| 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 | |
| 64 | static int newseg(struct ipc_namespace *, struct ipc_params *); |
| 65 | static void shm_open(struct vm_area_struct *vma); |
| 66 | static void shm_close(struct vm_area_struct *vma); |
| 67 | static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); |
| 68 | #ifdef CONFIG_PROC_FS |
| 69 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); |
| 70 | #endif |
| 71 | |
| 72 | void shm_init_ns(struct ipc_namespace *ns) |
| 73 | { |
| 74 | ns->shm_ctlmax = SHMMAX; |
| 75 | ns->shm_ctlall = SHMALL; |
| 76 | ns->shm_ctlmni = SHMMNI; |
| 77 | ns->shm_tot = 0; |
| 78 | ipc_init_ids(&ns->ids[IPC_SHM_IDS]); |
| 79 | } |
| 80 | |
| 81 | /* |
| 82 | * Called with shm_ids.rw_mutex (writer) and the shp structure locked. |
| 83 | * Only shm_ids.rw_mutex remains locked on exit. |
| 84 | */ |
| 85 | static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
| 86 | { |
| 87 | struct shmid_kernel *shp; |
| 88 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 89 | |
| 90 | if (shp->shm_nattch){ |
| 91 | shp->shm_perm.mode |= SHM_DEST; |
| 92 | /* Do not find it any more */ |
| 93 | shp->shm_perm.key = IPC_PRIVATE; |
| 94 | shm_unlock(shp); |
| 95 | } else |
| 96 | shm_destroy(ns, shp); |
| 97 | } |
| 98 | |
| 99 | #ifdef CONFIG_IPC_NS |
| 100 | void shm_exit_ns(struct ipc_namespace *ns) |
| 101 | { |
| 102 | free_ipcs(ns, &shm_ids(ns), do_shm_rmid); |
| 103 | } |
| 104 | #endif |
| 105 | |
| 106 | void __init shm_init (void) |
| 107 | { |
| 108 | shm_init_ns(&init_ipc_ns); |
| 109 | ipc_init_proc_interface("sysvipc/shm", |
| 110 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", |
| 111 | IPC_SHM_IDS, sysvipc_shm_proc_show); |
| 112 | } |
| 113 | |
| 114 | /* |
| 115 | * shm_lock_(check_)down routines are called in the paths where the rw_mutex |
| 116 | * is held to protect access to the idr tree. |
| 117 | */ |
| 118 | static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns, |
| 119 | int id) |
| 120 | { |
| 121 | struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id); |
| 122 | |
| 123 | if (IS_ERR(ipcp)) |
| 124 | return (struct shmid_kernel *)ipcp; |
| 125 | |
| 126 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 127 | } |
| 128 | |
| 129 | /* |
| 130 | * shm_lock_(check_) routines are called in the paths where the rw_mutex |
| 131 | * is not held. |
| 132 | */ |
| 133 | static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) |
| 134 | { |
| 135 | struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); |
| 136 | |
| 137 | if (IS_ERR(ipcp)) |
| 138 | return (struct shmid_kernel *)ipcp; |
| 139 | |
| 140 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 141 | } |
| 142 | |
| 143 | static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns, |
| 144 | int id) |
| 145 | { |
| 146 | struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id); |
| 147 | |
| 148 | if (IS_ERR(ipcp)) |
| 149 | return (struct shmid_kernel *)ipcp; |
| 150 | |
| 151 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
| 152 | } |
| 153 | |
| 154 | static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) |
| 155 | { |
| 156 | ipc_rmid(&shm_ids(ns), &s->shm_perm); |
| 157 | } |
| 158 | |
| 159 | |
| 160 | /* This is called by fork, once for every shm attach. */ |
| 161 | static void shm_open(struct vm_area_struct *vma) |
| 162 | { |
| 163 | struct file *file = vma->vm_file; |
| 164 | struct shm_file_data *sfd = shm_file_data(file); |
| 165 | struct shmid_kernel *shp; |
| 166 | |
| 167 | shp = shm_lock(sfd->ns, sfd->id); |
| 168 | BUG_ON(IS_ERR(shp)); |
| 169 | shp->shm_atim = get_seconds(); |
| 170 | shp->shm_lprid = task_tgid_vnr(current); |
| 171 | shp->shm_nattch++; |
| 172 | shm_unlock(shp); |
| 173 | } |
| 174 | |
| 175 | /* |
| 176 | * shm_destroy - free the struct shmid_kernel |
| 177 | * |
| 178 | * @ns: namespace |
| 179 | * @shp: struct to free |
| 180 | * |
| 181 | * It has to be called with shp and shm_ids.rw_mutex (writer) locked, |
| 182 | * but returns with shp unlocked and freed. |
| 183 | */ |
| 184 | static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) |
| 185 | { |
| 186 | ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 187 | shm_rmid(ns, shp); |
| 188 | shm_unlock(shp); |
| 189 | if (!is_file_hugepages(shp->shm_file)) |
| 190 | shmem_lock(shp->shm_file, 0, shp->mlock_user); |
| 191 | else |
| 192 | user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, |
| 193 | shp->mlock_user); |
| 194 | fput (shp->shm_file); |
| 195 | security_shm_free(shp); |
| 196 | ipc_rcu_putref(shp); |
| 197 | } |
| 198 | |
| 199 | /* |
| 200 | * remove the attach descriptor vma. |
| 201 | * free memory for segment if it is marked destroyed. |
| 202 | * The descriptor has already been removed from the current->mm->mmap list |
| 203 | * and will later be kfree()d. |
| 204 | */ |
| 205 | static void shm_close(struct vm_area_struct *vma) |
| 206 | { |
| 207 | struct file * file = vma->vm_file; |
| 208 | struct shm_file_data *sfd = shm_file_data(file); |
| 209 | struct shmid_kernel *shp; |
| 210 | struct ipc_namespace *ns = sfd->ns; |
| 211 | |
| 212 | down_write(&shm_ids(ns).rw_mutex); |
| 213 | /* remove from the list of attaches of the shm segment */ |
| 214 | shp = shm_lock_down(ns, sfd->id); |
| 215 | BUG_ON(IS_ERR(shp)); |
| 216 | shp->shm_lprid = task_tgid_vnr(current); |
| 217 | shp->shm_dtim = get_seconds(); |
| 218 | shp->shm_nattch--; |
| 219 | if(shp->shm_nattch == 0 && |
| 220 | shp->shm_perm.mode & SHM_DEST) |
| 221 | shm_destroy(ns, shp); |
| 222 | else |
| 223 | shm_unlock(shp); |
| 224 | up_write(&shm_ids(ns).rw_mutex); |
| 225 | } |
| 226 | |
| 227 | static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 228 | { |
| 229 | struct file *file = vma->vm_file; |
| 230 | struct shm_file_data *sfd = shm_file_data(file); |
| 231 | |
| 232 | return sfd->vm_ops->fault(vma, vmf); |
| 233 | } |
| 234 | |
| 235 | #ifdef CONFIG_NUMA |
| 236 | static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
| 237 | { |
| 238 | struct file *file = vma->vm_file; |
| 239 | struct shm_file_data *sfd = shm_file_data(file); |
| 240 | int err = 0; |
| 241 | if (sfd->vm_ops->set_policy) |
| 242 | err = sfd->vm_ops->set_policy(vma, new); |
| 243 | return err; |
| 244 | } |
| 245 | |
| 246 | static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, |
| 247 | unsigned long addr) |
| 248 | { |
| 249 | struct file *file = vma->vm_file; |
| 250 | struct shm_file_data *sfd = shm_file_data(file); |
| 251 | struct mempolicy *pol = NULL; |
| 252 | |
| 253 | if (sfd->vm_ops->get_policy) |
| 254 | pol = sfd->vm_ops->get_policy(vma, addr); |
| 255 | else if (vma->vm_policy) |
| 256 | pol = vma->vm_policy; |
| 257 | |
| 258 | return pol; |
| 259 | } |
| 260 | #endif |
| 261 | |
| 262 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) |
| 263 | { |
| 264 | struct shm_file_data *sfd = shm_file_data(file); |
| 265 | int ret; |
| 266 | |
| 267 | ret = sfd->file->f_op->mmap(sfd->file, vma); |
| 268 | if (ret != 0) |
| 269 | return ret; |
| 270 | sfd->vm_ops = vma->vm_ops; |
| 271 | #ifdef CONFIG_MMU |
| 272 | BUG_ON(!sfd->vm_ops->fault); |
| 273 | #endif |
| 274 | vma->vm_ops = &shm_vm_ops; |
| 275 | shm_open(vma); |
| 276 | |
| 277 | return ret; |
| 278 | } |
| 279 | |
| 280 | static int shm_release(struct inode *ino, struct file *file) |
| 281 | { |
| 282 | struct shm_file_data *sfd = shm_file_data(file); |
| 283 | |
| 284 | put_ipc_ns(sfd->ns); |
| 285 | shm_file_data(file) = NULL; |
| 286 | kfree(sfd); |
| 287 | return 0; |
| 288 | } |
| 289 | |
| 290 | static int shm_fsync(struct file *file, struct dentry *dentry, int datasync) |
| 291 | { |
| 292 | int (*fsync) (struct file *, struct dentry *, int datasync); |
| 293 | struct shm_file_data *sfd = shm_file_data(file); |
| 294 | int ret = -EINVAL; |
| 295 | |
| 296 | fsync = sfd->file->f_op->fsync; |
| 297 | if (fsync) |
| 298 | ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync); |
| 299 | return ret; |
| 300 | } |
| 301 | |
| 302 | static unsigned long shm_get_unmapped_area(struct file *file, |
| 303 | unsigned long addr, unsigned long len, unsigned long pgoff, |
| 304 | unsigned long flags) |
| 305 | { |
| 306 | struct shm_file_data *sfd = shm_file_data(file); |
| 307 | return get_unmapped_area(sfd->file, addr, len, pgoff, flags); |
| 308 | } |
| 309 | |
| 310 | int is_file_shm_hugepages(struct file *file) |
| 311 | { |
| 312 | int ret = 0; |
| 313 | |
| 314 | if (file->f_op == &shm_file_operations) { |
| 315 | struct shm_file_data *sfd; |
| 316 | sfd = shm_file_data(file); |
| 317 | ret = is_file_hugepages(sfd->file); |
| 318 | } |
| 319 | return ret; |
| 320 | } |
| 321 | |
| 322 | static const struct file_operations shm_file_operations = { |
| 323 | .mmap = shm_mmap, |
| 324 | .fsync = shm_fsync, |
| 325 | .release = shm_release, |
| 326 | .get_unmapped_area = shm_get_unmapped_area, |
| 327 | }; |
| 328 | |
| 329 | static struct vm_operations_struct shm_vm_ops = { |
| 330 | .open = shm_open, /* callback for a new vm-area open */ |
| 331 | .close = shm_close, /* callback for when the vm-area is released */ |
| 332 | .fault = shm_fault, |
| 333 | #if defined(CONFIG_NUMA) |
| 334 | .set_policy = shm_set_policy, |
| 335 | .get_policy = shm_get_policy, |
| 336 | #endif |
| 337 | }; |
| 338 | |
| 339 | /** |
| 340 | * newseg - Create a new shared memory segment |
| 341 | * @ns: namespace |
| 342 | * @params: ptr to the structure that contains key, size and shmflg |
| 343 | * |
| 344 | * Called with shm_ids.rw_mutex held as a writer. |
| 345 | */ |
| 346 | |
| 347 | static int newseg(struct ipc_namespace *ns, struct ipc_params *params) |
| 348 | { |
| 349 | key_t key = params->key; |
| 350 | int shmflg = params->flg; |
| 351 | size_t size = params->u.size; |
| 352 | int error; |
| 353 | struct shmid_kernel *shp; |
| 354 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; |
| 355 | struct file * file; |
| 356 | char name[13]; |
| 357 | int id; |
| 358 | |
| 359 | if (size < SHMMIN || size > ns->shm_ctlmax) |
| 360 | return -EINVAL; |
| 361 | |
| 362 | if (ns->shm_tot + numpages > ns->shm_ctlall) |
| 363 | return -ENOSPC; |
| 364 | |
| 365 | shp = ipc_rcu_alloc(sizeof(*shp)); |
| 366 | if (!shp) |
| 367 | return -ENOMEM; |
| 368 | |
| 369 | shp->shm_perm.key = key; |
| 370 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
| 371 | shp->mlock_user = NULL; |
| 372 | |
| 373 | shp->shm_perm.security = NULL; |
| 374 | error = security_shm_alloc(shp); |
| 375 | if (error) { |
| 376 | ipc_rcu_putref(shp); |
| 377 | return error; |
| 378 | } |
| 379 | |
| 380 | sprintf (name, "SYSV%08x", key); |
| 381 | if (shmflg & SHM_HUGETLB) { |
| 382 | /* hugetlb_file_setup takes care of mlock user accounting */ |
| 383 | file = hugetlb_file_setup(name, size); |
| 384 | shp->mlock_user = current->user; |
| 385 | } else { |
| 386 | int acctflag = VM_ACCOUNT; |
| 387 | /* |
| 388 | * Do not allow no accounting for OVERCOMMIT_NEVER, even |
| 389 | * if it's asked for. |
| 390 | */ |
| 391 | if ((shmflg & SHM_NORESERVE) && |
| 392 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) |
| 393 | acctflag = 0; |
| 394 | file = shmem_file_setup(name, size, acctflag); |
| 395 | } |
| 396 | error = PTR_ERR(file); |
| 397 | if (IS_ERR(file)) |
| 398 | goto no_file; |
| 399 | |
| 400 | id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); |
| 401 | if (id < 0) { |
| 402 | error = id; |
| 403 | goto no_id; |
| 404 | } |
| 405 | |
| 406 | shp->shm_cprid = task_tgid_vnr(current); |
| 407 | shp->shm_lprid = 0; |
| 408 | shp->shm_atim = shp->shm_dtim = 0; |
| 409 | shp->shm_ctim = get_seconds(); |
| 410 | shp->shm_segsz = size; |
| 411 | shp->shm_nattch = 0; |
| 412 | shp->shm_file = file; |
| 413 | /* |
| 414 | * shmid gets reported as "inode#" in /proc/pid/maps. |
| 415 | * proc-ps tools use this. Changing this will break them. |
| 416 | */ |
| 417 | file->f_dentry->d_inode->i_ino = shp->shm_perm.id; |
| 418 | |
| 419 | ns->shm_tot += numpages; |
| 420 | error = shp->shm_perm.id; |
| 421 | shm_unlock(shp); |
| 422 | return error; |
| 423 | |
| 424 | no_id: |
| 425 | fput(file); |
| 426 | no_file: |
| 427 | security_shm_free(shp); |
| 428 | ipc_rcu_putref(shp); |
| 429 | return error; |
| 430 | } |
| 431 | |
| 432 | /* |
| 433 | * Called with shm_ids.rw_mutex and ipcp locked. |
| 434 | */ |
| 435 | static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) |
| 436 | { |
| 437 | struct shmid_kernel *shp; |
| 438 | |
| 439 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 440 | return security_shm_associate(shp, shmflg); |
| 441 | } |
| 442 | |
| 443 | /* |
| 444 | * Called with shm_ids.rw_mutex and ipcp locked. |
| 445 | */ |
| 446 | static inline int shm_more_checks(struct kern_ipc_perm *ipcp, |
| 447 | struct ipc_params *params) |
| 448 | { |
| 449 | struct shmid_kernel *shp; |
| 450 | |
| 451 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 452 | if (shp->shm_segsz < params->u.size) |
| 453 | return -EINVAL; |
| 454 | |
| 455 | return 0; |
| 456 | } |
| 457 | |
| 458 | asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) |
| 459 | { |
| 460 | struct ipc_namespace *ns; |
| 461 | struct ipc_ops shm_ops; |
| 462 | struct ipc_params shm_params; |
| 463 | |
| 464 | ns = current->nsproxy->ipc_ns; |
| 465 | |
| 466 | shm_ops.getnew = newseg; |
| 467 | shm_ops.associate = shm_security; |
| 468 | shm_ops.more_checks = shm_more_checks; |
| 469 | |
| 470 | shm_params.key = key; |
| 471 | shm_params.flg = shmflg; |
| 472 | shm_params.u.size = size; |
| 473 | |
| 474 | return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); |
| 475 | } |
| 476 | |
| 477 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) |
| 478 | { |
| 479 | switch(version) { |
| 480 | case IPC_64: |
| 481 | return copy_to_user(buf, in, sizeof(*in)); |
| 482 | case IPC_OLD: |
| 483 | { |
| 484 | struct shmid_ds out; |
| 485 | |
| 486 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); |
| 487 | out.shm_segsz = in->shm_segsz; |
| 488 | out.shm_atime = in->shm_atime; |
| 489 | out.shm_dtime = in->shm_dtime; |
| 490 | out.shm_ctime = in->shm_ctime; |
| 491 | out.shm_cpid = in->shm_cpid; |
| 492 | out.shm_lpid = in->shm_lpid; |
| 493 | out.shm_nattch = in->shm_nattch; |
| 494 | |
| 495 | return copy_to_user(buf, &out, sizeof(out)); |
| 496 | } |
| 497 | default: |
| 498 | return -EINVAL; |
| 499 | } |
| 500 | } |
| 501 | |
| 502 | static inline unsigned long |
| 503 | copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) |
| 504 | { |
| 505 | switch(version) { |
| 506 | case IPC_64: |
| 507 | if (copy_from_user(out, buf, sizeof(*out))) |
| 508 | return -EFAULT; |
| 509 | return 0; |
| 510 | case IPC_OLD: |
| 511 | { |
| 512 | struct shmid_ds tbuf_old; |
| 513 | |
| 514 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) |
| 515 | return -EFAULT; |
| 516 | |
| 517 | out->shm_perm.uid = tbuf_old.shm_perm.uid; |
| 518 | out->shm_perm.gid = tbuf_old.shm_perm.gid; |
| 519 | out->shm_perm.mode = tbuf_old.shm_perm.mode; |
| 520 | |
| 521 | return 0; |
| 522 | } |
| 523 | default: |
| 524 | return -EINVAL; |
| 525 | } |
| 526 | } |
| 527 | |
| 528 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) |
| 529 | { |
| 530 | switch(version) { |
| 531 | case IPC_64: |
| 532 | return copy_to_user(buf, in, sizeof(*in)); |
| 533 | case IPC_OLD: |
| 534 | { |
| 535 | struct shminfo out; |
| 536 | |
| 537 | if(in->shmmax > INT_MAX) |
| 538 | out.shmmax = INT_MAX; |
| 539 | else |
| 540 | out.shmmax = (int)in->shmmax; |
| 541 | |
| 542 | out.shmmin = in->shmmin; |
| 543 | out.shmmni = in->shmmni; |
| 544 | out.shmseg = in->shmseg; |
| 545 | out.shmall = in->shmall; |
| 546 | |
| 547 | return copy_to_user(buf, &out, sizeof(out)); |
| 548 | } |
| 549 | default: |
| 550 | return -EINVAL; |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | /* |
| 555 | * Called with shm_ids.rw_mutex held as a reader |
| 556 | */ |
| 557 | static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, |
| 558 | unsigned long *swp) |
| 559 | { |
| 560 | int next_id; |
| 561 | int total, in_use; |
| 562 | |
| 563 | *rss = 0; |
| 564 | *swp = 0; |
| 565 | |
| 566 | in_use = shm_ids(ns).in_use; |
| 567 | |
| 568 | for (total = 0, next_id = 0; total < in_use; next_id++) { |
| 569 | struct shmid_kernel *shp; |
| 570 | struct inode *inode; |
| 571 | |
| 572 | shp = idr_find(&shm_ids(ns).ipcs_idr, next_id); |
| 573 | if (shp == NULL) |
| 574 | continue; |
| 575 | |
| 576 | inode = shp->shm_file->f_path.dentry->d_inode; |
| 577 | |
| 578 | if (is_file_hugepages(shp->shm_file)) { |
| 579 | struct address_space *mapping = inode->i_mapping; |
| 580 | struct hstate *h = hstate_file(shp->shm_file); |
| 581 | *rss += pages_per_huge_page(h) * mapping->nrpages; |
| 582 | } else { |
| 583 | struct shmem_inode_info *info = SHMEM_I(inode); |
| 584 | spin_lock(&info->lock); |
| 585 | *rss += inode->i_mapping->nrpages; |
| 586 | *swp += info->swapped; |
| 587 | spin_unlock(&info->lock); |
| 588 | } |
| 589 | |
| 590 | total++; |
| 591 | } |
| 592 | } |
| 593 | |
| 594 | /* |
| 595 | * This function handles some shmctl commands which require the rw_mutex |
| 596 | * to be held in write mode. |
| 597 | * NOTE: no locks must be held, the rw_mutex is taken inside this function. |
| 598 | */ |
| 599 | static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, |
| 600 | struct shmid_ds __user *buf, int version) |
| 601 | { |
| 602 | struct kern_ipc_perm *ipcp; |
| 603 | struct shmid64_ds shmid64; |
| 604 | struct shmid_kernel *shp; |
| 605 | int err; |
| 606 | |
| 607 | if (cmd == IPC_SET) { |
| 608 | if (copy_shmid_from_user(&shmid64, buf, version)) |
| 609 | return -EFAULT; |
| 610 | } |
| 611 | |
| 612 | ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0); |
| 613 | if (IS_ERR(ipcp)) |
| 614 | return PTR_ERR(ipcp); |
| 615 | |
| 616 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
| 617 | |
| 618 | err = security_shm_shmctl(shp, cmd); |
| 619 | if (err) |
| 620 | goto out_unlock; |
| 621 | switch (cmd) { |
| 622 | case IPC_RMID: |
| 623 | do_shm_rmid(ns, ipcp); |
| 624 | goto out_up; |
| 625 | case IPC_SET: |
| 626 | ipc_update_perm(&shmid64.shm_perm, ipcp); |
| 627 | shp->shm_ctim = get_seconds(); |
| 628 | break; |
| 629 | default: |
| 630 | err = -EINVAL; |
| 631 | } |
| 632 | out_unlock: |
| 633 | shm_unlock(shp); |
| 634 | out_up: |
| 635 | up_write(&shm_ids(ns).rw_mutex); |
| 636 | return err; |
| 637 | } |
| 638 | |
| 639 | asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf) |
| 640 | { |
| 641 | struct shmid_kernel *shp; |
| 642 | int err, version; |
| 643 | struct ipc_namespace *ns; |
| 644 | |
| 645 | if (cmd < 0 || shmid < 0) { |
| 646 | err = -EINVAL; |
| 647 | goto out; |
| 648 | } |
| 649 | |
| 650 | version = ipc_parse_version(&cmd); |
| 651 | ns = current->nsproxy->ipc_ns; |
| 652 | |
| 653 | switch (cmd) { /* replace with proc interface ? */ |
| 654 | case IPC_INFO: |
| 655 | { |
| 656 | struct shminfo64 shminfo; |
| 657 | |
| 658 | err = security_shm_shmctl(NULL, cmd); |
| 659 | if (err) |
| 660 | return err; |
| 661 | |
| 662 | memset(&shminfo,0,sizeof(shminfo)); |
| 663 | shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; |
| 664 | shminfo.shmmax = ns->shm_ctlmax; |
| 665 | shminfo.shmall = ns->shm_ctlall; |
| 666 | |
| 667 | shminfo.shmmin = SHMMIN; |
| 668 | if(copy_shminfo_to_user (buf, &shminfo, version)) |
| 669 | return -EFAULT; |
| 670 | |
| 671 | down_read(&shm_ids(ns).rw_mutex); |
| 672 | err = ipc_get_maxid(&shm_ids(ns)); |
| 673 | up_read(&shm_ids(ns).rw_mutex); |
| 674 | |
| 675 | if(err<0) |
| 676 | err = 0; |
| 677 | goto out; |
| 678 | } |
| 679 | case SHM_INFO: |
| 680 | { |
| 681 | struct shm_info shm_info; |
| 682 | |
| 683 | err = security_shm_shmctl(NULL, cmd); |
| 684 | if (err) |
| 685 | return err; |
| 686 | |
| 687 | memset(&shm_info,0,sizeof(shm_info)); |
| 688 | down_read(&shm_ids(ns).rw_mutex); |
| 689 | shm_info.used_ids = shm_ids(ns).in_use; |
| 690 | shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); |
| 691 | shm_info.shm_tot = ns->shm_tot; |
| 692 | shm_info.swap_attempts = 0; |
| 693 | shm_info.swap_successes = 0; |
| 694 | err = ipc_get_maxid(&shm_ids(ns)); |
| 695 | up_read(&shm_ids(ns).rw_mutex); |
| 696 | if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { |
| 697 | err = -EFAULT; |
| 698 | goto out; |
| 699 | } |
| 700 | |
| 701 | err = err < 0 ? 0 : err; |
| 702 | goto out; |
| 703 | } |
| 704 | case SHM_STAT: |
| 705 | case IPC_STAT: |
| 706 | { |
| 707 | struct shmid64_ds tbuf; |
| 708 | int result; |
| 709 | |
| 710 | if (!buf) { |
| 711 | err = -EFAULT; |
| 712 | goto out; |
| 713 | } |
| 714 | |
| 715 | if (cmd == SHM_STAT) { |
| 716 | shp = shm_lock(ns, shmid); |
| 717 | if (IS_ERR(shp)) { |
| 718 | err = PTR_ERR(shp); |
| 719 | goto out; |
| 720 | } |
| 721 | result = shp->shm_perm.id; |
| 722 | } else { |
| 723 | shp = shm_lock_check(ns, shmid); |
| 724 | if (IS_ERR(shp)) { |
| 725 | err = PTR_ERR(shp); |
| 726 | goto out; |
| 727 | } |
| 728 | result = 0; |
| 729 | } |
| 730 | err=-EACCES; |
| 731 | if (ipcperms (&shp->shm_perm, S_IRUGO)) |
| 732 | goto out_unlock; |
| 733 | err = security_shm_shmctl(shp, cmd); |
| 734 | if (err) |
| 735 | goto out_unlock; |
| 736 | memset(&tbuf, 0, sizeof(tbuf)); |
| 737 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); |
| 738 | tbuf.shm_segsz = shp->shm_segsz; |
| 739 | tbuf.shm_atime = shp->shm_atim; |
| 740 | tbuf.shm_dtime = shp->shm_dtim; |
| 741 | tbuf.shm_ctime = shp->shm_ctim; |
| 742 | tbuf.shm_cpid = shp->shm_cprid; |
| 743 | tbuf.shm_lpid = shp->shm_lprid; |
| 744 | tbuf.shm_nattch = shp->shm_nattch; |
| 745 | shm_unlock(shp); |
| 746 | if(copy_shmid_to_user (buf, &tbuf, version)) |
| 747 | err = -EFAULT; |
| 748 | else |
| 749 | err = result; |
| 750 | goto out; |
| 751 | } |
| 752 | case SHM_LOCK: |
| 753 | case SHM_UNLOCK: |
| 754 | { |
| 755 | shp = shm_lock_check(ns, shmid); |
| 756 | if (IS_ERR(shp)) { |
| 757 | err = PTR_ERR(shp); |
| 758 | goto out; |
| 759 | } |
| 760 | |
| 761 | err = audit_ipc_obj(&(shp->shm_perm)); |
| 762 | if (err) |
| 763 | goto out_unlock; |
| 764 | |
| 765 | if (!capable(CAP_IPC_LOCK)) { |
| 766 | err = -EPERM; |
| 767 | if (current->euid != shp->shm_perm.uid && |
| 768 | current->euid != shp->shm_perm.cuid) |
| 769 | goto out_unlock; |
| 770 | if (cmd == SHM_LOCK && |
| 771 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) |
| 772 | goto out_unlock; |
| 773 | } |
| 774 | |
| 775 | err = security_shm_shmctl(shp, cmd); |
| 776 | if (err) |
| 777 | goto out_unlock; |
| 778 | |
| 779 | if(cmd==SHM_LOCK) { |
| 780 | struct user_struct * user = current->user; |
| 781 | if (!is_file_hugepages(shp->shm_file)) { |
| 782 | err = shmem_lock(shp->shm_file, 1, user); |
| 783 | if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ |
| 784 | shp->shm_perm.mode |= SHM_LOCKED; |
| 785 | shp->mlock_user = user; |
| 786 | } |
| 787 | } |
| 788 | } else if (!is_file_hugepages(shp->shm_file)) { |
| 789 | shmem_lock(shp->shm_file, 0, shp->mlock_user); |
| 790 | shp->shm_perm.mode &= ~SHM_LOCKED; |
| 791 | shp->mlock_user = NULL; |
| 792 | } |
| 793 | shm_unlock(shp); |
| 794 | goto out; |
| 795 | } |
| 796 | case IPC_RMID: |
| 797 | case IPC_SET: |
| 798 | err = shmctl_down(ns, shmid, cmd, buf, version); |
| 799 | return err; |
| 800 | default: |
| 801 | return -EINVAL; |
| 802 | } |
| 803 | |
| 804 | out_unlock: |
| 805 | shm_unlock(shp); |
| 806 | out: |
| 807 | return err; |
| 808 | } |
| 809 | |
| 810 | /* |
| 811 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. |
| 812 | * |
| 813 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The |
| 814 | * "raddr" thing points to kernel space, and there has to be a wrapper around |
| 815 | * this. |
| 816 | */ |
| 817 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) |
| 818 | { |
| 819 | struct shmid_kernel *shp; |
| 820 | unsigned long addr; |
| 821 | unsigned long size; |
| 822 | struct file * file; |
| 823 | int err; |
| 824 | unsigned long flags; |
| 825 | unsigned long prot; |
| 826 | int acc_mode; |
| 827 | unsigned long user_addr; |
| 828 | struct ipc_namespace *ns; |
| 829 | struct shm_file_data *sfd; |
| 830 | struct path path; |
| 831 | mode_t f_mode; |
| 832 | |
| 833 | err = -EINVAL; |
| 834 | if (shmid < 0) |
| 835 | goto out; |
| 836 | else if ((addr = (ulong)shmaddr)) { |
| 837 | if (addr & (SHMLBA-1)) { |
| 838 | if (shmflg & SHM_RND) |
| 839 | addr &= ~(SHMLBA-1); /* round down */ |
| 840 | else |
| 841 | #ifndef __ARCH_FORCE_SHMLBA |
| 842 | if (addr & ~PAGE_MASK) |
| 843 | #endif |
| 844 | goto out; |
| 845 | } |
| 846 | flags = MAP_SHARED | MAP_FIXED; |
| 847 | } else { |
| 848 | if ((shmflg & SHM_REMAP)) |
| 849 | goto out; |
| 850 | |
| 851 | flags = MAP_SHARED; |
| 852 | } |
| 853 | |
| 854 | if (shmflg & SHM_RDONLY) { |
| 855 | prot = PROT_READ; |
| 856 | acc_mode = S_IRUGO; |
| 857 | f_mode = FMODE_READ; |
| 858 | } else { |
| 859 | prot = PROT_READ | PROT_WRITE; |
| 860 | acc_mode = S_IRUGO | S_IWUGO; |
| 861 | f_mode = FMODE_READ | FMODE_WRITE; |
| 862 | } |
| 863 | if (shmflg & SHM_EXEC) { |
| 864 | prot |= PROT_EXEC; |
| 865 | acc_mode |= S_IXUGO; |
| 866 | } |
| 867 | |
| 868 | /* |
| 869 | * We cannot rely on the fs check since SYSV IPC does have an |
| 870 | * additional creator id... |
| 871 | */ |
| 872 | ns = current->nsproxy->ipc_ns; |
| 873 | shp = shm_lock_check(ns, shmid); |
| 874 | if (IS_ERR(shp)) { |
| 875 | err = PTR_ERR(shp); |
| 876 | goto out; |
| 877 | } |
| 878 | |
| 879 | err = -EACCES; |
| 880 | if (ipcperms(&shp->shm_perm, acc_mode)) |
| 881 | goto out_unlock; |
| 882 | |
| 883 | err = security_shm_shmat(shp, shmaddr, shmflg); |
| 884 | if (err) |
| 885 | goto out_unlock; |
| 886 | |
| 887 | path.dentry = dget(shp->shm_file->f_path.dentry); |
| 888 | path.mnt = shp->shm_file->f_path.mnt; |
| 889 | shp->shm_nattch++; |
| 890 | size = i_size_read(path.dentry->d_inode); |
| 891 | shm_unlock(shp); |
| 892 | |
| 893 | err = -ENOMEM; |
| 894 | sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); |
| 895 | if (!sfd) |
| 896 | goto out_put_dentry; |
| 897 | |
| 898 | file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations); |
| 899 | if (!file) |
| 900 | goto out_free; |
| 901 | |
| 902 | file->private_data = sfd; |
| 903 | file->f_mapping = shp->shm_file->f_mapping; |
| 904 | sfd->id = shp->shm_perm.id; |
| 905 | sfd->ns = get_ipc_ns(ns); |
| 906 | sfd->file = shp->shm_file; |
| 907 | sfd->vm_ops = NULL; |
| 908 | |
| 909 | down_write(¤t->mm->mmap_sem); |
| 910 | if (addr && !(shmflg & SHM_REMAP)) { |
| 911 | err = -EINVAL; |
| 912 | if (find_vma_intersection(current->mm, addr, addr + size)) |
| 913 | goto invalid; |
| 914 | /* |
| 915 | * If shm segment goes below stack, make sure there is some |
| 916 | * space left for the stack to grow (at least 4 pages). |
| 917 | */ |
| 918 | if (addr < current->mm->start_stack && |
| 919 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) |
| 920 | goto invalid; |
| 921 | } |
| 922 | |
| 923 | user_addr = do_mmap (file, addr, size, prot, flags, 0); |
| 924 | *raddr = user_addr; |
| 925 | err = 0; |
| 926 | if (IS_ERR_VALUE(user_addr)) |
| 927 | err = (long)user_addr; |
| 928 | invalid: |
| 929 | up_write(¤t->mm->mmap_sem); |
| 930 | |
| 931 | fput(file); |
| 932 | |
| 933 | out_nattch: |
| 934 | down_write(&shm_ids(ns).rw_mutex); |
| 935 | shp = shm_lock_down(ns, shmid); |
| 936 | BUG_ON(IS_ERR(shp)); |
| 937 | shp->shm_nattch--; |
| 938 | if(shp->shm_nattch == 0 && |
| 939 | shp->shm_perm.mode & SHM_DEST) |
| 940 | shm_destroy(ns, shp); |
| 941 | else |
| 942 | shm_unlock(shp); |
| 943 | up_write(&shm_ids(ns).rw_mutex); |
| 944 | |
| 945 | out: |
| 946 | return err; |
| 947 | |
| 948 | out_unlock: |
| 949 | shm_unlock(shp); |
| 950 | goto out; |
| 951 | |
| 952 | out_free: |
| 953 | kfree(sfd); |
| 954 | out_put_dentry: |
| 955 | dput(path.dentry); |
| 956 | goto out_nattch; |
| 957 | } |
| 958 | |
| 959 | asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) |
| 960 | { |
| 961 | unsigned long ret; |
| 962 | long err; |
| 963 | |
| 964 | err = do_shmat(shmid, shmaddr, shmflg, &ret); |
| 965 | if (err) |
| 966 | return err; |
| 967 | force_successful_syscall_return(); |
| 968 | return (long)ret; |
| 969 | } |
| 970 | |
| 971 | /* |
| 972 | * detach and kill segment if marked destroyed. |
| 973 | * The work is done in shm_close. |
| 974 | */ |
| 975 | asmlinkage long sys_shmdt(char __user *shmaddr) |
| 976 | { |
| 977 | struct mm_struct *mm = current->mm; |
| 978 | struct vm_area_struct *vma, *next; |
| 979 | unsigned long addr = (unsigned long)shmaddr; |
| 980 | loff_t size = 0; |
| 981 | int retval = -EINVAL; |
| 982 | |
| 983 | if (addr & ~PAGE_MASK) |
| 984 | return retval; |
| 985 | |
| 986 | down_write(&mm->mmap_sem); |
| 987 | |
| 988 | /* |
| 989 | * This function tries to be smart and unmap shm segments that |
| 990 | * were modified by partial mlock or munmap calls: |
| 991 | * - It first determines the size of the shm segment that should be |
| 992 | * unmapped: It searches for a vma that is backed by shm and that |
| 993 | * started at address shmaddr. It records it's size and then unmaps |
| 994 | * it. |
| 995 | * - Then it unmaps all shm vmas that started at shmaddr and that |
| 996 | * are within the initially determined size. |
| 997 | * Errors from do_munmap are ignored: the function only fails if |
| 998 | * it's called with invalid parameters or if it's called to unmap |
| 999 | * a part of a vma. Both calls in this function are for full vmas, |
| 1000 | * the parameters are directly copied from the vma itself and always |
| 1001 | * valid - therefore do_munmap cannot fail. (famous last words?) |
| 1002 | */ |
| 1003 | /* |
| 1004 | * If it had been mremap()'d, the starting address would not |
| 1005 | * match the usual checks anyway. So assume all vma's are |
| 1006 | * above the starting address given. |
| 1007 | */ |
| 1008 | vma = find_vma(mm, addr); |
| 1009 | |
| 1010 | while (vma) { |
| 1011 | next = vma->vm_next; |
| 1012 | |
| 1013 | /* |
| 1014 | * Check if the starting address would match, i.e. it's |
| 1015 | * a fragment created by mprotect() and/or munmap(), or it |
| 1016 | * otherwise it starts at this address with no hassles. |
| 1017 | */ |
| 1018 | if ((vma->vm_ops == &shm_vm_ops) && |
| 1019 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { |
| 1020 | |
| 1021 | |
| 1022 | size = vma->vm_file->f_path.dentry->d_inode->i_size; |
| 1023 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| 1024 | /* |
| 1025 | * We discovered the size of the shm segment, so |
| 1026 | * break out of here and fall through to the next |
| 1027 | * loop that uses the size information to stop |
| 1028 | * searching for matching vma's. |
| 1029 | */ |
| 1030 | retval = 0; |
| 1031 | vma = next; |
| 1032 | break; |
| 1033 | } |
| 1034 | vma = next; |
| 1035 | } |
| 1036 | |
| 1037 | /* |
| 1038 | * We need look no further than the maximum address a fragment |
| 1039 | * could possibly have landed at. Also cast things to loff_t to |
| 1040 | * prevent overflows and make comparisions vs. equal-width types. |
| 1041 | */ |
| 1042 | size = PAGE_ALIGN(size); |
| 1043 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { |
| 1044 | next = vma->vm_next; |
| 1045 | |
| 1046 | /* finding a matching vma now does not alter retval */ |
| 1047 | if ((vma->vm_ops == &shm_vm_ops) && |
| 1048 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) |
| 1049 | |
| 1050 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| 1051 | vma = next; |
| 1052 | } |
| 1053 | |
| 1054 | up_write(&mm->mmap_sem); |
| 1055 | return retval; |
| 1056 | } |
| 1057 | |
| 1058 | #ifdef CONFIG_PROC_FS |
| 1059 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
| 1060 | { |
| 1061 | struct shmid_kernel *shp = it; |
| 1062 | |
| 1063 | #if BITS_PER_LONG <= 32 |
| 1064 | #define SIZE_SPEC "%10lu" |
| 1065 | #else |
| 1066 | #define SIZE_SPEC "%21lu" |
| 1067 | #endif |
| 1068 | |
| 1069 | return seq_printf(s, |
| 1070 | "%10d %10d %4o " SIZE_SPEC " %5u %5u " |
| 1071 | "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n", |
| 1072 | shp->shm_perm.key, |
| 1073 | shp->shm_perm.id, |
| 1074 | shp->shm_perm.mode, |
| 1075 | shp->shm_segsz, |
| 1076 | shp->shm_cprid, |
| 1077 | shp->shm_lprid, |
| 1078 | shp->shm_nattch, |
| 1079 | shp->shm_perm.uid, |
| 1080 | shp->shm_perm.gid, |
| 1081 | shp->shm_perm.cuid, |
| 1082 | shp->shm_perm.cgid, |
| 1083 | shp->shm_atim, |
| 1084 | shp->shm_dtim, |
| 1085 | shp->shm_ctim); |
| 1086 | } |
| 1087 | #endif |