| 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/config.h>
|
| 26 | #include <linux/slab.h>
|
| 27 | #include <linux/file.h>
|
| 28 | #include <linux/mman.h>
|
| 29 | #include <linux/a.out.h>
|
| 30 | #include <linux/stat.h>
|
| 31 | #include <linux/fcntl.h>
|
| 32 | #include <linux/smp_lock.h>
|
| 33 | #include <linux/init.h>
|
| 34 | #include <linux/pagemap.h>
|
| 35 | #include <linux/highmem.h>
|
| 36 | #include <linux/spinlock.h>
|
| 37 | #include <linux/key.h>
|
| 38 | #include <linux/personality.h>
|
| 39 | #include <linux/binfmts.h>
|
| 40 | #include <linux/swap.h>
|
| 41 | #include <linux/utsname.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/acct.h>
|
| 51 |
|
| 52 | #include <asm/uaccess.h>
|
| 53 | #include <asm/mmu_context.h>
|
| 54 |
|
| 55 | #ifdef CONFIG_KMOD
|
| 56 | #include <linux/kmod.h>
|
| 57 | #endif
|
| 58 |
|
| 59 | int core_uses_pid;
|
| 60 | char core_pattern[65] = "core";
|
| 61 | int suid_dumpable = 0;
|
| 62 |
|
| 63 | EXPORT_SYMBOL(suid_dumpable);
|
| 64 |
|
| 65 |
|
| 66 | static struct linux_binfmt *formats;
|
| 67 | static DEFINE_RWLOCK(binfmt_lock);
|
| 68 |
|
| 69 | int register_binfmt(struct linux_binfmt * fmt)
|
| 70 | {
|
| 71 | struct linux_binfmt ** tmp = &formats;
|
| 72 |
|
| 73 | if (!fmt)
|
| 74 | return -EINVAL;
|
| 75 | if (fmt->next)
|
| 76 | return -EBUSY;
|
| 77 | write_lock(&binfmt_lock);
|
| 78 | while (*tmp) {
|
| 79 | if (fmt == *tmp) {
|
| 80 | write_unlock(&binfmt_lock);
|
| 81 | return -EBUSY;
|
| 82 | }
|
| 83 | tmp = &(*tmp)->next;
|
| 84 | }
|
| 85 | fmt->next = formats;
|
| 86 | formats = fmt;
|
| 87 | write_unlock(&binfmt_lock);
|
| 88 | return 0;
|
| 89 | }
|
| 90 |
|
| 91 | EXPORT_SYMBOL(register_binfmt);
|
| 92 |
|
| 93 | int unregister_binfmt(struct linux_binfmt * fmt)
|
| 94 | {
|
| 95 | struct linux_binfmt ** tmp = &formats;
|
| 96 |
|
| 97 | write_lock(&binfmt_lock);
|
| 98 | while (*tmp) {
|
| 99 | if (fmt == *tmp) {
|
| 100 | *tmp = fmt->next;
|
| 101 | write_unlock(&binfmt_lock);
|
| 102 | return 0;
|
| 103 | }
|
| 104 | tmp = &(*tmp)->next;
|
| 105 | }
|
| 106 | write_unlock(&binfmt_lock);
|
| 107 | return -EINVAL;
|
| 108 | }
|
| 109 |
|
| 110 | EXPORT_SYMBOL(unregister_binfmt);
|
| 111 |
|
| 112 | static inline void put_binfmt(struct linux_binfmt * fmt)
|
| 113 | {
|
| 114 | module_put(fmt->module);
|
| 115 | }
|
| 116 |
|
| 117 | |
| 118 | * Note that a shared library must be both readable and executable due to
|
| 119 | * security reasons.
|
| 120 | *
|
| 121 | * Also note that we take the address to load from from the file itself.
|
| 122 |
|
| 123 | asmlinkage long sys_uselib(const char __user * library)
|
| 124 | {
|
| 125 | struct file * file;
|
| 126 | struct nameidata nd;
|
| 127 | int error;
|
| 128 |
|
| 129 | nd.intent.open.flags = FMODE_READ;
|
| 130 | error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
|
| 131 | if (error)
|
| 132 | goto out;
|
| 133 |
|
| 134 | error = -EINVAL;
|
| 135 | if (!S_ISREG(nd.dentry->d_inode->i_mode))
|
| 136 | goto exit;
|
| 137 |
|
| 138 | error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd);
|
| 139 | if (error)
|
| 140 | goto exit;
|
| 141 |
|
| 142 | file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
|
| 143 | error = PTR_ERR(file);
|
| 144 | if (IS_ERR(file))
|
| 145 | goto out;
|
| 146 |
|
| 147 | error = -ENOEXEC;
|
| 148 | if(file->f_op) {
|
| 149 | struct linux_binfmt * fmt;
|
| 150 |
|
| 151 | read_lock(&binfmt_lock);
|
| 152 | for (fmt = formats ; fmt ; fmt = fmt->next) {
|
| 153 | if (!fmt->load_shlib)
|
| 154 | continue;
|
| 155 | if (!try_module_get(fmt->module))
|
| 156 | continue;
|
| 157 | read_unlock(&binfmt_lock);
|
| 158 | error = fmt->load_shlib(file);
|
| 159 | read_lock(&binfmt_lock);
|
| 160 | put_binfmt(fmt);
|
| 161 | if (error != -ENOEXEC)
|
| 162 | break;
|
| 163 | }
|
| 164 | read_unlock(&binfmt_lock);
|
| 165 | }
|
| 166 | fput(file);
|
| 167 | out:
|
| 168 | return error;
|
| 169 | exit:
|
| 170 | path_release(&nd);
|
| 171 | goto out;
|
| 172 | }
|
| 173 |
|
| 174 | |
| 175 | * count() counts the number of strings in array ARGV.
|
| 176 |
|
| 177 | static int count(char __user * __user * argv, int max)
|
| 178 | {
|
| 179 | int i = 0;
|
| 180 |
|
| 181 | if (argv != NULL) {
|
| 182 | for (;;) {
|
| 183 | char __user * p;
|
| 184 |
|
| 185 | if (get_user(p, argv))
|
| 186 | return -EFAULT;
|
| 187 | if (!p)
|
| 188 | break;
|
| 189 | argv++;
|
| 190 | if(++i > max)
|
| 191 | return -E2BIG;
|
| 192 | cond_resched();
|
| 193 | }
|
| 194 | }
|
| 195 | return i;
|
| 196 | }
|
| 197 |
|
| 198 | |
| 199 | * 'copy_strings()' copies argument/environment strings from user
|
| 200 | * memory to free pages in kernel mem. These are in a format ready
|
| 201 | * to be put directly into the top of new user memory.
|
| 202 |
|
| 203 | static int copy_strings(int argc, char __user * __user * argv,
|
| 204 | struct linux_binprm *bprm)
|
| 205 | {
|
| 206 | struct page *kmapped_page = NULL;
|
| 207 | char *kaddr = NULL;
|
| 208 | int ret;
|
| 209 |
|
| 210 | while (argc-- > 0) {
|
| 211 | char __user *str;
|
| 212 | int len;
|
| 213 | unsigned long pos;
|
| 214 |
|
| 215 | if (get_user(str, argv+argc) ||
|
| 216 | !(len = strnlen_user(str, bprm->p))) {
|
| 217 | ret = -EFAULT;
|
| 218 | goto out;
|
| 219 | }
|
| 220 |
|
| 221 | if (bprm->p < len) {
|
| 222 | ret = -E2BIG;
|
| 223 | goto out;
|
| 224 | }
|
| 225 |
|
| 226 | bprm->p -= len;
|
| 227 |
|
| 228 | pos = bprm->p;
|
| 229 |
|
| 230 | while (len > 0) {
|
| 231 | int i, new, err;
|
| 232 | int offset, bytes_to_copy;
|
| 233 | struct page *page;
|
| 234 |
|
| 235 | offset = pos % PAGE_SIZE;
|
| 236 | i = pos/PAGE_SIZE;
|
| 237 | page = bprm->page[i];
|
| 238 | new = 0;
|
| 239 | if (!page) {
|
| 240 | page = alloc_page(GFP_HIGHUSER);
|
| 241 | bprm->page[i] = page;
|
| 242 | if (!page) {
|
| 243 | ret = -ENOMEM;
|
| 244 | goto out;
|
| 245 | }
|
| 246 | new = 1;
|
| 247 | }
|
| 248 |
|
| 249 | if (page != kmapped_page) {
|
| 250 | if (kmapped_page)
|
| 251 | kunmap(kmapped_page);
|
| 252 | kmapped_page = page;
|
| 253 | kaddr = kmap(kmapped_page);
|
| 254 | }
|
| 255 | if (new && offset)
|
| 256 | memset(kaddr, 0, offset);
|
| 257 | bytes_to_copy = PAGE_SIZE - offset;
|
| 258 | if (bytes_to_copy > len) {
|
| 259 | bytes_to_copy = len;
|
| 260 | if (new)
|
| 261 | memset(kaddr+offset+len, 0,
|
| 262 | PAGE_SIZE-offset-len);
|
| 263 | }
|
| 264 | err = copy_from_user(kaddr+offset, str, bytes_to_copy);
|
| 265 | if (err) {
|
| 266 | ret = -EFAULT;
|
| 267 | goto out;
|
| 268 | }
|
| 269 |
|
| 270 | pos += bytes_to_copy;
|
| 271 | str += bytes_to_copy;
|
| 272 | len -= bytes_to_copy;
|
| 273 | }
|
| 274 | }
|
| 275 | ret = 0;
|
| 276 | out:
|
| 277 | if (kmapped_page)
|
| 278 | kunmap(kmapped_page);
|
| 279 | return ret;
|
| 280 | }
|
| 281 |
|
| 282 | |
| 283 | * Like copy_strings, but get argv and its values from kernel memory.
|
| 284 |
|
| 285 | int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm)
|
| 286 | {
|
| 287 | int r;
|
| 288 | mm_segment_t oldfs = get_fs();
|
| 289 | set_fs(KERNEL_DS);
|
| 290 | r = copy_strings(argc, (char __user * __user *)argv, bprm);
|
| 291 | set_fs(oldfs);
|
| 292 | return r;
|
| 293 | }
|
| 294 |
|
| 295 | EXPORT_SYMBOL(copy_strings_kernel);
|
| 296 |
|
| 297 | #ifdef CONFIG_MMU
|
| 298 | |
| 299 | * This routine is used to map in a page into an address space: needed by
|
| 300 | * execve() for the initial stack and environment pages.
|
| 301 | *
|
| 302 | * vma->vm_mm->mmap_sem is held for writing.
|
| 303 |
|
| 304 | void install_arg_page(struct vm_area_struct *vma,
|
| 305 | struct page *page, unsigned long address)
|
| 306 | {
|
| 307 | struct mm_struct *mm = vma->vm_mm;
|
| 308 | pgd_t * pgd;
|
| 309 | pud_t * pud;
|
| 310 | pmd_t * pmd;
|
| 311 | pte_t * pte;
|
| 312 |
|
| 313 | if (unlikely(anon_vma_prepare(vma)))
|
| 314 | goto out_sig;
|
| 315 |
|
| 316 | flush_dcache_page(page);
|
| 317 | pgd = pgd_offset(mm, address);
|
| 318 |
|
| 319 | spin_lock(&mm->page_table_lock);
|
| 320 | pud = pud_alloc(mm, pgd, address);
|
| 321 | if (!pud)
|
| 322 | goto out;
|
| 323 | pmd = pmd_alloc(mm, pud, address);
|
| 324 | if (!pmd)
|
| 325 | goto out;
|
| 326 | pte = pte_alloc_map(mm, pmd, address);
|
| 327 | if (!pte)
|
| 328 | goto out;
|
| 329 | if (!pte_none(*pte)) {
|
| 330 | pte_unmap(pte);
|
| 331 | goto out;
|
| 332 | }
|
| 333 | inc_mm_counter(mm, rss);
|
| 334 | lru_cache_add_active(page);
|
| 335 | set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte(
|
| 336 | page, vma->vm_page_prot))));
|
| 337 | page_add_anon_rmap(page, vma, address);
|
| 338 | pte_unmap(pte);
|
| 339 | spin_unlock(&mm->page_table_lock);
|
| 340 |
|
| 341 |
|
| 342 | return;
|
| 343 | out:
|
| 344 | spin_unlock(&mm->page_table_lock);
|
| 345 | out_sig:
|
| 346 | __free_page(page);
|
| 347 | force_sig(SIGKILL, current);
|
| 348 | }
|
| 349 |
|
| 350 | #define EXTRA_STACK_VM_PAGES 20
|
| 351 |
|
| 352 | int setup_arg_pages(struct linux_binprm *bprm,
|
| 353 | unsigned long stack_top,
|
| 354 | int executable_stack)
|
| 355 | {
|
| 356 | unsigned long stack_base;
|
| 357 | struct vm_area_struct *mpnt;
|
| 358 | struct mm_struct *mm = current->mm;
|
| 359 | int i, ret;
|
| 360 | long arg_size;
|
| 361 |
|
| 362 | #ifdef CONFIG_STACK_GROWSUP
|
| 363 | |
| 364 | * stack space.
|
| 365 |
|
| 366 | int offset, j;
|
| 367 | char *to, *from;
|
| 368 |
|
| 369 |
|
| 370 | i = 0;
|
| 371 | for (j = 0; j < MAX_ARG_PAGES; j++) {
|
| 372 | struct page *page = bprm->page[j];
|
| 373 | if (!page)
|
| 374 | continue;
|
| 375 | bprm->page[i++] = page;
|
| 376 | }
|
| 377 |
|
| 378 |
|
| 379 | offset = bprm->p % PAGE_SIZE;
|
| 380 | to = kmap(bprm->page[0]);
|
| 381 | for (j = 1; j < i; j++) {
|
| 382 | memmove(to, to + offset, PAGE_SIZE - offset);
|
| 383 | from = kmap(bprm->page[j]);
|
| 384 | memcpy(to + PAGE_SIZE - offset, from, offset);
|
| 385 | kunmap(bprm->page[j - 1]);
|
| 386 | to = from;
|
| 387 | }
|
| 388 | memmove(to, to + offset, PAGE_SIZE - offset);
|
| 389 | kunmap(bprm->page[j - 1]);
|
| 390 |
|
| 391 |
|
| 392 | stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max;
|
| 393 | if (stack_base > (1 << 30))
|
| 394 | stack_base = 1 << 30;
|
| 395 | stack_base = PAGE_ALIGN(stack_top - stack_base);
|
| 396 |
|
| 397 |
|
| 398 | bprm->p = stack_base + PAGE_SIZE * i - offset;
|
| 399 |
|
| 400 | mm->arg_start = stack_base;
|
| 401 | arg_size = i << PAGE_SHIFT;
|
| 402 |
|
| 403 |
|
| 404 | while (i < MAX_ARG_PAGES)
|
| 405 | bprm->page[i++] = NULL;
|
| 406 | #else
|
| 407 | stack_base = arch_align_stack(stack_top - MAX_ARG_PAGES*PAGE_SIZE);
|
| 408 | stack_base = PAGE_ALIGN(stack_base);
|
| 409 | bprm->p += stack_base;
|
| 410 | mm->arg_start = bprm->p;
|
| 411 | arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);
|
| 412 | #endif
|
| 413 |
|
| 414 | arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE;
|
| 415 |
|
| 416 | if (bprm->loader)
|
| 417 | bprm->loader += stack_base;
|
| 418 | bprm->exec += stack_base;
|
| 419 |
|
| 420 | mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
|
| 421 | if (!mpnt)
|
| 422 | return -ENOMEM;
|
| 423 |
|
| 424 | if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) {
|
| 425 | kmem_cache_free(vm_area_cachep, mpnt);
|
| 426 | return -ENOMEM;
|
| 427 | }
|
| 428 |
|
| 429 | memset(mpnt, 0, sizeof(*mpnt));
|
| 430 |
|
| 431 | down_write(&mm->mmap_sem);
|
| 432 | {
|
| 433 | mpnt->vm_mm = mm;
|
| 434 | #ifdef CONFIG_STACK_GROWSUP
|
| 435 | mpnt->vm_start = stack_base;
|
| 436 | mpnt->vm_end = stack_base + arg_size;
|
| 437 | #else
|
| 438 | mpnt->vm_end = stack_top;
|
| 439 | mpnt->vm_start = mpnt->vm_end - arg_size;
|
| 440 | #endif
|
| 441 | |
| 442 | * for EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X
|
| 443 | * and leave alone (arch default) otherwise.
|
| 444 | if (unlikely(executable_stack == EXSTACK_ENABLE_X))
|
| 445 | mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC;
|
| 446 | else if (executable_stack == EXSTACK_DISABLE_X)
|
| 447 | mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC;
|
| 448 | else
|
| 449 | mpnt->vm_flags = VM_STACK_FLAGS;
|
| 450 | mpnt->vm_flags |= mm->def_flags;
|
| 451 | mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7];
|
| 452 | if ((ret = insert_vm_struct(mm, mpnt))) {
|
| 453 | up_write(&mm->mmap_sem);
|
| 454 | kmem_cache_free(vm_area_cachep, mpnt);
|
| 455 | return ret;
|
| 456 | }
|
| 457 | mm->stack_vm = mm->total_vm = vma_pages(mpnt);
|
| 458 | }
|
| 459 |
|
| 460 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
|
| 461 | struct page *page = bprm->page[i];
|
| 462 | if (page) {
|
| 463 | bprm->page[i] = NULL;
|
| 464 | install_arg_page(mpnt, page, stack_base);
|
| 465 | }
|
| 466 | stack_base += PAGE_SIZE;
|
| 467 | }
|
| 468 | up_write(&mm->mmap_sem);
|
| 469 |
|
| 470 | return 0;
|
| 471 | }
|
| 472 |
|
| 473 | EXPORT_SYMBOL(setup_arg_pages);
|
| 474 |
|
| 475 | #define free_arg_pages(bprm) do { } while (0)
|
| 476 |
|
| 477 | #else
|
| 478 |
|
| 479 | static inline void free_arg_pages(struct linux_binprm *bprm)
|
| 480 | {
|
| 481 | int i;
|
| 482 |
|
| 483 | for (i = 0; i < MAX_ARG_PAGES; i++) {
|
| 484 | if (bprm->page[i])
|
| 485 | __free_page(bprm->page[i]);
|
| 486 | bprm->page[i] = NULL;
|
| 487 | }
|
| 488 | }
|
| 489 |
|
| 490 | #endif
|
| 491 |
|
| 492 | struct file *open_exec(const char *name)
|
| 493 | {
|
| 494 | struct nameidata nd;
|
| 495 | int err;
|
| 496 | struct file *file;
|
| 497 |
|
| 498 | nd.intent.open.flags = FMODE_READ;
|
| 499 | err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd);
|
| 500 | file = ERR_PTR(err);
|
| 501 |
|
| 502 | if (!err) {
|
| 503 | struct inode *inode = nd.dentry->d_inode;
|
| 504 | file = ERR_PTR(-EACCES);
|
| 505 | if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&
|
| 506 | S_ISREG(inode->i_mode)) {
|
| 507 | int err = permission(inode, MAY_EXEC, &nd);
|
| 508 | if (!err && !(inode->i_mode & 0111))
|
| 509 | err = -EACCES;
|
| 510 | file = ERR_PTR(err);
|
| 511 | if (!err) {
|
| 512 | file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
|
| 513 | if (!IS_ERR(file)) {
|
| 514 | err = deny_write_access(file);
|
| 515 | if (err) {
|
| 516 | fput(file);
|
| 517 | file = ERR_PTR(err);
|
| 518 | }
|
| 519 | }
|
| 520 | out:
|
| 521 | return file;
|
| 522 | }
|
| 523 | }
|
| 524 | path_release(&nd);
|
| 525 | }
|
| 526 | goto out;
|
| 527 | }
|
| 528 |
|
| 529 | EXPORT_SYMBOL(open_exec);
|
| 530 |
|
| 531 | int kernel_read(struct file *file, unsigned long offset,
|
| 532 | char *addr, unsigned long count)
|
| 533 | {
|
| 534 | mm_segment_t old_fs;
|
| 535 | loff_t pos = offset;
|
| 536 | int result;
|
| 537 |
|
| 538 | old_fs = get_fs();
|
| 539 | set_fs(get_ds());
|
| 540 |
|
| 541 | result = vfs_read(file, (void __user *)addr, count, &pos);
|
| 542 | set_fs(old_fs);
|
| 543 | return result;
|
| 544 | }
|
| 545 |
|
| 546 | EXPORT_SYMBOL(kernel_read);
|
| 547 |
|
| 548 | static int exec_mmap(struct mm_struct *mm)
|
| 549 | {
|
| 550 | struct task_struct *tsk;
|
| 551 | struct mm_struct * old_mm, *active_mm;
|
| 552 |
|
| 553 |
|
| 554 | tsk = current;
|
| 555 | old_mm = current->mm;
|
| 556 | mm_release(tsk, old_mm);
|
| 557 |
|
| 558 | if (old_mm) {
|
| 559 | |
| 560 | * Make sure that if there is a core dump in progress
|
| 561 | * for the old mm, we get out and die instead of going
|
| 562 | * through with the exec. We must hold mmap_sem around
|
| 563 | * checking core_waiters and changing tsk->mm. The
|
| 564 | * core-inducing thread will increment core_waiters for
|
| 565 | * each thread whose ->mm == old_mm.
|
| 566 |
|
| 567 | down_read(&old_mm->mmap_sem);
|
| 568 | if (unlikely(old_mm->core_waiters)) {
|
| 569 | up_read(&old_mm->mmap_sem);
|
| 570 | return -EINTR;
|
| 571 | }
|
| 572 | }
|
| 573 | task_lock(tsk);
|
| 574 | active_mm = tsk->active_mm;
|
| 575 | tsk->mm = mm;
|
| 576 | tsk->active_mm = mm;
|
| 577 | activate_mm(active_mm, mm);
|
| 578 | task_unlock(tsk);
|
| 579 | arch_pick_mmap_layout(mm);
|
| 580 | if (old_mm) {
|
| 581 | up_read(&old_mm->mmap_sem);
|
| 582 | if (active_mm != old_mm) BUG();
|
| 583 | mmput(old_mm);
|
| 584 | return 0;
|
| 585 | }
|
| 586 | mmdrop(active_mm);
|
| 587 | return 0;
|
| 588 | }
|
| 589 |
|
| 590 | |
| 591 | * This function makes sure the current process has its own signal table,
|
| 592 | * so that flush_signal_handlers can later reset the handlers without
|
| 593 | * disturbing other processes. (Other processes might share the signal
|
| 594 | * table via the CLONE_SIGHAND option to clone().)
|
| 595 |
|
| 596 | static inline int de_thread(struct task_struct *tsk)
|
| 597 | {
|
| 598 | struct signal_struct *sig = tsk->signal;
|
| 599 | struct sighand_struct *newsighand, *oldsighand = tsk->sighand;
|
| 600 | spinlock_t *lock = &oldsighand->siglock;
|
| 601 | int count;
|
| 602 |
|
| 603 | |
| 604 | * If we don't share sighandlers, then we aren't sharing anything
|
| 605 | * and we can just re-use it all.
|
| 606 |
|
| 607 | if (atomic_read(&oldsighand->count) <= 1) {
|
| 608 | BUG_ON(atomic_read(&sig->count) != 1);
|
| 609 | exit_itimers(sig);
|
| 610 | return 0;
|
| 611 | }
|
| 612 |
|
| 613 | newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
|
| 614 | if (!newsighand)
|
| 615 | return -ENOMEM;
|
| 616 |
|
| 617 | if (thread_group_empty(current))
|
| 618 | goto no_thread_group;
|
| 619 |
|
| 620 | |
| 621 | * Kill all other threads in the thread group.
|
| 622 | * We must hold tasklist_lock to call zap_other_threads.
|
| 623 |
|
| 624 | read_lock(&tasklist_lock);
|
| 625 | spin_lock_irq(lock);
|
| 626 | if (sig->flags & SIGNAL_GROUP_EXIT) {
|
| 627 | |
| 628 | * Another group action in progress, just
|
| 629 | * return so that the signal is processed.
|
| 630 |
|
| 631 | spin_unlock_irq(lock);
|
| 632 | read_unlock(&tasklist_lock);
|
| 633 | kmem_cache_free(sighand_cachep, newsighand);
|
| 634 | return -EAGAIN;
|
| 635 | }
|
| 636 | zap_other_threads(current);
|
| 637 | read_unlock(&tasklist_lock);
|
| 638 |
|
| 639 | |
| 640 | * Account for the thread group leader hanging around:
|
| 641 |
|
| 642 | count = 2;
|
| 643 | if (thread_group_leader(current))
|
| 644 | count = 1;
|
| 645 | else {
|
| 646 | |
| 647 | * The SIGALRM timer survives the exec, but needs to point
|
| 648 | * at us as the new group leader now. We have a race with
|
| 649 | * a timer firing now getting the old leader, so we need to
|
| 650 | * synchronize with any firing (by calling del_timer_sync)
|
| 651 | * before we can safely let the old group leader die.
|
| 652 |
|
| 653 | sig->real_timer.data = (unsigned long)current;
|
| 654 | if (del_timer_sync(&sig->real_timer))
|
| 655 | add_timer(&sig->real_timer);
|
| 656 | }
|
| 657 | while (atomic_read(&sig->count) > count) {
|
| 658 | sig->group_exit_task = current;
|
| 659 | sig->notify_count = count;
|
| 660 | __set_current_state(TASK_UNINTERRUPTIBLE);
|
| 661 | spin_unlock_irq(lock);
|
| 662 | schedule();
|
| 663 | spin_lock_irq(lock);
|
| 664 | }
|
| 665 | sig->group_exit_task = NULL;
|
| 666 | sig->notify_count = 0;
|
| 667 | sig->real_timer.data = (unsigned long)current;
|
| 668 | spin_unlock_irq(lock);
|
| 669 |
|
| 670 | |
| 671 | * At this point all other threads have exited, all we have to
|
| 672 | * do is to wait for the thread group leader to become inactive,
|
| 673 | * and to assume its PID:
|
| 674 |
|
| 675 | if (!thread_group_leader(current)) {
|
| 676 | struct task_struct *leader = current->group_leader, *parent;
|
| 677 | struct dentry *proc_dentry1, *proc_dentry2;
|
| 678 | unsigned long exit_state, ptrace;
|
| 679 |
|
| 680 | |
| 681 | * Wait for the thread group leader to be a zombie.
|
| 682 | * It should already be zombie at this point, most
|
| 683 | * of the time.
|
| 684 |
|
| 685 | while (leader->exit_state != EXIT_ZOMBIE)
|
| 686 | yield();
|
| 687 |
|
| 688 | spin_lock(&leader->proc_lock);
|
| 689 | spin_lock(¤t->proc_lock);
|
| 690 | proc_dentry1 = proc_pid_unhash(current);
|
| 691 | proc_dentry2 = proc_pid_unhash(leader);
|
| 692 | write_lock_irq(&tasklist_lock);
|
| 693 |
|
| 694 | BUG_ON(leader->tgid != current->tgid);
|
| 695 | BUG_ON(current->pid == current->tgid);
|
| 696 | |
| 697 | * An exec() starts a new thread group with the
|
| 698 | * TGID of the previous thread group. Rehash the
|
| 699 | * two threads with a switched PID, and release
|
| 700 | * the former thread group leader:
|
| 701 |
|
| 702 | ptrace = leader->ptrace;
|
| 703 | parent = leader->parent;
|
| 704 | if (unlikely(ptrace) && unlikely(parent == current)) {
|
| 705 | |
| 706 | * Joker was ptracing his own group leader,
|
| 707 | * and now he wants to be his own parent!
|
| 708 | * We can't have that.
|
| 709 |
|
| 710 | ptrace = 0;
|
| 711 | }
|
| 712 |
|
| 713 | ptrace_unlink(current);
|
| 714 | ptrace_unlink(leader);
|
| 715 | remove_parent(current);
|
| 716 | remove_parent(leader);
|
| 717 |
|
| 718 | switch_exec_pids(leader, current);
|
| 719 |
|
| 720 | current->parent = current->real_parent = leader->real_parent;
|
| 721 | leader->parent = leader->real_parent = child_reaper;
|
| 722 | current->group_leader = current;
|
| 723 | leader->group_leader = leader;
|
| 724 |
|
| 725 | add_parent(current, current->parent);
|
| 726 | add_parent(leader, leader->parent);
|
| 727 | if (ptrace) {
|
| 728 | current->ptrace = ptrace;
|
| 729 | __ptrace_link(current, parent);
|
| 730 | }
|
| 731 |
|
| 732 | list_del(¤t->tasks);
|
| 733 | list_add_tail(¤t->tasks, &init_task.tasks);
|
| 734 | current->exit_signal = SIGCHLD;
|
| 735 | exit_state = leader->exit_state;
|
| 736 |
|
| 737 | write_unlock_irq(&tasklist_lock);
|
| 738 | spin_unlock(&leader->proc_lock);
|
| 739 | spin_unlock(¤t->proc_lock);
|
| 740 | proc_pid_flush(proc_dentry1);
|
| 741 | proc_pid_flush(proc_dentry2);
|
| 742 |
|
| 743 | BUG_ON(exit_state != EXIT_ZOMBIE);
|
| 744 | release_task(leader);
|
| 745 | }
|
| 746 |
|
| 747 | |
| 748 | * Now there are really no other threads at all,
|
| 749 | * so it's safe to stop telling them to kill themselves.
|
| 750 |
|
| 751 | sig->flags = 0;
|
| 752 |
|
| 753 | no_thread_group:
|
| 754 | BUG_ON(atomic_read(&sig->count) != 1);
|
| 755 | exit_itimers(sig);
|
| 756 |
|
| 757 | if (atomic_read(&oldsighand->count) == 1) {
|
| 758 | |
| 759 | * Now that we nuked the rest of the thread group,
|
| 760 | * it turns out we are not sharing sighand any more either.
|
| 761 | * So we can just keep it.
|
| 762 |
|
| 763 | kmem_cache_free(sighand_cachep, newsighand);
|
| 764 | } else {
|
| 765 | |
| 766 | * Move our state over to newsighand and switch it in.
|
| 767 |
|
| 768 | spin_lock_init(&newsighand->siglock);
|
| 769 | atomic_set(&newsighand->count, 1);
|
| 770 | memcpy(newsighand->action, oldsighand->action,
|
| 771 | sizeof(newsighand->action));
|
| 772 |
|
| 773 | write_lock_irq(&tasklist_lock);
|
| 774 | spin_lock(&oldsighand->siglock);
|
| 775 | spin_lock(&newsighand->siglock);
|
| 776 |
|
| 777 | current->sighand = newsighand;
|
| 778 | recalc_sigpending();
|
| 779 |
|
| 780 | spin_unlock(&newsighand->siglock);
|
| 781 | spin_unlock(&oldsighand->siglock);
|
| 782 | write_unlock_irq(&tasklist_lock);
|
| 783 |
|
| 784 | if (atomic_dec_and_test(&oldsighand->count))
|
| 785 | kmem_cache_free(sighand_cachep, oldsighand);
|
| 786 | }
|
| 787 |
|
| 788 | BUG_ON(!thread_group_empty(current));
|
| 789 | BUG_ON(!thread_group_leader(current));
|
| 790 | return 0;
|
| 791 | }
|
| 792 |
|
| 793 | |
| 794 | * These functions flushes out all traces of the currently running executable
|
| 795 | * so that a new one can be started
|
| 796 |
|
| 797 |
|
| 798 | static inline void flush_old_files(struct files_struct * files)
|
| 799 | {
|
| 800 | long j = -1;
|
| 801 |
|
| 802 | spin_lock(&files->file_lock);
|
| 803 | for (;;) {
|
| 804 | unsigned long set, i;
|
| 805 |
|
| 806 | j++;
|
| 807 | i = j * __NFDBITS;
|
| 808 | if (i >= files->max_fds || i >= files->max_fdset)
|
| 809 | break;
|
| 810 | set = files->close_on_exec->fds_bits[j];
|
| 811 | if (!set)
|
| 812 | continue;
|
| 813 | files->close_on_exec->fds_bits[j] = 0;
|
| 814 | spin_unlock(&files->file_lock);
|
| 815 | for ( ; set ; i++,set >>= 1) {
|
| 816 | if (set & 1) {
|
| 817 | sys_close(i);
|
| 818 | }
|
| 819 | }
|
| 820 | spin_lock(&files->file_lock);
|
| 821 |
|
| 822 | }
|
| 823 | spin_unlock(&files->file_lock);
|
| 824 | }
|
| 825 |
|
| 826 | void get_task_comm(char *buf, struct task_struct *tsk)
|
| 827 | {
|
| 828 |
|
| 829 | task_lock(tsk);
|
| 830 | strncpy(buf, tsk->comm, sizeof(tsk->comm));
|
| 831 | task_unlock(tsk);
|
| 832 | }
|
| 833 |
|
| 834 | void set_task_comm(struct task_struct *tsk, char *buf)
|
| 835 | {
|
| 836 | task_lock(tsk);
|
| 837 | strlcpy(tsk->comm, buf, sizeof(tsk->comm));
|
| 838 | task_unlock(tsk);
|
| 839 | }
|
| 840 |
|
| 841 | int flush_old_exec(struct linux_binprm * bprm)
|
| 842 | {
|
| 843 | char * name;
|
| 844 | int i, ch, retval;
|
| 845 | struct files_struct *files;
|
| 846 | char tcomm[sizeof(current->comm)];
|
| 847 |
|
| 848 | |
| 849 | * Make sure we have a private signal table and that
|
| 850 | * we are unassociated from the previous thread group.
|
| 851 |
|
| 852 | retval = de_thread(current);
|
| 853 | if (retval)
|
| 854 | goto out;
|
| 855 |
|
| 856 | |
| 857 | * Make sure we have private file handles. Ask the
|
| 858 | * fork helper to do the work for us and the exit
|
| 859 | * helper to do the cleanup of the old one.
|
| 860 |
|
| 861 | files = current->files;
|
| 862 | retval = unshare_files();
|
| 863 | if (retval)
|
| 864 | goto out;
|
| 865 | |
| 866 | * Release all of the old mmap stuff
|
| 867 |
|
| 868 | retval = exec_mmap(bprm->mm);
|
| 869 | if (retval)
|
| 870 | goto mmap_failed;
|
| 871 |
|
| 872 | bprm->mm = NULL;
|
| 873 |
|
| 874 |
|
| 875 | steal_locks(files);
|
| 876 | put_files_struct(files);
|
| 877 |
|
| 878 | current->sas_ss_sp = current->sas_ss_size = 0;
|
| 879 |
|
| 880 | if (current->euid == current->uid && current->egid == current->gid)
|
| 881 | current->mm->dumpable = 1;
|
| 882 | else
|
| 883 | current->mm->dumpable = suid_dumpable;
|
| 884 |
|
| 885 | name = bprm->filename;
|
| 886 |
|
| 887 |
|
| 888 | for (i=0; (ch = *(name++)) != '\0';) {
|
| 889 | if (ch == '/')
|
| 890 | i = 0;
|
| 891 | else
|
| 892 | if (i < (sizeof(tcomm) - 1))
|
| 893 | tcomm[i++] = ch;
|
| 894 | }
|
| 895 | tcomm[i] = '\0';
|
| 896 | set_task_comm(current, tcomm);
|
| 897 |
|
| 898 | current->flags &= ~PF_RANDOMIZE;
|
| 899 | flush_thread();
|
| 900 |
|
| 901 | if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
|
| 902 | permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
|
| 903 | (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
|
| 904 | suid_keys(current);
|
| 905 | current->mm->dumpable = suid_dumpable;
|
| 906 | }
|
| 907 |
|
| 908 | |
| 909 | group
|
| 910 |
|
| 911 | current->self_exec_id++;
|
| 912 |
|
| 913 | flush_signal_handlers(current, 0);
|
| 914 | flush_old_files(current->files);
|
| 915 |
|
| 916 | return 0;
|
| 917 |
|
| 918 | mmap_failed:
|
| 919 | put_files_struct(current->files);
|
| 920 | current->files = files;
|
| 921 | out:
|
| 922 | return retval;
|
| 923 | }
|
| 924 |
|
| 925 | EXPORT_SYMBOL(flush_old_exec);
|
| 926 |
|
| 927 | |
| 928 | * Fill the binprm structure from the inode.
|
| 929 | * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
|
| 930 |
|
| 931 | int prepare_binprm(struct linux_binprm *bprm)
|
| 932 | {
|
| 933 | int mode;
|
| 934 | struct inode * inode = bprm->file->f_dentry->d_inode;
|
| 935 | int retval;
|
| 936 |
|
| 937 | mode = inode->i_mode;
|
| 938 | |
| 939 | * Check execute perms again - if the caller has CAP_DAC_OVERRIDE,
|
| 940 | * generic_permission lets a non-executable through
|
| 941 |
|
| 942 | if (!(mode & 0111))
|
| 943 | return -EACCES;
|
| 944 | if (bprm->file->f_op == NULL)
|
| 945 | return -EACCES;
|
| 946 |
|
| 947 | bprm->e_uid = current->euid;
|
| 948 | bprm->e_gid = current->egid;
|
| 949 |
|
| 950 | if(!(bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)) {
|
| 951 |
|
| 952 | if (mode & S_ISUID) {
|
| 953 | current->personality &= ~PER_CLEAR_ON_SETID;
|
| 954 | bprm->e_uid = inode->i_uid;
|
| 955 | }
|
| 956 |
|
| 957 |
|
| 958 | |
| 959 | * If setgid is set but no group execute bit then this
|
| 960 | * is a candidate for mandatory locking, not a setgid
|
| 961 | * executable.
|
| 962 |
|
| 963 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
|
| 964 | current->personality &= ~PER_CLEAR_ON_SETID;
|
| 965 | bprm->e_gid = inode->i_gid;
|
| 966 | }
|
| 967 | }
|
| 968 |
|
| 969 |
|
| 970 | retval = security_bprm_set(bprm);
|
| 971 | if (retval)
|
| 972 | return retval;
|
| 973 |
|
| 974 | memset(bprm->buf,0,BINPRM_BUF_SIZE);
|
| 975 | return kernel_read(bprm->file,0,bprm->buf,BINPRM_BUF_SIZE);
|
| 976 | }
|
| 977 |
|
| 978 | EXPORT_SYMBOL(prepare_binprm);
|
| 979 |
|
| 980 | static inline int unsafe_exec(struct task_struct *p)
|
| 981 | {
|
| 982 | int unsafe = 0;
|
| 983 | if (p->ptrace & PT_PTRACED) {
|
| 984 | if (p->ptrace & PT_PTRACE_CAP)
|
| 985 | unsafe |= LSM_UNSAFE_PTRACE_CAP;
|
| 986 | else
|
| 987 | unsafe |= LSM_UNSAFE_PTRACE;
|
| 988 | }
|
| 989 | if (atomic_read(&p->fs->count) > 1 ||
|
| 990 | atomic_read(&p->files->count) > 1 ||
|
| 991 | atomic_read(&p->sighand->count) > 1)
|
| 992 | unsafe |= LSM_UNSAFE_SHARE;
|
| 993 |
|
| 994 | return unsafe;
|
| 995 | }
|
| 996 |
|
| 997 | void compute_creds(struct linux_binprm *bprm)
|
| 998 | {
|
| 999 | int unsafe;
|
| 1000 |
|
| 1001 | if (bprm->e_uid != current->uid)
|
| 1002 | suid_keys(current);
|
| 1003 | exec_keys(current);
|
| 1004 |
|
| 1005 | task_lock(current);
|
| 1006 | unsafe = unsafe_exec(current);
|
| 1007 | security_bprm_apply_creds(bprm, unsafe);
|
| 1008 | task_unlock(current);
|
| 1009 | security_bprm_post_apply_creds(bprm);
|
| 1010 | }
|
| 1011 |
|
| 1012 | EXPORT_SYMBOL(compute_creds);
|
| 1013 |
|
| 1014 | void remove_arg_zero(struct linux_binprm *bprm)
|
| 1015 | {
|
| 1016 | if (bprm->argc) {
|
| 1017 | unsigned long offset;
|
| 1018 | char * kaddr;
|
| 1019 | struct page *page;
|
| 1020 |
|
| 1021 | offset = bprm->p % PAGE_SIZE;
|
| 1022 | goto inside;
|
| 1023 |
|
| 1024 | while (bprm->p++, *(kaddr+offset++)) {
|
| 1025 | if (offset != PAGE_SIZE)
|
| 1026 | continue;
|
| 1027 | offset = 0;
|
| 1028 | kunmap_atomic(kaddr, KM_USER0);
|
| 1029 | inside:
|
| 1030 | page = bprm->page[bprm->p/PAGE_SIZE];
|
| 1031 | kaddr = kmap_atomic(page, KM_USER0);
|
| 1032 | }
|
| 1033 | kunmap_atomic(kaddr, KM_USER0);
|
| 1034 | bprm->argc--;
|
| 1035 | }
|
| 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 |
|
| 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 |
|
| 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 | |
| 1078 | but it does not matter
|
| 1079 | }
|
| 1080 | }
|
| 1081 | #endif
|
| 1082 | retval = security_bprm_check(bprm);
|
| 1083 | if (retval)
|
| 1084 | return retval;
|
| 1085 |
|
| 1086 |
|
| 1087 |
|
| 1088 | set_fs(USER_DS);
|
| 1089 | retval = -ENOENT;
|
| 1090 | for (try=0; try<2; try++) {
|
| 1091 | read_lock(&binfmt_lock);
|
| 1092 | for (fmt = formats ; fmt ; fmt = fmt->next) {
|
| 1093 | int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
|
| 1094 | if (!fn)
|
| 1095 | continue;
|
| 1096 | if (!try_module_get(fmt->module))
|
| 1097 | continue;
|
| 1098 | read_unlock(&binfmt_lock);
|
| 1099 | retval = fn(bprm, regs);
|
| 1100 | if (retval >= 0) {
|
| 1101 | put_binfmt(fmt);
|
| 1102 | allow_write_access(bprm->file);
|
| 1103 | if (bprm->file)
|
| 1104 | fput(bprm->file);
|
| 1105 | bprm->file = NULL;
|
| 1106 | current->did_exec = 1;
|
| 1107 | return retval;
|
| 1108 | }
|
| 1109 | read_lock(&binfmt_lock);
|
| 1110 | put_binfmt(fmt);
|
| 1111 | if (retval != -ENOEXEC || bprm->mm == NULL)
|
| 1112 | break;
|
| 1113 | if (!bprm->file) {
|
| 1114 | read_unlock(&binfmt_lock);
|
| 1115 | return retval;
|
| 1116 | }
|
| 1117 | }
|
| 1118 | read_unlock(&binfmt_lock);
|
| 1119 | if (retval != -ENOEXEC || bprm->mm == NULL) {
|
| 1120 | break;
|
| 1121 | #ifdef CONFIG_KMOD
|
| 1122 | }else{
|
| 1123 | #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
|
| 1124 | if (printable(bprm->buf[0]) &&
|
| 1125 | printable(bprm->buf[1]) &&
|
| 1126 | printable(bprm->buf[2]) &&
|
| 1127 | printable(bprm->buf[3]))
|
| 1128 | break;
|
| 1129 | request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
|
| 1130 | #endif
|
| 1131 | }
|
| 1132 | }
|
| 1133 | return retval;
|
| 1134 | }
|
| 1135 |
|
| 1136 | EXPORT_SYMBOL(search_binary_handler);
|
| 1137 |
|
| 1138 | |
| 1139 | * sys_execve() executes a new program.
|
| 1140 |
|
| 1141 | int do_execve(char * filename,
|
| 1142 | char __user *__user *argv,
|
| 1143 | char __user *__user *envp,
|
| 1144 | struct pt_regs * regs)
|
| 1145 | {
|
| 1146 | struct linux_binprm *bprm;
|
| 1147 | struct file *file;
|
| 1148 | int retval;
|
| 1149 | int i;
|
| 1150 |
|
| 1151 | retval = -ENOMEM;
|
| 1152 | bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
|
| 1153 | if (!bprm)
|
| 1154 | goto out_ret;
|
| 1155 | memset(bprm, 0, sizeof(*bprm));
|
| 1156 |
|
| 1157 | file = open_exec(filename);
|
| 1158 | retval = PTR_ERR(file);
|
| 1159 | if (IS_ERR(file))
|
| 1160 | goto out_kfree;
|
| 1161 |
|
| 1162 | sched_exec();
|
| 1163 |
|
| 1164 | bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
|
| 1165 |
|
| 1166 | bprm->file = file;
|
| 1167 | bprm->filename = filename;
|
| 1168 | bprm->interp = filename;
|
| 1169 | bprm->mm = mm_alloc();
|
| 1170 | retval = -ENOMEM;
|
| 1171 | if (!bprm->mm)
|
| 1172 | goto out_file;
|
| 1173 |
|
| 1174 | retval = init_new_context(current, bprm->mm);
|
| 1175 | if (retval < 0)
|
| 1176 | goto out_mm;
|
| 1177 |
|
| 1178 | bprm->argc = count(argv, bprm->p / sizeof(void *));
|
| 1179 | if ((retval = bprm->argc) < 0)
|
| 1180 | goto out_mm;
|
| 1181 |
|
| 1182 | bprm->envc = count(envp, bprm->p / sizeof(void *));
|
| 1183 | if ((retval = bprm->envc) < 0)
|
| 1184 | goto out_mm;
|
| 1185 |
|
| 1186 | retval = security_bprm_alloc(bprm);
|
| 1187 | if (retval)
|
| 1188 | goto out;
|
| 1189 |
|
| 1190 | retval = prepare_binprm(bprm);
|
| 1191 | if (retval < 0)
|
| 1192 | goto out;
|
| 1193 |
|
| 1194 | retval = copy_strings_kernel(1, &bprm->filename, bprm);
|
| 1195 | if (retval < 0)
|
| 1196 | goto out;
|
| 1197 |
|
| 1198 | bprm->exec = bprm->p;
|
| 1199 | retval = copy_strings(bprm->envc, envp, bprm);
|
| 1200 | if (retval < 0)
|
| 1201 | goto out;
|
| 1202 |
|
| 1203 | retval = copy_strings(bprm->argc, argv, bprm);
|
| 1204 | if (retval < 0)
|
| 1205 | goto out;
|
| 1206 |
|
| 1207 | retval = search_binary_handler(bprm,regs);
|
| 1208 | if (retval >= 0) {
|
| 1209 | free_arg_pages(bprm);
|
| 1210 |
|
| 1211 |
|
| 1212 | security_bprm_free(bprm);
|
| 1213 | acct_update_integrals(current);
|
| 1214 | update_mem_hiwater(current);
|
| 1215 | kfree(bprm);
|
| 1216 | return retval;
|
| 1217 | }
|
| 1218 |
|
| 1219 | out:
|
| 1220 |
|
| 1221 | for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
|
| 1222 | struct page * page = bprm->page[i];
|
| 1223 | if (page)
|
| 1224 | __free_page(page);
|
| 1225 | }
|
| 1226 |
|
| 1227 | if (bprm->security)
|
| 1228 | security_bprm_free(bprm);
|
| 1229 |
|
| 1230 | out_mm:
|
| 1231 | if (bprm->mm)
|
| 1232 | mmdrop(bprm->mm);
|
| 1233 |
|
| 1234 | out_file:
|
| 1235 | if (bprm->file) {
|
| 1236 | allow_write_access(bprm->file);
|
| 1237 | fput(bprm->file);
|
| 1238 | }
|
| 1239 |
|
| 1240 | out_kfree:
|
| 1241 | kfree(bprm);
|
| 1242 |
|
| 1243 | out_ret:
|
| 1244 | return retval;
|
| 1245 | }
|
| 1246 |
|
| 1247 | int set_binfmt(struct linux_binfmt *new)
|
| 1248 | {
|
| 1249 | struct linux_binfmt *old = current->binfmt;
|
| 1250 |
|
| 1251 | if (new) {
|
| 1252 | if (!try_module_get(new->module))
|
| 1253 | return -1;
|
| 1254 | }
|
| 1255 | current->binfmt = new;
|
| 1256 | if (old)
|
| 1257 | module_put(old->module);
|
| 1258 | return 0;
|
| 1259 | }
|
| 1260 |
|
| 1261 | EXPORT_SYMBOL(set_binfmt);
|
| 1262 |
|
| 1263 | #define CORENAME_MAX_SIZE 64
|
| 1264 |
|
| 1265 | |
| 1266 | * name into corename, which must have space for at least
|
| 1267 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
|
| 1268 |
|
| 1269 | static void format_corename(char *corename, const char *pattern, long signr)
|
| 1270 | {
|
| 1271 | const char *pat_ptr = pattern;
|
| 1272 | char *out_ptr = corename;
|
| 1273 | char *const out_end = corename + CORENAME_MAX_SIZE;
|
| 1274 | int rc;
|
| 1275 | int pid_in_pattern = 0;
|
| 1276 |
|
| 1277 | |
| 1278 | space
|
| 1279 | while (*pat_ptr) {
|
| 1280 | if (*pat_ptr != '%') {
|
| 1281 | if (out_ptr == out_end)
|
| 1282 | goto out;
|
| 1283 | *out_ptr++ = *pat_ptr++;
|
| 1284 | } else {
|
| 1285 | switch (*++pat_ptr) {
|
| 1286 | case 0:
|
| 1287 | goto out;
|
| 1288 |
|
| 1289 | case '%':
|
| 1290 | if (out_ptr == out_end)
|
| 1291 | goto out;
|
| 1292 | *out_ptr++ = '%';
|
| 1293 | break;
|
| 1294 |
|
| 1295 | case 'p':
|
| 1296 | pid_in_pattern = 1;
|
| 1297 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1298 | "%d", current->tgid);
|
| 1299 | if (rc > out_end - out_ptr)
|
| 1300 | goto out;
|
| 1301 | out_ptr += rc;
|
| 1302 | break;
|
| 1303 |
|
| 1304 | case 'u':
|
| 1305 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1306 | "%d", current->uid);
|
| 1307 | if (rc > out_end - out_ptr)
|
| 1308 | goto out;
|
| 1309 | out_ptr += rc;
|
| 1310 | break;
|
| 1311 |
|
| 1312 | case 'g':
|
| 1313 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1314 | "%d", current->gid);
|
| 1315 | if (rc > out_end - out_ptr)
|
| 1316 | goto out;
|
| 1317 | out_ptr += rc;
|
| 1318 | break;
|
| 1319 |
|
| 1320 | case 's':
|
| 1321 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1322 | "%ld", signr);
|
| 1323 | if (rc > out_end - out_ptr)
|
| 1324 | goto out;
|
| 1325 | out_ptr += rc;
|
| 1326 | break;
|
| 1327 |
|
| 1328 | case 't': {
|
| 1329 | struct timeval tv;
|
| 1330 | do_gettimeofday(&tv);
|
| 1331 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1332 | "%lu", tv.tv_sec);
|
| 1333 | if (rc > out_end - out_ptr)
|
| 1334 | goto out;
|
| 1335 | out_ptr += rc;
|
| 1336 | break;
|
| 1337 | }
|
| 1338 |
|
| 1339 | case 'h':
|
| 1340 | down_read(&uts_sem);
|
| 1341 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1342 | "%s", system_utsname.nodename);
|
| 1343 | up_read(&uts_sem);
|
| 1344 | if (rc > out_end - out_ptr)
|
| 1345 | goto out;
|
| 1346 | out_ptr += rc;
|
| 1347 | break;
|
| 1348 |
|
| 1349 | case 'e':
|
| 1350 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1351 | "%s", current->comm);
|
| 1352 | if (rc > out_end - out_ptr)
|
| 1353 | goto out;
|
| 1354 | out_ptr += rc;
|
| 1355 | break;
|
| 1356 | default:
|
| 1357 | break;
|
| 1358 | }
|
| 1359 | ++pat_ptr;
|
| 1360 | }
|
| 1361 | }
|
| 1362 | |
| 1363 | *
|
| 1364 | * If core_pattern does not include a %p (as is the default)
|
| 1365 | * and core_uses_pid is set, then .%pid will be appended to
|
| 1366 | * the filename
|
| 1367 | if (!pid_in_pattern
|
| 1368 | && (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)) {
|
| 1369 | rc = snprintf(out_ptr, out_end - out_ptr,
|
| 1370 | ".%d", current->tgid);
|
| 1371 | if (rc > out_end - out_ptr)
|
| 1372 | goto out;
|
| 1373 | out_ptr += rc;
|
| 1374 | }
|
| 1375 | out:
|
| 1376 | *out_ptr = 0;
|
| 1377 | }
|
| 1378 |
|
| 1379 | static void zap_threads (struct mm_struct *mm)
|
| 1380 | {
|
| 1381 | struct task_struct *g, *p;
|
| 1382 | struct task_struct *tsk = current;
|
| 1383 | struct completion *vfork_done = tsk->vfork_done;
|
| 1384 | int traced = 0;
|
| 1385 |
|
| 1386 | |
| 1387 | * Make sure nobody is waiting for us to release the VM,
|
| 1388 | * otherwise we can deadlock when we wait on each other
|
| 1389 |
|
| 1390 | if (vfork_done) {
|
| 1391 | tsk->vfork_done = NULL;
|
| 1392 | complete(vfork_done);
|
| 1393 | }
|
| 1394 |
|
| 1395 | read_lock(&tasklist_lock);
|
| 1396 | do_each_thread(g,p)
|
| 1397 | if (mm == p->mm && p != tsk) {
|
| 1398 | force_sig_specific(SIGKILL, p);
|
| 1399 | mm->core_waiters++;
|
| 1400 | if (unlikely(p->ptrace) &&
|
| 1401 | unlikely(p->parent->mm == mm))
|
| 1402 | traced = 1;
|
| 1403 | }
|
| 1404 | while_each_thread(g,p);
|
| 1405 |
|
| 1406 | read_unlock(&tasklist_lock);
|
| 1407 |
|
| 1408 | if (unlikely(traced)) {
|
| 1409 | |
| 1410 | * We are zapping a thread and the thread it ptraces.
|
| 1411 | * If the tracee went into a ptrace stop for exit tracing,
|
| 1412 | * we could deadlock since the tracer is waiting for this
|
| 1413 | * coredump to finish. Detach them so they can both die.
|
| 1414 |
|
| 1415 | write_lock_irq(&tasklist_lock);
|
| 1416 | do_each_thread(g,p) {
|
| 1417 | if (mm == p->mm && p != tsk &&
|
| 1418 | p->ptrace && p->parent->mm == mm) {
|
| 1419 | __ptrace_unlink(p);
|
| 1420 | }
|
| 1421 | } while_each_thread(g,p);
|
| 1422 | write_unlock_irq(&tasklist_lock);
|
| 1423 | }
|
| 1424 | }
|
| 1425 |
|
| 1426 | static void coredump_wait(struct mm_struct *mm)
|
| 1427 | {
|
| 1428 | DECLARE_COMPLETION(startup_done);
|
| 1429 |
|
| 1430 | mm->core_waiters++;
|
| 1431 | mm->core_startup_done = &startup_done;
|
| 1432 |
|
| 1433 |
|
| 1434 | yield();
|
| 1435 |
|
| 1436 | zap_threads(mm);
|
| 1437 | if (--mm->core_waiters) {
|
| 1438 | up_write(&mm->mmap_sem);
|
| 1439 | wait_for_completion(&startup_done);
|
| 1440 | } else
|
| 1441 | up_write(&mm->mmap_sem);
|
| 1442 | BUG_ON(mm->core_waiters);
|
| 1443 | }
|
| 1444 |
|
| 1445 | int do_coredump(long signr, int exit_code, struct pt_regs * regs)
|
| 1446 | {
|
| 1447 | char corename[CORENAME_MAX_SIZE + 1];
|
| 1448 | struct mm_struct *mm = current->mm;
|
| 1449 | struct linux_binfmt * binfmt;
|
| 1450 | struct inode * inode;
|
| 1451 | struct file * file;
|
| 1452 | int retval = 0;
|
| 1453 | int fsuid = current->fsuid;
|
| 1454 | int flag = 0;
|
| 1455 |
|
| 1456 | binfmt = current->binfmt;
|
| 1457 | if (!binfmt || !binfmt->core_dump)
|
| 1458 | goto fail;
|
| 1459 | down_write(&mm->mmap_sem);
|
| 1460 | if (!mm->dumpable) {
|
| 1461 | up_write(&mm->mmap_sem);
|
| 1462 | goto fail;
|
| 1463 | }
|
| 1464 |
|
| 1465 | |
| 1466 | * We cannot trust fsuid as being the "true" uid of the
|
| 1467 | * process nor do we know its entire history. We only know it
|
| 1468 | * was tainted so we dump it as root in mode 2.
|
| 1469 |
|
| 1470 | if (mm->dumpable == 2) {
|
| 1471 | flag = O_EXCL;
|
| 1472 | current->fsuid = 0;
|
| 1473 | }
|
| 1474 | mm->dumpable = 0;
|
| 1475 | init_completion(&mm->core_done);
|
| 1476 | spin_lock_irq(¤t->sighand->siglock);
|
| 1477 | current->signal->flags = SIGNAL_GROUP_EXIT;
|
| 1478 | current->signal->group_exit_code = exit_code;
|
| 1479 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1480 | coredump_wait(mm);
|
| 1481 |
|
| 1482 | |
| 1483 | * Clear any false indication of pending signals that might
|
| 1484 | * be seen by the filesystem code called to write the core file.
|
| 1485 |
|
| 1486 | current->signal->group_stop_count = 0;
|
| 1487 | clear_thread_flag(TIF_SIGPENDING);
|
| 1488 |
|
| 1489 | if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
|
| 1490 | goto fail_unlock;
|
| 1491 |
|
| 1492 | |
| 1493 | * lock_kernel() because format_corename() is controlled by sysctl, which
|
| 1494 | * uses lock_kernel()
|
| 1495 |
|
| 1496 | lock_kernel();
|
| 1497 | format_corename(corename, core_pattern, signr);
|
| 1498 | unlock_kernel();
|
| 1499 | file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
|
| 1500 | if (IS_ERR(file))
|
| 1501 | goto fail_unlock;
|
| 1502 | inode = file->f_dentry->d_inode;
|
| 1503 | if (inode->i_nlink > 1)
|
| 1504 | goto close_fail;
|
| 1505 | if (d_unhashed(file->f_dentry))
|
| 1506 | goto close_fail;
|
| 1507 |
|
| 1508 | if (!S_ISREG(inode->i_mode))
|
| 1509 | goto close_fail;
|
| 1510 | if (!file->f_op)
|
| 1511 | goto close_fail;
|
| 1512 | if (!file->f_op->write)
|
| 1513 | goto close_fail;
|
| 1514 | if (do_truncate(file->f_dentry, 0) != 0)
|
| 1515 | goto close_fail;
|
| 1516 |
|
| 1517 | retval = binfmt->core_dump(signr, regs, file);
|
| 1518 |
|
| 1519 | if (retval)
|
| 1520 | current->signal->group_exit_code |= 0x80;
|
| 1521 | close_fail:
|
| 1522 | filp_close(file, NULL);
|
| 1523 | fail_unlock:
|
| 1524 | current->fsuid = fsuid;
|
| 1525 | complete_all(&mm->core_done);
|
| 1526 | fail:
|
| 1527 | return retval;
|
| 1528 | }
|