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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
  43 #include <asm/uaccess.h>
  44
  45 #include "util.h"
  46
  47 struct shm_file_data {
  48         int id;
  49         struct ipc_namespace *ns;
  50         struct file *file;
  51         const struct vm_operations_struct *vm_ops;
  52 };
  53
  54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
  55
  56 static const struct file_operations shm_file_operations;
  57 static struct vm_operations_struct shm_vm_ops;
  58
  59 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
  60
  61 #define shm_unlock(shp)                 \
  62         ipc_unlock(&(shp)->shm_perm)
  63 #define shm_buildid(id, seq)    ipc_buildid(id, seq)
  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_)down routines are called in the paths where the rw_mutex
 117  * is held to protect access to the idr tree.
 118  */
 119 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
 120                                                 int id)
 121 {
 122         struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
 123
 124         if (IS_ERR(ipcp))
 125                 return (struct shmid_kernel *)ipcp;
 126
 127         return container_of(ipcp, struct shmid_kernel, shm_perm);
 128 }
 129
 130 static inline struct shmid_kernel *shm_lock_check_down(
 131                                                 struct ipc_namespace *ns,
 132                                                 int id)
 133 {
 134         struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
 135
 136         if (IS_ERR(ipcp))
 137                 return (struct shmid_kernel *)ipcp;
 138
 139         return container_of(ipcp, struct shmid_kernel, shm_perm);
 140 }
 141
 142 /*
 143  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 144  * is not held.
 145  */
 146 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 147 {
 148         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 149
 150         if (IS_ERR(ipcp))
 151                 return (struct shmid_kernel *)ipcp;
 152
 153         return container_of(ipcp, struct shmid_kernel, shm_perm);
 154 }
 155
 156 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 157                                                 int id)
 158 {
 159         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 160
 161         if (IS_ERR(ipcp))
 162                 return (struct shmid_kernel *)ipcp;
 163
 164         return container_of(ipcp, struct shmid_kernel, shm_perm);
 165 }
 166
 167 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 168 {
 169         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 170 }
 171
 172 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 173 {
 174         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 175 }
 176
 177
 178
 179 /* This is called by fork, once for every shm attach. */
 180 static void shm_open(struct vm_area_struct *vma)
 181 {
 182         struct file *file = vma->vm_file;
 183         struct shm_file_data *sfd = shm_file_data(file);
 184         struct shmid_kernel *shp;
 185
 186         shp = shm_lock(sfd->ns, sfd->id);
 187         BUG_ON(IS_ERR(shp));
 188         shp->shm_atim = get_seconds();
 189         shp->shm_lprid = task_tgid_vnr(current);
 190         shp->shm_nattch++;
 191         shm_unlock(shp);
 192 }
 193
 194 /*
 195  * shm_destroy - free the struct shmid_kernel
 196  *
 197  * @ns: namespace
 198  * @shp: struct to free
 199  *
 200  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 201  * but returns with shp unlocked and freed.
 202  */
 203 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 204 {
 205         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 206         shm_rmid(ns, shp);
 207         shm_unlock(shp);
 208         if (!is_file_hugepages(shp->shm_file))
 209                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 210         else
 211                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 212                                                 shp->mlock_user);
 213         fput (shp->shm_file);
 214         security_shm_free(shp);
 215         ipc_rcu_putref(shp);
 216 }
 217
 218 /*
 219  * remove the attach descriptor vma.
 220  * free memory for segment if it is marked destroyed.
 221  * The descriptor has already been removed from the current->mm->mmap list
 222  * and will later be kfree()d.
 223  */
 224 static void shm_close(struct vm_area_struct *vma)
 225 {
 226         struct file * file = vma->vm_file;
 227         struct shm_file_data *sfd = shm_file_data(file);
 228         struct shmid_kernel *shp;
 229         struct ipc_namespace *ns = sfd->ns;
 230
 231         down_write(&shm_ids(ns).rw_mutex);
 232         /* remove from the list of attaches of the shm segment */
 233         shp = shm_lock_down(ns, sfd->id);
 234         BUG_ON(IS_ERR(shp));
 235         shp->shm_lprid = task_tgid_vnr(current);
 236         shp->shm_dtim = get_seconds();
 237         shp->shm_nattch--;
 238         if(shp->shm_nattch == 0 &&
 239            shp->shm_perm.mode & SHM_DEST)
 240                 shm_destroy(ns, shp);
 241         else
 242                 shm_unlock(shp);
 243         up_write(&shm_ids(ns).rw_mutex);
 244 }
 245
 246 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 247 {
 248         struct file *file = vma->vm_file;
 249         struct shm_file_data *sfd = shm_file_data(file);
 250
 251         return sfd->vm_ops->fault(vma, vmf);
 252 }
 253
 254 #ifdef CONFIG_NUMA
 255 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 256 {
 257         struct file *file = vma->vm_file;
 258         struct shm_file_data *sfd = shm_file_data(file);
 259         int err = 0;
 260         if (sfd->vm_ops->set_policy)
 261                 err = sfd->vm_ops->set_policy(vma, new);
 262         return err;
 263 }
 264
 265 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 266                                         unsigned long addr)
 267 {
 268         struct file *file = vma->vm_file;
 269         struct shm_file_data *sfd = shm_file_data(file);
 270         struct mempolicy *pol = NULL;
 271
 272         if (sfd->vm_ops->get_policy)
 273                 pol = sfd->vm_ops->get_policy(vma, addr);
 274         else if (vma->vm_policy)
 275                 pol = vma->vm_policy;
 276         else
 277                 pol = current->mempolicy;
 278         return pol;
 279 }
 280 #endif
 281
 282 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 283 {
 284         struct shm_file_data *sfd = shm_file_data(file);
 285         int ret;
 286
 287         ret = sfd->file->f_op->mmap(sfd->file, vma);
 288         if (ret != 0)
 289                 return ret;
 290         sfd->vm_ops = vma->vm_ops;
 291 #ifdef CONFIG_MMU
 292         BUG_ON(!sfd->vm_ops->fault);
 293 #endif
 294         vma->vm_ops = &shm_vm_ops;
 295         shm_open(vma);
 296
 297         return ret;
 298 }
 299
 300 static int shm_release(struct inode *ino, struct file *file)
 301 {
 302         struct shm_file_data *sfd = shm_file_data(file);
 303
 304         put_ipc_ns(sfd->ns);
 305         shm_file_data(file) = NULL;
 306         kfree(sfd);
 307         return 0;
 308 }
 309
 310 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 311 {
 312         int (*fsync) (struct file *, struct dentry *, int datasync);
 313         struct shm_file_data *sfd = shm_file_data(file);
 314         int ret = -EINVAL;
 315
 316         fsync = sfd->file->f_op->fsync;
 317         if (fsync)
 318                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 319         return ret;
 320 }
 321
 322 static unsigned long shm_get_unmapped_area(struct file *file,
 323         unsigned long addr, unsigned long len, unsigned long pgoff,
 324         unsigned long flags)
 325 {
 326         struct shm_file_data *sfd = shm_file_data(file);
 327         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 328 }
 329
 330 int is_file_shm_hugepages(struct file *file)
 331 {
 332         int ret = 0;
 333
 334         if (file->f_op == &shm_file_operations) {
 335                 struct shm_file_data *sfd;
 336                 sfd = shm_file_data(file);
 337                 ret = is_file_hugepages(sfd->file);
 338         }
 339         return ret;
 340 }
 341
 342 static const struct file_operations shm_file_operations = {
 343         .mmap           = shm_mmap,
 344         .fsync          = shm_fsync,
 345         .release        = shm_release,
 346         .get_unmapped_area      = shm_get_unmapped_area,
 347 };
 348
 349 static struct vm_operations_struct shm_vm_ops = {
 350         .open   = shm_open,     /* callback for a new vm-area open */
 351         .close  = shm_close,    /* callback for when the vm-area is released */
 352         .fault  = shm_fault,
 353 #if defined(CONFIG_NUMA)
 354         .set_policy = shm_set_policy,
 355         .get_policy = shm_get_policy,
 356 #endif
 357 };
 358
 359 /**
 360  * newseg - Create a new shared memory segment
 361  * @ns: namespace
 362  * @params: ptr to the structure that contains key, size and shmflg
 363  *
 364  * Called with shm_ids.rw_mutex held as a writer.
 365  */
 366
 367 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 368 {
 369         key_t key = params->key;
 370         int shmflg = params->flg;
 371         size_t size = params->u.size;
 372         int error;
 373         struct shmid_kernel *shp;
 374         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 375         struct file * file;
 376         char name[13];
 377         int id;
 378
 379         if (size < SHMMIN || size > ns->shm_ctlmax)
 380                 return -EINVAL;
 381
 382         if (ns->shm_tot + numpages > ns->shm_ctlall)
 383                 return -ENOSPC;
 384
 385         shp = ipc_rcu_alloc(sizeof(*shp));
 386         if (!shp)
 387                 return -ENOMEM;
 388
 389         shp->shm_perm.key = key;
 390         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 391         shp->mlock_user = NULL;
 392
 393         shp->shm_perm.security = NULL;
 394         error = security_shm_alloc(shp);
 395         if (error) {
 396                 ipc_rcu_putref(shp);
 397                 return error;
 398         }
 399
 400         sprintf (name, "SYSV%08x", key);
 401         if (shmflg & SHM_HUGETLB) {
 402                 /* hugetlb_file_setup takes care of mlock user accounting */
 403                 file = hugetlb_file_setup(name, size);
 404                 shp->mlock_user = current->user;
 405         } else {
 406                 int acctflag = VM_ACCOUNT;
 407                 /*
 408                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 409                  * if it's asked for.
 410                  */
 411                 if  ((shmflg & SHM_NORESERVE) &&
 412                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 413                         acctflag = 0;
 414                 file = shmem_file_setup(name, size, acctflag);
 415         }
 416         error = PTR_ERR(file);
 417         if (IS_ERR(file))
 418                 goto no_file;
 419
 420         id = shm_addid(ns, shp);
 421         if (id < 0) {
 422                 error = id;
 423                 goto no_id;
 424         }
 425
 426         shp->shm_cprid = task_tgid_vnr(current);
 427         shp->shm_lprid = 0;
 428         shp->shm_atim = shp->shm_dtim = 0;
 429         shp->shm_ctim = get_seconds();
 430         shp->shm_segsz = size;
 431         shp->shm_nattch = 0;
 432         shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
 433         shp->shm_file = file;
 434         /*
 435          * shmid gets reported as "inode#" in /proc/pid/maps.
 436          * proc-ps tools use this. Changing this will break them.
 437          */
 438         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 439
 440         ns->shm_tot += numpages;
 441         error = shp->shm_perm.id;
 442         shm_unlock(shp);
 443         return error;
 444
 445 no_id:
 446         fput(file);
 447 no_file:
 448         security_shm_free(shp);
 449         ipc_rcu_putref(shp);
 450         return error;
 451 }
 452
 453 /*
 454  * Called with shm_ids.rw_mutex and ipcp locked.
 455  */
 456 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 457 {
 458         struct shmid_kernel *shp;
 459
 460         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 461         return security_shm_associate(shp, shmflg);
 462 }
 463
 464 /*
 465  * Called with shm_ids.rw_mutex and ipcp locked.
 466  */
 467 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 468                                 struct ipc_params *params)
 469 {
 470         struct shmid_kernel *shp;
 471
 472         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 473         if (shp->shm_segsz < params->u.size)
 474                 return -EINVAL;
 475
 476         return 0;
 477 }
 478
 479 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 480 {
 481         struct ipc_namespace *ns;
 482         struct ipc_ops shm_ops;
 483         struct ipc_params shm_params;
 484
 485         ns = current->nsproxy->ipc_ns;
 486
 487         shm_ops.getnew = newseg;
 488         shm_ops.associate = shm_security;
 489         shm_ops.more_checks = shm_more_checks;
 490
 491         shm_params.key = key;
 492         shm_params.flg = shmflg;
 493         shm_params.u.size = size;
 494
 495         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 496 }
 497
 498 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 499 {
 500         switch(version) {
 501         case IPC_64:
 502                 return copy_to_user(buf, in, sizeof(*in));
 503         case IPC_OLD:
 504             {
 505                 struct shmid_ds out;
 506
 507                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 508                 out.shm_segsz   = in->shm_segsz;
 509                 out.shm_atime   = in->shm_atime;
 510                 out.shm_dtime   = in->shm_dtime;
 511                 out.shm_ctime   = in->shm_ctime;
 512                 out.shm_cpid    = in->shm_cpid;
 513                 out.shm_lpid    = in->shm_lpid;
 514                 out.shm_nattch  = in->shm_nattch;
 515
 516                 return copy_to_user(buf, &out, sizeof(out));
 517             }
 518         default:
 519                 return -EINVAL;
 520         }
 521 }
 522
 523 struct shm_setbuf {
 524         uid_t   uid;
 525         gid_t   gid;
 526         mode_t  mode;
 527 };
 528
 529 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 530 {
 531         switch(version) {
 532         case IPC_64:
 533             {
 534                 struct shmid64_ds tbuf;
 535
 536                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 537                         return -EFAULT;
 538
 539                 out->uid        = tbuf.shm_perm.uid;
 540                 out->gid        = tbuf.shm_perm.gid;
 541                 out->mode       = tbuf.shm_perm.mode;
 542
 543                 return 0;
 544             }
 545         case IPC_OLD:
 546             {
 547                 struct shmid_ds tbuf_old;
 548
 549                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 550                         return -EFAULT;
 551
 552                 out->uid        = tbuf_old.shm_perm.uid;
 553                 out->gid        = tbuf_old.shm_perm.gid;
 554                 out->mode       = tbuf_old.shm_perm.mode;
 555
 556                 return 0;
 557             }
 558         default:
 559                 return -EINVAL;
 560         }
 561 }
 562
 563 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 564 {
 565         switch(version) {
 566         case IPC_64:
 567                 return copy_to_user(buf, in, sizeof(*in));
 568         case IPC_OLD:
 569             {
 570                 struct shminfo out;
 571
 572                 if(in->shmmax > INT_MAX)
 573                         out.shmmax = INT_MAX;
 574                 else
 575                         out.shmmax = (int)in->shmmax;
 576
 577                 out.shmmin      = in->shmmin;
 578                 out.shmmni      = in->shmmni;
 579                 out.shmseg      = in->shmseg;
 580                 out.shmall      = in->shmall;
 581
 582                 return copy_to_user(buf, &out, sizeof(out));
 583             }
 584         default:
 585                 return -EINVAL;
 586         }
 587 }
 588
 589 /*
 590  * Called with shm_ids.rw_mutex held as a reader
 591  */
 592 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 593                 unsigned long *swp)
 594 {
 595         int next_id;
 596         int total, in_use;
 597
 598         *rss = 0;
 599         *swp = 0;
 600
 601         in_use = shm_ids(ns).in_use;
 602
 603         for (total = 0, next_id = 0; total < in_use; next_id++) {
 604                 struct shmid_kernel *shp;
 605                 struct inode *inode;
 606
 607                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 608                 if (shp == NULL)
 609                         continue;
 610
 611                 inode = shp->shm_file->f_path.dentry->d_inode;
 612
 613                 if (is_file_hugepages(shp->shm_file)) {
 614                         struct address_space *mapping = inode->i_mapping;
 615                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 616                 } else {
 617                         struct shmem_inode_info *info = SHMEM_I(inode);
 618                         spin_lock(&info->lock);
 619                         *rss += inode->i_mapping->nrpages;
 620                         *swp += info->swapped;
 621                         spin_unlock(&info->lock);
 622                 }
 623
 624                 total++;
 625         }
 626 }
 627
 628 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 629 {
 630         struct shm_setbuf setbuf;
 631         struct shmid_kernel *shp;
 632         int err, version;
 633         struct ipc_namespace *ns;
 634
 635         if (cmd < 0 || shmid < 0) {
 636                 err = -EINVAL;
 637                 goto out;
 638         }
 639
 640         version = ipc_parse_version(&cmd);
 641         ns = current->nsproxy->ipc_ns;
 642
 643         switch (cmd) { /* replace with proc interface ? */
 644         case IPC_INFO:
 645         {
 646                 struct shminfo64 shminfo;
 647
 648                 err = security_shm_shmctl(NULL, cmd);
 649                 if (err)
 650                         return err;
 651
 652                 memset(&shminfo,0,sizeof(shminfo));
 653                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 654                 shminfo.shmmax = ns->shm_ctlmax;
 655                 shminfo.shmall = ns->shm_ctlall;
 656
 657                 shminfo.shmmin = SHMMIN;
 658                 if(copy_shminfo_to_user (buf, &shminfo, version))
 659                         return -EFAULT;
 660
 661                 down_read(&shm_ids(ns).rw_mutex);
 662                 err = ipc_get_maxid(&shm_ids(ns));
 663                 up_read(&shm_ids(ns).rw_mutex);
 664
 665                 if(err<0)
 666                         err = 0;
 667                 goto out;
 668         }
 669         case SHM_INFO:
 670         {
 671                 struct shm_info shm_info;
 672
 673                 err = security_shm_shmctl(NULL, cmd);
 674                 if (err)
 675                         return err;
 676
 677                 memset(&shm_info,0,sizeof(shm_info));
 678                 down_read(&shm_ids(ns).rw_mutex);
 679                 shm_info.used_ids = shm_ids(ns).in_use;
 680                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 681                 shm_info.shm_tot = ns->shm_tot;
 682                 shm_info.swap_attempts = 0;
 683                 shm_info.swap_successes = 0;
 684                 err = ipc_get_maxid(&shm_ids(ns));
 685                 up_read(&shm_ids(ns).rw_mutex);
 686                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 687                         err = -EFAULT;
 688                         goto out;
 689                 }
 690
 691                 err = err < 0 ? 0 : err;
 692                 goto out;
 693         }
 694         case SHM_STAT:
 695         case IPC_STAT:
 696         {
 697                 struct shmid64_ds tbuf;
 698                 int result;
 699
 700                 if (!buf) {
 701                         err = -EFAULT;
 702                         goto out;
 703                 }
 704
 705                 if (cmd == SHM_STAT) {
 706                         shp = shm_lock(ns, shmid);
 707                         if (IS_ERR(shp)) {
 708                                 err = PTR_ERR(shp);
 709                                 goto out;
 710                         }
 711                         result = shp->shm_perm.id;
 712                 } else {
 713                         shp = shm_lock_check(ns, shmid);
 714                         if (IS_ERR(shp)) {
 715                                 err = PTR_ERR(shp);
 716                                 goto out;
 717                         }
 718                         result = 0;
 719                 }
 720                 err=-EACCES;
 721                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 722                         goto out_unlock;
 723                 err = security_shm_shmctl(shp, cmd);
 724                 if (err)
 725                         goto out_unlock;
 726                 memset(&tbuf, 0, sizeof(tbuf));
 727                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 728                 tbuf.shm_segsz  = shp->shm_segsz;
 729                 tbuf.shm_atime  = shp->shm_atim;
 730                 tbuf.shm_dtime  = shp->shm_dtim;
 731                 tbuf.shm_ctime  = shp->shm_ctim;
 732                 tbuf.shm_cpid   = shp->shm_cprid;
 733                 tbuf.shm_lpid   = shp->shm_lprid;
 734                 tbuf.shm_nattch = shp->shm_nattch;
 735                 shm_unlock(shp);
 736                 if(copy_shmid_to_user (buf, &tbuf, version))
 737                         err = -EFAULT;
 738                 else
 739                         err = result;
 740                 goto out;
 741         }
 742         case SHM_LOCK:
 743         case SHM_UNLOCK:
 744         {
 745                 shp = shm_lock_check(ns, shmid);
 746                 if (IS_ERR(shp)) {
 747                         err = PTR_ERR(shp);
 748                         goto out;
 749                 }
 750
 751                 err = audit_ipc_obj(&(shp->shm_perm));
 752                 if (err)
 753                         goto out_unlock;
 754
 755                 if (!capable(CAP_IPC_LOCK)) {
 756                         err = -EPERM;
 757                         if (current->euid != shp->shm_perm.uid &&
 758                             current->euid != shp->shm_perm.cuid)
 759                                 goto out_unlock;
 760                         if (cmd == SHM_LOCK &&
 761                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 762                                 goto out_unlock;
 763                 }
 764
 765                 err = security_shm_shmctl(shp, cmd);
 766                 if (err)
 767                         goto out_unlock;
 768
 769                 if(cmd==SHM_LOCK) {
 770                         struct user_struct * user = current->user;
 771                         if (!is_file_hugepages(shp->shm_file)) {
 772                                 err = shmem_lock(shp->shm_file, 1, user);
 773                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 774                                         shp->shm_perm.mode |= SHM_LOCKED;
 775                                         shp->mlock_user = user;
 776                                 }
 777                         }
 778                 } else if (!is_file_hugepages(shp->shm_file)) {
 779                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 780                         shp->shm_perm.mode &= ~SHM_LOCKED;
 781                         shp->mlock_user = NULL;
 782                 }
 783                 shm_unlock(shp);
 784                 goto out;
 785         }
 786         case IPC_RMID:
 787         {
 788                 /*
 789                  *      We cannot simply remove the file. The SVID states
 790                  *      that the block remains until the last person
 791                  *      detaches from it, then is deleted. A shmat() on
 792                  *      an RMID segment is legal in older Linux and if
 793                  *      we change it apps break...
 794                  *
 795                  *      Instead we set a destroyed flag, and then blow
 796                  *      the name away when the usage hits zero.
 797                  */
 798                 down_write(&shm_ids(ns).rw_mutex);
 799                 shp = shm_lock_check_down(ns, shmid);
 800                 if (IS_ERR(shp)) {
 801                         err = PTR_ERR(shp);
 802                         goto out_up;
 803                 }
 804
 805                 err = audit_ipc_obj(&(shp->shm_perm));
 806                 if (err)
 807                         goto out_unlock_up;
 808
 809                 if (current->euid != shp->shm_perm.uid &&
 810                     current->euid != shp->shm_perm.cuid &&
 811                     !capable(CAP_SYS_ADMIN)) {
 812                         err=-EPERM;
 813                         goto out_unlock_up;
 814                 }
 815
 816                 err = security_shm_shmctl(shp, cmd);
 817                 if (err)
 818                         goto out_unlock_up;
 819
 820                 do_shm_rmid(ns, &shp->shm_perm);
 821                 up_write(&shm_ids(ns).rw_mutex);
 822                 goto out;
 823         }
 824
 825         case IPC_SET:
 826         {
 827                 if (!buf) {
 828                         err = -EFAULT;
 829                         goto out;
 830                 }
 831
 832                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 833                         err = -EFAULT;
 834                         goto out;
 835                 }
 836                 down_write(&shm_ids(ns).rw_mutex);
 837                 shp = shm_lock_check_down(ns, shmid);
 838                 if (IS_ERR(shp)) {
 839                         err = PTR_ERR(shp);
 840                         goto out_up;
 841                 }
 842                 err = audit_ipc_obj(&(shp->shm_perm));
 843                 if (err)
 844                         goto out_unlock_up;
 845                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 846                 if (err)
 847                         goto out_unlock_up;
 848                 err=-EPERM;
 849                 if (current->euid != shp->shm_perm.uid &&
 850                     current->euid != shp->shm_perm.cuid &&
 851                     !capable(CAP_SYS_ADMIN)) {
 852                         goto out_unlock_up;
 853                 }
 854
 855                 err = security_shm_shmctl(shp, cmd);
 856                 if (err)
 857                         goto out_unlock_up;
 858
 859                 shp->shm_perm.uid = setbuf.uid;
 860                 shp->shm_perm.gid = setbuf.gid;
 861                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 862                         | (setbuf.mode & S_IRWXUGO);
 863                 shp->shm_ctim = get_seconds();
 864                 break;
 865         }
 866
 867         default:
 868                 err = -EINVAL;
 869                 goto out;
 870         }
 871
 872         err = 0;
 873 out_unlock_up:
 874         shm_unlock(shp);
 875 out_up:
 876         up_write(&shm_ids(ns).rw_mutex);
 877         goto out;
 878 out_unlock:
 879         shm_unlock(shp);
 880 out:
 881         return err;
 882 }
 883
 884 /*
 885  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 886  *
 887  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 888  * "raddr" thing points to kernel space, and there has to be a wrapper around
 889  * this.
 890  */
 891 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 892 {
 893         struct shmid_kernel *shp;
 894         unsigned long addr;
 895         unsigned long size;
 896         struct file * file;
 897         int    err;
 898         unsigned long flags;
 899         unsigned long prot;
 900         int acc_mode;
 901         unsigned long user_addr;
 902         struct ipc_namespace *ns;
 903         struct shm_file_data *sfd;
 904         struct path path;
 905         mode_t f_mode;
 906
 907         err = -EINVAL;
 908         if (shmid < 0)
 909                 goto out;
 910         else if ((addr = (ulong)shmaddr)) {
 911                 if (addr & (SHMLBA-1)) {
 912                         if (shmflg & SHM_RND)
 913                                 addr &= ~(SHMLBA-1);       /* round down */
 914                         else
 915 #ifndef __ARCH_FORCE_SHMLBA
 916                                 if (addr & ~PAGE_MASK)
 917 #endif
 918                                         goto out;
 919                 }
 920                 flags = MAP_SHARED | MAP_FIXED;
 921         } else {
 922                 if ((shmflg & SHM_REMAP))
 923                         goto out;
 924
 925                 flags = MAP_SHARED;
 926         }
 927
 928         if (shmflg & SHM_RDONLY) {
 929                 prot = PROT_READ;
 930                 acc_mode = S_IRUGO;
 931                 f_mode = FMODE_READ;
 932         } else {
 933                 prot = PROT_READ | PROT_WRITE;
 934                 acc_mode = S_IRUGO | S_IWUGO;
 935                 f_mode = FMODE_READ | FMODE_WRITE;
 936         }
 937         if (shmflg & SHM_EXEC) {
 938                 prot |= PROT_EXEC;
 939                 acc_mode |= S_IXUGO;
 940         }
 941
 942         /*
 943          * We cannot rely on the fs check since SYSV IPC does have an
 944          * additional creator id...
 945          */
 946         ns = current->nsproxy->ipc_ns;
 947         shp = shm_lock_check(ns, shmid);
 948         if (IS_ERR(shp)) {
 949                 err = PTR_ERR(shp);
 950                 goto out;
 951         }
 952
 953         err = -EACCES;
 954         if (ipcperms(&shp->shm_perm, acc_mode))
 955                 goto out_unlock;
 956
 957         err = security_shm_shmat(shp, shmaddr, shmflg);
 958         if (err)
 959                 goto out_unlock;
 960
 961         path.dentry = dget(shp->shm_file->f_path.dentry);
 962         path.mnt    = shp->shm_file->f_path.mnt;
 963         shp->shm_nattch++;
 964         size = i_size_read(path.dentry->d_inode);
 965         shm_unlock(shp);
 966
 967         err = -ENOMEM;
 968         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
 969         if (!sfd)
 970                 goto out_put_dentry;
 971
 972         err = -ENOMEM;
 973
 974         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
 975         if (!file)
 976                 goto out_free;
 977
 978         file->private_data = sfd;
 979         file->f_mapping = shp->shm_file->f_mapping;
 980         sfd->id = shp->shm_perm.id;
 981         sfd->ns = get_ipc_ns(ns);
 982         sfd->file = shp->shm_file;
 983         sfd->vm_ops = NULL;
 984
 985         down_write(&current->mm->mmap_sem);
 986         if (addr && !(shmflg & SHM_REMAP)) {
 987                 err = -EINVAL;
 988                 if (find_vma_intersection(current->mm, addr, addr + size))
 989                         goto invalid;
 990                 /*
 991                  * If shm segment goes below stack, make sure there is some
 992                  * space left for the stack to grow (at least 4 pages).
 993                  */
 994                 if (addr < current->mm->start_stack &&
 995                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
 996                         goto invalid;
 997         }
 998
 999         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1000         *raddr = user_addr;
1001         err = 0;
1002         if (IS_ERR_VALUE(user_addr))
1003                 err = (long)user_addr;
1004 invalid:
1005         up_write(&current->mm->mmap_sem);
1006
1007         fput(file);
1008
1009 out_nattch:
1010         down_write(&shm_ids(ns).rw_mutex);
1011         shp = shm_lock_down(ns, shmid);
1012         BUG_ON(IS_ERR(shp));
1013         shp->shm_nattch--;
1014         if(shp->shm_nattch == 0 &&
1015            shp->shm_perm.mode & SHM_DEST)
1016                 shm_destroy(ns, shp);
1017         else
1018                 shm_unlock(shp);
1019         up_write(&shm_ids(ns).rw_mutex);
1020
1021 out:
1022         return err;
1023
1024 out_unlock:
1025         shm_unlock(shp);
1026         goto out;
1027
1028 out_free:
1029         kfree(sfd);
1030 out_put_dentry:
1031         dput(path.dentry);
1032         goto out_nattch;
1033 }
1034
1035 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1036 {
1037         unsigned long ret;
1038         long err;
1039
1040         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1041         if (err)
1042                 return err;
1043         force_successful_syscall_return();
1044         return (long)ret;
1045 }
1046
1047 /*
1048  * detach and kill segment if marked destroyed.
1049  * The work is done in shm_close.
1050  */
1051 asmlinkage long sys_shmdt(char __user *shmaddr)
1052 {
1053         struct mm_struct *mm = current->mm;
1054         struct vm_area_struct *vma, *next;
1055         unsigned long addr = (unsigned long)shmaddr;
1056         loff_t size = 0;
1057         int retval = -EINVAL;
1058
1059         if (addr & ~PAGE_MASK)
1060                 return retval;
1061
1062         down_write(&mm->mmap_sem);
1063
1064         /*
1065          * This function tries to be smart and unmap shm segments that
1066          * were modified by partial mlock or munmap calls:
1067          * - It first determines the size of the shm segment that should be
1068          *   unmapped: It searches for a vma that is backed by shm and that
1069          *   started at address shmaddr. It records it's size and then unmaps
1070          *   it.
1071          * - Then it unmaps all shm vmas that started at shmaddr and that
1072          *   are within the initially determined size.
1073          * Errors from do_munmap are ignored: the function only fails if
1074          * it's called with invalid parameters or if it's called to unmap
1075          * a part of a vma. Both calls in this function are for full vmas,
1076          * the parameters are directly copied from the vma itself and always
1077          * valid - therefore do_munmap cannot fail. (famous last words?)
1078          */
1079         /*
1080          * If it had been mremap()'d, the starting address would not
1081          * match the usual checks anyway. So assume all vma's are
1082          * above the starting address given.
1083          */
1084         vma = find_vma(mm, addr);
1085
1086         while (vma) {
1087                 next = vma->vm_next;
1088
1089                 /*
1090                  * Check if the starting address would match, i.e. it's
1091                  * a fragment created by mprotect() and/or munmap(), or it
1092                  * otherwise it starts at this address with no hassles.
1093                  */
1094                 if ((vma->vm_ops == &shm_vm_ops) &&
1095                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1096
1097
1098                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1099                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1100                         /*
1101                          * We discovered the size of the shm segment, so
1102                          * break out of here and fall through to the next
1103                          * loop that uses the size information to stop
1104                          * searching for matching vma's.
1105                          */
1106                         retval = 0;
1107                         vma = next;
1108                         break;
1109                 }
1110                 vma = next;
1111         }
1112
1113         /*
1114          * We need look no further than the maximum address a fragment
1115          * could possibly have landed at. Also cast things to loff_t to
1116          * prevent overflows and make comparisions vs. equal-width types.
1117          */
1118         size = PAGE_ALIGN(size);
1119         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1120                 next = vma->vm_next;
1121
1122                 /* finding a matching vma now does not alter retval */
1123                 if ((vma->vm_ops == &shm_vm_ops) &&
1124                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1125
1126                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1127                 vma = next;
1128         }
1129
1130         up_write(&mm->mmap_sem);
1131         return retval;
1132 }
1133
1134 #ifdef CONFIG_PROC_FS
1135 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1136 {
1137         struct shmid_kernel *shp = it;
1138         char *format;
1139
1140 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1141 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1142
1143         if (sizeof(size_t) <= sizeof(int))
1144                 format = SMALL_STRING;
1145         else
1146                 format = BIG_STRING;
1147         return seq_printf(s, format,
1148                           shp->shm_perm.key,
1149                           shp->shm_perm.id,
1150                           shp->shm_perm.mode,
1151                           shp->shm_segsz,
1152                           shp->shm_cprid,
1153                           shp->shm_lprid,
1154                           shp->shm_nattch,
1155                           shp->shm_perm.uid,
1156                           shp->shm_perm.gid,
1157                           shp->shm_perm.cuid,
1158                           shp->shm_perm.cgid,
1159                           shp->shm_atim,
1160                           shp->shm_dtim,
1161                           shp->shm_ctim);
1162 }
1163 #endif