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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/mutex.h>
  39 #include <linux/nsproxy.h>
  40 #include <linux/mount.h>
  41
  42 #include <asm/uaccess.h>
  43
  44 #include "util.h"
  45
  46 struct shm_file_data {
  47         int id;
  48         struct ipc_namespace *ns;
  49         struct file *file;
  50         const struct vm_operations_struct *vm_ops;
  51 };
  52
  53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  54
  55 static const struct file_operations shm_file_operations;
  56 static struct vm_operations_struct shm_vm_ops;
  57
  58 static struct ipc_ids init_shm_ids;
  59
  60 #define shm_ids(ns)     (*((ns)->ids[IPC_SHM_IDS]))
  61
  62 #define shm_unlock(shp)                 \
  63         ipc_unlock(&(shp)->shm_perm)
  64 #define shm_buildid(ns, id, seq)        \
  65         ipc_buildid(&shm_ids(ns), id, seq)
  66
  67 static int newseg(struct ipc_namespace *, struct ipc_params *);
  68 static void shm_open(struct vm_area_struct *vma);
  69 static void shm_close(struct vm_area_struct *vma);
  70 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  71 #ifdef CONFIG_PROC_FS
  72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  73 #endif
  74
  75 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
  76 {
  77         ns->ids[IPC_SHM_IDS] = ids;
  78         ns->shm_ctlmax = SHMMAX;
  79         ns->shm_ctlall = SHMALL;
  80         ns->shm_ctlmni = SHMMNI;
  81         ns->shm_tot = 0;
  82         ipc_init_ids(ids);
  83 }
  84
  85 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
  86 {
  87         if (shp->shm_nattch){
  88                 shp->shm_perm.mode |= SHM_DEST;
  89                 /* Do not find it any more */
  90                 shp->shm_perm.key = IPC_PRIVATE;
  91                 shm_unlock(shp);
  92         } else
  93                 shm_destroy(ns, shp);
  94 }
  95
  96 int shm_init_ns(struct ipc_namespace *ns)
  97 {
  98         struct ipc_ids *ids;
  99
 100         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 101         if (ids == NULL)
 102                 return -ENOMEM;
 103
 104         __shm_init_ns(ns, ids);
 105         return 0;
 106 }
 107
 108 void shm_exit_ns(struct ipc_namespace *ns)
 109 {
 110         struct shmid_kernel *shp;
 111         int next_id;
 112         int total, in_use;
 113
 114         mutex_lock(&shm_ids(ns).mutex);
 115
 116         in_use = shm_ids(ns).in_use;
 117
 118         for (total = 0, next_id = 0; total < in_use; next_id++) {
 119                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 120                 if (shp == NULL)
 121                         continue;
 122                 ipc_lock_by_ptr(&shp->shm_perm);
 123                 do_shm_rmid(ns, shp);
 124                 total++;
 125         }
 126         mutex_unlock(&shm_ids(ns).mutex);
 127
 128         kfree(ns->ids[IPC_SHM_IDS]);
 129         ns->ids[IPC_SHM_IDS] = NULL;
 130 }
 131
 132 void __init shm_init (void)
 133 {
 134         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 135         ipc_init_proc_interface("sysvipc/shm",
 136                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 137                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 138 }
 139
 140 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 141 {
 142         return (struct shmid_kernel *) ipc_lock(&shm_ids(ns), id);
 143 }
 144
 145 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 146                                                 int id)
 147 {
 148         return (struct shmid_kernel *) ipc_lock_check(&shm_ids(ns), id);
 149 }
 150
 151 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 152 {
 153         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 154 }
 155
 156 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 157 {
 158         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 159 }
 160
 161
 162
 163 /* This is called by fork, once for every shm attach. */
 164 static void shm_open(struct vm_area_struct *vma)
 165 {
 166         struct file *file = vma->vm_file;
 167         struct shm_file_data *sfd = shm_file_data(file);
 168         struct shmid_kernel *shp;
 169
 170         shp = shm_lock(sfd->ns, sfd->id);
 171         BUG_ON(IS_ERR(shp));
 172         shp->shm_atim = get_seconds();
 173         shp->shm_lprid = task_tgid_vnr(current);
 174         shp->shm_nattch++;
 175         shm_unlock(shp);
 176 }
 177
 178 /*
 179  * shm_destroy - free the struct shmid_kernel
 180  *
 181  * @shp: struct to free
 182  *
 183  * It has to be called with shp and shm_ids.mutex locked,
 184  * but returns with shp unlocked and freed.
 185  */
 186 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 187 {
 188         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 189         shm_rmid(ns, shp);
 190         shm_unlock(shp);
 191         if (!is_file_hugepages(shp->shm_file))
 192                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 193         else
 194                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 195                                                 shp->mlock_user);
 196         fput (shp->shm_file);
 197         security_shm_free(shp);
 198         ipc_rcu_putref(shp);
 199 }
 200
 201 /*
 202  * remove the attach descriptor vma.
 203  * free memory for segment if it is marked destroyed.
 204  * The descriptor has already been removed from the current->mm->mmap list
 205  * and will later be kfree()d.
 206  */
 207 static void shm_close(struct vm_area_struct *vma)
 208 {
 209         struct file * file = vma->vm_file;
 210         struct shm_file_data *sfd = shm_file_data(file);
 211         struct shmid_kernel *shp;
 212         struct ipc_namespace *ns = sfd->ns;
 213
 214         mutex_lock(&shm_ids(ns).mutex);
 215         /* remove from the list of attaches of the shm segment */
 216         shp = shm_lock(ns, sfd->id);
 217         BUG_ON(IS_ERR(shp));
 218         shp->shm_lprid = task_tgid_vnr(current);
 219         shp->shm_dtim = get_seconds();
 220         shp->shm_nattch--;
 221         if(shp->shm_nattch == 0 &&
 222            shp->shm_perm.mode & SHM_DEST)
 223                 shm_destroy(ns, shp);
 224         else
 225                 shm_unlock(shp);
 226         mutex_unlock(&shm_ids(ns).mutex);
 227 }
 228
 229 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 230 {
 231         struct file *file = vma->vm_file;
 232         struct shm_file_data *sfd = shm_file_data(file);
 233
 234         return sfd->vm_ops->fault(vma, vmf);
 235 }
 236
 237 #ifdef CONFIG_NUMA
 238 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 239 {
 240         struct file *file = vma->vm_file;
 241         struct shm_file_data *sfd = shm_file_data(file);
 242         int err = 0;
 243         if (sfd->vm_ops->set_policy)
 244                 err = sfd->vm_ops->set_policy(vma, new);
 245         return err;
 246 }
 247
 248 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 249                                         unsigned long addr)
 250 {
 251         struct file *file = vma->vm_file;
 252         struct shm_file_data *sfd = shm_file_data(file);
 253         struct mempolicy *pol = NULL;
 254
 255         if (sfd->vm_ops->get_policy)
 256                 pol = sfd->vm_ops->get_policy(vma, addr);
 257         else if (vma->vm_policy)
 258                 pol = vma->vm_policy;
 259         else
 260                 pol = current->mempolicy;
 261         return pol;
 262 }
 263 #endif
 264
 265 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 266 {
 267         struct shm_file_data *sfd = shm_file_data(file);
 268         int ret;
 269
 270         ret = sfd->file->f_op->mmap(sfd->file, vma);
 271         if (ret != 0)
 272                 return ret;
 273         sfd->vm_ops = vma->vm_ops;
 274 #ifdef CONFIG_MMU
 275         BUG_ON(!sfd->vm_ops->fault);
 276 #endif
 277         vma->vm_ops = &shm_vm_ops;
 278         shm_open(vma);
 279
 280         return ret;
 281 }
 282
 283 static int shm_release(struct inode *ino, struct file *file)
 284 {
 285         struct shm_file_data *sfd = shm_file_data(file);
 286
 287         put_ipc_ns(sfd->ns);
 288         shm_file_data(file) = NULL;
 289         kfree(sfd);
 290         return 0;
 291 }
 292
 293 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 294 {
 295         int (*fsync) (struct file *, struct dentry *, int datasync);
 296         struct shm_file_data *sfd = shm_file_data(file);
 297         int ret = -EINVAL;
 298
 299         fsync = sfd->file->f_op->fsync;
 300         if (fsync)
 301                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 302         return ret;
 303 }
 304
 305 static unsigned long shm_get_unmapped_area(struct file *file,
 306         unsigned long addr, unsigned long len, unsigned long pgoff,
 307         unsigned long flags)
 308 {
 309         struct shm_file_data *sfd = shm_file_data(file);
 310         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 311 }
 312
 313 int is_file_shm_hugepages(struct file *file)
 314 {
 315         int ret = 0;
 316
 317         if (file->f_op == &shm_file_operations) {
 318                 struct shm_file_data *sfd;
 319                 sfd = shm_file_data(file);
 320                 ret = is_file_hugepages(sfd->file);
 321         }
 322         return ret;
 323 }
 324
 325 static const struct file_operations shm_file_operations = {
 326         .mmap           = shm_mmap,
 327         .fsync          = shm_fsync,
 328         .release        = shm_release,
 329         .get_unmapped_area      = shm_get_unmapped_area,
 330 };
 331
 332 static struct vm_operations_struct shm_vm_ops = {
 333         .open   = shm_open,     /* callback for a new vm-area open */
 334         .close  = shm_close,    /* callback for when the vm-area is released */
 335         .fault  = shm_fault,
 336 #if defined(CONFIG_NUMA)
 337         .set_policy = shm_set_policy,
 338         .get_policy = shm_get_policy,
 339 #endif
 340 };
 341
 342 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 343 {
 344         key_t key = params->key;
 345         int shmflg = params->flg;
 346         size_t size = params->u.size;
 347         int error;
 348         struct shmid_kernel *shp;
 349         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 350         struct file * file;
 351         char name[13];
 352         int id;
 353
 354         if (size < SHMMIN || size > ns->shm_ctlmax)
 355                 return -EINVAL;
 356
 357         if (ns->shm_tot + numpages > ns->shm_ctlall)
 358                 return -ENOSPC;
 359
 360         shp = ipc_rcu_alloc(sizeof(*shp));
 361         if (!shp)
 362                 return -ENOMEM;
 363
 364         shp->shm_perm.key = key;
 365         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 366         shp->mlock_user = NULL;
 367
 368         shp->shm_perm.security = NULL;
 369         error = security_shm_alloc(shp);
 370         if (error) {
 371                 ipc_rcu_putref(shp);
 372                 return error;
 373         }
 374
 375         sprintf (name, "SYSV%08x", key);
 376         if (shmflg & SHM_HUGETLB) {
 377                 /* hugetlb_file_setup takes care of mlock user accounting */
 378                 file = hugetlb_file_setup(name, size);
 379                 shp->mlock_user = current->user;
 380         } else {
 381                 int acctflag = VM_ACCOUNT;
 382                 /*
 383                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 384                  * if it's asked for.
 385                  */
 386                 if  ((shmflg & SHM_NORESERVE) &&
 387                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 388                         acctflag = 0;
 389                 file = shmem_file_setup(name, size, acctflag);
 390         }
 391         error = PTR_ERR(file);
 392         if (IS_ERR(file))
 393                 goto no_file;
 394
 395         error = -ENOSPC;
 396         id = shm_addid(ns, shp);
 397         if(id == -1)
 398                 goto no_id;
 399
 400         shp->shm_cprid = task_tgid_vnr(current);
 401         shp->shm_lprid = 0;
 402         shp->shm_atim = shp->shm_dtim = 0;
 403         shp->shm_ctim = get_seconds();
 404         shp->shm_segsz = size;
 405         shp->shm_nattch = 0;
 406         shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
 407         shp->shm_file = file;
 408         /*
 409          * shmid gets reported as "inode#" in /proc/pid/maps.
 410          * proc-ps tools use this. Changing this will break them.
 411          */
 412         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 413
 414         ns->shm_tot += numpages;
 415         error = shp->shm_perm.id;
 416         shm_unlock(shp);
 417         return error;
 418
 419 no_id:
 420         fput(file);
 421 no_file:
 422         security_shm_free(shp);
 423         ipc_rcu_putref(shp);
 424         return error;
 425 }
 426
 427 static inline int shm_security(void *shp, int shmflg)
 428 {
 429         return security_shm_associate((struct shmid_kernel *) shp, shmflg);
 430 }
 431
 432 static inline int shm_more_checks(void *shp, struct ipc_params *params)
 433 {
 434         if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size)
 435                 return -EINVAL;
 436
 437         return 0;
 438 }
 439
 440 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 441 {
 442         struct ipc_namespace *ns;
 443         struct ipc_ops shm_ops;
 444         struct ipc_params shm_params;
 445
 446         ns = current->nsproxy->ipc_ns;
 447
 448         shm_ops.getnew = newseg;
 449         shm_ops.associate = shm_security;
 450         shm_ops.more_checks = shm_more_checks;
 451
 452         shm_params.key = key;
 453         shm_params.flg = shmflg;
 454         shm_params.u.size = size;
 455
 456         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 457 }
 458
 459 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 460 {
 461         switch(version) {
 462         case IPC_64:
 463                 return copy_to_user(buf, in, sizeof(*in));
 464         case IPC_OLD:
 465             {
 466                 struct shmid_ds out;
 467
 468                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 469                 out.shm_segsz   = in->shm_segsz;
 470                 out.shm_atime   = in->shm_atime;
 471                 out.shm_dtime   = in->shm_dtime;
 472                 out.shm_ctime   = in->shm_ctime;
 473                 out.shm_cpid    = in->shm_cpid;
 474                 out.shm_lpid    = in->shm_lpid;
 475                 out.shm_nattch  = in->shm_nattch;
 476
 477                 return copy_to_user(buf, &out, sizeof(out));
 478             }
 479         default:
 480                 return -EINVAL;
 481         }
 482 }
 483
 484 struct shm_setbuf {
 485         uid_t   uid;
 486         gid_t   gid;
 487         mode_t  mode;
 488 };
 489
 490 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 491 {
 492         switch(version) {
 493         case IPC_64:
 494             {
 495                 struct shmid64_ds tbuf;
 496
 497                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 498                         return -EFAULT;
 499
 500                 out->uid        = tbuf.shm_perm.uid;
 501                 out->gid        = tbuf.shm_perm.gid;
 502                 out->mode       = tbuf.shm_perm.mode;
 503
 504                 return 0;
 505             }
 506         case IPC_OLD:
 507             {
 508                 struct shmid_ds tbuf_old;
 509
 510                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 511                         return -EFAULT;
 512
 513                 out->uid        = tbuf_old.shm_perm.uid;
 514                 out->gid        = tbuf_old.shm_perm.gid;
 515                 out->mode       = tbuf_old.shm_perm.mode;
 516
 517                 return 0;
 518             }
 519         default:
 520                 return -EINVAL;
 521         }
 522 }
 523
 524 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 525 {
 526         switch(version) {
 527         case IPC_64:
 528                 return copy_to_user(buf, in, sizeof(*in));
 529         case IPC_OLD:
 530             {
 531                 struct shminfo out;
 532
 533                 if(in->shmmax > INT_MAX)
 534                         out.shmmax = INT_MAX;
 535                 else
 536                         out.shmmax = (int)in->shmmax;
 537
 538                 out.shmmin      = in->shmmin;
 539                 out.shmmni      = in->shmmni;
 540                 out.shmseg      = in->shmseg;
 541                 out.shmall      = in->shmall;
 542
 543                 return copy_to_user(buf, &out, sizeof(out));
 544             }
 545         default:
 546                 return -EINVAL;
 547         }
 548 }
 549
 550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 551                 unsigned long *swp)
 552 {
 553         int next_id;
 554         int total, in_use;
 555
 556         *rss = 0;
 557         *swp = 0;
 558
 559         in_use = shm_ids(ns).in_use;
 560
 561         for (total = 0, next_id = 0; total < in_use; next_id++) {
 562                 struct shmid_kernel *shp;
 563                 struct inode *inode;
 564
 565                 /*
 566                  * idr_find() is called via shm_get(), so with shm_ids.mutex
 567                  * locked. Since ipc_addid() is also called with
 568                  * shm_ids.mutex down, there is no need to add read barriers
 569                  * here to gurantee the writes in ipc_addid() are seen in
 570                  * order here (for Alpha).
 571                  * However idr_find() itself does not necessary require
 572                  * ipc_ids.mutex down. So if idr_find() is used by other
 573                  * places without ipc_ids.mutex down, then it needs read
 574                  * read memory barriers as ipc_lock() does.
 575                  */
 576
 577                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 578                 if (shp == NULL)
 579                         continue;
 580
 581                 inode = shp->shm_file->f_path.dentry->d_inode;
 582
 583                 if (is_file_hugepages(shp->shm_file)) {
 584                         struct address_space *mapping = inode->i_mapping;
 585                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 586                 } else {
 587                         struct shmem_inode_info *info = SHMEM_I(inode);
 588                         spin_lock(&info->lock);
 589                         *rss += inode->i_mapping->nrpages;
 590                         *swp += info->swapped;
 591                         spin_unlock(&info->lock);
 592                 }
 593
 594                 total++;
 595         }
 596 }
 597
 598 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 599 {
 600         struct shm_setbuf setbuf;
 601         struct shmid_kernel *shp;
 602         int err, version;
 603         struct ipc_namespace *ns;
 604
 605         if (cmd < 0 || shmid < 0) {
 606                 err = -EINVAL;
 607                 goto out;
 608         }
 609
 610         version = ipc_parse_version(&cmd);
 611         ns = current->nsproxy->ipc_ns;
 612
 613         switch (cmd) { /* replace with proc interface ? */
 614         case IPC_INFO:
 615         {
 616                 struct shminfo64 shminfo;
 617
 618                 err = security_shm_shmctl(NULL, cmd);
 619                 if (err)
 620                         return err;
 621
 622                 memset(&shminfo,0,sizeof(shminfo));
 623                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 624                 shminfo.shmmax = ns->shm_ctlmax;
 625                 shminfo.shmall = ns->shm_ctlall;
 626
 627                 shminfo.shmmin = SHMMIN;
 628                 if(copy_shminfo_to_user (buf, &shminfo, version))
 629                         return -EFAULT;
 630                 /* reading a integer is always atomic */
 631                 err = ipc_get_maxid(&shm_ids(ns));
 632                 if(err<0)
 633                         err = 0;
 634                 goto out;
 635         }
 636         case SHM_INFO:
 637         {
 638                 struct shm_info shm_info;
 639
 640                 err = security_shm_shmctl(NULL, cmd);
 641                 if (err)
 642                         return err;
 643
 644                 memset(&shm_info,0,sizeof(shm_info));
 645                 mutex_lock(&shm_ids(ns).mutex);
 646                 shm_info.used_ids = shm_ids(ns).in_use;
 647                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 648                 shm_info.shm_tot = ns->shm_tot;
 649                 shm_info.swap_attempts = 0;
 650                 shm_info.swap_successes = 0;
 651                 err = ipc_get_maxid(&shm_ids(ns));
 652                 mutex_unlock(&shm_ids(ns).mutex);
 653                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 654                         err = -EFAULT;
 655                         goto out;
 656                 }
 657
 658                 err = err < 0 ? 0 : err;
 659                 goto out;
 660         }
 661         case SHM_STAT:
 662         case IPC_STAT:
 663         {
 664                 struct shmid64_ds tbuf;
 665                 int result;
 666
 667                 if (!buf) {
 668                         err = -EFAULT;
 669                         goto out;
 670                 }
 671
 672                 if (cmd == SHM_STAT) {
 673                         shp = shm_lock(ns, shmid);
 674                         if (IS_ERR(shp)) {
 675                                 err = PTR_ERR(shp);
 676                                 goto out;
 677                         }
 678                         result = shp->shm_perm.id;
 679                 } else {
 680                         shp = shm_lock_check(ns, shmid);
 681                         if (IS_ERR(shp)) {
 682                                 err = PTR_ERR(shp);
 683                                 goto out;
 684                         }
 685                         result = 0;
 686                 }
 687                 err=-EACCES;
 688                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 689                         goto out_unlock;
 690                 err = security_shm_shmctl(shp, cmd);
 691                 if (err)
 692                         goto out_unlock;
 693                 memset(&tbuf, 0, sizeof(tbuf));
 694                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 695                 tbuf.shm_segsz  = shp->shm_segsz;
 696                 tbuf.shm_atime  = shp->shm_atim;
 697                 tbuf.shm_dtime  = shp->shm_dtim;
 698                 tbuf.shm_ctime  = shp->shm_ctim;
 699                 tbuf.shm_cpid   = shp->shm_cprid;
 700                 tbuf.shm_lpid   = shp->shm_lprid;
 701                 tbuf.shm_nattch = shp->shm_nattch;
 702                 shm_unlock(shp);
 703                 if(copy_shmid_to_user (buf, &tbuf, version))
 704                         err = -EFAULT;
 705                 else
 706                         err = result;
 707                 goto out;
 708         }
 709         case SHM_LOCK:
 710         case SHM_UNLOCK:
 711         {
 712                 shp = shm_lock_check(ns, shmid);
 713                 if (IS_ERR(shp)) {
 714                         err = PTR_ERR(shp);
 715                         goto out;
 716                 }
 717
 718                 err = audit_ipc_obj(&(shp->shm_perm));
 719                 if (err)
 720                         goto out_unlock;
 721
 722                 if (!capable(CAP_IPC_LOCK)) {
 723                         err = -EPERM;
 724                         if (current->euid != shp->shm_perm.uid &&
 725                             current->euid != shp->shm_perm.cuid)
 726                                 goto out_unlock;
 727                         if (cmd == SHM_LOCK &&
 728                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 729                                 goto out_unlock;
 730                 }
 731
 732                 err = security_shm_shmctl(shp, cmd);
 733                 if (err)
 734                         goto out_unlock;
 735
 736                 if(cmd==SHM_LOCK) {
 737                         struct user_struct * user = current->user;
 738                         if (!is_file_hugepages(shp->shm_file)) {
 739                                 err = shmem_lock(shp->shm_file, 1, user);
 740                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 741                                         shp->shm_perm.mode |= SHM_LOCKED;
 742                                         shp->mlock_user = user;
 743                                 }
 744                         }
 745                 } else if (!is_file_hugepages(shp->shm_file)) {
 746                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 747                         shp->shm_perm.mode &= ~SHM_LOCKED;
 748                         shp->mlock_user = NULL;
 749                 }
 750                 shm_unlock(shp);
 751                 goto out;
 752         }
 753         case IPC_RMID:
 754         {
 755                 /*
 756                  *      We cannot simply remove the file. The SVID states
 757                  *      that the block remains until the last person
 758                  *      detaches from it, then is deleted. A shmat() on
 759                  *      an RMID segment is legal in older Linux and if
 760                  *      we change it apps break...
 761                  *
 762                  *      Instead we set a destroyed flag, and then blow
 763                  *      the name away when the usage hits zero.
 764                  */
 765                 mutex_lock(&shm_ids(ns).mutex);
 766                 shp = shm_lock_check(ns, shmid);
 767                 if (IS_ERR(shp)) {
 768                         err = PTR_ERR(shp);
 769                         goto out_up;
 770                 }
 771
 772                 err = audit_ipc_obj(&(shp->shm_perm));
 773                 if (err)
 774                         goto out_unlock_up;
 775
 776                 if (current->euid != shp->shm_perm.uid &&
 777                     current->euid != shp->shm_perm.cuid &&
 778                     !capable(CAP_SYS_ADMIN)) {
 779                         err=-EPERM;
 780                         goto out_unlock_up;
 781                 }
 782
 783                 err = security_shm_shmctl(shp, cmd);
 784                 if (err)
 785                         goto out_unlock_up;
 786
 787                 do_shm_rmid(ns, shp);
 788                 mutex_unlock(&shm_ids(ns).mutex);
 789                 goto out;
 790         }
 791
 792         case IPC_SET:
 793         {
 794                 if (!buf) {
 795                         err = -EFAULT;
 796                         goto out;
 797                 }
 798
 799                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 800                         err = -EFAULT;
 801                         goto out;
 802                 }
 803                 mutex_lock(&shm_ids(ns).mutex);
 804                 shp = shm_lock_check(ns, shmid);
 805                 if (IS_ERR(shp)) {
 806                         err = PTR_ERR(shp);
 807                         goto out_up;
 808                 }
 809                 err = audit_ipc_obj(&(shp->shm_perm));
 810                 if (err)
 811                         goto out_unlock_up;
 812                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 813                 if (err)
 814                         goto out_unlock_up;
 815                 err=-EPERM;
 816                 if (current->euid != shp->shm_perm.uid &&
 817                     current->euid != shp->shm_perm.cuid &&
 818                     !capable(CAP_SYS_ADMIN)) {
 819                         goto out_unlock_up;
 820                 }
 821
 822                 err = security_shm_shmctl(shp, cmd);
 823                 if (err)
 824                         goto out_unlock_up;
 825
 826                 shp->shm_perm.uid = setbuf.uid;
 827                 shp->shm_perm.gid = setbuf.gid;
 828                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 829                         | (setbuf.mode & S_IRWXUGO);
 830                 shp->shm_ctim = get_seconds();
 831                 break;
 832         }
 833
 834         default:
 835                 err = -EINVAL;
 836                 goto out;
 837         }
 838
 839         err = 0;
 840 out_unlock_up:
 841         shm_unlock(shp);
 842 out_up:
 843         mutex_unlock(&shm_ids(ns).mutex);
 844         goto out;
 845 out_unlock:
 846         shm_unlock(shp);
 847 out:
 848         return err;
 849 }
 850
 851 /*
 852  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 853  *
 854  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 855  * "raddr" thing points to kernel space, and there has to be a wrapper around
 856  * this.
 857  */
 858 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 859 {
 860         struct shmid_kernel *shp;
 861         unsigned long addr;
 862         unsigned long size;
 863         struct file * file;
 864         int    err;
 865         unsigned long flags;
 866         unsigned long prot;
 867         int acc_mode;
 868         unsigned long user_addr;
 869         struct ipc_namespace *ns;
 870         struct shm_file_data *sfd;
 871         struct path path;
 872         mode_t f_mode;
 873
 874         err = -EINVAL;
 875         if (shmid < 0)
 876                 goto out;
 877         else if ((addr = (ulong)shmaddr)) {
 878                 if (addr & (SHMLBA-1)) {
 879                         if (shmflg & SHM_RND)
 880                                 addr &= ~(SHMLBA-1);       /* round down */
 881                         else
 882 #ifndef __ARCH_FORCE_SHMLBA
 883                                 if (addr & ~PAGE_MASK)
 884 #endif
 885                                         goto out;
 886                 }
 887                 flags = MAP_SHARED | MAP_FIXED;
 888         } else {
 889                 if ((shmflg & SHM_REMAP))
 890                         goto out;
 891
 892                 flags = MAP_SHARED;
 893         }
 894
 895         if (shmflg & SHM_RDONLY) {
 896                 prot = PROT_READ;
 897                 acc_mode = S_IRUGO;
 898                 f_mode = FMODE_READ;
 899         } else {
 900                 prot = PROT_READ | PROT_WRITE;
 901                 acc_mode = S_IRUGO | S_IWUGO;
 902                 f_mode = FMODE_READ | FMODE_WRITE;
 903         }
 904         if (shmflg & SHM_EXEC) {
 905                 prot |= PROT_EXEC;
 906                 acc_mode |= S_IXUGO;
 907         }
 908
 909         /*
 910          * We cannot rely on the fs check since SYSV IPC does have an
 911          * additional creator id...
 912          */
 913         ns = current->nsproxy->ipc_ns;
 914         shp = shm_lock_check(ns, shmid);
 915         if (IS_ERR(shp)) {
 916                 err = PTR_ERR(shp);
 917                 goto out;
 918         }
 919
 920         err = -EACCES;
 921         if (ipcperms(&shp->shm_perm, acc_mode))
 922                 goto out_unlock;
 923
 924         err = security_shm_shmat(shp, shmaddr, shmflg);
 925         if (err)
 926                 goto out_unlock;
 927
 928         path.dentry = dget(shp->shm_file->f_path.dentry);
 929         path.mnt    = shp->shm_file->f_path.mnt;
 930         shp->shm_nattch++;
 931         size = i_size_read(path.dentry->d_inode);
 932         shm_unlock(shp);
 933
 934         err = -ENOMEM;
 935         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 936         if (!sfd)
 937                 goto out_put_dentry;
 938
 939         err = -ENOMEM;
 940
 941         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 942         if (!file)
 943                 goto out_free;
 944
 945         file->private_data = sfd;
 946         file->f_mapping = shp->shm_file->f_mapping;
 947         sfd->id = shp->shm_perm.id;
 948         sfd->ns = get_ipc_ns(ns);
 949         sfd->file = shp->shm_file;
 950         sfd->vm_ops = NULL;
 951
 952         down_write(&current->mm->mmap_sem);
 953         if (addr && !(shmflg & SHM_REMAP)) {
 954                 err = -EINVAL;
 955                 if (find_vma_intersection(current->mm, addr, addr + size))
 956                         goto invalid;
 957                 /*
 958                  * If shm segment goes below stack, make sure there is some
 959                  * space left for the stack to grow (at least 4 pages).
 960                  */
 961                 if (addr < current->mm->start_stack &&
 962                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 963                         goto invalid;
 964         }
 965
 966         user_addr = do_mmap (file, addr, size, prot, flags, 0);
 967         *raddr = user_addr;
 968         err = 0;
 969         if (IS_ERR_VALUE(user_addr))
 970                 err = (long)user_addr;
 971 invalid:
 972         up_write(&current->mm->mmap_sem);
 973
 974         fput(file);
 975
 976 out_nattch:
 977         mutex_lock(&shm_ids(ns).mutex);
 978         shp = shm_lock(ns, shmid);
 979         BUG_ON(IS_ERR(shp));
 980         shp->shm_nattch--;
 981         if(shp->shm_nattch == 0 &&
 982            shp->shm_perm.mode & SHM_DEST)
 983                 shm_destroy(ns, shp);
 984         else
 985                 shm_unlock(shp);
 986         mutex_unlock(&shm_ids(ns).mutex);
 987
 988 out:
 989         return err;
 990
 991 out_unlock:
 992         shm_unlock(shp);
 993         goto out;
 994
 995 out_free:
 996         kfree(sfd);
 997 out_put_dentry:
 998         dput(path.dentry);
 999         goto out_nattch;
1000 }
1001
1002 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1003 {
1004         unsigned long ret;
1005         long err;
1006
1007         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1008         if (err)
1009                 return err;
1010         force_successful_syscall_return();
1011         return (long)ret;
1012 }
1013
1014 /*
1015  * detach and kill segment if marked destroyed.
1016  * The work is done in shm_close.
1017  */
1018 asmlinkage long sys_shmdt(char __user *shmaddr)
1019 {
1020         struct mm_struct *mm = current->mm;
1021         struct vm_area_struct *vma, *next;
1022         unsigned long addr = (unsigned long)shmaddr;
1023         loff_t size = 0;
1024         int retval = -EINVAL;
1025
1026         if (addr & ~PAGE_MASK)
1027                 return retval;
1028
1029         down_write(&mm->mmap_sem);
1030
1031         /*
1032          * This function tries to be smart and unmap shm segments that
1033          * were modified by partial mlock or munmap calls:
1034          * - It first determines the size of the shm segment that should be
1035          *   unmapped: It searches for a vma that is backed by shm and that
1036          *   started at address shmaddr. It records it's size and then unmaps
1037          *   it.
1038          * - Then it unmaps all shm vmas that started at shmaddr and that
1039          *   are within the initially determined size.
1040          * Errors from do_munmap are ignored: the function only fails if
1041          * it's called with invalid parameters or if it's called to unmap
1042          * a part of a vma. Both calls in this function are for full vmas,
1043          * the parameters are directly copied from the vma itself and always
1044          * valid - therefore do_munmap cannot fail. (famous last words?)
1045          */
1046         /*
1047          * If it had been mremap()'d, the starting address would not
1048          * match the usual checks anyway. So assume all vma's are
1049          * above the starting address given.
1050          */
1051         vma = find_vma(mm, addr);
1052
1053         while (vma) {
1054                 next = vma->vm_next;
1055
1056                 /*
1057                  * Check if the starting address would match, i.e. it's
1058                  * a fragment created by mprotect() and/or munmap(), or it
1059                  * otherwise it starts at this address with no hassles.
1060                  */
1061                 if ((vma->vm_ops == &shm_vm_ops) &&
1062                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1063
1064
1065                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1066                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1067                         /*
1068                          * We discovered the size of the shm segment, so
1069                          * break out of here and fall through to the next
1070                          * loop that uses the size information to stop
1071                          * searching for matching vma's.
1072                          */
1073                         retval = 0;
1074                         vma = next;
1075                         break;
1076                 }
1077                 vma = next;
1078         }
1079
1080         /*
1081          * We need look no further than the maximum address a fragment
1082          * could possibly have landed at. Also cast things to loff_t to
1083          * prevent overflows and make comparisions vs. equal-width types.
1084          */
1085         size = PAGE_ALIGN(size);
1086         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1087                 next = vma->vm_next;
1088
1089                 /* finding a matching vma now does not alter retval */
1090                 if ((vma->vm_ops == &shm_vm_ops) &&
1091                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1092
1093                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1094                 vma = next;
1095         }
1096
1097         up_write(&mm->mmap_sem);
1098         return retval;
1099 }
1100
1101 #ifdef CONFIG_PROC_FS
1102 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1103 {
1104         struct shmid_kernel *shp = it;
1105         char *format;
1106
1107 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1108 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1109
1110         if (sizeof(size_t) <= sizeof(int))
1111                 format = SMALL_STRING;
1112         else
1113                 format = BIG_STRING;
1114         return seq_printf(s, format,
1115                           shp->shm_perm.key,
1116                           shp->shm_perm.id,
1117                           shp->shm_perm.mode,
1118                           shp->shm_segsz,
1119                           shp->shm_cprid,
1120                           shp->shm_lprid,
1121                           shp->shm_nattch,
1122                           shp->shm_perm.uid,
1123                           shp->shm_perm.gid,
1124                           shp->shm_perm.cuid,
1125                           shp->shm_perm.cgid,
1126                           shp->shm_atim,
1127                           shp->shm_dtim,
1128                           shp->shm_ctim);
1129 }
1130 #endif