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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 static struct ipc_ids init_shm_ids;
  60
  61 #define shm_ids(ns)     (*((ns)->ids[IPC_SHM_IDS]))
  62
  63 #define shm_unlock(shp)                 \
  64         ipc_unlock(&(shp)->shm_perm)
  65 #define shm_buildid(id, seq)    ipc_buildid(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 /*
  86  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
  87  * Only shm_ids.rw_mutex remains locked on exit.
  88  */
  89 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
  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 int shm_init_ns(struct ipc_namespace *ns)
 102 {
 103         struct ipc_ids *ids;
 104
 105         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
 106         if (ids == NULL)
 107                 return -ENOMEM;
 108
 109         __shm_init_ns(ns, ids);
 110         return 0;
 111 }
 112
 113 void shm_exit_ns(struct ipc_namespace *ns)
 114 {
 115         struct shmid_kernel *shp;
 116         struct kern_ipc_perm *perm;
 117         int next_id;
 118         int total, in_use;
 119
 120         down_write(&shm_ids(ns).rw_mutex);
 121
 122         in_use = shm_ids(ns).in_use;
 123
 124         for (total = 0, next_id = 0; total < in_use; next_id++) {
 125                 perm = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 126                 if (perm == NULL)
 127                         continue;
 128                 ipc_lock_by_ptr(perm);
 129                 shp = container_of(perm, struct shmid_kernel, shm_perm);
 130                 do_shm_rmid(ns, shp);
 131                 total++;
 132         }
 133         up_write(&shm_ids(ns).rw_mutex);
 134
 135         kfree(ns->ids[IPC_SHM_IDS]);
 136         ns->ids[IPC_SHM_IDS] = NULL;
 137 }
 138 #endif
 139
 140 void __init shm_init (void)
 141 {
 142         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
 143         ipc_init_proc_interface("sysvipc/shm",
 144                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
 145                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
 146 }
 147
 148 /*
 149  * shm_lock_(check_)down routines are called in the paths where the rw_mutex
 150  * is held to protect access to the idr tree.
 151  */
 152 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
 153                                                 int id)
 154 {
 155         struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
 156
 157         if (IS_ERR(ipcp))
 158                 return (struct shmid_kernel *)ipcp;
 159
 160         return container_of(ipcp, struct shmid_kernel, shm_perm);
 161 }
 162
 163 static inline struct shmid_kernel *shm_lock_check_down(
 164                                                 struct ipc_namespace *ns,
 165                                                 int id)
 166 {
 167         struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
 168
 169         if (IS_ERR(ipcp))
 170                 return (struct shmid_kernel *)ipcp;
 171
 172         return container_of(ipcp, struct shmid_kernel, shm_perm);
 173 }
 174
 175 /*
 176  * shm_lock_(check_) routines are called in the paths where the rw_mutex
 177  * is not held.
 178  */
 179 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 180 {
 181         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
 182
 183         if (IS_ERR(ipcp))
 184                 return (struct shmid_kernel *)ipcp;
 185
 186         return container_of(ipcp, struct shmid_kernel, shm_perm);
 187 }
 188
 189 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
 190                                                 int id)
 191 {
 192         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
 193
 194         if (IS_ERR(ipcp))
 195                 return (struct shmid_kernel *)ipcp;
 196
 197         return container_of(ipcp, struct shmid_kernel, shm_perm);
 198 }
 199
 200 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 201 {
 202         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 203 }
 204
 205 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 206 {
 207         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 208 }
 209
 210
 211
 212 /* This is called by fork, once for every shm attach. */
 213 static void shm_open(struct vm_area_struct *vma)
 214 {
 215         struct file *file = vma->vm_file;
 216         struct shm_file_data *sfd = shm_file_data(file);
 217         struct shmid_kernel *shp;
 218
 219         shp = shm_lock(sfd->ns, sfd->id);
 220         BUG_ON(IS_ERR(shp));
 221         shp->shm_atim = get_seconds();
 222         shp->shm_lprid = task_tgid_vnr(current);
 223         shp->shm_nattch++;
 224         shm_unlock(shp);
 225 }
 226
 227 /*
 228  * shm_destroy - free the struct shmid_kernel
 229  *
 230  * @ns: namespace
 231  * @shp: struct to free
 232  *
 233  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
 234  * but returns with shp unlocked and freed.
 235  */
 236 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 237 {
 238         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
 239         shm_rmid(ns, shp);
 240         shm_unlock(shp);
 241         if (!is_file_hugepages(shp->shm_file))
 242                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
 243         else
 244                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
 245                                                 shp->mlock_user);
 246         fput (shp->shm_file);
 247         security_shm_free(shp);
 248         ipc_rcu_putref(shp);
 249 }
 250
 251 /*
 252  * remove the attach descriptor vma.
 253  * free memory for segment if it is marked destroyed.
 254  * The descriptor has already been removed from the current->mm->mmap list
 255  * and will later be kfree()d.
 256  */
 257 static void shm_close(struct vm_area_struct *vma)
 258 {
 259         struct file * file = vma->vm_file;
 260         struct shm_file_data *sfd = shm_file_data(file);
 261         struct shmid_kernel *shp;
 262         struct ipc_namespace *ns = sfd->ns;
 263
 264         down_write(&shm_ids(ns).rw_mutex);
 265         /* remove from the list of attaches of the shm segment */
 266         shp = shm_lock_down(ns, sfd->id);
 267         BUG_ON(IS_ERR(shp));
 268         shp->shm_lprid = task_tgid_vnr(current);
 269         shp->shm_dtim = get_seconds();
 270         shp->shm_nattch--;
 271         if(shp->shm_nattch == 0 &&
 272            shp->shm_perm.mode & SHM_DEST)
 273                 shm_destroy(ns, shp);
 274         else
 275                 shm_unlock(shp);
 276         up_write(&shm_ids(ns).rw_mutex);
 277 }
 278
 279 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 280 {
 281         struct file *file = vma->vm_file;
 282         struct shm_file_data *sfd = shm_file_data(file);
 283
 284         return sfd->vm_ops->fault(vma, vmf);
 285 }
 286
 287 #ifdef CONFIG_NUMA
 288 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 289 {
 290         struct file *file = vma->vm_file;
 291         struct shm_file_data *sfd = shm_file_data(file);
 292         int err = 0;
 293         if (sfd->vm_ops->set_policy)
 294                 err = sfd->vm_ops->set_policy(vma, new);
 295         return err;
 296 }
 297
 298 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 299                                         unsigned long addr)
 300 {
 301         struct file *file = vma->vm_file;
 302         struct shm_file_data *sfd = shm_file_data(file);
 303         struct mempolicy *pol = NULL;
 304
 305         if (sfd->vm_ops->get_policy)
 306                 pol = sfd->vm_ops->get_policy(vma, addr);
 307         else if (vma->vm_policy)
 308                 pol = vma->vm_policy;
 309         else
 310                 pol = current->mempolicy;
 311         return pol;
 312 }
 313 #endif
 314
 315 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
 316 {
 317         struct shm_file_data *sfd = shm_file_data(file);
 318         int ret;
 319
 320         ret = sfd->file->f_op->mmap(sfd->file, vma);
 321         if (ret != 0)
 322                 return ret;
 323         sfd->vm_ops = vma->vm_ops;
 324 #ifdef CONFIG_MMU
 325         BUG_ON(!sfd->vm_ops->fault);
 326 #endif
 327         vma->vm_ops = &shm_vm_ops;
 328         shm_open(vma);
 329
 330         return ret;
 331 }
 332
 333 static int shm_release(struct inode *ino, struct file *file)
 334 {
 335         struct shm_file_data *sfd = shm_file_data(file);
 336
 337         put_ipc_ns(sfd->ns);
 338         shm_file_data(file) = NULL;
 339         kfree(sfd);
 340         return 0;
 341 }
 342
 343 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
 344 {
 345         int (*fsync) (struct file *, struct dentry *, int datasync);
 346         struct shm_file_data *sfd = shm_file_data(file);
 347         int ret = -EINVAL;
 348
 349         fsync = sfd->file->f_op->fsync;
 350         if (fsync)
 351                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
 352         return ret;
 353 }
 354
 355 static unsigned long shm_get_unmapped_area(struct file *file,
 356         unsigned long addr, unsigned long len, unsigned long pgoff,
 357         unsigned long flags)
 358 {
 359         struct shm_file_data *sfd = shm_file_data(file);
 360         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
 361 }
 362
 363 int is_file_shm_hugepages(struct file *file)
 364 {
 365         int ret = 0;
 366
 367         if (file->f_op == &shm_file_operations) {
 368                 struct shm_file_data *sfd;
 369                 sfd = shm_file_data(file);
 370                 ret = is_file_hugepages(sfd->file);
 371         }
 372         return ret;
 373 }
 374
 375 static const struct file_operations shm_file_operations = {
 376         .mmap           = shm_mmap,
 377         .fsync          = shm_fsync,
 378         .release        = shm_release,
 379         .get_unmapped_area      = shm_get_unmapped_area,
 380 };
 381
 382 static struct vm_operations_struct shm_vm_ops = {
 383         .open   = shm_open,     /* callback for a new vm-area open */
 384         .close  = shm_close,    /* callback for when the vm-area is released */
 385         .fault  = shm_fault,
 386 #if defined(CONFIG_NUMA)
 387         .set_policy = shm_set_policy,
 388         .get_policy = shm_get_policy,
 389 #endif
 390 };
 391
 392 /**
 393  * newseg - Create a new shared memory segment
 394  * @ns: namespace
 395  * @params: ptr to the structure that contains key, size and shmflg
 396  *
 397  * Called with shm_ids.rw_mutex held as a writer.
 398  */
 399
 400 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 401 {
 402         key_t key = params->key;
 403         int shmflg = params->flg;
 404         size_t size = params->u.size;
 405         int error;
 406         struct shmid_kernel *shp;
 407         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
 408         struct file * file;
 409         char name[13];
 410         int id;
 411
 412         if (size < SHMMIN || size > ns->shm_ctlmax)
 413                 return -EINVAL;
 414
 415         if (ns->shm_tot + numpages > ns->shm_ctlall)
 416                 return -ENOSPC;
 417
 418         shp = ipc_rcu_alloc(sizeof(*shp));
 419         if (!shp)
 420                 return -ENOMEM;
 421
 422         shp->shm_perm.key = key;
 423         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
 424         shp->mlock_user = NULL;
 425
 426         shp->shm_perm.security = NULL;
 427         error = security_shm_alloc(shp);
 428         if (error) {
 429                 ipc_rcu_putref(shp);
 430                 return error;
 431         }
 432
 433         sprintf (name, "SYSV%08x", key);
 434         if (shmflg & SHM_HUGETLB) {
 435                 /* hugetlb_file_setup takes care of mlock user accounting */
 436                 file = hugetlb_file_setup(name, size);
 437                 shp->mlock_user = current->user;
 438         } else {
 439                 int acctflag = VM_ACCOUNT;
 440                 /*
 441                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
 442                  * if it's asked for.
 443                  */
 444                 if  ((shmflg & SHM_NORESERVE) &&
 445                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
 446                         acctflag = 0;
 447                 file = shmem_file_setup(name, size, acctflag);
 448         }
 449         error = PTR_ERR(file);
 450         if (IS_ERR(file))
 451                 goto no_file;
 452
 453         id = shm_addid(ns, shp);
 454         if (id < 0) {
 455                 error = id;
 456                 goto no_id;
 457         }
 458
 459         shp->shm_cprid = task_tgid_vnr(current);
 460         shp->shm_lprid = 0;
 461         shp->shm_atim = shp->shm_dtim = 0;
 462         shp->shm_ctim = get_seconds();
 463         shp->shm_segsz = size;
 464         shp->shm_nattch = 0;
 465         shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
 466         shp->shm_file = file;
 467         /*
 468          * shmid gets reported as "inode#" in /proc/pid/maps.
 469          * proc-ps tools use this. Changing this will break them.
 470          */
 471         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 472
 473         ns->shm_tot += numpages;
 474         error = shp->shm_perm.id;
 475         shm_unlock(shp);
 476         return error;
 477
 478 no_id:
 479         fput(file);
 480 no_file:
 481         security_shm_free(shp);
 482         ipc_rcu_putref(shp);
 483         return error;
 484 }
 485
 486 /*
 487  * Called with shm_ids.rw_mutex and ipcp locked.
 488  */
 489 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 490 {
 491         struct shmid_kernel *shp;
 492
 493         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 494         return security_shm_associate(shp, shmflg);
 495 }
 496
 497 /*
 498  * Called with shm_ids.rw_mutex and ipcp locked.
 499  */
 500 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
 501                                 struct ipc_params *params)
 502 {
 503         struct shmid_kernel *shp;
 504
 505         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
 506         if (shp->shm_segsz < params->u.size)
 507                 return -EINVAL;
 508
 509         return 0;
 510 }
 511
 512 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 513 {
 514         struct ipc_namespace *ns;
 515         struct ipc_ops shm_ops;
 516         struct ipc_params shm_params;
 517
 518         ns = current->nsproxy->ipc_ns;
 519
 520         shm_ops.getnew = newseg;
 521         shm_ops.associate = shm_security;
 522         shm_ops.more_checks = shm_more_checks;
 523
 524         shm_params.key = key;
 525         shm_params.flg = shmflg;
 526         shm_params.u.size = size;
 527
 528         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 529 }
 530
 531 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
 532 {
 533         switch(version) {
 534         case IPC_64:
 535                 return copy_to_user(buf, in, sizeof(*in));
 536         case IPC_OLD:
 537             {
 538                 struct shmid_ds out;
 539
 540                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
 541                 out.shm_segsz   = in->shm_segsz;
 542                 out.shm_atime   = in->shm_atime;
 543                 out.shm_dtime   = in->shm_dtime;
 544                 out.shm_ctime   = in->shm_ctime;
 545                 out.shm_cpid    = in->shm_cpid;
 546                 out.shm_lpid    = in->shm_lpid;
 547                 out.shm_nattch  = in->shm_nattch;
 548
 549                 return copy_to_user(buf, &out, sizeof(out));
 550             }
 551         default:
 552                 return -EINVAL;
 553         }
 554 }
 555
 556 struct shm_setbuf {
 557         uid_t   uid;
 558         gid_t   gid;
 559         mode_t  mode;
 560 };
 561
 562 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
 563 {
 564         switch(version) {
 565         case IPC_64:
 566             {
 567                 struct shmid64_ds tbuf;
 568
 569                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
 570                         return -EFAULT;
 571
 572                 out->uid        = tbuf.shm_perm.uid;
 573                 out->gid        = tbuf.shm_perm.gid;
 574                 out->mode       = tbuf.shm_perm.mode;
 575
 576                 return 0;
 577             }
 578         case IPC_OLD:
 579             {
 580                 struct shmid_ds tbuf_old;
 581
 582                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
 583                         return -EFAULT;
 584
 585                 out->uid        = tbuf_old.shm_perm.uid;
 586                 out->gid        = tbuf_old.shm_perm.gid;
 587                 out->mode       = tbuf_old.shm_perm.mode;
 588
 589                 return 0;
 590             }
 591         default:
 592                 return -EINVAL;
 593         }
 594 }
 595
 596 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
 597 {
 598         switch(version) {
 599         case IPC_64:
 600                 return copy_to_user(buf, in, sizeof(*in));
 601         case IPC_OLD:
 602             {
 603                 struct shminfo out;
 604
 605                 if(in->shmmax > INT_MAX)
 606                         out.shmmax = INT_MAX;
 607                 else
 608                         out.shmmax = (int)in->shmmax;
 609
 610                 out.shmmin      = in->shmmin;
 611                 out.shmmni      = in->shmmni;
 612                 out.shmseg      = in->shmseg;
 613                 out.shmall      = in->shmall;
 614
 615                 return copy_to_user(buf, &out, sizeof(out));
 616             }
 617         default:
 618                 return -EINVAL;
 619         }
 620 }
 621
 622 /*
 623  * Called with shm_ids.rw_mutex held as a reader
 624  */
 625 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
 626                 unsigned long *swp)
 627 {
 628         int next_id;
 629         int total, in_use;
 630
 631         *rss = 0;
 632         *swp = 0;
 633
 634         in_use = shm_ids(ns).in_use;
 635
 636         for (total = 0, next_id = 0; total < in_use; next_id++) {
 637                 struct shmid_kernel *shp;
 638                 struct inode *inode;
 639
 640                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
 641                 if (shp == NULL)
 642                         continue;
 643
 644                 inode = shp->shm_file->f_path.dentry->d_inode;
 645
 646                 if (is_file_hugepages(shp->shm_file)) {
 647                         struct address_space *mapping = inode->i_mapping;
 648                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
 649                 } else {
 650                         struct shmem_inode_info *info = SHMEM_I(inode);
 651                         spin_lock(&info->lock);
 652                         *rss += inode->i_mapping->nrpages;
 653                         *swp += info->swapped;
 654                         spin_unlock(&info->lock);
 655                 }
 656
 657                 total++;
 658         }
 659 }
 660
 661 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 662 {
 663         struct shm_setbuf setbuf;
 664         struct shmid_kernel *shp;
 665         int err, version;
 666         struct ipc_namespace *ns;
 667
 668         if (cmd < 0 || shmid < 0) {
 669                 err = -EINVAL;
 670                 goto out;
 671         }
 672
 673         version = ipc_parse_version(&cmd);
 674         ns = current->nsproxy->ipc_ns;
 675
 676         switch (cmd) { /* replace with proc interface ? */
 677         case IPC_INFO:
 678         {
 679                 struct shminfo64 shminfo;
 680
 681                 err = security_shm_shmctl(NULL, cmd);
 682                 if (err)
 683                         return err;
 684
 685                 memset(&shminfo,0,sizeof(shminfo));
 686                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
 687                 shminfo.shmmax = ns->shm_ctlmax;
 688                 shminfo.shmall = ns->shm_ctlall;
 689
 690                 shminfo.shmmin = SHMMIN;
 691                 if(copy_shminfo_to_user (buf, &shminfo, version))
 692                         return -EFAULT;
 693
 694                 down_read(&shm_ids(ns).rw_mutex);
 695                 err = ipc_get_maxid(&shm_ids(ns));
 696                 up_read(&shm_ids(ns).rw_mutex);
 697
 698                 if(err<0)
 699                         err = 0;
 700                 goto out;
 701         }
 702         case SHM_INFO:
 703         {
 704                 struct shm_info shm_info;
 705
 706                 err = security_shm_shmctl(NULL, cmd);
 707                 if (err)
 708                         return err;
 709
 710                 memset(&shm_info,0,sizeof(shm_info));
 711                 down_read(&shm_ids(ns).rw_mutex);
 712                 shm_info.used_ids = shm_ids(ns).in_use;
 713                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
 714                 shm_info.shm_tot = ns->shm_tot;
 715                 shm_info.swap_attempts = 0;
 716                 shm_info.swap_successes = 0;
 717                 err = ipc_get_maxid(&shm_ids(ns));
 718                 up_read(&shm_ids(ns).rw_mutex);
 719                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 720                         err = -EFAULT;
 721                         goto out;
 722                 }
 723
 724                 err = err < 0 ? 0 : err;
 725                 goto out;
 726         }
 727         case SHM_STAT:
 728         case IPC_STAT:
 729         {
 730                 struct shmid64_ds tbuf;
 731                 int result;
 732
 733                 if (!buf) {
 734                         err = -EFAULT;
 735                         goto out;
 736                 }
 737
 738                 if (cmd == SHM_STAT) {
 739                         shp = shm_lock(ns, shmid);
 740                         if (IS_ERR(shp)) {
 741                                 err = PTR_ERR(shp);
 742                                 goto out;
 743                         }
 744                         result = shp->shm_perm.id;
 745                 } else {
 746                         shp = shm_lock_check(ns, shmid);
 747                         if (IS_ERR(shp)) {
 748                                 err = PTR_ERR(shp);
 749                                 goto out;
 750                         }
 751                         result = 0;
 752                 }
 753                 err=-EACCES;
 754                 if (ipcperms (&shp->shm_perm, S_IRUGO))
 755                         goto out_unlock;
 756                 err = security_shm_shmctl(shp, cmd);
 757                 if (err)
 758                         goto out_unlock;
 759                 memset(&tbuf, 0, sizeof(tbuf));
 760                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
 761                 tbuf.shm_segsz  = shp->shm_segsz;
 762                 tbuf.shm_atime  = shp->shm_atim;
 763                 tbuf.shm_dtime  = shp->shm_dtim;
 764                 tbuf.shm_ctime  = shp->shm_ctim;
 765                 tbuf.shm_cpid   = shp->shm_cprid;
 766                 tbuf.shm_lpid   = shp->shm_lprid;
 767                 tbuf.shm_nattch = shp->shm_nattch;
 768                 shm_unlock(shp);
 769                 if(copy_shmid_to_user (buf, &tbuf, version))
 770                         err = -EFAULT;
 771                 else
 772                         err = result;
 773                 goto out;
 774         }
 775         case SHM_LOCK:
 776         case SHM_UNLOCK:
 777         {
 778                 shp = shm_lock_check(ns, shmid);
 779                 if (IS_ERR(shp)) {
 780                         err = PTR_ERR(shp);
 781                         goto out;
 782                 }
 783
 784                 err = audit_ipc_obj(&(shp->shm_perm));
 785                 if (err)
 786                         goto out_unlock;
 787
 788                 if (!capable(CAP_IPC_LOCK)) {
 789                         err = -EPERM;
 790                         if (current->euid != shp->shm_perm.uid &&
 791                             current->euid != shp->shm_perm.cuid)
 792                                 goto out_unlock;
 793                         if (cmd == SHM_LOCK &&
 794                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
 795                                 goto out_unlock;
 796                 }
 797
 798                 err = security_shm_shmctl(shp, cmd);
 799                 if (err)
 800                         goto out_unlock;
 801
 802                 if(cmd==SHM_LOCK) {
 803                         struct user_struct * user = current->user;
 804                         if (!is_file_hugepages(shp->shm_file)) {
 805                                 err = shmem_lock(shp->shm_file, 1, user);
 806                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
 807                                         shp->shm_perm.mode |= SHM_LOCKED;
 808                                         shp->mlock_user = user;
 809                                 }
 810                         }
 811                 } else if (!is_file_hugepages(shp->shm_file)) {
 812                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
 813                         shp->shm_perm.mode &= ~SHM_LOCKED;
 814                         shp->mlock_user = NULL;
 815                 }
 816                 shm_unlock(shp);
 817                 goto out;
 818         }
 819         case IPC_RMID:
 820         {
 821                 /*
 822                  *      We cannot simply remove the file. The SVID states
 823                  *      that the block remains until the last person
 824                  *      detaches from it, then is deleted. A shmat() on
 825                  *      an RMID segment is legal in older Linux and if
 826                  *      we change it apps break...
 827                  *
 828                  *      Instead we set a destroyed flag, and then blow
 829                  *      the name away when the usage hits zero.
 830                  */
 831                 down_write(&shm_ids(ns).rw_mutex);
 832                 shp = shm_lock_check_down(ns, shmid);
 833                 if (IS_ERR(shp)) {
 834                         err = PTR_ERR(shp);
 835                         goto out_up;
 836                 }
 837
 838                 err = audit_ipc_obj(&(shp->shm_perm));
 839                 if (err)
 840                         goto out_unlock_up;
 841
 842                 if (current->euid != shp->shm_perm.uid &&
 843                     current->euid != shp->shm_perm.cuid &&
 844                     !capable(CAP_SYS_ADMIN)) {
 845                         err=-EPERM;
 846                         goto out_unlock_up;
 847                 }
 848
 849                 err = security_shm_shmctl(shp, cmd);
 850                 if (err)
 851                         goto out_unlock_up;
 852
 853                 do_shm_rmid(ns, shp);
 854                 up_write(&shm_ids(ns).rw_mutex);
 855                 goto out;
 856         }
 857
 858         case IPC_SET:
 859         {
 860                 if (!buf) {
 861                         err = -EFAULT;
 862                         goto out;
 863                 }
 864
 865                 if (copy_shmid_from_user (&setbuf, buf, version)) {
 866                         err = -EFAULT;
 867                         goto out;
 868                 }
 869                 down_write(&shm_ids(ns).rw_mutex);
 870                 shp = shm_lock_check_down(ns, shmid);
 871                 if (IS_ERR(shp)) {
 872                         err = PTR_ERR(shp);
 873                         goto out_up;
 874                 }
 875                 err = audit_ipc_obj(&(shp->shm_perm));
 876                 if (err)
 877                         goto out_unlock_up;
 878                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
 879                 if (err)
 880                         goto out_unlock_up;
 881                 err=-EPERM;
 882                 if (current->euid != shp->shm_perm.uid &&
 883                     current->euid != shp->shm_perm.cuid &&
 884                     !capable(CAP_SYS_ADMIN)) {
 885                         goto out_unlock_up;
 886                 }
 887
 888                 err = security_shm_shmctl(shp, cmd);
 889                 if (err)
 890                         goto out_unlock_up;
 891
 892                 shp->shm_perm.uid = setbuf.uid;
 893                 shp->shm_perm.gid = setbuf.gid;
 894                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
 895                         | (setbuf.mode & S_IRWXUGO);
 896                 shp->shm_ctim = get_seconds();
 897                 break;
 898         }
 899
 900         default:
 901                 err = -EINVAL;
 902                 goto out;
 903         }
 904
 905         err = 0;
 906 out_unlock_up:
 907         shm_unlock(shp);
 908 out_up:
 909         up_write(&shm_ids(ns).rw_mutex);
 910         goto out;
 911 out_unlock:
 912         shm_unlock(shp);
 913 out:
 914         return err;
 915 }
 916
 917 /*
 918  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 919  *
 920  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 921  * "raddr" thing points to kernel space, and there has to be a wrapper around
 922  * this.
 923  */
 924 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
 925 {
 926         struct shmid_kernel *shp;
 927         unsigned long addr;
 928         unsigned long size;
 929         struct file * file;
 930         int    err;
 931         unsigned long flags;
 932         unsigned long prot;
 933         int acc_mode;
 934         unsigned long user_addr;
 935         struct ipc_namespace *ns;
 936         struct shm_file_data *sfd;
 937         struct path path;
 938         mode_t f_mode;
 939
 940         err = -EINVAL;
 941         if (shmid < 0)
 942                 goto out;
 943         else if ((addr = (ulong)shmaddr)) {
 944                 if (addr & (SHMLBA-1)) {
 945                         if (shmflg & SHM_RND)
 946                                 addr &= ~(SHMLBA-1);       /* round down */
 947                         else
 948 #ifndef __ARCH_FORCE_SHMLBA
 949                                 if (addr & ~PAGE_MASK)
 950 #endif
 951                                         goto out;
 952                 }
 953                 flags = MAP_SHARED | MAP_FIXED;
 954         } else {
 955                 if ((shmflg & SHM_REMAP))
 956                         goto out;
 957
 958                 flags = MAP_SHARED;
 959         }
 960
 961         if (shmflg & SHM_RDONLY) {
 962                 prot = PROT_READ;
 963                 acc_mode = S_IRUGO;
 964                 f_mode = FMODE_READ;
 965         } else {
 966                 prot = PROT_READ | PROT_WRITE;
 967                 acc_mode = S_IRUGO | S_IWUGO;
 968                 f_mode = FMODE_READ | FMODE_WRITE;
 969         }
 970         if (shmflg & SHM_EXEC) {
 971                 prot |= PROT_EXEC;
 972                 acc_mode |= S_IXUGO;
 973         }
 974
 975         /*
 976          * We cannot rely on the fs check since SYSV IPC does have an
 977          * additional creator id...
 978          */
 979         ns = current->nsproxy->ipc_ns;
 980         shp = shm_lock_check(ns, shmid);
 981         if (IS_ERR(shp)) {
 982                 err = PTR_ERR(shp);
 983                 goto out;
 984         }
 985
 986         err = -EACCES;
 987         if (ipcperms(&shp->shm_perm, acc_mode))
 988                 goto out_unlock;
 989
 990         err = security_shm_shmat(shp, shmaddr, shmflg);
 991         if (err)
 992                 goto out_unlock;
 993
 994         path.dentry = dget(shp->shm_file->f_path.dentry);
 995         path.mnt    = shp->shm_file->f_path.mnt;
 996         shp->shm_nattch++;
 997         size = i_size_read(path.dentry->d_inode);
 998         shm_unlock(shp);
 999
1000         err = -ENOMEM;
1001         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1002         if (!sfd)
1003                 goto out_put_dentry;
1004
1005         err = -ENOMEM;
1006
1007         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
1008         if (!file)
1009                 goto out_free;
1010
1011         file->private_data = sfd;
1012         file->f_mapping = shp->shm_file->f_mapping;
1013         sfd->id = shp->shm_perm.id;
1014         sfd->ns = get_ipc_ns(ns);
1015         sfd->file = shp->shm_file;
1016         sfd->vm_ops = NULL;
1017
1018         down_write(&current->mm->mmap_sem);
1019         if (addr && !(shmflg & SHM_REMAP)) {
1020                 err = -EINVAL;
1021                 if (find_vma_intersection(current->mm, addr, addr + size))
1022                         goto invalid;
1023                 /*
1024                  * If shm segment goes below stack, make sure there is some
1025                  * space left for the stack to grow (at least 4 pages).
1026                  */
1027                 if (addr < current->mm->start_stack &&
1028                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1029                         goto invalid;
1030         }
1031
1032         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1033         *raddr = user_addr;
1034         err = 0;
1035         if (IS_ERR_VALUE(user_addr))
1036                 err = (long)user_addr;
1037 invalid:
1038         up_write(&current->mm->mmap_sem);
1039
1040         fput(file);
1041
1042 out_nattch:
1043         down_write(&shm_ids(ns).rw_mutex);
1044         shp = shm_lock_down(ns, shmid);
1045         BUG_ON(IS_ERR(shp));
1046         shp->shm_nattch--;
1047         if(shp->shm_nattch == 0 &&
1048            shp->shm_perm.mode & SHM_DEST)
1049                 shm_destroy(ns, shp);
1050         else
1051                 shm_unlock(shp);
1052         up_write(&shm_ids(ns).rw_mutex);
1053
1054 out:
1055         return err;
1056
1057 out_unlock:
1058         shm_unlock(shp);
1059         goto out;
1060
1061 out_free:
1062         kfree(sfd);
1063 out_put_dentry:
1064         dput(path.dentry);
1065         goto out_nattch;
1066 }
1067
1068 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1069 {
1070         unsigned long ret;
1071         long err;
1072
1073         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1074         if (err)
1075                 return err;
1076         force_successful_syscall_return();
1077         return (long)ret;
1078 }
1079
1080 /*
1081  * detach and kill segment if marked destroyed.
1082  * The work is done in shm_close.
1083  */
1084 asmlinkage long sys_shmdt(char __user *shmaddr)
1085 {
1086         struct mm_struct *mm = current->mm;
1087         struct vm_area_struct *vma, *next;
1088         unsigned long addr = (unsigned long)shmaddr;
1089         loff_t size = 0;
1090         int retval = -EINVAL;
1091
1092         if (addr & ~PAGE_MASK)
1093                 return retval;
1094
1095         down_write(&mm->mmap_sem);
1096
1097         /*
1098          * This function tries to be smart and unmap shm segments that
1099          * were modified by partial mlock or munmap calls:
1100          * - It first determines the size of the shm segment that should be
1101          *   unmapped: It searches for a vma that is backed by shm and that
1102          *   started at address shmaddr. It records it's size and then unmaps
1103          *   it.
1104          * - Then it unmaps all shm vmas that started at shmaddr and that
1105          *   are within the initially determined size.
1106          * Errors from do_munmap are ignored: the function only fails if
1107          * it's called with invalid parameters or if it's called to unmap
1108          * a part of a vma. Both calls in this function are for full vmas,
1109          * the parameters are directly copied from the vma itself and always
1110          * valid - therefore do_munmap cannot fail. (famous last words?)
1111          */
1112         /*
1113          * If it had been mremap()'d, the starting address would not
1114          * match the usual checks anyway. So assume all vma's are
1115          * above the starting address given.
1116          */
1117         vma = find_vma(mm, addr);
1118
1119         while (vma) {
1120                 next = vma->vm_next;
1121
1122                 /*
1123                  * Check if the starting address would match, i.e. it's
1124                  * a fragment created by mprotect() and/or munmap(), or it
1125                  * otherwise it starts at this address with no hassles.
1126                  */
1127                 if ((vma->vm_ops == &shm_vm_ops) &&
1128                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1129
1130
1131                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1132                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1133                         /*
1134                          * We discovered the size of the shm segment, so
1135                          * break out of here and fall through to the next
1136                          * loop that uses the size information to stop
1137                          * searching for matching vma's.
1138                          */
1139                         retval = 0;
1140                         vma = next;
1141                         break;
1142                 }
1143                 vma = next;
1144         }
1145
1146         /*
1147          * We need look no further than the maximum address a fragment
1148          * could possibly have landed at. Also cast things to loff_t to
1149          * prevent overflows and make comparisions vs. equal-width types.
1150          */
1151         size = PAGE_ALIGN(size);
1152         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1153                 next = vma->vm_next;
1154
1155                 /* finding a matching vma now does not alter retval */
1156                 if ((vma->vm_ops == &shm_vm_ops) &&
1157                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1158
1159                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1160                 vma = next;
1161         }
1162
1163         up_write(&mm->mmap_sem);
1164         return retval;
1165 }
1166
1167 #ifdef CONFIG_PROC_FS
1168 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1169 {
1170         struct shmid_kernel *shp = it;
1171         char *format;
1172
1173 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1174 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1175
1176         if (sizeof(size_t) <= sizeof(int))
1177                 format = SMALL_STRING;
1178         else
1179                 format = BIG_STRING;
1180         return seq_printf(s, format,
1181                           shp->shm_perm.key,
1182                           shp->shm_perm.id,
1183                           shp->shm_perm.mode,
1184                           shp->shm_segsz,
1185                           shp->shm_cprid,
1186                           shp->shm_lprid,
1187                           shp->shm_nattch,
1188                           shp->shm_perm.uid,
1189                           shp->shm_perm.gid,
1190                           shp->shm_perm.cuid,
1191                           shp->shm_perm.cgid,
1192                           shp->shm_atim,
1193                           shp->shm_dtim,
1194                           shp->shm_ctim);
1195 }
1196 #endif