1 /* 2 * linux/fs/exec.c 3 * 4 * Copyright (C) 1991, 1992 Linus Torvalds 5 */ 6 7 /* 8 * #!-checking implemented by tytso. 9 */ 10 /* 11 * Demand-loading implemented 01.12.91 - no need to read anything but 12 * the header into memory. The inode of the executable is put into 13 * "current->executable", and page faults do the actual loading. Clean. 14 * 15 * Once more I can proudly say that linux stood up to being changed: it 16 * was less than 2 hours work to get demand-loading completely implemented. 17 * 18 * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, 19 * current->executable is only used by the procfs. This allows a dispatch 20 * table to check for several different types of binary formats. We keep 21 * trying until we recognize the file or we run out of supported binary 22 * formats. 23 */ 24 25 #include <linux/slab.h> 26 #include <linux/file.h> 27 #include <linux/mman.h> 28 #include <linux/a.out.h> 29 #include <linux/stat.h> 30 #include <linux/fcntl.h> 31 #include <linux/smp_lock.h> 32 #include <linux/init.h> 33 #include <linux/pagemap.h> 34 #include <linux/highmem.h> 35 #include <linux/spinlock.h> 36 #include <linux/key.h> 37 #include <linux/personality.h> 38 #include <linux/binfmts.h> 39 #include <linux/swap.h> 40 #include <linux/utsname.h> 41 #include <linux/pid_namespace.h> 42 #include <linux/module.h> 43 #include <linux/namei.h> 44 #include <linux/proc_fs.h> 45 #include <linux/ptrace.h> 46 #include <linux/mount.h> 47 #include <linux/security.h> 48 #include <linux/syscalls.h> 49 #include <linux/rmap.h> 50 #include <linux/tsacct_kern.h> 51 #include <linux/cn_proc.h> 52 #include <linux/audit.h> 53 #include <linux/signalfd.h> 54 55 #include <asm/uaccess.h> 56 #include <asm/mmu_context.h> 57 58 #ifdef CONFIG_KMOD 59 #include <linux/kmod.h> 60 #endif 61 62 int core_uses_pid; 63 char core_pattern[128] = "core"; 64 int suid_dumpable = 0; 65 66 EXPORT_SYMBOL(suid_dumpable); 67 /* The maximal length of core_pattern is also specified in sysctl.c */ 68 69 static struct linux_binfmt *formats; 70 static DEFINE_RWLOCK(binfmt_lock); 71 72 int register_binfmt(struct linux_binfmt * fmt) 73 { 74 struct linux_binfmt ** tmp = &formats; 75 76 if (!fmt) 77 return -EINVAL; 78 if (fmt->next) 79 return -EBUSY; 80 write_lock(&binfmt_lock); 81 while (*tmp) { 82 if (fmt == *tmp) { 83 write_unlock(&binfmt_lock); 84 return -EBUSY; 85 } 86 tmp = &(*tmp)->next; 87 } 88 fmt->next = formats; 89 formats = fmt; 90 write_unlock(&binfmt_lock); 91 return 0; 92 } 93 94 EXPORT_SYMBOL(register_binfmt); 95 96 int unregister_binfmt(struct linux_binfmt * fmt) 97 { 98 struct linux_binfmt ** tmp = &formats; 99 100 write_lock(&binfmt_lock); 101 while (*tmp) { 102 if (fmt == *tmp) { 103 *tmp = fmt->next; 104 fmt->next = NULL; 105 write_unlock(&binfmt_lock); 106 return 0; 107 } 108 tmp = &(*tmp)->next; 109 } 110 write_unlock(&binfmt_lock); 111 return -EINVAL; 112 } 113 114 EXPORT_SYMBOL(unregister_binfmt); 115 116 static inline void put_binfmt(struct linux_binfmt * fmt) 117 { 118 module_put(fmt->module); 119 } 120 121 /* 122 * Note that a shared library must be both readable and executable due to 123 * security reasons. 124 * 125 * Also note that we take the address to load from from the file itself. 126 */ 127 asmlinkage long sys_uselib(const char __user * library) 128 { 129 struct file * file; 130 struct nameidata nd; 131 int error; 132 133 error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); 134 if (error) 135 goto out; 136 137 error = -EINVAL; 138 if (!S_ISREG(nd.dentry->d_inode->i_mode)) 139 goto exit; 140 141 error = vfs_permission(&nd, MAY_READ | MAY_EXEC); 142 if (error) 143 goto exit; 144 145 file = nameidata_to_filp(&nd, O_RDONLY); 146 error = PTR_ERR(file); 147 if (IS_ERR(file)) 148 goto out; 149 150 error = -ENOEXEC; 151 if(file->f_op) { 152 struct linux_binfmt * fmt; 153 154 read_lock(&binfmt_lock); 155 for (fmt = formats ; fmt ; fmt = fmt->next) { 156 if (!fmt->load_shlib) 157 continue; 158 if (!try_module_get(fmt->module)) 159 continue; 160 read_unlock(&binfmt_lock); 161 error = fmt->load_shlib(file); 162 read_lock(&binfmt_lock); 163 put_binfmt(fmt); 164 if (error != -ENOEXEC) 165 break; 166 } 167 read_unlock(&binfmt_lock); 168 } 169 fput(file); 170 out: 171 return error; 172 exit: 173 release_open_intent(&nd); 174 path_release(&nd); 175 goto out; 176 } 177 178 /* 179 * count() counts the number of strings in array ARGV. 180 */ 181 static int count(char __user * __user * argv, int max) 182 { 183 int i = 0; 184 185 if (argv != NULL) { 186 for (;;) { 187 char __user * p; 188 189 if (get_user(p, argv)) 190 return -EFAULT; 191 if (!p) 192 break; 193 argv++; 194 if(++i > max) 195 return -E2BIG; 196 cond_resched(); 197 } 198 } 199 return i; 200 } 201 202 /* 203 * 'copy_strings()' copies argument/environment strings from user 204 * memory to free pages in kernel mem. These are in a format ready 205 * to be put directly into the top of new user memory. 206 */ 207 static int copy_strings(int argc, char __user * __user * argv, 208 struct linux_binprm *bprm) 209 { 210 struct page *kmapped_page = NULL; 211 char *kaddr = NULL; 212 int ret; 213 214 while (argc-- > 0) { 215 char __user *str; 216 int len; 217 unsigned long pos; 218 219 if (get_user(str, argv+argc) || 220 !(len = strnlen_user(str, bprm->p))) { 221 ret = -EFAULT; 222 goto out; 223 } 224 225 if (bprm->p < len) { 226 ret = -E2BIG; 227 goto out; 228 } 229 230 bprm->p -= len; 231 /* XXX: add architecture specific overflow check here. */ 232 pos = bprm->p; 233 234 while (len > 0) { 235 int i, new, err; 236 int offset, bytes_to_copy; 237 struct page *page; 238 239 offset = pos % PAGE_SIZE; 240 i = pos/PAGE_SIZE; 241 page = bprm->page[i]; 242 new = 0; 243 if (!page) { 244 page = alloc_page(GFP_HIGHUSER); 245 bprm->page[i] = page; 246 if (!page) { 247 ret = -ENOMEM; 248 goto out; 249 } 250 new = 1; 251 } 252 253 if (page != kmapped_page) { 254 if (kmapped_page) 255 kunmap(kmapped_page); 256 kmapped_page = page; 257 kaddr = kmap(kmapped_page); 258 } 259 if (new && offset) 260 memset(kaddr, 0, offset); 261 bytes_to_copy = PAGE_SIZE - offset; 262 if (bytes_to_copy > len) { 263 bytes_to_copy = len; 264 if (new) 265 memset(kaddr+offset+len, 0, 266 PAGE_SIZE-offset-len); 267 } 268 err = copy_from_user(kaddr+offset, str, bytes_to_copy); 269 if (err) { 270 ret = -EFAULT; 271 goto out; 272 } 273 274 pos += bytes_to_copy; 275 str += bytes_to_copy; 276 len -= bytes_to_copy; 277 } 278 } 279 ret = 0; 280 out: 281 if (kmapped_page) 282 kunmap(kmapped_page); 283 return ret; 284 } 285 286 /* 287 * Like copy_strings, but get argv and its values from kernel memory. 288 */ 289 int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) 290 { 291 int r; 292 mm_segment_t oldfs = get_fs(); 293 set_fs(KERNEL_DS); 294 r = copy_strings(argc, (char __user * __user *)argv, bprm); 295 set_fs(oldfs); 296 return r; 297 } 298 299 EXPORT_SYMBOL(copy_strings_kernel); 300 301 #ifdef CONFIG_MMU 302 /* 303 * This routine is used to map in a page into an address space: needed by 304 * execve() for the initial stack and environment pages. 305 * 306 * vma->vm_mm->mmap_sem is held for writing. 307 */ 308 void install_arg_page(struct vm_area_struct *vma, 309 struct page *page, unsigned long address) 310 { 311 struct mm_struct *mm = vma->vm_mm; 312 pte_t * pte; 313 spinlock_t *ptl; 314 315 if (unlikely(anon_vma_prepare(vma))) 316 goto out; 317 318 flush_dcache_page(page); 319 pte = get_locked_pte(mm, address, &ptl); 320 if (!pte) 321 goto out; 322 if (!pte_none(*pte)) { 323 pte_unmap_unlock(pte, ptl); 324 goto out; 325 } 326 inc_mm_counter(mm, anon_rss); 327 lru_cache_add_active(page); 328 set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte( 329 page, vma->vm_page_prot)))); 330 page_add_new_anon_rmap(page, vma, address); 331 pte_unmap_unlock(pte, ptl); 332 333 /* no need for flush_tlb */ 334 return; 335 out: 336 __free_page(page); 337 force_sig(SIGKILL, current); 338 } 339 340 #define EXTRA_STACK_VM_PAGES 20 /* random */ 341 342 int setup_arg_pages(struct linux_binprm *bprm, 343 unsigned long stack_top, 344 int executable_stack) 345 { 346 unsigned long stack_base; 347 struct vm_area_struct *mpnt; 348 struct mm_struct *mm = current->mm; 349 int i, ret; 350 long arg_size; 351 352 #ifdef CONFIG_STACK_GROWSUP 353 /* Move the argument and environment strings to the bottom of the 354 * stack space. 355 */ 356 int offset, j; 357 char *to, *from; 358 359 /* Start by shifting all the pages down */ 360 i = 0; 361 for (j = 0; j < MAX_ARG_PAGES; j++) { 362 struct page *page = bprm->page[j]; 363 if (!page) 364 continue; 365 bprm->page[i++] = page; 366 } 367 368 /* Now move them within their pages */ 369 offset = bprm->p % PAGE_SIZE; 370 to = kmap(bprm->page[0]); 371 for (j = 1; j < i; j++) { 372 memmove(to, to + offset, PAGE_SIZE - offset); 373 from = kmap(bprm->page[j]); 374 memcpy(to + PAGE_SIZE - offset, from, offset); 375 kunmap(bprm->page[j - 1]); 376 to = from; 377 } 378 memmove(to, to + offset, PAGE_SIZE - offset); 379 kunmap(bprm->page[j - 1]); 380 381 /* Limit stack size to 1GB */ 382 stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; 383 if (stack_base > (1 << 30)) 384 stack_base = 1 << 30; 385 stack_base = PAGE_ALIGN(stack_top - stack_base); 386 387 /* Adjust bprm->p to point to the end of the strings. */ 388 bprm->p = stack_base + PAGE_SIZE * i - offset; 389 390 mm->arg_start = stack_base; 391 arg_size = i << PAGE_SHIFT; 392 393 /* zero pages that were copied above */ 394 while (i < MAX_ARG_PAGES) 395 bprm->page[i++] = NULL; 396 #else 397 stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE); 398 stack_base = PAGE_ALIGN(stack_base); 399 bprm->p += stack_base; 400 mm->arg_start = bprm->p; 401 arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start); 402 #endif 403 404 arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE; 405 406 if (bprm->loader) 407 bprm->loader += stack_base; 408 bprm->exec += stack_base; 409 410 mpnt = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); 411 if (!mpnt) 412 return -ENOMEM; 413 414 down_write(&mm->mmap_sem); 415 { 416 mpnt->vm_mm = mm; 417 #ifdef CONFIG_STACK_GROWSUP 418 mpnt->vm_start = stack_base; 419 mpnt->vm_end = stack_base + arg_size; 420 #else 421 mpnt->vm_end = stack_top; 422 mpnt->vm_start = mpnt->vm_end - arg_size; 423 #endif 424 /* Adjust stack execute permissions; explicitly enable 425 * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X 426 * and leave alone (arch default) otherwise. */ 427 if (unlikely(executable_stack == EXSTACK_ENABLE_X)) 428 mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC; 429 else if (executable_stack == EXSTACK_DISABLE_X) 430 mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC; 431 else 432 mpnt->vm_flags = VM_STACK_FLAGS; 433 mpnt->vm_flags |= mm->def_flags; 434 mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7]; 435 if ((ret = insert_vm_struct(mm, mpnt))) { 436 up_write(&mm->mmap_sem); 437 kmem_cache_free(vm_area_cachep, mpnt); 438 return ret; 439 } 440 mm->stack_vm = mm->total_vm = vma_pages(mpnt); 441 } 442 443 for (i = 0 ; i < MAX_ARG_PAGES ; i++) { 444 struct page *page = bprm->page[i]; 445 if (page) { 446 bprm->page[i] = NULL; 447 install_arg_page(mpnt, page, stack_base); 448 } 449 stack_base += PAGE_SIZE; 450 } 451 up_write(&mm->mmap_sem); 452 453 return 0; 454 } 455 456 EXPORT_SYMBOL(setup_arg_pages); 457 458 #define free_arg_pages(bprm) do { } while (0) 459 460 #else 461 462 static inline void free_arg_pages(struct linux_binprm *bprm) 463 { 464 int i; 465 466 for (i = 0; i < MAX_ARG_PAGES; i++) { 467 if (bprm->page[i]) 468 __free_page(bprm->page[i]); 469 bprm->page[i] = NULL; 470 } 471 } 472 473 #endif /* CONFIG_MMU */ 474 475 struct file *open_exec(const char *name) 476 { 477 struct nameidata nd; 478 int err; 479 struct file *file; 480 481 err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); 482 file = ERR_PTR(err); 483 484 if (!err) { 485 struct inode *inode = nd.dentry->d_inode; 486 file = ERR_PTR(-EACCES); 487 if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && 488 S_ISREG(inode->i_mode)) { 489 int err = vfs_permission(&nd, MAY_EXEC); 490 file = ERR_PTR(err); 491 if (!err) { 492 file = nameidata_to_filp(&nd, O_RDONLY); 493 if (!IS_ERR(file)) { 494 err = deny_write_access(file); 495 if (err) { 496 fput(file); 497 file = ERR_PTR(err); 498 } 499 } 500 out: 501 return file; 502 } 503 } 504 release_open_intent(&nd); 505 path_release(&nd); 506 } 507 goto out; 508 } 509 510 EXPORT_SYMBOL(open_exec); 511 512 int kernel_read(struct file *file, unsigned long offset, 513 char *addr, unsigned long count) 514 { 515 mm_segment_t old_fs; 516 loff_t pos = offset; 517 int result; 518 519 old_fs = get_fs(); 520 set_fs(get_ds()); 521 /* The cast to a user pointer is valid due to the set_fs() */ 522 result = vfs_read(file, (void __user *)addr, count, &pos); 523 set_fs(old_fs); 524 return result; 525 } 526 527 EXPORT_SYMBOL(kernel_read); 528 529 static int exec_mmap(struct mm_struct *mm) 530 { 531 struct task_struct *tsk; 532 struct mm_struct * old_mm, *active_mm; 533 534 /* Notify parent that we're no longer interested in the old VM */ 535 tsk = current; 536 old_mm = current->mm; 537 mm_release(tsk, old_mm); 538 539 if (old_mm) { 540 /* 541 * Make sure that if there is a core dump in progress 542 * for the old mm, we get out and die instead of going 543 * through with the exec. We must hold mmap_sem around 544 * checking core_waiters and changing tsk->mm. The 545 * core-inducing thread will increment core_waiters for 546 * each thread whose ->mm == old_mm. 547 */ 548 down_read(&old_mm->mmap_sem); 549 if (unlikely(old_mm->core_waiters)) { 550 up_read(&old_mm->mmap_sem); 551 return -EINTR; 552 } 553 } 554 task_lock(tsk); 555 active_mm = tsk->active_mm; 556 tsk->mm = mm; 557 tsk->active_mm = mm; 558 activate_mm(active_mm, mm); 559 task_unlock(tsk); 560 arch_pick_mmap_layout(mm); 561 if (old_mm) { 562 up_read(&old_mm->mmap_sem); 563 BUG_ON(active_mm != old_mm); 564 mmput(old_mm); 565 return 0; 566 } 567 mmdrop(active_mm); 568 return 0; 569 } 570 571 /* 572 * This function makes sure the current process has its own signal table, 573 * so that flush_signal_handlers can later reset the handlers without 574 * disturbing other processes. (Other processes might share the signal 575 * table via the CLONE_SIGHAND option to clone().) 576 */ 577 static int de_thread(struct task_struct *tsk) 578 { 579 struct signal_struct *sig = tsk->signal; 580 struct sighand_struct *newsighand, *oldsighand = tsk->sighand; 581 spinlock_t *lock = &oldsighand->siglock; 582 struct task_struct *leader = NULL; 583 int count; 584 585 /* 586 * Tell all the sighand listeners that this sighand has 587 * been detached. The signalfd_detach() function grabs the 588 * sighand lock, if signal listeners are present on the sighand. 589 */ 590 signalfd_detach(tsk); 591 592 /* 593 * If we don't share sighandlers, then we aren't sharing anything 594 * and we can just re-use it all. 595 */ 596 if (atomic_read(&oldsighand->count) <= 1) { 597 BUG_ON(atomic_read(&sig->count) != 1); 598 exit_itimers(sig); 599 return 0; 600 } 601 602 newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); 603 if (!newsighand) 604 return -ENOMEM; 605 606 if (thread_group_empty(tsk)) 607 goto no_thread_group; 608 609 /* 610 * Kill all other threads in the thread group. 611 * We must hold tasklist_lock to call zap_other_threads. 612 */ 613 read_lock(&tasklist_lock); 614 spin_lock_irq(lock); 615 if (sig->flags & SIGNAL_GROUP_EXIT) { 616 /* 617 * Another group action in progress, just 618 * return so that the signal is processed. 619 */ 620 spin_unlock_irq(lock); 621 read_unlock(&tasklist_lock); 622 kmem_cache_free(sighand_cachep, newsighand); 623 return -EAGAIN; 624 } 625 626 /* 627 * child_reaper ignores SIGKILL, change it now. 628 * Reparenting needs write_lock on tasklist_lock, 629 * so it is safe to do it under read_lock. 630 */ 631 if (unlikely(tsk->group_leader == child_reaper(tsk))) 632 tsk->nsproxy->pid_ns->child_reaper = tsk; 633 634 zap_other_threads(tsk); 635 read_unlock(&tasklist_lock); 636 637 /* 638 * Account for the thread group leader hanging around: 639 */ 640 count = 1; 641 if (!thread_group_leader(tsk)) { 642 count = 2; 643 /* 644 * The SIGALRM timer survives the exec, but needs to point 645 * at us as the new group leader now. We have a race with 646 * a timer firing now getting the old leader, so we need to 647 * synchronize with any firing (by calling del_timer_sync) 648 * before we can safely let the old group leader die. 649 */ 650 sig->tsk = tsk; 651 spin_unlock_irq(lock); 652 if (hrtimer_cancel(&sig->real_timer)) 653 hrtimer_restart(&sig->real_timer); 654 spin_lock_irq(lock); 655 } 656 while (atomic_read(&sig->count) > count) { 657 sig->group_exit_task = tsk; 658 sig->notify_count = count; 659 __set_current_state(TASK_UNINTERRUPTIBLE); 660 spin_unlock_irq(lock); 661 schedule(); 662 spin_lock_irq(lock); 663 } 664 sig->group_exit_task = NULL; 665 sig->notify_count = 0; 666 spin_unlock_irq(lock); 667 668 /* 669 * At this point all other threads have exited, all we have to 670 * do is to wait for the thread group leader to become inactive, 671 * and to assume its PID: 672 */ 673 if (!thread_group_leader(tsk)) { 674 /* 675 * Wait for the thread group leader to be a zombie. 676 * It should already be zombie at this point, most 677 * of the time. 678 */ 679 leader = tsk->group_leader; 680 while (leader->exit_state != EXIT_ZOMBIE) 681 yield(); 682 683 /* 684 * The only record we have of the real-time age of a 685 * process, regardless of execs it's done, is start_time. 686 * All the past CPU time is accumulated in signal_struct 687 * from sister threads now dead. But in this non-leader 688 * exec, nothing survives from the original leader thread, 689 * whose birth marks the true age of this process now. 690 * When we take on its identity by switching to its PID, we 691 * also take its birthdate (always earlier than our own). 692 */ 693 tsk->start_time = leader->start_time; 694 695 write_lock_irq(&tasklist_lock); 696 697 BUG_ON(leader->tgid != tsk->tgid); 698 BUG_ON(tsk->pid == tsk->tgid); 699 /* 700 * An exec() starts a new thread group with the 701 * TGID of the previous thread group. Rehash the 702 * two threads with a switched PID, and release 703 * the former thread group leader: 704 */ 705 706 /* Become a process group leader with the old leader's pid. 707 * The old leader becomes a thread of the this thread group. 708 * Note: The old leader also uses this pid until release_task 709 * is called. Odd but simple and correct. 710 */ 711 detach_pid(tsk, PIDTYPE_PID); 712 tsk->pid = leader->pid; 713 attach_pid(tsk, PIDTYPE_PID, find_pid(tsk->pid)); 714 transfer_pid(leader, tsk, PIDTYPE_PGID); 715 transfer_pid(leader, tsk, PIDTYPE_SID); 716 list_replace_rcu(&leader->tasks, &tsk->tasks); 717 718 tsk->group_leader = tsk; 719 leader->group_leader = tsk; 720 721 tsk->exit_signal = SIGCHLD; 722 723 BUG_ON(leader->exit_state != EXIT_ZOMBIE); 724 leader->exit_state = EXIT_DEAD; 725 726 write_unlock_irq(&tasklist_lock); 727 } 728 729 /* 730 * There may be one thread left which is just exiting, 731 * but it's safe to stop telling the group to kill themselves. 732 */ 733 sig->flags = 0; 734 735 no_thread_group: 736 exit_itimers(sig); 737 if (leader) 738 release_task(leader); 739 740 BUG_ON(atomic_read(&sig->count) != 1); 741 742 if (atomic_read(&oldsighand->count) == 1) { 743 /* 744 * Now that we nuked the rest of the thread group, 745 * it turns out we are not sharing sighand any more either. 746 * So we can just keep it. 747 */ 748 kmem_cache_free(sighand_cachep, newsighand); 749 } else { 750 /* 751 * Move our state over to newsighand and switch it in. 752 */ 753 atomic_set(&newsighand->count, 1); 754 memcpy(newsighand->action, oldsighand->action, 755 sizeof(newsighand->action)); 756 757 write_lock_irq(&tasklist_lock); 758 spin_lock(&oldsighand->siglock); 759 spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING); 760 761 rcu_assign_pointer(tsk->sighand, newsighand); 762 recalc_sigpending(); 763 764 spin_unlock(&newsighand->siglock); 765 spin_unlock(&oldsighand->siglock); 766 write_unlock_irq(&tasklist_lock); 767 768 __cleanup_sighand(oldsighand); 769 } 770 771 BUG_ON(!thread_group_leader(tsk)); 772 return 0; 773 } 774 775 /* 776 * These functions flushes out all traces of the currently running executable 777 * so that a new one can be started 778 */ 779 780 static void flush_old_files(struct files_struct * files) 781 { 782 long j = -1; 783 struct fdtable *fdt; 784 785 spin_lock(&files->file_lock); 786 for (;;) { 787 unsigned long set, i; 788 789 j++; 790 i = j * __NFDBITS; 791 fdt = files_fdtable(files); 792 if (i >= fdt->max_fds) 793 break; 794 set = fdt->close_on_exec->fds_bits[j]; 795 if (!set) 796 continue; 797 fdt->close_on_exec->fds_bits[j] = 0; 798 spin_unlock(&files->file_lock); 799 for ( ; set ; i++,set >>= 1) { 800 if (set & 1) { 801 sys_close(i); 802 } 803 } 804 spin_lock(&files->file_lock); 805 806 } 807 spin_unlock(&files->file_lock); 808 } 809 810 void get_task_comm(char *buf, struct task_struct *tsk) 811 { 812 /* buf must be at least sizeof(tsk->comm) in size */ 813 task_lock(tsk); 814 strncpy(buf, tsk->comm, sizeof(tsk->comm)); 815 task_unlock(tsk); 816 } 817 818 void set_task_comm(struct task_struct *tsk, char *buf) 819 { 820 task_lock(tsk); 821 strlcpy(tsk->comm, buf, sizeof(tsk->comm)); 822 task_unlock(tsk); 823 } 824 825 int flush_old_exec(struct linux_binprm * bprm) 826 { 827 char * name; 828 int i, ch, retval; 829 struct files_struct *files; 830 char tcomm[sizeof(current->comm)]; 831 832 /* 833 * Make sure we have a private signal table and that 834 * we are unassociated from the previous thread group. 835 */ 836 retval = de_thread(current); 837 if (retval) 838 goto out; 839 840 /* 841 * Make sure we have private file handles. Ask the 842 * fork helper to do the work for us and the exit 843 * helper to do the cleanup of the old one. 844 */ 845 files = current->files; /* refcounted so safe to hold */ 846 retval = unshare_files(); 847 if (retval) 848 goto out; 849 /* 850 * Release all of the old mmap stuff 851 */ 852 retval = exec_mmap(bprm->mm); 853 if (retval) 854 goto mmap_failed; 855 856 bprm->mm = NULL; /* We're using it now */ 857 858 /* This is the point of no return */ 859 put_files_struct(files); 860 861 current->sas_ss_sp = current->sas_ss_size = 0; 862 863 if (current->euid == current->uid && current->egid == current->gid) 864 current->mm->dumpable = 1; 865 else 866 current->mm->dumpable = suid_dumpable; 867 868 name = bprm->filename; 869 870 /* Copies the binary name from after last slash */ 871 for (i=0; (ch = *(name++)) != '\0';) { 872 if (ch == '/') 873 i = 0; /* overwrite what we wrote */ 874 else 875 if (i < (sizeof(tcomm) - 1)) 876 tcomm[i++] = ch; 877 } 878 tcomm[i] = '\0'; 879 set_task_comm(current, tcomm); 880 881 current->flags &= ~PF_RANDOMIZE; 882 flush_thread(); 883 884 /* Set the new mm task size. We have to do that late because it may 885 * depend on TIF_32BIT which is only updated in flush_thread() on 886 * some architectures like powerpc 887 */ 888 current->mm->task_size = TASK_SIZE; 889 890 if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || 891 file_permission(bprm->file, MAY_READ) || 892 (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { 893 suid_keys(current); 894 current->mm->dumpable = suid_dumpable; 895 } 896 897 /* An exec changes our domain. We are no longer part of the thread 898 group */ 899 900 current->self_exec_id++; 901 902 flush_signal_handlers(current, 0); 903 flush_old_files(current->files); 904 905 return 0; 906 907 mmap_failed: 908 reset_files_struct(current, files); 909 out: 910 return retval; 911 } 912 913 EXPORT_SYMBOL(flush_old_exec); 914 915 /* 916 * Fill the binprm structure from the inode. 917 * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes 918 */ 919 int prepare_binprm(struct linux_binprm *bprm) 920 { 921 int mode; 922 struct inode * inode = bprm->file->f_path.dentry->d_inode; 923 int retval; 924 925 mode = inode->i_mode; 926 if (bprm->file->f_op == NULL) 927 return -EACCES; 928 929 bprm->e_uid = current->euid; 930 bprm->e_gid = current->egid; 931 932 if(!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) { 933 /* Set-uid? */ 934 if (mode & S_ISUID) { 935 current->personality &= ~PER_CLEAR_ON_SETID; 936 bprm->e_uid = inode->i_uid; 937 } 938 939 /* Set-gid? */ 940 /* 941 * If setgid is set but no group execute bit then this 942 * is a candidate for mandatory locking, not a setgid 943 * executable. 944 */ 945 if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { 946 current->personality &= ~PER_CLEAR_ON_SETID; 947 bprm->e_gid = inode->i_gid; 948 } 949 } 950 951 /* fill in binprm security blob */ 952 retval = security_bprm_set(bprm); 953 if (retval) 954 return retval; 955 956 memset(bprm->buf,0,BINPRM_BUF_SIZE); 957 return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE); 958 } 959 960 EXPORT_SYMBOL(prepare_binprm); 961 962 static int unsafe_exec(struct task_struct *p) 963 { 964 int unsafe = 0; 965 if (p->ptrace & PT_PTRACED) { 966 if (p->ptrace & PT_PTRACE_CAP) 967 unsafe |= LSM_UNSAFE_PTRACE_CAP; 968 else 969 unsafe |= LSM_UNSAFE_PTRACE; 970 } 971 if (atomic_read(&p->fs->count) > 1 || 972 atomic_read(&p->files->count) > 1 || 973 atomic_read(&p->sighand->count) > 1) 974 unsafe |= LSM_UNSAFE_SHARE; 975 976 return unsafe; 977 } 978 979 void compute_creds(struct linux_binprm *bprm) 980 { 981 int unsafe; 982 983 if (bprm->e_uid != current->uid) 984 suid_keys(current); 985 exec_keys(current); 986 987 task_lock(current); 988 unsafe = unsafe_exec(current); 989 security_bprm_apply_creds(bprm, unsafe); 990 task_unlock(current); 991 security_bprm_post_apply_creds(bprm); 992 } 993 EXPORT_SYMBOL(compute_creds); 994 995 /* 996 * Arguments are '\0' separated strings found at the location bprm->p 997 * points to; chop off the first by relocating brpm->p to right after 998 * the first '\0' encountered. 999 */ 1000 void remove_arg_zero(struct linux_binprm *bprm) 1001 { 1002 if (bprm->argc) { 1003 char ch; 1004 1005 do { 1006 unsigned long offset; 1007 unsigned long index; 1008 char *kaddr; 1009 struct page *page; 1010 1011 offset = bprm->p & ~PAGE_MASK; 1012 index = bprm->p >> PAGE_SHIFT; 1013 1014 page = bprm->page[index]; 1015 kaddr = kmap_atomic(page, KM_USER0); 1016 1017 /* run through page until we reach end or find NUL */ 1018 do { 1019 ch = *(kaddr + offset); 1020 1021 /* discard that character... */ 1022 bprm->p++; 1023 offset++; 1024 } while (offset < PAGE_SIZE && ch != '\0'); 1025 1026 kunmap_atomic(kaddr, KM_USER0); 1027 1028 /* free the old page */ 1029 if (offset == PAGE_SIZE) { 1030 __free_page(page); 1031 bprm->page[index] = NULL; 1032 } 1033 } while (ch != '\0'); 1034 1035 bprm->argc--; 1036 } 1037 } 1038 EXPORT_SYMBOL(remove_arg_zero); 1039 1040 /* 1041 * cycle the list of binary formats handler, until one recognizes the image 1042 */ 1043 int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) 1044 { 1045 int try,retval; 1046 struct linux_binfmt *fmt; 1047 #ifdef __alpha__ 1048 /* handle /sbin/loader.. */ 1049 { 1050 struct exec * eh = (struct exec *) bprm->buf; 1051 1052 if (!bprm->loader && eh->fh.f_magic == 0x183 && 1053 (eh->fh.f_flags & 0x3000) == 0x3000) 1054 { 1055 struct file * file; 1056 unsigned long loader; 1057 1058 allow_write_access(bprm->file); 1059 fput(bprm->file); 1060 bprm->file = NULL; 1061 1062 loader = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); 1063 1064 file = open_exec("/sbin/loader"); 1065 retval = PTR_ERR(file); 1066 if (IS_ERR(file)) 1067 return retval; 1068 1069 /* Remember if the application is TASO. */ 1070 bprm->sh_bang = eh->ah.entry < 0x100000000UL; 1071 1072 bprm->file = file; 1073 bprm->loader = loader; 1074 retval = prepare_binprm(bprm); 1075 if (retval<0) 1076 return retval; 1077 /* should call search_binary_handler recursively here, 1078 but it does not matter */ 1079 } 1080 } 1081 #endif 1082 retval = security_bprm_check(bprm); 1083 if (retval) 1084 return retval; 1085 1086 /* kernel module loader fixup */ 1087 /* so we don't try to load run modprobe in kernel space. */ 1088 set_fs(USER_DS); 1089 1090 retval = audit_bprm(bprm); 1091 if (retval) 1092 return retval; 1093 1094 retval = -ENOENT; 1095 for (try=0; try<2; try++) { 1096 read_lock(&binfmt_lock); 1097 for (fmt = formats ; fmt ; fmt = fmt->next) { 1098 int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; 1099 if (!fn) 1100 continue; 1101 if (!try_module_get(fmt->module)) 1102 continue; 1103 read_unlock(&binfmt_lock); 1104 retval = fn(bprm, regs); 1105 if (retval >= 0) { 1106 put_binfmt(fmt); 1107 allow_write_access(bprm->file); 1108 if (bprm->file) 1109 fput(bprm->file); 1110 bprm->file = NULL; 1111 current->did_exec = 1; 1112 proc_exec_connector(current); 1113 return retval; 1114 } 1115 read_lock(&binfmt_lock); 1116 put_binfmt(fmt); 1117 if (retval != -ENOEXEC || bprm->mm == NULL) 1118 break; 1119 if (!bprm->file) { 1120 read_unlock(&binfmt_lock); 1121 return retval; 1122 } 1123 } 1124 read_unlock(&binfmt_lock); 1125 if (retval != -ENOEXEC || bprm->mm == NULL) { 1126 break; 1127 #ifdef CONFIG_KMOD 1128 }else{ 1129 #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) 1130 if (printable(bprm->buf[0]) && 1131 printable(bprm->buf[1]) && 1132 printable(bprm->buf[2]) && 1133 printable(bprm->buf[3])) 1134 break; /* -ENOEXEC */ 1135 request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); 1136 #endif 1137 } 1138 } 1139 return retval; 1140 } 1141 1142 EXPORT_SYMBOL(search_binary_handler); 1143 1144 /* 1145 * sys_execve() executes a new program. 1146 */ 1147 int do_execve(char * filename, 1148 char __user *__user *argv, 1149 char __user *__user *envp, 1150 struct pt_regs * regs) 1151 { 1152 struct linux_binprm *bprm; 1153 struct file *file; 1154 int retval; 1155 int i; 1156 1157 retval = -ENOMEM; 1158 bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); 1159 if (!bprm) 1160 goto out_ret; 1161 1162 file = open_exec(filename); 1163 retval = PTR_ERR(file); 1164 if (IS_ERR(file)) 1165 goto out_kfree; 1166 1167 sched_exec(); 1168 1169 bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *); 1170 1171 bprm->file = file; 1172 bprm->filename = filename; 1173 bprm->interp = filename; 1174 bprm->mm = mm_alloc(); 1175 retval = -ENOMEM; 1176 if (!bprm->mm) 1177 goto out_file; 1178 1179 retval = init_new_context(current, bprm->mm); 1180 if (retval < 0) 1181 goto out_mm; 1182 1183 bprm->argc = count(argv, bprm->p / sizeof(void *)); 1184 if ((retval = bprm->argc) < 0) 1185 goto out_mm; 1186 1187 bprm->envc = count(envp, bprm->p / sizeof(void *)); 1188 if ((retval = bprm->envc) < 0) 1189 goto out_mm; 1190 1191 retval = security_bprm_alloc(bprm); 1192 if (retval) 1193 goto out; 1194 1195 retval = prepare_binprm(bprm); 1196 if (retval < 0) 1197 goto out; 1198 1199 retval = copy_strings_kernel(1, &bprm->filename, bprm); 1200 if (retval < 0) 1201 goto out; 1202 1203 bprm->exec = bprm->p; 1204 retval = copy_strings(bprm->envc, envp, bprm); 1205 if (retval < 0) 1206 goto out; 1207 1208 retval = copy_strings(bprm->argc, argv, bprm); 1209 if (retval < 0) 1210 goto out; 1211 1212 retval = search_binary_handler(bprm,regs); 1213 if (retval >= 0) { 1214 free_arg_pages(bprm); 1215 1216 /* execve success */ 1217 security_bprm_free(bprm); 1218 acct_update_integrals(current); 1219 kfree(bprm); 1220 return retval; 1221 } 1222 1223 out: 1224 /* Something went wrong, return the inode and free the argument pages*/ 1225 for (i = 0 ; i < MAX_ARG_PAGES ; i++) { 1226 struct page * page = bprm->page[i]; 1227 if (page) 1228 __free_page(page); 1229 } 1230 1231 if (bprm->security) 1232 security_bprm_free(bprm); 1233 1234 out_mm: 1235 if (bprm->mm) 1236 mmdrop(bprm->mm); 1237 1238 out_file: 1239 if (bprm->file) { 1240 allow_write_access(bprm->file); 1241 fput(bprm->file); 1242 } 1243 1244 out_kfree: 1245 kfree(bprm); 1246 1247 out_ret: 1248 return retval; 1249 } 1250 1251 int set_binfmt(struct linux_binfmt *new) 1252 { 1253 struct linux_binfmt *old = current->binfmt; 1254 1255 if (new) { 1256 if (!try_module_get(new->module)) 1257 return -1; 1258 } 1259 current->binfmt = new; 1260 if (old) 1261 module_put(old->module); 1262 return 0; 1263 } 1264 1265 EXPORT_SYMBOL(set_binfmt); 1266 1267 #define CORENAME_MAX_SIZE 64 1268 1269 /* format_corename will inspect the pattern parameter, and output a 1270 * name into corename, which must have space for at least 1271 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. 1272 */ 1273 static int format_corename(char *corename, const char *pattern, long signr) 1274 { 1275 const char *pat_ptr = pattern; 1276 char *out_ptr = corename; 1277 char *const out_end = corename + CORENAME_MAX_SIZE; 1278 int rc; 1279 int pid_in_pattern = 0; 1280 int ispipe = 0; 1281 1282 if (*pattern == '|') 1283 ispipe = 1; 1284 1285 /* Repeat as long as we have more pattern to process and more output 1286 space */ 1287 while (*pat_ptr) { 1288 if (*pat_ptr != '%') { 1289 if (out_ptr == out_end) 1290 goto out; 1291 *out_ptr++ = *pat_ptr++; 1292 } else { 1293 switch (*++pat_ptr) { 1294 case 0: 1295 goto out; 1296 /* Double percent, output one percent */ 1297 case '%': 1298 if (out_ptr == out_end) 1299 goto out; 1300 *out_ptr++ = '%'; 1301 break; 1302 /* pid */ 1303 case 'p': 1304 pid_in_pattern = 1; 1305 rc = snprintf(out_ptr, out_end - out_ptr, 1306 "%d", current->tgid); 1307 if (rc > out_end - out_ptr) 1308 goto out; 1309 out_ptr += rc; 1310 break; 1311 /* uid */ 1312 case 'u': 1313 rc = snprintf(out_ptr, out_end - out_ptr, 1314 "%d", current->uid); 1315 if (rc > out_end - out_ptr) 1316 goto out; 1317 out_ptr += rc; 1318 break; 1319 /* gid */ 1320 case 'g': 1321 rc = snprintf(out_ptr, out_end - out_ptr, 1322 "%d", current->gid); 1323 if (rc > out_end - out_ptr) 1324 goto out; 1325 out_ptr += rc; 1326 break; 1327 /* signal that caused the coredump */ 1328 case 's': 1329 rc = snprintf(out_ptr, out_end - out_ptr, 1330 "%ld", signr); 1331 if (rc > out_end - out_ptr) 1332 goto out; 1333 out_ptr += rc; 1334 break; 1335 /* UNIX time of coredump */ 1336 case 't': { 1337 struct timeval tv; 1338 do_gettimeofday(&tv); 1339 rc = snprintf(out_ptr, out_end - out_ptr, 1340 "%lu", tv.tv_sec); 1341 if (rc > out_end - out_ptr) 1342 goto out; 1343 out_ptr += rc; 1344 break; 1345 } 1346 /* hostname */ 1347 case 'h': 1348 down_read(&uts_sem); 1349 rc = snprintf(out_ptr, out_end - out_ptr, 1350 "%s", utsname()->nodename); 1351 up_read(&uts_sem); 1352 if (rc > out_end - out_ptr) 1353 goto out; 1354 out_ptr += rc; 1355 break; 1356 /* executable */ 1357 case 'e': 1358 rc = snprintf(out_ptr, out_end - out_ptr, 1359 "%s", current->comm); 1360 if (rc > out_end - out_ptr) 1361 goto out; 1362 out_ptr += rc; 1363 break; 1364 default: 1365 break; 1366 } 1367 ++pat_ptr; 1368 } 1369 } 1370 /* Backward compatibility with core_uses_pid: 1371 * 1372 * If core_pattern does not include a %p (as is the default) 1373 * and core_uses_pid is set, then .%pid will be appended to 1374 * the filename. Do not do this for piped commands. */ 1375 if (!ispipe && !pid_in_pattern 1376 && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) { 1377 rc = snprintf(out_ptr, out_end - out_ptr, 1378 ".%d", current->tgid); 1379 if (rc > out_end - out_ptr) 1380 goto out; 1381 out_ptr += rc; 1382 } 1383 out: 1384 *out_ptr = 0; 1385 return ispipe; 1386 } 1387 1388 static void zap_process(struct task_struct *start) 1389 { 1390 struct task_struct *t; 1391 1392 start->signal->flags = SIGNAL_GROUP_EXIT; 1393 start->signal->group_stop_count = 0; 1394 1395 t = start; 1396 do { 1397 if (t != current && t->mm) { 1398 t->mm->core_waiters++; 1399 sigaddset(&t->pending.signal, SIGKILL); 1400 signal_wake_up(t, 1); 1401 } 1402 } while ((t = next_thread(t)) != start); 1403 } 1404 1405 static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, 1406 int exit_code) 1407 { 1408 struct task_struct *g, *p; 1409 unsigned long flags; 1410 int err = -EAGAIN; 1411 1412 spin_lock_irq(&tsk->sighand->siglock); 1413 if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT)) { 1414 tsk->signal->group_exit_code = exit_code; 1415 zap_process(tsk); 1416 err = 0; 1417 } 1418 spin_unlock_irq(&tsk->sighand->siglock); 1419 if (err) 1420 return err; 1421 1422 if (atomic_read(&mm->mm_users) == mm->core_waiters + 1) 1423 goto done; 1424 1425 rcu_read_lock(); 1426 for_each_process(g) { 1427 if (g == tsk->group_leader) 1428 continue; 1429 1430 p = g; 1431 do { 1432 if (p->mm) { 1433 if (p->mm == mm) { 1434 /* 1435 * p->sighand can't disappear, but 1436 * may be changed by de_thread() 1437 */ 1438 lock_task_sighand(p, &flags); 1439 zap_process(p); 1440 unlock_task_sighand(p, &flags); 1441 } 1442 break; 1443 } 1444 } while ((p = next_thread(p)) != g); 1445 } 1446 rcu_read_unlock(); 1447 done: 1448 return mm->core_waiters; 1449 } 1450 1451 static int coredump_wait(int exit_code) 1452 { 1453 struct task_struct *tsk = current; 1454 struct mm_struct *mm = tsk->mm; 1455 struct completion startup_done; 1456 struct completion *vfork_done; 1457 int core_waiters; 1458 1459 init_completion(&mm->core_done); 1460 init_completion(&startup_done); 1461 mm->core_startup_done = &startup_done; 1462 1463 core_waiters = zap_threads(tsk, mm, exit_code); 1464 up_write(&mm->mmap_sem); 1465 1466 if (unlikely(core_waiters < 0)) 1467 goto fail; 1468 1469 /* 1470 * Make sure nobody is waiting for us to release the VM, 1471 * otherwise we can deadlock when we wait on each other 1472 */ 1473 vfork_done = tsk->vfork_done; 1474 if (vfork_done) { 1475 tsk->vfork_done = NULL; 1476 complete(vfork_done); 1477 } 1478 1479 if (core_waiters) 1480 wait_for_completion(&startup_done); 1481 fail: 1482 BUG_ON(mm->core_waiters); 1483 return core_waiters; 1484 } 1485 1486 int do_coredump(long signr, int exit_code, struct pt_regs * regs) 1487 { 1488 char corename[CORENAME_MAX_SIZE + 1]; 1489 struct mm_struct *mm = current->mm; 1490 struct linux_binfmt * binfmt; 1491 struct inode * inode; 1492 struct file * file; 1493 int retval = 0; 1494 int fsuid = current->fsuid; 1495 int flag = 0; 1496 int ispipe = 0; 1497 1498 audit_core_dumps(signr); 1499 1500 binfmt = current->binfmt; 1501 if (!binfmt || !binfmt->core_dump) 1502 goto fail; 1503 down_write(&mm->mmap_sem); 1504 if (!mm->dumpable) { 1505 up_write(&mm->mmap_sem); 1506 goto fail; 1507 } 1508 1509 /* 1510 * We cannot trust fsuid as being the "true" uid of the 1511 * process nor do we know its entire history. We only know it 1512 * was tainted so we dump it as root in mode 2. 1513 */ 1514 if (mm->dumpable == 2) { /* Setuid core dump mode */ 1515 flag = O_EXCL; /* Stop rewrite attacks */ 1516 current->fsuid = 0; /* Dump root private */ 1517 } 1518 mm->dumpable = 0; 1519 1520 retval = coredump_wait(exit_code); 1521 if (retval < 0) 1522 goto fail; 1523 1524 /* 1525 * Clear any false indication of pending signals that might 1526 * be seen by the filesystem code called to write the core file. 1527 */ 1528 clear_thread_flag(TIF_SIGPENDING); 1529 1530 if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) 1531 goto fail_unlock; 1532 1533 /* 1534 * lock_kernel() because format_corename() is controlled by sysctl, which 1535 * uses lock_kernel() 1536 */ 1537 lock_kernel(); 1538 ispipe = format_corename(corename, core_pattern, signr); 1539 unlock_kernel(); 1540 if (ispipe) { 1541 /* SIGPIPE can happen, but it's just never processed */ 1542 if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) { 1543 printk(KERN_INFO "Core dump to %s pipe failed\n", 1544 corename); 1545 goto fail_unlock; 1546 } 1547 } else 1548 file = filp_open(corename, 1549 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 1550 0600); 1551 if (IS_ERR(file)) 1552 goto fail_unlock; 1553 inode = file->f_path.dentry->d_inode; 1554 if (inode->i_nlink > 1) 1555 goto close_fail; /* multiple links - don't dump */ 1556 if (!ispipe && d_unhashed(file->f_path.dentry)) 1557 goto close_fail; 1558 1559 /* AK: actually i see no reason to not allow this for named pipes etc., 1560 but keep the previous behaviour for now. */ 1561 if (!ispipe && !S_ISREG(inode->i_mode)) 1562 goto close_fail; 1563 if (!file->f_op) 1564 goto close_fail; 1565 if (!file->f_op->write) 1566 goto close_fail; 1567 if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) 1568 goto close_fail; 1569 1570 retval = binfmt->core_dump(signr, regs, file); 1571 1572 if (retval) 1573 current->signal->group_exit_code |= 0x80; 1574 close_fail: 1575 filp_close(file, NULL); 1576 fail_unlock: 1577 current->fsuid = fsuid; 1578 complete_all(&mm->core_done); 1579 fail: 1580 return retval; 1581 } 1582