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
  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(id, seq)    ipc_buildid(id, seq)
  65
  66 static int newseg(struct ipc_namespace *, struct ipc_params *);
  67 static void shm_open(struct vm_area_struct *vma);
  68 static void shm_close(struct vm_area_struct *vma);
  69 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
  70 #ifdef CONFIG_PROC_FS
  71 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
  72 #endif
  73
  74 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
  75 {
  76         ns->ids[IPC_SHM_IDS] = ids;
  77         ns->shm_ctlmax = SHMMAX;
  78         ns->shm_ctlall = SHMALL;
  79         ns->shm_ctlmni = SHMMNI;
  80         ns->shm_tot = 0;
  81         ipc_init_ids(ids);
  82 }
  83
  84 /*
  85  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  86  * Only shm_ids.rw_mutex remains locked on exit.
  87  */
  88 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
  89 {
  90         if (shp->shm_nattch){
  91                 shp->shm_perm.mode |= SHM_DEST;
  92                 /* Do not find it any more */
  93                 shp->shm_perm.key = IPC_PRIVATE;
  94                 shm_unlock(shp);
  95         } else
  96                 shm_destroy(ns, shp);
  97 }
  98
  99 int shm_init_ns(struct ipc_namespace *ns)
 100 {
 101         struct ipc_ids *ids;
 102
 103         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 104         if (ids == NULL)
 105                 return -ENOMEM;
 106
 107         __shm_init_ns(ns, ids);
 108         return 0;
 109 }
 110
 111 void shm_exit_ns(struct ipc_namespace *ns)
 112 {
 113         struct shmid_kernel *shp;
 114         int next_id;
 115         int total, in_use;
 116
 117         down_write(&shm_ids(ns).rw_mutex);
 118
 119         in_use = shm_ids(ns).in_use;
 120
 121         for (total = 0, next_id = 0; total < in_use; next_id++) {
 122                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 123                 if (shp == NULL)
 124                         continue;
 125                 ipc_lock_by_ptr(&shp->shm_perm);
 126                 do_shm_rmid(ns, shp);
 127                 total++;
 128         }
 129         up_write(&shm_ids(ns).rw_mutex);
 130
 131         kfree(ns->ids[IPC_SHM_IDS]);
 132         ns->ids[IPC_SHM_IDS] = NULL;
 133 }
 134
 135 void __init shm_init (void)
 136 {
 137         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 138         ipc_init_proc_interface("sysvipc/shm",
 139                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 140                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 141 }
 142
 143 /*
 144  * shm_lock_(check_)down routines are called in the paths where the rw_mutex
 145  * is held to protect access to the idr tree.
 146  */
 147 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
 148                                                 int id)
 149 {
 150         struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
 151
 152         return container_of(ipcp, struct shmid_kernel, shm_perm);
 153 }
 154
 155 static inline struct shmid_kernel *shm_lock_check_down(
 156                                                 struct ipc_namespace *ns,
 157                                                 int id)
 158 {
 159         struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
 160
 161         return container_of(ipcp, struct shmid_kernel, shm_perm);
 162 }
 163
 164 /*
 165  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 166  * is not held.
 167  */
 168 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 169 {
 170         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 171
 172         return container_of(ipcp, struct shmid_kernel, shm_perm);
 173 }
 174
 175 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 176                                                 int id)
 177 {
 178         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 179
 180         return container_of(ipcp, struct shmid_kernel, shm_perm);
 181 }
 182
 183 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 184 {
 185         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 186 }
 187
 188 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 189 {
 190         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 191 }
 192
 193
 194
 195 /* This is called by fork, once for every shm attach. */
 196 static void shm_open(struct vm_area_struct *vma)
 197 {
 198         struct file *file = vma->vm_file;
 199         struct shm_file_data *sfd = shm_file_data(file);
 200         struct shmid_kernel *shp;
 201
 202         shp = shm_lock(sfd->ns, sfd->id);
 203         BUG_ON(IS_ERR(shp));
 204         shp->shm_atim = get_seconds();
 205         shp->shm_lprid = task_tgid_vnr(current);
 206         shp->shm_nattch++;
 207         shm_unlock(shp);
 208 }
 209
 210 /*
 211  * shm_destroy - free the struct shmid_kernel
 212  *
 213  * @ns: namespace
 214  * @shp: struct to free
 215  *
 216  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 217  * but returns with shp unlocked and freed.
 218  */
 219 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 220 {
 221         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 222         shm_rmid(ns, shp);
 223         shm_unlock(shp);
 224         if (!is_file_hugepages(shp->shm_file))
 225                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 226         else
 227                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 228                                                 shp->mlock_user);
 229         fput (shp->shm_file);
 230         security_shm_free(shp);
 231         ipc_rcu_putref(shp);
 232 }
 233
 234 /*
 235  * remove the attach descriptor vma.
 236  * free memory for segment if it is marked destroyed.
 237  * The descriptor has already been removed from the current->mm->mmap list
 238  * and will later be kfree()d.
 239  */
 240 static void shm_close(struct vm_area_struct *vma)
 241 {
 242         struct file * file = vma->vm_file;
 243         struct shm_file_data *sfd = shm_file_data(file);
 244         struct shmid_kernel *shp;
 245         struct ipc_namespace *ns = sfd->ns;
 246
 247         down_write(&shm_ids(ns).rw_mutex);
 248         /* remove from the list of attaches of the shm segment */
 249         shp = shm_lock_down(ns, sfd->id);
 250         BUG_ON(IS_ERR(shp));
 251         shp->shm_lprid = task_tgid_vnr(current);
 252         shp->shm_dtim = get_seconds();
 253         shp->shm_nattch--;
 254         if(shp->shm_nattch == 0 &&
 255            shp->shm_perm.mode & SHM_DEST)
 256                 shm_destroy(ns, shp);
 257         else
 258                 shm_unlock(shp);
 259         up_write(&shm_ids(ns).rw_mutex);
 260 }
 261
 262 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 263 {
 264         struct file *file = vma->vm_file;
 265         struct shm_file_data *sfd = shm_file_data(file);
 266
 267         return sfd->vm_ops->fault(vma, vmf);
 268 }
 269
 270 #ifdef CONFIG_NUMA
 271 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 272 {
 273         struct file *file = vma->vm_file;
 274         struct shm_file_data *sfd = shm_file_data(file);
 275         int err = 0;
 276         if (sfd->vm_ops->set_policy)
 277                 err = sfd->vm_ops->set_policy(vma, new);
 278         return err;
 279 }
 280
 281 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 282                                         unsigned long addr)
 283 {
 284         struct file *file = vma->vm_file;
 285         struct shm_file_data *sfd = shm_file_data(file);
 286         struct mempolicy *pol = NULL;
 287
 288         if (sfd->vm_ops->get_policy)
 289                 pol = sfd->vm_ops->get_policy(vma, addr);
 290         else if (vma->vm_policy)
 291                 pol = vma->vm_policy;
 292         else
 293                 pol = current->mempolicy;
 294         return pol;
 295 }
 296 #endif
 297
 298 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 299 {
 300         struct shm_file_data *sfd = shm_file_data(file);
 301         int ret;
 302
 303         ret = sfd->file->f_op->mmap(sfd->file, vma);
 304         if (ret != 0)
 305                 return ret;
 306         sfd->vm_ops = vma->vm_ops;
 307 #ifdef CONFIG_MMU
 308         BUG_ON(!sfd->vm_ops->fault);
 309 #endif
 310         vma->vm_ops = &shm_vm_ops;
 311         shm_open(vma);
 312
 313         return ret;
 314 }
 315
 316 static int shm_release(struct inode *ino, struct file *file)
 317 {
 318         struct shm_file_data *sfd = shm_file_data(file);
 319
 320         put_ipc_ns(sfd->ns);
 321         shm_file_data(file) = NULL;
 322         kfree(sfd);
 323         return 0;
 324 }
 325
 326 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 327 {
 328         int (*fsync) (struct file *, struct dentry *, int datasync);
 329         struct shm_file_data *sfd = shm_file_data(file);
 330         int ret = -EINVAL;
 331
 332         fsync = sfd->file->f_op->fsync;
 333         if (fsync)
 334                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 335         return ret;
 336 }
 337
 338 static unsigned long shm_get_unmapped_area(struct file *file,
 339         unsigned long addr, unsigned long len, unsigned long pgoff,
 340         unsigned long flags)
 341 {
 342         struct shm_file_data *sfd = shm_file_data(file);
 343         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 344 }
 345
 346 int is_file_shm_hugepages(struct file *file)
 347 {
 348         int ret = 0;
 349
 350         if (file->f_op == &shm_file_operations) {
 351                 struct shm_file_data *sfd;
 352                 sfd = shm_file_data(file);
 353                 ret = is_file_hugepages(sfd->file);
 354         }
 355         return ret;
 356 }
 357
 358 static const struct file_operations shm_file_operations = {
 359         .mmap           = shm_mmap,
 360         .fsync          = shm_fsync,
 361         .release        = shm_release,
 362         .get_unmapped_area      = shm_get_unmapped_area,
 363 };
 364
 365 static struct vm_operations_struct shm_vm_ops = {
 366         .open   = shm_open,     /* callback for a new vm-area open */
 367         .close  = shm_close,    /* callback for when the vm-area is released */
 368         .fault  = shm_fault,
 369 #if defined(CONFIG_NUMA)
 370         .set_policy = shm_set_policy,
 371         .get_policy = shm_get_policy,
 372 #endif
 373 };
 374
 375 /**
 376  * newseg - Create a new shared memory segment
 377  * @ns: namespace
 378  * @params: ptr to the structure that contains key, size and shmflg
 379  *
 380  * Called with shm_ids.rw_mutex held as a writer.
 381  */
 382
 383 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 384 {
 385         key_t key = params->key;
 386         int shmflg = params->flg;
 387         size_t size = params->u.size;
 388         int error;
 389         struct shmid_kernel *shp;
 390         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 391         struct file * file;
 392         char name[13];
 393         int id;
 394
 395         if (size < SHMMIN || size > ns->shm_ctlmax)
 396                 return -EINVAL;
 397
 398         if (ns->shm_tot + numpages > ns->shm_ctlall)
 399                 return -ENOSPC;
 400
 401         shp = ipc_rcu_alloc(sizeof(*shp));
 402         if (!shp)
 403                 return -ENOMEM;
 404
 405         shp->shm_perm.key = key;
 406         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 407         shp->mlock_user = NULL;
 408
 409         shp->shm_perm.security = NULL;
 410         error = security_shm_alloc(shp);
 411         if (error) {
 412                 ipc_rcu_putref(shp);
 413                 return error;
 414         }
 415
 416         sprintf (name, "SYSV%08x", key);
 417         if (shmflg & SHM_HUGETLB) {
 418                 /* hugetlb_file_setup takes care of mlock user accounting */
 419                 file = hugetlb_file_setup(name, size);
 420                 shp->mlock_user = current->user;
 421         } else {
 422                 int acctflag = VM_ACCOUNT;
 423                 /*
 424                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 425                  * if it's asked for.
 426                  */
 427                 if  ((shmflg & SHM_NORESERVE) &&
 428                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 429                         acctflag = 0;
 430                 file = shmem_file_setup(name, size, acctflag);
 431         }
 432         error = PTR_ERR(file);
 433         if (IS_ERR(file))
 434                 goto no_file;
 435
 436         id = shm_addid(ns, shp);
 437         if (id < 0) {
 438                 error = id;
 439                 goto no_id;
 440         }
 441
 442         shp->shm_cprid = task_tgid_vnr(current);
 443         shp->shm_lprid = 0;
 444         shp->shm_atim = shp->shm_dtim = 0;
 445         shp->shm_ctim = get_seconds();
 446         shp->shm_segsz = size;
 447         shp->shm_nattch = 0;
 448         shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
 449         shp->shm_file = file;
 450         /*
 451          * shmid gets reported as "inode#" in /proc/pid/maps.
 452          * proc-ps tools use this. Changing this will break them.
 453          */
 454         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 455
 456         ns->shm_tot += numpages;
 457         error = shp->shm_perm.id;
 458         shm_unlock(shp);
 459         return error;
 460
 461 no_id:
 462         fput(file);
 463 no_file:
 464         security_shm_free(shp);
 465         ipc_rcu_putref(shp);
 466         return error;
 467 }
 468
 469 /*
 470  * Called with shm_ids.rw_mutex and ipcp locked.
 471  */
 472 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 473 {
 474         struct shmid_kernel *shp;
 475
 476         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 477         return security_shm_associate(shp, shmflg);
 478 }
 479
 480 /*
 481  * Called with shm_ids.rw_mutex and ipcp locked.
 482  */
 483 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 484                                 struct ipc_params *params)
 485 {
 486         struct shmid_kernel *shp;
 487
 488         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 489         if (shp->shm_segsz < params->u.size)
 490                 return -EINVAL;
 491
 492         return 0;
 493 }
 494
 495 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 496 {
 497         struct ipc_namespace *ns;
 498         struct ipc_ops shm_ops;
 499         struct ipc_params shm_params;
 500
 501         ns = current->nsproxy->ipc_ns;
 502
 503         shm_ops.getnew = newseg;
 504         shm_ops.associate = shm_security;
 505         shm_ops.more_checks = shm_more_checks;
 506
 507         shm_params.key = key;
 508         shm_params.flg = shmflg;
 509         shm_params.u.size = size;
 510
 511         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 512 }
 513
 514 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 515 {
 516         switch(version) {
 517         case IPC_64:
 518                 return copy_to_user(buf, in, sizeof(*in));
 519         case IPC_OLD:
 520             {
 521                 struct shmid_ds out;
 522
 523                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 524                 out.shm_segsz   = in->shm_segsz;
 525                 out.shm_atime   = in->shm_atime;
 526                 out.shm_dtime   = in->shm_dtime;
 527                 out.shm_ctime   = in->shm_ctime;
 528                 out.shm_cpid    = in->shm_cpid;
 529                 out.shm_lpid    = in->shm_lpid;
 530                 out.shm_nattch  = in->shm_nattch;
 531
 532                 return copy_to_user(buf, &out, sizeof(out));
 533             }
 534         default:
 535                 return -EINVAL;
 536         }
 537 }
 538
 539 struct shm_setbuf {
 540         uid_t   uid;
 541         gid_t   gid;
 542         mode_t  mode;
 543 };
 544
 545 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 546 {
 547         switch(version) {
 548         case IPC_64:
 549             {
 550                 struct shmid64_ds tbuf;
 551
 552                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 553                         return -EFAULT;
 554
 555                 out->uid        = tbuf.shm_perm.uid;
 556                 out->gid        = tbuf.shm_perm.gid;
 557                 out->mode       = tbuf.shm_perm.mode;
 558
 559                 return 0;
 560             }
 561         case IPC_OLD:
 562             {
 563                 struct shmid_ds tbuf_old;
 564
 565                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 566                         return -EFAULT;
 567
 568                 out->uid        = tbuf_old.shm_perm.uid;
 569                 out->gid        = tbuf_old.shm_perm.gid;
 570                 out->mode       = tbuf_old.shm_perm.mode;
 571
 572                 return 0;
 573             }
 574         default:
 575                 return -EINVAL;
 576         }
 577 }
 578
 579 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 580 {
 581         switch(version) {
 582         case IPC_64:
 583                 return copy_to_user(buf, in, sizeof(*in));
 584         case IPC_OLD:
 585             {
 586                 struct shminfo out;
 587
 588                 if(in->shmmax > INT_MAX)
 589                         out.shmmax = INT_MAX;
 590                 else
 591                         out.shmmax = (int)in->shmmax;
 592
 593                 out.shmmin      = in->shmmin;
 594                 out.shmmni      = in->shmmni;
 595                 out.shmseg      = in->shmseg;
 596                 out.shmall      = in->shmall;
 597
 598                 return copy_to_user(buf, &out, sizeof(out));
 599             }
 600         default:
 601                 return -EINVAL;
 602         }
 603 }
 604
 605 /*
 606  * Called with shm_ids.rw_mutex held as a reader
 607  */
 608 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 609                 unsigned long *swp)
 610 {
 611         int next_id;
 612         int total, in_use;
 613
 614         *rss = 0;
 615         *swp = 0;
 616
 617         in_use = shm_ids(ns).in_use;
 618
 619         for (total = 0, next_id = 0; total < in_use; next_id++) {
 620                 struct shmid_kernel *shp;
 621                 struct inode *inode;
 622
 623                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 624                 if (shp == NULL)
 625                         continue;
 626
 627                 inode = shp->shm_file->f_path.dentry->d_inode;
 628
 629                 if (is_file_hugepages(shp->shm_file)) {
 630                         struct address_space *mapping = inode->i_mapping;
 631                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 632                 } else {
 633                         struct shmem_inode_info *info = SHMEM_I(inode);
 634                         spin_lock(&info->lock);
 635                         *rss += inode->i_mapping->nrpages;
 636                         *swp += info->swapped;
 637                         spin_unlock(&info->lock);
 638                 }
 639
 640                 total++;
 641         }
 642 }
 643
 644 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 645 {
 646         struct shm_setbuf setbuf;
 647         struct shmid_kernel *shp;
 648         int err, version;
 649         struct ipc_namespace *ns;
 650
 651         if (cmd < 0 || shmid < 0) {
 652                 err = -EINVAL;
 653                 goto out;
 654         }
 655
 656         version = ipc_parse_version(&cmd);
 657         ns = current->nsproxy->ipc_ns;
 658
 659         switch (cmd) { /* replace with proc interface ? */
 660         case IPC_INFO:
 661         {
 662                 struct shminfo64 shminfo;
 663
 664                 err = security_shm_shmctl(NULL, cmd);
 665                 if (err)
 666                         return err;
 667
 668                 memset(&shminfo,0,sizeof(shminfo));
 669                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 670                 shminfo.shmmax = ns->shm_ctlmax;
 671                 shminfo.shmall = ns->shm_ctlall;
 672
 673                 shminfo.shmmin = SHMMIN;
 674                 if(copy_shminfo_to_user (buf, &shminfo, version))
 675                         return -EFAULT;
 676
 677                 down_read(&shm_ids(ns).rw_mutex);
 678                 err = ipc_get_maxid(&shm_ids(ns));
 679                 up_read(&shm_ids(ns).rw_mutex);
 680
 681                 if(err<0)
 682                         err = 0;
 683                 goto out;
 684         }
 685         case SHM_INFO:
 686         {
 687                 struct shm_info shm_info;
 688
 689                 err = security_shm_shmctl(NULL, cmd);
 690                 if (err)
 691                         return err;
 692
 693                 memset(&shm_info,0,sizeof(shm_info));
 694                 down_read(&shm_ids(ns).rw_mutex);
 695                 shm_info.used_ids = shm_ids(ns).in_use;
 696                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 697                 shm_info.shm_tot = ns->shm_tot;
 698                 shm_info.swap_attempts = 0;
 699                 shm_info.swap_successes = 0;
 700                 err = ipc_get_maxid(&shm_ids(ns));
 701                 up_read(&shm_ids(ns).rw_mutex);
 702                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 703                         err = -EFAULT;
 704                         goto out;
 705                 }
 706
 707                 err = err < 0 ? 0 : err;
 708                 goto out;
 709         }
 710         case SHM_STAT:
 711         case IPC_STAT:
 712         {
 713                 struct shmid64_ds tbuf;
 714                 int result;
 715
 716                 if (!buf) {
 717                         err = -EFAULT;
 718                         goto out;
 719                 }
 720
 721                 if (cmd == SHM_STAT) {
 722                         shp = shm_lock(ns, shmid);
 723                         if (IS_ERR(shp)) {
 724                                 err = PTR_ERR(shp);
 725                                 goto out;
 726                         }
 727                         result = shp->shm_perm.id;
 728                 } else {
 729                         shp = shm_lock_check(ns, shmid);
 730                         if (IS_ERR(shp)) {
 731                                 err = PTR_ERR(shp);
 732                                 goto out;
 733                         }
 734                         result = 0;
 735                 }
 736                 err=-EACCES;
 737                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 738                         goto out_unlock;
 739                 err = security_shm_shmctl(shp, cmd);
 740                 if (err)
 741                         goto out_unlock;
 742                 memset(&tbuf, 0, sizeof(tbuf));
 743                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 744                 tbuf.shm_segsz  = shp->shm_segsz;
 745                 tbuf.shm_atime  = shp->shm_atim;
 746                 tbuf.shm_dtime  = shp->shm_dtim;
 747                 tbuf.shm_ctime  = shp->shm_ctim;
 748                 tbuf.shm_cpid   = shp->shm_cprid;
 749                 tbuf.shm_lpid   = shp->shm_lprid;
 750                 tbuf.shm_nattch = shp->shm_nattch;
 751                 shm_unlock(shp);
 752                 if(copy_shmid_to_user (buf, &tbuf, version))
 753                         err = -EFAULT;
 754                 else
 755                         err = result;
 756                 goto out;
 757         }
 758         case SHM_LOCK:
 759         case SHM_UNLOCK:
 760         {
 761                 shp = shm_lock_check(ns, shmid);
 762                 if (IS_ERR(shp)) {
 763                         err = PTR_ERR(shp);
 764                         goto out;
 765                 }
 766
 767                 err = audit_ipc_obj(&(shp->shm_perm));
 768                 if (err)
 769                         goto out_unlock;
 770
 771                 if (!capable(CAP_IPC_LOCK)) {
 772                         err = -EPERM;
 773                         if (current->euid != shp->shm_perm.uid &&
 774                             current->euid != shp->shm_perm.cuid)
 775                                 goto out_unlock;
 776                         if (cmd == SHM_LOCK &&
 777                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 778                                 goto out_unlock;
 779                 }
 780
 781                 err = security_shm_shmctl(shp, cmd);
 782                 if (err)
 783                         goto out_unlock;
 784
 785                 if(cmd==SHM_LOCK) {
 786                         struct user_struct * user = current->user;
 787                         if (!is_file_hugepages(shp->shm_file)) {
 788                                 err = shmem_lock(shp->shm_file, 1, user);
 789                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 790                                         shp->shm_perm.mode |= SHM_LOCKED;
 791                                         shp->mlock_user = user;
 792                                 }
 793                         }
 794                 } else if (!is_file_hugepages(shp->shm_file)) {
 795                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 796                         shp->shm_perm.mode &= ~SHM_LOCKED;
 797                         shp->mlock_user = NULL;
 798                 }
 799                 shm_unlock(shp);
 800                 goto out;
 801         }
 802         case IPC_RMID:
 803         {
 804                 /*
 805                  *      We cannot simply remove the file. The SVID states
 806                  *      that the block remains until the last person
 807                  *      detaches from it, then is deleted. A shmat() on
 808                  *      an RMID segment is legal in older Linux and if
 809                  *      we change it apps break...
 810                  *
 811                  *      Instead we set a destroyed flag, and then blow
 812                  *      the name away when the usage hits zero.
 813                  */
 814                 down_write(&shm_ids(ns).rw_mutex);
 815                 shp = shm_lock_check_down(ns, shmid);
 816                 if (IS_ERR(shp)) {
 817                         err = PTR_ERR(shp);
 818                         goto out_up;
 819                 }
 820
 821                 err = audit_ipc_obj(&(shp->shm_perm));
 822                 if (err)
 823                         goto out_unlock_up;
 824
 825                 if (current->euid != shp->shm_perm.uid &&
 826                     current->euid != shp->shm_perm.cuid &&
 827                     !capable(CAP_SYS_ADMIN)) {
 828                         err=-EPERM;
 829                         goto out_unlock_up;
 830                 }
 831
 832                 err = security_shm_shmctl(shp, cmd);
 833                 if (err)
 834                         goto out_unlock_up;
 835
 836                 do_shm_rmid(ns, shp);
 837                 up_write(&shm_ids(ns).rw_mutex);
 838                 goto out;
 839         }
 840
 841         case IPC_SET:
 842         {
 843                 if (!buf) {
 844                         err = -EFAULT;
 845                         goto out;
 846                 }
 847
 848                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 849                         err = -EFAULT;
 850                         goto out;
 851                 }
 852                 down_write(&shm_ids(ns).rw_mutex);
 853                 shp = shm_lock_check_down(ns, shmid);
 854                 if (IS_ERR(shp)) {
 855                         err = PTR_ERR(shp);
 856                         goto out_up;
 857                 }
 858                 err = audit_ipc_obj(&(shp->shm_perm));
 859                 if (err)
 860                         goto out_unlock_up;
 861                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 862                 if (err)
 863                         goto out_unlock_up;
 864                 err=-EPERM;
 865                 if (current->euid != shp->shm_perm.uid &&
 866                     current->euid != shp->shm_perm.cuid &&
 867                     !capable(CAP_SYS_ADMIN)) {
 868                         goto out_unlock_up;
 869                 }
 870
 871                 err = security_shm_shmctl(shp, cmd);
 872                 if (err)
 873                         goto out_unlock_up;
 874
 875                 shp->shm_perm.uid = setbuf.uid;
 876                 shp->shm_perm.gid = setbuf.gid;
 877                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 878                         | (setbuf.mode & S_IRWXUGO);
 879                 shp->shm_ctim = get_seconds();
 880                 break;
 881         }
 882
 883         default:
 884                 err = -EINVAL;
 885                 goto out;
 886         }
 887
 888         err = 0;
 889 out_unlock_up:
 890         shm_unlock(shp);
 891 out_up:
 892         up_write(&shm_ids(ns).rw_mutex);
 893         goto out;
 894 out_unlock:
 895         shm_unlock(shp);
 896 out:
 897         return err;
 898 }
 899
 900 /*
 901  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 902  *
 903  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 904  * "raddr" thing points to kernel space, and there has to be a wrapper around
 905  * this.
 906  */
 907 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 908 {
 909         struct shmid_kernel *shp;
 910         unsigned long addr;
 911         unsigned long size;
 912         struct file * file;
 913         int    err;
 914         unsigned long flags;
 915         unsigned long prot;
 916         int acc_mode;
 917         unsigned long user_addr;
 918         struct ipc_namespace *ns;
 919         struct shm_file_data *sfd;
 920         struct path path;
 921         mode_t f_mode;
 922
 923         err = -EINVAL;
 924         if (shmid < 0)
 925                 goto out;
 926         else if ((addr = (ulong)shmaddr)) {
 927                 if (addr & (SHMLBA-1)) {
 928                         if (shmflg & SHM_RND)
 929                                 addr &= ~(SHMLBA-1);       /* round down */
 930                         else
 931 #ifndef __ARCH_FORCE_SHMLBA
 932                                 if (addr & ~PAGE_MASK)
 933 #endif
 934                                         goto out;
 935                 }
 936                 flags = MAP_SHARED | MAP_FIXED;
 937         } else {
 938                 if ((shmflg & SHM_REMAP))
 939                         goto out;
 940
 941                 flags = MAP_SHARED;
 942         }
 943
 944         if (shmflg & SHM_RDONLY) {
 945                 prot = PROT_READ;
 946                 acc_mode = S_IRUGO;
 947                 f_mode = FMODE_READ;
 948         } else {
 949                 prot = PROT_READ | PROT_WRITE;
 950                 acc_mode = S_IRUGO | S_IWUGO;
 951                 f_mode = FMODE_READ | FMODE_WRITE;
 952         }
 953         if (shmflg & SHM_EXEC) {
 954                 prot |= PROT_EXEC;
 955                 acc_mode |= S_IXUGO;
 956         }
 957
 958         /*
 959          * We cannot rely on the fs check since SYSV IPC does have an
 960          * additional creator id...
 961          */
 962         ns = current->nsproxy->ipc_ns;
 963         shp = shm_lock_check(ns, shmid);
 964         if (IS_ERR(shp)) {
 965                 err = PTR_ERR(shp);
 966                 goto out;
 967         }
 968
 969         err = -EACCES;
 970         if (ipcperms(&shp->shm_perm, acc_mode))
 971                 goto out_unlock;
 972
 973         err = security_shm_shmat(shp, shmaddr, shmflg);
 974         if (err)
 975                 goto out_unlock;
 976
 977         path.dentry = dget(shp->shm_file->f_path.dentry);
 978         path.mnt    = shp->shm_file->f_path.mnt;
 979         shp->shm_nattch++;
 980         size = i_size_read(path.dentry->d_inode);
 981         shm_unlock(shp);
 982
 983         err = -ENOMEM;
 984         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 985         if (!sfd)
 986                 goto out_put_dentry;
 987
 988         err = -ENOMEM;
 989
 990         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 991         if (!file)
 992                 goto out_free;
 993
 994         file->private_data = sfd;
 995         file->f_mapping = shp->shm_file->f_mapping;
 996         sfd->id = shp->shm_perm.id;
 997         sfd->ns = get_ipc_ns(ns);
 998         sfd->file = shp->shm_file;
 999         sfd->vm_ops = NULL;
1000
1001         down_write(&current->mm->mmap_sem);
1002         if (addr && !(shmflg & SHM_REMAP)) {
1003                 err = -EINVAL;
1004                 if (find_vma_intersection(current->mm, addr, addr + size))
1005                         goto invalid;
1006                 /*
1007                  * If shm segment goes below stack, make sure there is some
1008                  * space left for the stack to grow (at least 4 pages).
1009                  */
1010                 if (addr < current->mm->start_stack &&
1011                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1012                         goto invalid;
1013         }
1014
1015         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1016         *raddr = user_addr;
1017         err = 0;
1018         if (IS_ERR_VALUE(user_addr))
1019                 err = (long)user_addr;
1020 invalid:
1021         up_write(&current->mm->mmap_sem);
1022
1023         fput(file);
1024
1025 out_nattch:
1026         down_write(&shm_ids(ns).rw_mutex);
1027         shp = shm_lock_down(ns, shmid);
1028         BUG_ON(IS_ERR(shp));
1029         shp->shm_nattch--;
1030         if(shp->shm_nattch == 0 &&
1031            shp->shm_perm.mode & SHM_DEST)
1032                 shm_destroy(ns, shp);
1033         else
1034                 shm_unlock(shp);
1035         up_write(&shm_ids(ns).rw_mutex);
1036
1037 out:
1038         return err;
1039
1040 out_unlock:
1041         shm_unlock(shp);
1042         goto out;
1043
1044 out_free:
1045         kfree(sfd);
1046 out_put_dentry:
1047         dput(path.dentry);
1048         goto out_nattch;
1049 }
1050
1051 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1052 {
1053         unsigned long ret;
1054         long err;
1055
1056         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1057         if (err)
1058                 return err;
1059         force_successful_syscall_return();
1060         return (long)ret;
1061 }
1062
1063 /*
1064  * detach and kill segment if marked destroyed.
1065  * The work is done in shm_close.
1066  */
1067 asmlinkage long sys_shmdt(char __user *shmaddr)
1068 {
1069         struct mm_struct *mm = current->mm;
1070         struct vm_area_struct *vma, *next;
1071         unsigned long addr = (unsigned long)shmaddr;
1072         loff_t size = 0;
1073         int retval = -EINVAL;
1074
1075         if (addr & ~PAGE_MASK)
1076                 return retval;
1077
1078         down_write(&mm->mmap_sem);
1079
1080         /*
1081          * This function tries to be smart and unmap shm segments that
1082          * were modified by partial mlock or munmap calls:
1083          * - It first determines the size of the shm segment that should be
1084          *   unmapped: It searches for a vma that is backed by shm and that
1085          *   started at address shmaddr. It records it's size and then unmaps
1086          *   it.
1087          * - Then it unmaps all shm vmas that started at shmaddr and that
1088          *   are within the initially determined size.
1089          * Errors from do_munmap are ignored: the function only fails if
1090          * it's called with invalid parameters or if it's called to unmap
1091          * a part of a vma. Both calls in this function are for full vmas,
1092          * the parameters are directly copied from the vma itself and always
1093          * valid - therefore do_munmap cannot fail. (famous last words?)
1094          */
1095         /*
1096          * If it had been mremap()'d, the starting address would not
1097          * match the usual checks anyway. So assume all vma's are
1098          * above the starting address given.
1099          */
1100         vma = find_vma(mm, addr);
1101
1102         while (vma) {
1103                 next = vma->vm_next;
1104
1105                 /*
1106                  * Check if the starting address would match, i.e. it's
1107                  * a fragment created by mprotect() and/or munmap(), or it
1108                  * otherwise it starts at this address with no hassles.
1109                  */
1110                 if ((vma->vm_ops == &shm_vm_ops) &&
1111                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1112
1113
1114                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1115                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1116                         /*
1117                          * We discovered the size of the shm segment, so
1118                          * break out of here and fall through to the next
1119                          * loop that uses the size information to stop
1120                          * searching for matching vma's.
1121                          */
1122                         retval = 0;
1123                         vma = next;
1124                         break;
1125                 }
1126                 vma = next;
1127         }
1128
1129         /*
1130          * We need look no further than the maximum address a fragment
1131          * could possibly have landed at. Also cast things to loff_t to
1132          * prevent overflows and make comparisions vs. equal-width types.
1133          */
1134         size = PAGE_ALIGN(size);
1135         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1136                 next = vma->vm_next;
1137
1138                 /* finding a matching vma now does not alter retval */
1139                 if ((vma->vm_ops == &shm_vm_ops) &&
1140                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1141
1142                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1143                 vma = next;
1144         }
1145
1146         up_write(&mm->mmap_sem);
1147         return retval;
1148 }
1149
1150 #ifdef CONFIG_PROC_FS
1151 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1152 {
1153         struct shmid_kernel *shp = it;
1154         char *format;
1155
1156 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1157 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1158
1159         if (sizeof(size_t) <= sizeof(int))
1160                 format = SMALL_STRING;
1161         else
1162                 format = BIG_STRING;
1163         return seq_printf(s, format,
1164                           shp->shm_perm.key,
1165                           shp->shm_perm.id,
1166                           shp->shm_perm.mode,
1167                           shp->shm_segsz,
1168                           shp->shm_cprid,
1169                           shp->shm_lprid,
1170                           shp->shm_nattch,
1171                           shp->shm_perm.uid,
1172                           shp->shm_perm.gid,
1173                           shp->shm_perm.cuid,
1174                           shp->shm_perm.cgid,
1175                           shp->shm_atim,
1176                           shp->shm_dtim,
1177                           shp->shm_ctim);
1178 }
1179 #endif