm_nattch,
1072                           shp->shm_perm.uid,
1073                           shp->shm_perm.gid,
1074                           shp->shm_perm.cuid,
1075                           shp->shm_perm.cgid,
1076                           shp->shm_atim,
1077                           shp->shm_dtim,
1078                           shp->shm_ctim);
1079 }
1080 #endif