| 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 | * Better ipc lock (kern_ipc_perm.lock) handling |
| 24 | * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013. |
| 25 | */ |
| 26 | |
| 27 | #include <linux/slab.h> |
| 28 | #include <linux/mm.h> |
| 29 | #include <linux/hugetlb.h> |
| 30 | #include <linux/shm.h> |
| 31 | #include <linux/init.h> |
| 32 | #include <linux/file.h> |
| 33 | #include <linux/mman.h> |
| 34 | #include <linux/shmem_fs.h> |
| 35 | #include <linux/security.h> |
| 36 | #include <linux/syscalls.h> |
| 37 | #include <linux/audit.h> |
| 38 | #include <linux/capability.h> |
| 39 | #include <linux/ptrace.h> |
| 40 | #include <linux/seq_file.h> |
| 41 | #include <linux/rwsem.h> |
| 42 | #include <linux/nsproxy.h> |
| 43 | #include <linux/mount.h> |
| 44 | #include <linux/ipc_namespace.h> |
| 45 | |
| 46 | #include <asm/uaccess.h> |
| 47 | |
| 48 | #include "util.h" |
| 49 | |
| 50 | struct shm_file_data { |
| 51 | int id; |
| 52 | struct ipc_namespace *ns; |
| 53 | struct file *file; |
| 54 | const struct vm_operations_struct *vm_ops; |
| 55 | }; |
| 56 | |
| 57 | #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) |
| 58 | |
| 59 | static const struct file_operations shm_file_operations; |
| 60 | static const struct vm_operations_struct shm_vm_ops; |
| 61 | |
| 62 | #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS]) |
| 63 | |
| 64 | #define shm_unlock(shp) \ |
| 65 | ipc_unlock(&(shp)->shm_perm) |
| 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 | void shm_init_ns(struct ipc_namespace *ns) |
| 76 | { |
| 77 | ns->shm_ctlmax = SHMMAX; |
| 78 | ns->shm_ctlall = SHMALL; |
| 79 | ns->shm_ctlmni = SHMMNI; |
| 80 | ns->shm_rmid_forced = 0; |
| 81 | ns->shm_tot = 0; |
| 82 | ipc_init_ids(&shm_ids(ns)); |
| 83 | } |
| 84 | |
| 85 | /* |
| 86 | * Called with shm_ids.rwsem (writer) and the shp structure locked. |
| 87 | * Only shm_ids.rwsem remains locked on exit. |
| 88 | */ |
| 89 | static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
| 90 | { |
| 91 | struct shmid_kernel *shp; |
| 92 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 93 | |
| 94 | if (shp->shm_nattch){ |
| 95 | shp->shm_perm.mode |= SHM_DEST; |
| 96 | /* Do not find it any more */ |
| 97 | shp->shm_perm.key = IPC_PRIVATE; |
| 98 | shm_unlock(shp); |
| 99 | } else |
| 100 | shm_destroy(ns, shp); |
| 101 | } |
| 102 | |
| 103 | #ifdef CONFIG_IPC_NS |
| 104 | void shm_exit_ns(struct ipc_namespace *ns) |
| 105 | { |
| 106 | free_ipcs(ns, &shm_ids(ns), do_shm_rmid); |
| 107 | idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr); |
| 108 | } |
| 109 | #endif |
| 110 | |
| 111 | static int __init ipc_ns_init(void) |
| 112 | { |
| 113 | shm_init_ns(&init_ipc_ns); |
| 114 | return 0; |
| 115 | } |
| 116 | |
| 117 | pure_initcall(ipc_ns_init); |
| 118 | |
| 119 | void __init shm_init (void) |
| 120 | { |
| 121 | ipc_init_proc_interface("sysvipc/shm", |
| 122 | #if BITS_PER_LONG <= 32 |
| 123 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", |
| 124 | #else |
| 125 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", |
| 126 | #endif |
| 127 | IPC_SHM_IDS, sysvipc_shm_proc_show); |
| 128 | } |
| 129 | |
| 130 | static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id) |
| 131 | { |
| 132 | struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id); |
| 133 | |
| 134 | if (IS_ERR(ipcp)) |
| 135 | return ERR_CAST(ipcp); |
| 136 | |
| 137 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 138 | } |
| 139 | |
| 140 | static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id) |
| 141 | { |
| 142 | struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id); |
| 143 | |
| 144 | if (IS_ERR(ipcp)) |
| 145 | return ERR_CAST(ipcp); |
| 146 | |
| 147 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 148 | } |
| 149 | |
| 150 | /* |
| 151 | * shm_lock_(check_) routines are called in the paths where the rwsem |
| 152 | * is not necessarily held. |
| 153 | */ |
| 154 | static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) |
| 155 | { |
| 156 | struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); |
| 157 | |
| 158 | if (IS_ERR(ipcp)) |
| 159 | return (struct shmid_kernel *)ipcp; |
| 160 | |
| 161 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 162 | } |
| 163 | |
| 164 | static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp) |
| 165 | { |
| 166 | rcu_read_lock(); |
| 167 | ipc_lock_object(&ipcp->shm_perm); |
| 168 | } |
| 169 | |
| 170 | static void shm_rcu_free(struct rcu_head *head) |
| 171 | { |
| 172 | struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); |
| 173 | struct shmid_kernel *shp = ipc_rcu_to_struct(p); |
| 174 | |
| 175 | security_shm_free(shp); |
| 176 | ipc_rcu_free(head); |
| 177 | } |
| 178 | |
| 179 | static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) |
| 180 | { |
| 181 | ipc_rmid(&shm_ids(ns), &s->shm_perm); |
| 182 | } |
| 183 | |
| 184 | |
| 185 | /* This is called by fork, once for every shm attach. */ |
| 186 | static void shm_open(struct vm_area_struct *vma) |
| 187 | { |
| 188 | struct file *file = vma->vm_file; |
| 189 | struct shm_file_data *sfd = shm_file_data(file); |
| 190 | struct shmid_kernel *shp; |
| 191 | |
| 192 | shp = shm_lock(sfd->ns, sfd->id); |
| 193 | BUG_ON(IS_ERR(shp)); |
| 194 | shp->shm_atim = get_seconds(); |
| 195 | shp->shm_lprid = task_tgid_vnr(current); |
| 196 | shp->shm_nattch++; |
| 197 | shm_unlock(shp); |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * shm_destroy - free the struct shmid_kernel |
| 202 | * |
| 203 | * @ns: namespace |
| 204 | * @shp: struct to free |
| 205 | * |
| 206 | * It has to be called with shp and shm_ids.rwsem (writer) locked, |
| 207 | * but returns with shp unlocked and freed. |
| 208 | */ |
| 209 | static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) |
| 210 | { |
| 211 | struct file *shm_file; |
| 212 | |
| 213 | shm_file = shp->shm_file; |
| 214 | shp->shm_file = NULL; |
| 215 | ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 216 | shm_rmid(ns, shp); |
| 217 | shm_unlock(shp); |
| 218 | if (!is_file_hugepages(shm_file)) |
| 219 | shmem_lock(shm_file, 0, shp->mlock_user); |
| 220 | else if (shp->mlock_user) |
| 221 | user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user); |
| 222 | fput(shm_file); |
| 223 | ipc_rcu_putref(shp, shm_rcu_free); |
| 224 | } |
| 225 | |
| 226 | /* |
| 227 | * shm_may_destroy - identifies whether shm segment should be destroyed now |
| 228 | * |
| 229 | * Returns true if and only if there are no active users of the segment and |
| 230 | * one of the following is true: |
| 231 | * |
| 232 | * 1) shmctl(id, IPC_RMID, NULL) was called for this shp |
| 233 | * |
| 234 | * 2) sysctl kernel.shm_rmid_forced is set to 1. |
| 235 | */ |
| 236 | static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) |
| 237 | { |
| 238 | return (shp->shm_nattch == 0) && |
| 239 | (ns->shm_rmid_forced || |
| 240 | (shp->shm_perm.mode & SHM_DEST)); |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * remove the attach descriptor vma. |
| 245 | * free memory for segment if it is marked destroyed. |
| 246 | * The descriptor has already been removed from the current->mm->mmap list |
| 247 | * and will later be kfree()d. |
| 248 | */ |
| 249 | static void shm_close(struct vm_area_struct *vma) |
| 250 | { |
| 251 | struct file * file = vma->vm_file; |
| 252 | struct shm_file_data *sfd = shm_file_data(file); |
| 253 | struct shmid_kernel *shp; |
| 254 | struct ipc_namespace *ns = sfd->ns; |
| 255 | |
| 256 | down_write(&shm_ids(ns).rwsem); |
| 257 | /* remove from the list of attaches of the shm segment */ |
| 258 | shp = shm_lock(ns, sfd->id); |
| 259 | BUG_ON(IS_ERR(shp)); |
| 260 | shp->shm_lprid = task_tgid_vnr(current); |
| 261 | shp->shm_dtim = get_seconds(); |
| 262 | shp->shm_nattch--; |
| 263 | if (shm_may_destroy(ns, shp)) |
| 264 | shm_destroy(ns, shp); |
| 265 | else |
| 266 | shm_unlock(shp); |
| 267 | up_write(&shm_ids(ns).rwsem); |
| 268 | } |
| 269 | |
| 270 | /* Called with ns->shm_ids(ns).rwsem locked */ |
| 271 | static int shm_try_destroy_current(int id, void *p, void *data) |
| 272 | { |
| 273 | struct ipc_namespace *ns = data; |
| 274 | struct kern_ipc_perm *ipcp = p; |
| 275 | struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 276 | |
| 277 | if (shp->shm_creator != current) |
| 278 | return 0; |
| 279 | |
| 280 | /* |
| 281 | * Mark it as orphaned to destroy the segment when |
| 282 | * kernel.shm_rmid_forced is changed. |
| 283 | * It is noop if the following shm_may_destroy() returns true. |
| 284 | */ |
| 285 | shp->shm_creator = NULL; |
| 286 | |
| 287 | /* |
| 288 | * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID |
| 289 | * is not set, it shouldn't be deleted here. |
| 290 | */ |
| 291 | if (!ns->shm_rmid_forced) |
| 292 | return 0; |
| 293 | |
| 294 | if (shm_may_destroy(ns, shp)) { |
| 295 | shm_lock_by_ptr(shp); |
| 296 | shm_destroy(ns, shp); |
| 297 | } |
| 298 | return 0; |
| 299 | } |
| 300 | |
| 301 | /* Called with ns->shm_ids(ns).rwsem locked */ |
| 302 | static int shm_try_destroy_orphaned(int id, void *p, void *data) |
| 303 | { |
| 304 | struct ipc_namespace *ns = data; |
| 305 | struct kern_ipc_perm *ipcp = p; |
| 306 | struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 307 | |
| 308 | /* |
| 309 | * We want to destroy segments without users and with already |
| 310 | * exit'ed originating process. |
| 311 | * |
| 312 | * As shp->* are changed under rwsem, it's safe to skip shp locking. |
| 313 | */ |
| 314 | if (shp->shm_creator != NULL) |
| 315 | return 0; |
| 316 | |
| 317 | if (shm_may_destroy(ns, shp)) { |
| 318 | shm_lock_by_ptr(shp); |
| 319 | shm_destroy(ns, shp); |
| 320 | } |
| 321 | return 0; |
| 322 | } |
| 323 | |
| 324 | void shm_destroy_orphaned(struct ipc_namespace *ns) |
| 325 | { |
| 326 | down_write(&shm_ids(ns).rwsem); |
| 327 | if (shm_ids(ns).in_use) |
| 328 | idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns); |
| 329 | up_write(&shm_ids(ns).rwsem); |
| 330 | } |
| 331 | |
| 332 | |
| 333 | void exit_shm(struct task_struct *task) |
| 334 | { |
| 335 | struct ipc_namespace *ns = task->nsproxy->ipc_ns; |
| 336 | |
| 337 | if (shm_ids(ns).in_use == 0) |
| 338 | return; |
| 339 | |
| 340 | /* Destroy all already created segments, but not mapped yet */ |
| 341 | down_write(&shm_ids(ns).rwsem); |
| 342 | if (shm_ids(ns).in_use) |
| 343 | idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns); |
| 344 | up_write(&shm_ids(ns).rwsem); |
| 345 | } |
| 346 | |
| 347 | static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 348 | { |
| 349 | struct file *file = vma->vm_file; |
| 350 | struct shm_file_data *sfd = shm_file_data(file); |
| 351 | |
| 352 | return sfd->vm_ops->fault(vma, vmf); |
| 353 | } |
| 354 | |
| 355 | #ifdef CONFIG_NUMA |
| 356 | static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
| 357 | { |
| 358 | struct file *file = vma->vm_file; |
| 359 | struct shm_file_data *sfd = shm_file_data(file); |
| 360 | int err = 0; |
| 361 | if (sfd->vm_ops->set_policy) |
| 362 | err = sfd->vm_ops->set_policy(vma, new); |
| 363 | return err; |
| 364 | } |
| 365 | |
| 366 | static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, |
| 367 | unsigned long addr) |
| 368 | { |
| 369 | struct file *file = vma->vm_file; |
| 370 | struct shm_file_data *sfd = shm_file_data(file); |
| 371 | struct mempolicy *pol = NULL; |
| 372 | |
| 373 | if (sfd->vm_ops->get_policy) |
| 374 | pol = sfd->vm_ops->get_policy(vma, addr); |
| 375 | else if (vma->vm_policy) |
| 376 | pol = vma->vm_policy; |
| 377 | |
| 378 | return pol; |
| 379 | } |
| 380 | #endif |
| 381 | |
| 382 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) |
| 383 | { |
| 384 | struct shm_file_data *sfd = shm_file_data(file); |
| 385 | int ret; |
| 386 | |
| 387 | ret = sfd->file->f_op->mmap(sfd->file, vma); |
| 388 | if (ret != 0) |
| 389 | return ret; |
| 390 | sfd->vm_ops = vma->vm_ops; |
| 391 | #ifdef CONFIG_MMU |
| 392 | BUG_ON(!sfd->vm_ops->fault); |
| 393 | #endif |
| 394 | vma->vm_ops = &shm_vm_ops; |
| 395 | shm_open(vma); |
| 396 | |
| 397 | return ret; |
| 398 | } |
| 399 | |
| 400 | static int shm_release(struct inode *ino, struct file *file) |
| 401 | { |
| 402 | struct shm_file_data *sfd = shm_file_data(file); |
| 403 | |
| 404 | put_ipc_ns(sfd->ns); |
| 405 | shm_file_data(file) = NULL; |
| 406 | kfree(sfd); |
| 407 | return 0; |
| 408 | } |
| 409 | |
| 410 | static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| 411 | { |
| 412 | struct shm_file_data *sfd = shm_file_data(file); |
| 413 | |
| 414 | if (!sfd->file->f_op->fsync) |
| 415 | return -EINVAL; |
| 416 | return sfd->file->f_op->fsync(sfd->file, start, end, datasync); |
| 417 | } |
| 418 | |
| 419 | static long shm_fallocate(struct file *file, int mode, loff_t offset, |
| 420 | loff_t len) |
| 421 | { |
| 422 | struct shm_file_data *sfd = shm_file_data(file); |
| 423 | |
| 424 | if (!sfd->file->f_op->fallocate) |
| 425 | return -EOPNOTSUPP; |
| 426 | return sfd->file->f_op->fallocate(file, mode, offset, len); |
| 427 | } |
| 428 | |
| 429 | static unsigned long shm_get_unmapped_area(struct file *file, |
| 430 | unsigned long addr, unsigned long len, unsigned long pgoff, |
| 431 | unsigned long flags) |
| 432 | { |
| 433 | struct shm_file_data *sfd = shm_file_data(file); |
| 434 | return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, |
| 435 | pgoff, flags); |
| 436 | } |
| 437 | |
| 438 | static const struct file_operations shm_file_operations = { |
| 439 | .mmap = shm_mmap, |
| 440 | .fsync = shm_fsync, |
| 441 | .release = shm_release, |
| 442 | #ifndef CONFIG_MMU |
| 443 | .get_unmapped_area = shm_get_unmapped_area, |
| 444 | #endif |
| 445 | .llseek = noop_llseek, |
| 446 | .fallocate = shm_fallocate, |
| 447 | }; |
| 448 | |
| 449 | static const struct file_operations shm_file_operations_huge = { |
| 450 | .mmap = shm_mmap, |
| 451 | .fsync = shm_fsync, |
| 452 | .release = shm_release, |
| 453 | .get_unmapped_area = shm_get_unmapped_area, |
| 454 | .llseek = noop_llseek, |
| 455 | .fallocate = shm_fallocate, |
| 456 | }; |
| 457 | |
| 458 | int is_file_shm_hugepages(struct file *file) |
| 459 | { |
| 460 | return file->f_op == &shm_file_operations_huge; |
| 461 | } |
| 462 | |
| 463 | static const struct vm_operations_struct shm_vm_ops = { |
| 464 | .open = shm_open, /* callback for a new vm-area open */ |
| 465 | .close = shm_close, /* callback for when the vm-area is released */ |
| 466 | .fault = shm_fault, |
| 467 | #if defined(CONFIG_NUMA) |
| 468 | .set_policy = shm_set_policy, |
| 469 | .get_policy = shm_get_policy, |
| 470 | #endif |
| 471 | }; |
| 472 | |
| 473 | /** |
| 474 | * newseg - Create a new shared memory segment |
| 475 | * @ns: namespace |
| 476 | * @params: ptr to the structure that contains key, size and shmflg |
| 477 | * |
| 478 | * Called with shm_ids.rwsem held as a writer. |
| 479 | */ |
| 480 | |
| 481 | static int newseg(struct ipc_namespace *ns, struct ipc_params *params) |
| 482 | { |
| 483 | key_t key = params->key; |
| 484 | int shmflg = params->flg; |
| 485 | size_t size = params->u.size; |
| 486 | int error; |
| 487 | struct shmid_kernel *shp; |
| 488 | size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 489 | struct file * file; |
| 490 | char name[13]; |
| 491 | int id; |
| 492 | vm_flags_t acctflag = 0; |
| 493 | |
| 494 | if (size < SHMMIN || size > ns->shm_ctlmax) |
| 495 | return -EINVAL; |
| 496 | |
| 497 | if (ns->shm_tot + numpages > ns->shm_ctlall) |
| 498 | return -ENOSPC; |
| 499 | |
| 500 | shp = ipc_rcu_alloc(sizeof(*shp)); |
| 501 | if (!shp) |
| 502 | return -ENOMEM; |
| 503 | |
| 504 | shp->shm_perm.key = key; |
| 505 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
| 506 | shp->mlock_user = NULL; |
| 507 | |
| 508 | shp->shm_perm.security = NULL; |
| 509 | error = security_shm_alloc(shp); |
| 510 | if (error) { |
| 511 | ipc_rcu_putref(shp, ipc_rcu_free); |
| 512 | return error; |
| 513 | } |
| 514 | |
| 515 | sprintf (name, "SYSV%08x", key); |
| 516 | if (shmflg & SHM_HUGETLB) { |
| 517 | struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) |
| 518 | & SHM_HUGE_MASK); |
| 519 | size_t hugesize; |
| 520 | |
| 521 | if (!hs) { |
| 522 | error = -EINVAL; |
| 523 | goto no_file; |
| 524 | } |
| 525 | hugesize = ALIGN(size, huge_page_size(hs)); |
| 526 | |
| 527 | /* hugetlb_file_setup applies strict accounting */ |
| 528 | if (shmflg & SHM_NORESERVE) |
| 529 | acctflag = VM_NORESERVE; |
| 530 | file = hugetlb_file_setup(name, hugesize, acctflag, |
| 531 | &shp->mlock_user, HUGETLB_SHMFS_INODE, |
| 532 | (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK); |
| 533 | } else { |
| 534 | /* |
| 535 | * Do not allow no accounting for OVERCOMMIT_NEVER, even |
| 536 | * if it's asked for. |
| 537 | */ |
| 538 | if ((shmflg & SHM_NORESERVE) && |
| 539 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) |
| 540 | acctflag = VM_NORESERVE; |
| 541 | file = shmem_file_setup(name, size, acctflag, 0); |
| 542 | } |
| 543 | error = PTR_ERR(file); |
| 544 | if (IS_ERR(file)) |
| 545 | goto no_file; |
| 546 | |
| 547 | shp->shm_cprid = task_tgid_vnr(current); |
| 548 | shp->shm_lprid = 0; |
| 549 | shp->shm_atim = shp->shm_dtim = 0; |
| 550 | shp->shm_ctim = get_seconds(); |
| 551 | shp->shm_segsz = size; |
| 552 | shp->shm_nattch = 0; |
| 553 | shp->shm_file = file; |
| 554 | shp->shm_creator = current; |
| 555 | |
| 556 | id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); |
| 557 | if (id < 0) { |
| 558 | error = id; |
| 559 | goto no_id; |
| 560 | } |
| 561 | |
| 562 | /* |
| 563 | * shmid gets reported as "inode#" in /proc/pid/maps. |
| 564 | * proc-ps tools use this. Changing this will break them. |
| 565 | */ |
| 566 | file_inode(file)->i_ino = shp->shm_perm.id; |
| 567 | |
| 568 | ns->shm_tot += numpages; |
| 569 | error = shp->shm_perm.id; |
| 570 | |
| 571 | ipc_unlock_object(&shp->shm_perm); |
| 572 | rcu_read_unlock(); |
| 573 | return error; |
| 574 | |
| 575 | no_id: |
| 576 | if (is_file_hugepages(file) && shp->mlock_user) |
| 577 | user_shm_unlock(size, shp->mlock_user); |
| 578 | fput(file); |
| 579 | no_file: |
| 580 | ipc_rcu_putref(shp, shm_rcu_free); |
| 581 | return error; |
| 582 | } |
| 583 | |
| 584 | /* |
| 585 | * Called with shm_ids.rwsem and ipcp locked. |
| 586 | */ |
| 587 | static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) |
| 588 | { |
| 589 | struct shmid_kernel *shp; |
| 590 | |
| 591 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 592 | return security_shm_associate(shp, shmflg); |
| 593 | } |
| 594 | |
| 595 | /* |
| 596 | * Called with shm_ids.rwsem and ipcp locked. |
| 597 | */ |
| 598 | static inline int shm_more_checks(struct kern_ipc_perm *ipcp, |
| 599 | struct ipc_params *params) |
| 600 | { |
| 601 | struct shmid_kernel *shp; |
| 602 | |
| 603 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 604 | if (shp->shm_segsz < params->u.size) |
| 605 | return -EINVAL; |
| 606 | |
| 607 | return 0; |
| 608 | } |
| 609 | |
| 610 | SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) |
| 611 | { |
| 612 | struct ipc_namespace *ns; |
| 613 | struct ipc_ops shm_ops; |
| 614 | struct ipc_params shm_params; |
| 615 | |
| 616 | ns = current->nsproxy->ipc_ns; |
| 617 | |
| 618 | shm_ops.getnew = newseg; |
| 619 | shm_ops.associate = shm_security; |
| 620 | shm_ops.more_checks = shm_more_checks; |
| 621 | |
| 622 | shm_params.key = key; |
| 623 | shm_params.flg = shmflg; |
| 624 | shm_params.u.size = size; |
| 625 | |
| 626 | return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); |
| 627 | } |
| 628 | |
| 629 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) |
| 630 | { |
| 631 | switch(version) { |
| 632 | case IPC_64: |
| 633 | return copy_to_user(buf, in, sizeof(*in)); |
| 634 | case IPC_OLD: |
| 635 | { |
| 636 | struct shmid_ds out; |
| 637 | |
| 638 | memset(&out, 0, sizeof(out)); |
| 639 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); |
| 640 | out.shm_segsz = in->shm_segsz; |
| 641 | out.shm_atime = in->shm_atime; |
| 642 | out.shm_dtime = in->shm_dtime; |
| 643 | out.shm_ctime = in->shm_ctime; |
| 644 | out.shm_cpid = in->shm_cpid; |
| 645 | out.shm_lpid = in->shm_lpid; |
| 646 | out.shm_nattch = in->shm_nattch; |
| 647 | |
| 648 | return copy_to_user(buf, &out, sizeof(out)); |
| 649 | } |
| 650 | default: |
| 651 | return -EINVAL; |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | static inline unsigned long |
| 656 | copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) |
| 657 | { |
| 658 | switch(version) { |
| 659 | case IPC_64: |
| 660 | if (copy_from_user(out, buf, sizeof(*out))) |
| 661 | return -EFAULT; |
| 662 | return 0; |
| 663 | case IPC_OLD: |
| 664 | { |
| 665 | struct shmid_ds tbuf_old; |
| 666 | |
| 667 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
| 668 | return -EFAULT; |
| 669 | |
| 670 | out->shm_perm.uid = tbuf_old.shm_perm.uid; |
| 671 | out->shm_perm.gid = tbuf_old.shm_perm.gid; |
| 672 | out->shm_perm.mode = tbuf_old.shm_perm.mode; |
| 673 | |
| 674 | return 0; |
| 675 | } |
| 676 | default: |
| 677 | return -EINVAL; |
| 678 | } |
| 679 | } |
| 680 | |
| 681 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) |
| 682 | { |
| 683 | switch(version) { |
| 684 | case IPC_64: |
| 685 | return copy_to_user(buf, in, sizeof(*in)); |
| 686 | case IPC_OLD: |
| 687 | { |
| 688 | struct shminfo out; |
| 689 | |
| 690 | if(in->shmmax > INT_MAX) |
| 691 | out.shmmax = INT_MAX; |
| 692 | else |
| 693 | out.shmmax = (int)in->shmmax; |
| 694 | |
| 695 | out.shmmin = in->shmmin; |
| 696 | out.shmmni = in->shmmni; |
| 697 | out.shmseg = in->shmseg; |
| 698 | out.shmall = in->shmall; |
| 699 | |
| 700 | return copy_to_user(buf, &out, sizeof(out)); |
| 701 | } |
| 702 | default: |
| 703 | return -EINVAL; |
| 704 | } |
| 705 | } |
| 706 | |
| 707 | /* |
| 708 | * Calculate and add used RSS and swap pages of a shm. |
| 709 | * Called with shm_ids.rwsem held as a reader |
| 710 | */ |
| 711 | static void shm_add_rss_swap(struct shmid_kernel *shp, |
| 712 | unsigned long *rss_add, unsigned long *swp_add) |
| 713 | { |
| 714 | struct inode *inode; |
| 715 | |
| 716 | inode = file_inode(shp->shm_file); |
| 717 | |
| 718 | if (is_file_hugepages(shp->shm_file)) { |
| 719 | struct address_space *mapping = inode->i_mapping; |
| 720 | struct hstate *h = hstate_file(shp->shm_file); |
| 721 | *rss_add += pages_per_huge_page(h) * mapping->nrpages; |
| 722 | } else { |
| 723 | #ifdef CONFIG_SHMEM |
| 724 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 725 | spin_lock(&info->lock); |
| 726 | *rss_add += inode->i_mapping->nrpages; |
| 727 | *swp_add += info->swapped; |
| 728 | spin_unlock(&info->lock); |
| 729 | #else |
| 730 | *rss_add += inode->i_mapping->nrpages; |
| 731 | #endif |
| 732 | } |
| 733 | } |
| 734 | |
| 735 | /* |
| 736 | * Called with shm_ids.rwsem held as a reader |
| 737 | */ |
| 738 | static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, |
| 739 | unsigned long *swp) |
| 740 | { |
| 741 | int next_id; |
| 742 | int total, in_use; |
| 743 | |
| 744 | *rss = 0; |
| 745 | *swp = 0; |
| 746 | |
| 747 | in_use = shm_ids(ns).in_use; |
| 748 | |
| 749 | for (total = 0, next_id = 0; total < in_use; next_id++) { |
| 750 | struct kern_ipc_perm *ipc; |
| 751 | struct shmid_kernel *shp; |
| 752 | |
| 753 | ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id); |
| 754 | if (ipc == NULL) |
| 755 | continue; |
| 756 | shp = container_of(ipc, struct shmid_kernel, shm_perm); |
| 757 | |
| 758 | shm_add_rss_swap(shp, rss, swp); |
| 759 | |
| 760 | total++; |
| 761 | } |
| 762 | } |
| 763 | |
| 764 | /* |
| 765 | * This function handles some shmctl commands which require the rwsem |
| 766 | * to be held in write mode. |
| 767 | * NOTE: no locks must be held, the rwsem is taken inside this function. |
| 768 | */ |
| 769 | static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, |
| 770 | struct shmid_ds __user *buf, int version) |
| 771 | { |
| 772 | struct kern_ipc_perm *ipcp; |
| 773 | struct shmid64_ds shmid64; |
| 774 | struct shmid_kernel *shp; |
| 775 | int err; |
| 776 | |
| 777 | if (cmd == IPC_SET) { |
| 778 | if (copy_shmid_from_user(&shmid64, buf, version)) |
| 779 | return -EFAULT; |
| 780 | } |
| 781 | |
| 782 | down_write(&shm_ids(ns).rwsem); |
| 783 | rcu_read_lock(); |
| 784 | |
| 785 | ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd, |
| 786 | &shmid64.shm_perm, 0); |
| 787 | if (IS_ERR(ipcp)) { |
| 788 | err = PTR_ERR(ipcp); |
| 789 | goto out_unlock1; |
| 790 | } |
| 791 | |
| 792 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 793 | |
| 794 | err = security_shm_shmctl(shp, cmd); |
| 795 | if (err) |
| 796 | goto out_unlock1; |
| 797 | |
| 798 | switch (cmd) { |
| 799 | case IPC_RMID: |
| 800 | ipc_lock_object(&shp->shm_perm); |
| 801 | /* do_shm_rmid unlocks the ipc object and rcu */ |
| 802 | do_shm_rmid(ns, ipcp); |
| 803 | goto out_up; |
| 804 | case IPC_SET: |
| 805 | ipc_lock_object(&shp->shm_perm); |
| 806 | err = ipc_update_perm(&shmid64.shm_perm, ipcp); |
| 807 | if (err) |
| 808 | goto out_unlock0; |
| 809 | shp->shm_ctim = get_seconds(); |
| 810 | break; |
| 811 | default: |
| 812 | err = -EINVAL; |
| 813 | goto out_unlock1; |
| 814 | } |
| 815 | |
| 816 | out_unlock0: |
| 817 | ipc_unlock_object(&shp->shm_perm); |
| 818 | out_unlock1: |
| 819 | rcu_read_unlock(); |
| 820 | out_up: |
| 821 | up_write(&shm_ids(ns).rwsem); |
| 822 | return err; |
| 823 | } |
| 824 | |
| 825 | static int shmctl_nolock(struct ipc_namespace *ns, int shmid, |
| 826 | int cmd, int version, void __user *buf) |
| 827 | { |
| 828 | int err; |
| 829 | struct shmid_kernel *shp; |
| 830 | |
| 831 | /* preliminary security checks for *_INFO */ |
| 832 | if (cmd == IPC_INFO || cmd == SHM_INFO) { |
| 833 | err = security_shm_shmctl(NULL, cmd); |
| 834 | if (err) |
| 835 | return err; |
| 836 | } |
| 837 | |
| 838 | switch (cmd) { |
| 839 | case IPC_INFO: |
| 840 | { |
| 841 | struct shminfo64 shminfo; |
| 842 | |
| 843 | memset(&shminfo, 0, sizeof(shminfo)); |
| 844 | shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; |
| 845 | shminfo.shmmax = ns->shm_ctlmax; |
| 846 | shminfo.shmall = ns->shm_ctlall; |
| 847 | |
| 848 | shminfo.shmmin = SHMMIN; |
| 849 | if(copy_shminfo_to_user (buf, &shminfo, version)) |
| 850 | return -EFAULT; |
| 851 | |
| 852 | down_read(&shm_ids(ns).rwsem); |
| 853 | err = ipc_get_maxid(&shm_ids(ns)); |
| 854 | up_read(&shm_ids(ns).rwsem); |
| 855 | |
| 856 | if(err<0) |
| 857 | err = 0; |
| 858 | goto out; |
| 859 | } |
| 860 | case SHM_INFO: |
| 861 | { |
| 862 | struct shm_info shm_info; |
| 863 | |
| 864 | memset(&shm_info, 0, sizeof(shm_info)); |
| 865 | down_read(&shm_ids(ns).rwsem); |
| 866 | shm_info.used_ids = shm_ids(ns).in_use; |
| 867 | shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); |
| 868 | shm_info.shm_tot = ns->shm_tot; |
| 869 | shm_info.swap_attempts = 0; |
| 870 | shm_info.swap_successes = 0; |
| 871 | err = ipc_get_maxid(&shm_ids(ns)); |
| 872 | up_read(&shm_ids(ns).rwsem); |
| 873 | if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { |
| 874 | err = -EFAULT; |
| 875 | goto out; |
| 876 | } |
| 877 | |
| 878 | err = err < 0 ? 0 : err; |
| 879 | goto out; |
| 880 | } |
| 881 | case SHM_STAT: |
| 882 | case IPC_STAT: |
| 883 | { |
| 884 | struct shmid64_ds tbuf; |
| 885 | int result; |
| 886 | |
| 887 | rcu_read_lock(); |
| 888 | if (cmd == SHM_STAT) { |
| 889 | shp = shm_obtain_object(ns, shmid); |
| 890 | if (IS_ERR(shp)) { |
| 891 | err = PTR_ERR(shp); |
| 892 | goto out_unlock; |
| 893 | } |
| 894 | result = shp->shm_perm.id; |
| 895 | } else { |
| 896 | shp = shm_obtain_object_check(ns, shmid); |
| 897 | if (IS_ERR(shp)) { |
| 898 | err = PTR_ERR(shp); |
| 899 | goto out_unlock; |
| 900 | } |
| 901 | result = 0; |
| 902 | } |
| 903 | |
| 904 | err = -EACCES; |
| 905 | if (ipcperms(ns, &shp->shm_perm, S_IRUGO)) |
| 906 | goto out_unlock; |
| 907 | |
| 908 | err = security_shm_shmctl(shp, cmd); |
| 909 | if (err) |
| 910 | goto out_unlock; |
| 911 | |
| 912 | memset(&tbuf, 0, sizeof(tbuf)); |
| 913 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); |
| 914 | tbuf.shm_segsz = shp->shm_segsz; |
| 915 | tbuf.shm_atime = shp->shm_atim; |
| 916 | tbuf.shm_dtime = shp->shm_dtim; |
| 917 | tbuf.shm_ctime = shp->shm_ctim; |
| 918 | tbuf.shm_cpid = shp->shm_cprid; |
| 919 | tbuf.shm_lpid = shp->shm_lprid; |
| 920 | tbuf.shm_nattch = shp->shm_nattch; |
| 921 | rcu_read_unlock(); |
| 922 | |
| 923 | if (copy_shmid_to_user(buf, &tbuf, version)) |
| 924 | err = -EFAULT; |
| 925 | else |
| 926 | err = result; |
| 927 | goto out; |
| 928 | } |
| 929 | default: |
| 930 | return -EINVAL; |
| 931 | } |
| 932 | |
| 933 | out_unlock: |
| 934 | rcu_read_unlock(); |
| 935 | out: |
| 936 | return err; |
| 937 | } |
| 938 | |
| 939 | SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) |
| 940 | { |
| 941 | struct shmid_kernel *shp; |
| 942 | int err, version; |
| 943 | struct ipc_namespace *ns; |
| 944 | |
| 945 | if (cmd < 0 || shmid < 0) |
| 946 | return -EINVAL; |
| 947 | |
| 948 | version = ipc_parse_version(&cmd); |
| 949 | ns = current->nsproxy->ipc_ns; |
| 950 | |
| 951 | switch (cmd) { |
| 952 | case IPC_INFO: |
| 953 | case SHM_INFO: |
| 954 | case SHM_STAT: |
| 955 | case IPC_STAT: |
| 956 | return shmctl_nolock(ns, shmid, cmd, version, buf); |
| 957 | case IPC_RMID: |
| 958 | case IPC_SET: |
| 959 | return shmctl_down(ns, shmid, cmd, buf, version); |
| 960 | case SHM_LOCK: |
| 961 | case SHM_UNLOCK: |
| 962 | { |
| 963 | struct file *shm_file; |
| 964 | |
| 965 | rcu_read_lock(); |
| 966 | shp = shm_obtain_object_check(ns, shmid); |
| 967 | if (IS_ERR(shp)) { |
| 968 | err = PTR_ERR(shp); |
| 969 | goto out_unlock1; |
| 970 | } |
| 971 | |
| 972 | audit_ipc_obj(&(shp->shm_perm)); |
| 973 | err = security_shm_shmctl(shp, cmd); |
| 974 | if (err) |
| 975 | goto out_unlock1; |
| 976 | |
| 977 | ipc_lock_object(&shp->shm_perm); |
| 978 | if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) { |
| 979 | kuid_t euid = current_euid(); |
| 980 | if (!uid_eq(euid, shp->shm_perm.uid) && |
| 981 | !uid_eq(euid, shp->shm_perm.cuid)) { |
| 982 | err = -EPERM; |
| 983 | goto out_unlock0; |
| 984 | } |
| 985 | if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) { |
| 986 | err = -EPERM; |
| 987 | goto out_unlock0; |
| 988 | } |
| 989 | } |
| 990 | |
| 991 | shm_file = shp->shm_file; |
| 992 | |
| 993 | /* check if shm_destroy() is tearing down shp */ |
| 994 | if (shm_file == NULL) { |
| 995 | err = -EIDRM; |
| 996 | goto out_unlock0; |
| 997 | } |
| 998 | |
| 999 | if (is_file_hugepages(shm_file)) |
| 1000 | goto out_unlock0; |
| 1001 | |
| 1002 | if (cmd == SHM_LOCK) { |
| 1003 | struct user_struct *user = current_user(); |
| 1004 | err = shmem_lock(shm_file, 1, user); |
| 1005 | if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) { |
| 1006 | shp->shm_perm.mode |= SHM_LOCKED; |
| 1007 | shp->mlock_user = user; |
| 1008 | } |
| 1009 | goto out_unlock0; |
| 1010 | } |
| 1011 | |
| 1012 | /* SHM_UNLOCK */ |
| 1013 | if (!(shp->shm_perm.mode & SHM_LOCKED)) |
| 1014 | goto out_unlock0; |
| 1015 | shmem_lock(shm_file, 0, shp->mlock_user); |
| 1016 | shp->shm_perm.mode &= ~SHM_LOCKED; |
| 1017 | shp->mlock_user = NULL; |
| 1018 | get_file(shm_file); |
| 1019 | ipc_unlock_object(&shp->shm_perm); |
| 1020 | rcu_read_unlock(); |
| 1021 | shmem_unlock_mapping(shm_file->f_mapping); |
| 1022 | |
| 1023 | fput(shm_file); |
| 1024 | return err; |
| 1025 | } |
| 1026 | default: |
| 1027 | return -EINVAL; |
| 1028 | } |
| 1029 | |
| 1030 | out_unlock0: |
| 1031 | ipc_unlock_object(&shp->shm_perm); |
| 1032 | out_unlock1: |
| 1033 | rcu_read_unlock(); |
| 1034 | return err; |
| 1035 | } |
| 1036 | |
| 1037 | /* |
| 1038 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. |
| 1039 | * |
| 1040 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The |
| 1041 | * "raddr" thing points to kernel space, and there has to be a wrapper around |
| 1042 | * this. |
| 1043 | */ |
| 1044 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, |
| 1045 | ulong *raddr, unsigned long shmlba) |
| 1046 | { |
| 1047 | struct shmid_kernel *shp; |
| 1048 | unsigned long addr; |
| 1049 | unsigned long size; |
| 1050 | struct file * file; |
| 1051 | int err; |
| 1052 | unsigned long flags; |
| 1053 | unsigned long prot; |
| 1054 | int acc_mode; |
| 1055 | struct ipc_namespace *ns; |
| 1056 | struct shm_file_data *sfd; |
| 1057 | struct path path; |
| 1058 | fmode_t f_mode; |
| 1059 | unsigned long populate = 0; |
| 1060 | |
| 1061 | err = -EINVAL; |
| 1062 | if (shmid < 0) |
| 1063 | goto out; |
| 1064 | else if ((addr = (ulong)shmaddr)) { |
| 1065 | if (addr & (shmlba - 1)) { |
| 1066 | /* |
| 1067 | * Round down to the nearest multiple of shmlba. |
| 1068 | * For sane do_mmap_pgoff() parameters, avoid |
| 1069 | * round downs that trigger nil-page and MAP_FIXED. |
| 1070 | */ |
| 1071 | if ((shmflg & SHM_RND) && addr >= shmlba) |
| 1072 | addr &= ~(shmlba - 1); |
| 1073 | else |
| 1074 | #ifndef __ARCH_FORCE_SHMLBA |
| 1075 | if (addr & ~PAGE_MASK) |
| 1076 | #endif |
| 1077 | goto out; |
| 1078 | } |
| 1079 | flags = MAP_SHARED | MAP_FIXED; |
| 1080 | } else { |
| 1081 | if ((shmflg & SHM_REMAP)) |
| 1082 | goto out; |
| 1083 | |
| 1084 | flags = MAP_SHARED; |
| 1085 | } |
| 1086 | |
| 1087 | if (shmflg & SHM_RDONLY) { |
| 1088 | prot = PROT_READ; |
| 1089 | acc_mode = S_IRUGO; |
| 1090 | f_mode = FMODE_READ; |
| 1091 | } else { |
| 1092 | prot = PROT_READ | PROT_WRITE; |
| 1093 | acc_mode = S_IRUGO | S_IWUGO; |
| 1094 | f_mode = FMODE_READ | FMODE_WRITE; |
| 1095 | } |
| 1096 | if (shmflg & SHM_EXEC) { |
| 1097 | prot |= PROT_EXEC; |
| 1098 | acc_mode |= S_IXUGO; |
| 1099 | } |
| 1100 | |
| 1101 | /* |
| 1102 | * We cannot rely on the fs check since SYSV IPC does have an |
| 1103 | * additional creator id... |
| 1104 | */ |
| 1105 | ns = current->nsproxy->ipc_ns; |
| 1106 | rcu_read_lock(); |
| 1107 | shp = shm_obtain_object_check(ns, shmid); |
| 1108 | if (IS_ERR(shp)) { |
| 1109 | err = PTR_ERR(shp); |
| 1110 | goto out_unlock; |
| 1111 | } |
| 1112 | |
| 1113 | err = -EACCES; |
| 1114 | if (ipcperms(ns, &shp->shm_perm, acc_mode)) |
| 1115 | goto out_unlock; |
| 1116 | |
| 1117 | err = security_shm_shmat(shp, shmaddr, shmflg); |
| 1118 | if (err) |
| 1119 | goto out_unlock; |
| 1120 | |
| 1121 | ipc_lock_object(&shp->shm_perm); |
| 1122 | |
| 1123 | /* check if shm_destroy() is tearing down shp */ |
| 1124 | if (shp->shm_file == NULL) { |
| 1125 | ipc_unlock_object(&shp->shm_perm); |
| 1126 | err = -EIDRM; |
| 1127 | goto out_unlock; |
| 1128 | } |
| 1129 | |
| 1130 | path = shp->shm_file->f_path; |
| 1131 | path_get(&path); |
| 1132 | shp->shm_nattch++; |
| 1133 | size = i_size_read(path.dentry->d_inode); |
| 1134 | ipc_unlock_object(&shp->shm_perm); |
| 1135 | rcu_read_unlock(); |
| 1136 | |
| 1137 | err = -ENOMEM; |
| 1138 | sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); |
| 1139 | if (!sfd) { |
| 1140 | path_put(&path); |
| 1141 | goto out_nattch; |
| 1142 | } |
| 1143 | |
| 1144 | file = alloc_file(&path, f_mode, |
| 1145 | is_file_hugepages(shp->shm_file) ? |
| 1146 | &shm_file_operations_huge : |
| 1147 | &shm_file_operations); |
| 1148 | err = PTR_ERR(file); |
| 1149 | if (IS_ERR(file)) { |
| 1150 | kfree(sfd); |
| 1151 | path_put(&path); |
| 1152 | goto out_nattch; |
| 1153 | } |
| 1154 | |
| 1155 | file->private_data = sfd; |
| 1156 | file->f_mapping = shp->shm_file->f_mapping; |
| 1157 | sfd->id = shp->shm_perm.id; |
| 1158 | sfd->ns = get_ipc_ns(ns); |
| 1159 | sfd->file = shp->shm_file; |
| 1160 | sfd->vm_ops = NULL; |
| 1161 | |
| 1162 | err = security_mmap_file(file, prot, flags); |
| 1163 | if (err) |
| 1164 | goto out_fput; |
| 1165 | |
| 1166 | down_write(¤t->mm->mmap_sem); |
| 1167 | if (addr && !(shmflg & SHM_REMAP)) { |
| 1168 | err = -EINVAL; |
| 1169 | if (find_vma_intersection(current->mm, addr, addr + size)) |
| 1170 | goto invalid; |
| 1171 | /* |
| 1172 | * If shm segment goes below stack, make sure there is some |
| 1173 | * space left for the stack to grow (at least 4 pages). |
| 1174 | */ |
| 1175 | if (addr < current->mm->start_stack && |
| 1176 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) |
| 1177 | goto invalid; |
| 1178 | } |
| 1179 | |
| 1180 | addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate); |
| 1181 | *raddr = addr; |
| 1182 | err = 0; |
| 1183 | if (IS_ERR_VALUE(addr)) |
| 1184 | err = (long)addr; |
| 1185 | invalid: |
| 1186 | up_write(¤t->mm->mmap_sem); |
| 1187 | if (populate) |
| 1188 | mm_populate(addr, populate); |
| 1189 | |
| 1190 | out_fput: |
| 1191 | fput(file); |
| 1192 | |
| 1193 | out_nattch: |
| 1194 | down_write(&shm_ids(ns).rwsem); |
| 1195 | shp = shm_lock(ns, shmid); |
| 1196 | BUG_ON(IS_ERR(shp)); |
| 1197 | shp->shm_nattch--; |
| 1198 | if (shm_may_destroy(ns, shp)) |
| 1199 | shm_destroy(ns, shp); |
| 1200 | else |
| 1201 | shm_unlock(shp); |
| 1202 | up_write(&shm_ids(ns).rwsem); |
| 1203 | return err; |
| 1204 | |
| 1205 | out_unlock: |
| 1206 | rcu_read_unlock(); |
| 1207 | out: |
| 1208 | return err; |
| 1209 | } |
| 1210 | |
| 1211 | SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) |
| 1212 | { |
| 1213 | unsigned long ret; |
| 1214 | long err; |
| 1215 | |
| 1216 | err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA); |
| 1217 | if (err) |
| 1218 | return err; |
| 1219 | force_successful_syscall_return(); |
| 1220 | return (long)ret; |
| 1221 | } |
| 1222 | |
| 1223 | /* |
| 1224 | * detach and kill segment if marked destroyed. |
| 1225 | * The work is done in shm_close. |
| 1226 | */ |
| 1227 | SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) |
| 1228 | { |
| 1229 | struct mm_struct *mm = current->mm; |
| 1230 | struct vm_area_struct *vma; |
| 1231 | unsigned long addr = (unsigned long)shmaddr; |
| 1232 | int retval = -EINVAL; |
| 1233 | #ifdef CONFIG_MMU |
| 1234 | loff_t size = 0; |
| 1235 | struct vm_area_struct *next; |
| 1236 | #endif |
| 1237 | |
| 1238 | if (addr & ~PAGE_MASK) |
| 1239 | return retval; |
| 1240 | |
| 1241 | down_write(&mm->mmap_sem); |
| 1242 | |
| 1243 | /* |
| 1244 | * This function tries to be smart and unmap shm segments that |
| 1245 | * were modified by partial mlock or munmap calls: |
| 1246 | * - It first determines the size of the shm segment that should be |
| 1247 | * unmapped: It searches for a vma that is backed by shm and that |
| 1248 | * started at address shmaddr. It records it's size and then unmaps |
| 1249 | * it. |
| 1250 | * - Then it unmaps all shm vmas that started at shmaddr and that |
| 1251 | * are within the initially determined size. |
| 1252 | * Errors from do_munmap are ignored: the function only fails if |
| 1253 | * it's called with invalid parameters or if it's called to unmap |
| 1254 | * a part of a vma. Both calls in this function are for full vmas, |
| 1255 | * the parameters are directly copied from the vma itself and always |
| 1256 | * valid - therefore do_munmap cannot fail. (famous last words?) |
| 1257 | */ |
| 1258 | /* |
| 1259 | * If it had been mremap()'d, the starting address would not |
| 1260 | * match the usual checks anyway. So assume all vma's are |
| 1261 | * above the starting address given. |
| 1262 | */ |
| 1263 | vma = find_vma(mm, addr); |
| 1264 | |
| 1265 | #ifdef CONFIG_MMU |
| 1266 | while (vma) { |
| 1267 | next = vma->vm_next; |
| 1268 | |
| 1269 | /* |
| 1270 | * Check if the starting address would match, i.e. it's |
| 1271 | * a fragment created by mprotect() and/or munmap(), or it |
| 1272 | * otherwise it starts at this address with no hassles. |
| 1273 | */ |
| 1274 | if ((vma->vm_ops == &shm_vm_ops) && |
| 1275 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { |
| 1276 | |
| 1277 | |
| 1278 | size = file_inode(vma->vm_file)->i_size; |
| 1279 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| 1280 | /* |
| 1281 | * We discovered the size of the shm segment, so |
| 1282 | * break out of here and fall through to the next |
| 1283 | * loop that uses the size information to stop |
| 1284 | * searching for matching vma's. |
| 1285 | */ |
| 1286 | retval = 0; |
| 1287 | vma = next; |
| 1288 | break; |
| 1289 | } |
| 1290 | vma = next; |
| 1291 | } |
| 1292 | |
| 1293 | /* |
| 1294 | * We need look no further than the maximum address a fragment |
| 1295 | * could possibly have landed at. Also cast things to loff_t to |
| 1296 | * prevent overflows and make comparisons vs. equal-width types. |
| 1297 | */ |
| 1298 | size = PAGE_ALIGN(size); |
| 1299 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { |
| 1300 | next = vma->vm_next; |
| 1301 | |
| 1302 | /* finding a matching vma now does not alter retval */ |
| 1303 | if ((vma->vm_ops == &shm_vm_ops) && |
| 1304 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) |
| 1305 | |
| 1306 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| 1307 | vma = next; |
| 1308 | } |
| 1309 | |
| 1310 | #else /* CONFIG_MMU */ |
| 1311 | /* under NOMMU conditions, the exact address to be destroyed must be |
| 1312 | * given */ |
| 1313 | if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { |
| 1314 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| 1315 | retval = 0; |
| 1316 | } |
| 1317 | |
| 1318 | #endif |
| 1319 | |
| 1320 | up_write(&mm->mmap_sem); |
| 1321 | return retval; |
| 1322 | } |
| 1323 | |
| 1324 | #ifdef CONFIG_PROC_FS |
| 1325 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
| 1326 | { |
| 1327 | struct user_namespace *user_ns = seq_user_ns(s); |
| 1328 | struct shmid_kernel *shp = it; |
| 1329 | unsigned long rss = 0, swp = 0; |
| 1330 | |
| 1331 | shm_add_rss_swap(shp, &rss, &swp); |
| 1332 | |
| 1333 | #if BITS_PER_LONG <= 32 |
| 1334 | #define SIZE_SPEC "%10lu" |
| 1335 | #else |
| 1336 | #define SIZE_SPEC "%21lu" |
| 1337 | #endif |
| 1338 | |
| 1339 | return seq_printf(s, |
| 1340 | "%10d %10d %4o " SIZE_SPEC " %5u %5u " |
| 1341 | "%5lu %5u %5u %5u %5u %10lu %10lu %10lu " |
| 1342 | SIZE_SPEC " " SIZE_SPEC "\n", |
| 1343 | shp->shm_perm.key, |
| 1344 | shp->shm_perm.id, |
| 1345 | shp->shm_perm.mode, |
| 1346 | shp->shm_segsz, |
| 1347 | shp->shm_cprid, |
| 1348 | shp->shm_lprid, |
| 1349 | shp->shm_nattch, |
| 1350 | from_kuid_munged(user_ns, shp->shm_perm.uid), |
| 1351 | from_kgid_munged(user_ns, shp->shm_perm.gid), |
| 1352 | from_kuid_munged(user_ns, shp->shm_perm.cuid), |
| 1353 | from_kgid_munged(user_ns, shp->shm_perm.cgid), |
| 1354 | shp->shm_atim, |
| 1355 | shp->shm_dtim, |
| 1356 | shp->shm_ctim, |
| 1357 | rss * PAGE_SIZE, |
| 1358 | swp * PAGE_SIZE); |
| 1359 | } |
| 1360 | #endif |