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