1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/fs/exec.c
   4 *
   5 *  Copyright (C) 1991, 1992  Linus Torvalds
   6 */
   7
   8/*
   9 * #!-checking implemented by tytso.
  10 */
  11/*
  12 * Demand-loading implemented 01.12.91 - no need to read anything but
  13 * the header into memory. The inode of the executable is put into
  14 * "current->executable", and page faults do the actual loading. Clean.
  15 *
  16 * Once more I can proudly say that linux stood up to being changed: it
  17 * was less than 2 hours work to get demand-loading completely implemented.
  18 *
  19 * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
  20 * current->executable is only used by the procfs.  This allows a dispatch
  21 * table to check for several different types  of binary formats.  We keep
  22 * trying until we recognize the file or we run out of supported binary
  23 * formats.
  24 */
  25
  26#include <linux/kernel_read_file.h>
  27#include <linux/slab.h>
  28#include <linux/file.h>
  29#include <linux/fdtable.h>
  30#include <linux/mm.h>
  31#include <linux/stat.h>
  32#include <linux/fcntl.h>
  33#include <linux/swap.h>
  34#include <linux/string.h>
  35#include <linux/init.h>
  36#include <linux/sched/mm.h>
  37#include <linux/sched/coredump.h>
  38#include <linux/sched/signal.h>
  39#include <linux/sched/numa_balancing.h>
  40#include <linux/sched/task.h>
  41#include <linux/pagemap.h>
  42#include <linux/perf_event.h>
  43#include <linux/highmem.h>
  44#include <linux/spinlock.h>
  45#include <linux/key.h>
  46#include <linux/personality.h>
  47#include <linux/binfmts.h>
  48#include <linux/utsname.h>
  49#include <linux/pid_namespace.h>
  50#include <linux/module.h>
  51#include <linux/namei.h>
  52#include <linux/mount.h>
  53#include <linux/security.h>
  54#include <linux/syscalls.h>
  55#include <linux/tsacct_kern.h>
  56#include <linux/cn_proc.h>
  57#include <linux/audit.h>
  58#include <linux/kmod.h>
  59#include <linux/fsnotify.h>
  60#include <linux/fs_struct.h>
  61#include <linux/oom.h>
  62#include <linux/compat.h>
  63#include <linux/vmalloc.h>
  64#include <linux/io_uring.h>
  65#include <linux/syscall_user_dispatch.h>
  66#include <linux/coredump.h>
  67#include <linux/time_namespace.h>
  68#include <linux/user_events.h>
  69#include <linux/rseq.h>
  70#include <linux/ksm.h>
  71
  72#include <linux/uaccess.h>
  73#include <asm/mmu_context.h>
  74#include <asm/tlb.h>
  75
  76#include <trace/events/task.h>
  77#include "internal.h"
  78
  79#include <trace/events/sched.h>
  80
  81static int bprm_creds_from_file(struct linux_binprm *bprm);
  82
  83int suid_dumpable = 0;
  84
  85static LIST_HEAD(formats);
  86static DEFINE_RWLOCK(binfmt_lock);
  87
  88void __register_binfmt(struct linux_binfmt * fmt, int insert)
  89{
  90	write_lock(&binfmt_lock);
  91	insert ? list_add(&fmt->lh, &formats) :
  92		 list_add_tail(&fmt->lh, &formats);
  93	write_unlock(&binfmt_lock);
  94}
  95
  96EXPORT_SYMBOL(__register_binfmt);
  97
  98void unregister_binfmt(struct linux_binfmt * fmt)
  99{
 100	write_lock(&binfmt_lock);
 101	list_del(&fmt->lh);
 102	write_unlock(&binfmt_lock);
 103}
 104
 105EXPORT_SYMBOL(unregister_binfmt);
 106
 107static inline void put_binfmt(struct linux_binfmt * fmt)
 108{
 109	module_put(fmt->module);
 110}
 111
 112bool path_noexec(const struct path *path)
 113{
 114	return (path->mnt->mnt_flags & MNT_NOEXEC) ||
 115	       (path->mnt->mnt_sb->s_iflags & SB_I_NOEXEC);
 116}
 117
 118#ifdef CONFIG_USELIB
 119/*
 120 * Note that a shared library must be both readable and executable due to
 121 * security reasons.
 122 *
 123 * Also note that we take the address to load from the file itself.
 124 */
 125SYSCALL_DEFINE1(uselib, const char __user *, library)
 126{
 127	struct linux_binfmt *fmt;
 128	struct file *file;
 129	struct filename *tmp = getname(library);
 130	int error = PTR_ERR(tmp);
 131	static const struct open_flags uselib_flags = {
 132		.open_flag = O_LARGEFILE | O_RDONLY,
 133		.acc_mode = MAY_READ | MAY_EXEC,
 134		.intent = LOOKUP_OPEN,
 135		.lookup_flags = LOOKUP_FOLLOW,
 136	};
 137
 138	if (IS_ERR(tmp))
 139		goto out;
 140
 141	file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);
 142	putname(tmp);
 143	error = PTR_ERR(file);
 144	if (IS_ERR(file))
 145		goto out;
 146
 147	/*
 148	 * may_open() has already checked for this, so it should be
 149	 * impossible to trip now. But we need to be extra cautious
 150	 * and check again at the very end too.
 151	 */
 152	error = -EACCES;
 153	if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
 154			 path_noexec(&file->f_path)))
 155		goto exit;
 156
 157	error = -ENOEXEC;
 158
 159	read_lock(&binfmt_lock);
 160	list_for_each_entry(fmt, &formats, lh) {
 161		if (!fmt->load_shlib)
 162			continue;
 163		if (!try_module_get(fmt->module))
 164			continue;
 165		read_unlock(&binfmt_lock);
 166		error = fmt->load_shlib(file);
 167		read_lock(&binfmt_lock);
 168		put_binfmt(fmt);
 169		if (error != -ENOEXEC)
 170			break;
 171	}
 172	read_unlock(&binfmt_lock);
 173exit:
 174	fput(file);
 175out:
 176	return error;
 177}
 178#endif /* #ifdef CONFIG_USELIB */
 179
 180#ifdef CONFIG_MMU
 181/*
 182 * The nascent bprm->mm is not visible until exec_mmap() but it can
 183 * use a lot of memory, account these pages in current->mm temporary
 184 * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
 185 * change the counter back via acct_arg_size(0).
 186 */
 187static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
 188{
 189	struct mm_struct *mm = current->mm;
 190	long diff = (long)(pages - bprm->vma_pages);
 191
 192	if (!mm || !diff)
 193		return;
 194
 195	bprm->vma_pages = pages;
 196	add_mm_counter(mm, MM_ANONPAGES, diff);
 197}
 198
 199static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 200		int write)
 201{
 202	struct page *page;
 203	struct vm_area_struct *vma = bprm->vma;
 204	struct mm_struct *mm = bprm->mm;
 205	int ret;
 206
 207	/*
 208	 * Avoid relying on expanding the stack down in GUP (which
 209	 * does not work for STACK_GROWSUP anyway), and just do it
 210	 * by hand ahead of time.
 211	 */
 212	if (write && pos < vma->vm_start) {
 213		mmap_write_lock(mm);
 214		ret = expand_downwards(vma, pos);
 215		if (unlikely(ret < 0)) {
 216			mmap_write_unlock(mm);
 217			return NULL;
 218		}
 219		mmap_write_downgrade(mm);
 220	} else
 221		mmap_read_lock(mm);
 222
 223	/*
 224	 * We are doing an exec().  'current' is the process
 225	 * doing the exec and 'mm' is the new process's mm.
 226	 */
 227	ret = get_user_pages_remote(mm, pos, 1,
 228			write ? FOLL_WRITE : 0,
 229			&page, NULL);
 230	mmap_read_unlock(mm);
 231	if (ret <= 0)
 232		return NULL;
 233
 234	if (write)
 235		acct_arg_size(bprm, vma_pages(vma));
 236
 237	return page;
 238}
 239
 240static void put_arg_page(struct page *page)
 241{
 242	put_page(page);
 243}
 244
 245static void free_arg_pages(struct linux_binprm *bprm)
 246{
 247}
 248
 249static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
 250		struct page *page)
 251{
 252	flush_cache_page(bprm->vma, pos, page_to_pfn(page));
 253}
 254
 255static int __bprm_mm_init(struct linux_binprm *bprm)
 256{
 257	int err;
 258	struct vm_area_struct *vma = NULL;
 259	struct mm_struct *mm = bprm->mm;
 260
 261	bprm->vma = vma = vm_area_alloc(mm);
 262	if (!vma)
 263		return -ENOMEM;
 264	vma_set_anonymous(vma);
 265
 266	if (mmap_write_lock_killable(mm)) {
 267		err = -EINTR;
 268		goto err_free;
 269	}
 270
 271	/*
 272	 * Need to be called with mmap write lock
 273	 * held, to avoid race with ksmd.
 274	 */
 275	err = ksm_execve(mm);
 276	if (err)
 277		goto err_ksm;
 278
 279	/*
 280	 * Place the stack at the largest stack address the architecture
 281	 * supports. Later, we'll move this to an appropriate place. We don't
 282	 * use STACK_TOP because that can depend on attributes which aren't
 283	 * configured yet.
 284	 */
 285	BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
 286	vma->vm_end = STACK_TOP_MAX;
 287	vma->vm_start = vma->vm_end - PAGE_SIZE;
 288	vm_flags_init(vma, VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP);
 289	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
 290
 291	err = insert_vm_struct(mm, vma);
 292	if (err)
 293		goto err;
 294
 295	mm->stack_vm = mm->total_vm = 1;
 296	mmap_write_unlock(mm);
 297	bprm->p = vma->vm_end - sizeof(void *);
 298	return 0;
 299err:
 300	ksm_exit(mm);
 301err_ksm:
 302	mmap_write_unlock(mm);
 303err_free:
 304	bprm->vma = NULL;
 305	vm_area_free(vma);
 306	return err;
 307}
 308
 309static bool valid_arg_len(struct linux_binprm *bprm, long len)
 310{
 311	return len <= MAX_ARG_STRLEN;
 312}
 313
 314#else
 315
 316static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
 317{
 318}
 319
 320static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
 321		int write)
 322{
 323	struct page *page;
 324
 325	page = bprm->page[pos / PAGE_SIZE];
 326	if (!page && write) {
 327		page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
 328		if (!page)
 329			return NULL;
 330		bprm->page[pos / PAGE_SIZE] = page;
 331	}
 332
 333	return page;
 334}
 335
 336static void put_arg_page(struct page *page)
 337{
 338}
 339
 340static void free_arg_page(struct linux_binprm *bprm, int i)
 341{
 342	if (bprm->page[i]) {
 343		__free_page(bprm->page[i]);
 344		bprm->page[i] = NULL;
 345	}
 346}
 347
 348static void free_arg_pages(struct linux_binprm *bprm)
 349{
 350	int i;
 351
 352	for (i = 0; i < MAX_ARG_PAGES; i++)
 353		free_arg_page(bprm, i);
 354}
 355
 356static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
 357		struct page *page)
 358{
 359}
 360
 361static int __bprm_mm_init(struct linux_binprm *bprm)
 362{
 363	bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
 364	return 0;
 365}
 366
 367static bool valid_arg_len(struct linux_binprm *bprm, long len)
 368{
 369	return len <= bprm->p;
 370}
 371
 372#endif /* CONFIG_MMU */
 373
 374/*
 375 * Create a new mm_struct and populate it with a temporary stack
 376 * vm_area_struct.  We don't have enough context at this point to set the stack
 377 * flags, permissions, and offset, so we use temporary values.  We'll update
 378 * them later in setup_arg_pages().
 379 */
 380static int bprm_mm_init(struct linux_binprm *bprm)
 381{
 382	int err;
 383	struct mm_struct *mm = NULL;
 384
 385	bprm->mm = mm = mm_alloc();
 386	err = -ENOMEM;
 387	if (!mm)
 388		goto err;
 389
 390	/* Save current stack limit for all calculations made during exec. */
 391	task_lock(current->group_leader);
 392	bprm->rlim_stack = current->signal->rlim[RLIMIT_STACK];
 393	task_unlock(current->group_leader);
 394
 395	err = __bprm_mm_init(bprm);
 396	if (err)
 397		goto err;
 398
 399	return 0;
 400
 401err:
 402	if (mm) {
 403		bprm->mm = NULL;
 404		mmdrop(mm);
 405	}
 406
 407	return err;
 408}
 409
 410struct user_arg_ptr {
 411#ifdef CONFIG_COMPAT
 412	bool is_compat;
 413#endif
 414	union {
 415		const char __user *const __user *native;
 416#ifdef CONFIG_COMPAT
 417		const compat_uptr_t __user *compat;
 418#endif
 419	} ptr;
 420};
 421
 422static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
 423{
 424	const char __user *native;
 425
 426#ifdef CONFIG_COMPAT
 427	if (unlikely(argv.is_compat)) {
 428		compat_uptr_t compat;
 429
 430		if (get_user(compat, argv.ptr.compat + nr))
 431			return ERR_PTR(-EFAULT);
 432
 433		return compat_ptr(compat);
 434	}
 435#endif
 436
 437	if (get_user(native, argv.ptr.native + nr))
 438		return ERR_PTR(-EFAULT);
 439
 440	return native;
 441}
 442
 443/*
 444 * count() counts the number of strings in array ARGV.
 445 */
 446static int count(struct user_arg_ptr argv, int max)
 447{
 448	int i = 0;
 449
 450	if (argv.ptr.native != NULL) {
 451		for (;;) {
 452			const char __user *p = get_user_arg_ptr(argv, i);
 453
 454			if (!p)
 455				break;
 456
 457			if (IS_ERR(p))
 458				return -EFAULT;
 459
 460			if (i >= max)
 461				return -E2BIG;
 462			++i;
 463
 464			if (fatal_signal_pending(current))
 465				return -ERESTARTNOHAND;
 466			cond_resched();
 467		}
 468	}
 469	return i;
 470}
 471
 472static int count_strings_kernel(const char *const *argv)
 473{
 474	int i;
 475
 476	if (!argv)
 477		return 0;
 478
 479	for (i = 0; argv[i]; ++i) {
 480		if (i >= MAX_ARG_STRINGS)
 481			return -E2BIG;
 482		if (fatal_signal_pending(current))
 483			return -ERESTARTNOHAND;
 484		cond_resched();
 485	}
 486	return i;
 487}
 488
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 489static int bprm_stack_limits(struct linux_binprm *bprm)
 490{
 491	unsigned long limit, ptr_size;
 492
 493	/*
 494	 * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM
 495	 * (whichever is smaller) for the argv+env strings.
 496	 * This ensures that:
 497	 *  - the remaining binfmt code will not run out of stack space,
 498	 *  - the program will have a reasonable amount of stack left
 499	 *    to work from.
 500	 */
 501	limit = _STK_LIM / 4 * 3;
 502	limit = min(limit, bprm->rlim_stack.rlim_cur / 4);
 503	/*
 504	 * We've historically supported up to 32 pages (ARG_MAX)
 505	 * of argument strings even with small stacks
 506	 */
 507	limit = max_t(unsigned long, limit, ARG_MAX);
 
 
 
 508	/*
 509	 * We must account for the size of all the argv and envp pointers to
 510	 * the argv and envp strings, since they will also take up space in
 511	 * the stack. They aren't stored until much later when we can't
 512	 * signal to the parent that the child has run out of stack space.
 513	 * Instead, calculate it here so it's possible to fail gracefully.
 514	 *
 515	 * In the case of argc = 0, make sure there is space for adding a
 516	 * empty string (which will bump argc to 1), to ensure confused
 517	 * userspace programs don't start processing from argv[1], thinking
 518	 * argc can never be 0, to keep them from walking envp by accident.
 519	 * See do_execveat_common().
 520	 */
 521	ptr_size = (max(bprm->argc, 1) + bprm->envc) * sizeof(void *);
 
 
 522	if (limit <= ptr_size)
 523		return -E2BIG;
 524	limit -= ptr_size;
 525
 526	bprm->argmin = bprm->p - limit;
 527	return 0;
 528}
 529
 530/*
 531 * 'copy_strings()' copies argument/environment strings from the old
 532 * processes's memory to the new process's stack.  The call to get_user_pages()
 533 * ensures the destination page is created and not swapped out.
 534 */
 535static int copy_strings(int argc, struct user_arg_ptr argv,
 536			struct linux_binprm *bprm)
 537{
 538	struct page *kmapped_page = NULL;
 539	char *kaddr = NULL;
 540	unsigned long kpos = 0;
 541	int ret;
 542
 543	while (argc-- > 0) {
 544		const char __user *str;
 545		int len;
 546		unsigned long pos;
 547
 548		ret = -EFAULT;
 549		str = get_user_arg_ptr(argv, argc);
 550		if (IS_ERR(str))
 551			goto out;
 552
 553		len = strnlen_user(str, MAX_ARG_STRLEN);
 554		if (!len)
 555			goto out;
 556
 557		ret = -E2BIG;
 558		if (!valid_arg_len(bprm, len))
 559			goto out;
 560
 561		/* We're going to work our way backwards. */
 562		pos = bprm->p;
 563		str += len;
 564		bprm->p -= len;
 565#ifdef CONFIG_MMU
 566		if (bprm->p < bprm->argmin)
 567			goto out;
 568#endif
 569
 570		while (len > 0) {
 571			int offset, bytes_to_copy;
 572
 573			if (fatal_signal_pending(current)) {
 574				ret = -ERESTARTNOHAND;
 575				goto out;
 576			}
 577			cond_resched();
 578
 579			offset = pos % PAGE_SIZE;
 580			if (offset == 0)
 581				offset = PAGE_SIZE;
 582
 583			bytes_to_copy = offset;
 584			if (bytes_to_copy > len)
 585				bytes_to_copy = len;
 586
 587			offset -= bytes_to_copy;
 588			pos -= bytes_to_copy;
 589			str -= bytes_to_copy;
 590			len -= bytes_to_copy;
 591
 592			if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
 593				struct page *page;
 594
 595				page = get_arg_page(bprm, pos, 1);
 596				if (!page) {
 597					ret = -E2BIG;
 598					goto out;
 599				}
 600
 601				if (kmapped_page) {
 602					flush_dcache_page(kmapped_page);
 603					kunmap_local(kaddr);
 604					put_arg_page(kmapped_page);
 605				}
 606				kmapped_page = page;
 607				kaddr = kmap_local_page(kmapped_page);
 608				kpos = pos & PAGE_MASK;
 609				flush_arg_page(bprm, kpos, kmapped_page);
 610			}
 611			if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
 612				ret = -EFAULT;
 613				goto out;
 614			}
 615		}
 616	}
 617	ret = 0;
 618out:
 619	if (kmapped_page) {
 620		flush_dcache_page(kmapped_page);
 621		kunmap_local(kaddr);
 622		put_arg_page(kmapped_page);
 623	}
 624	return ret;
 625}
 626
 627/*
 628 * Copy and argument/environment string from the kernel to the processes stack.
 629 */
 630int copy_string_kernel(const char *arg, struct linux_binprm *bprm)
 631{
 632	int len = strnlen(arg, MAX_ARG_STRLEN) + 1 /* terminating NUL */;
 633	unsigned long pos = bprm->p;
 634
 635	if (len == 0)
 636		return -EFAULT;
 637	if (!valid_arg_len(bprm, len))
 638		return -E2BIG;
 639
 640	/* We're going to work our way backwards. */
 641	arg += len;
 642	bprm->p -= len;
 643	if (IS_ENABLED(CONFIG_MMU) && bprm->p < bprm->argmin)
 644		return -E2BIG;
 645
 646	while (len > 0) {
 647		unsigned int bytes_to_copy = min_t(unsigned int, len,
 648				min_not_zero(offset_in_page(pos), PAGE_SIZE));
 649		struct page *page;
 650
 651		pos -= bytes_to_copy;
 652		arg -= bytes_to_copy;
 653		len -= bytes_to_copy;
 654
 655		page = get_arg_page(bprm, pos, 1);
 656		if (!page)
 657			return -E2BIG;
 658		flush_arg_page(bprm, pos & PAGE_MASK, page);
 659		memcpy_to_page(page, offset_in_page(pos), arg, bytes_to_copy);
 660		put_arg_page(page);
 661	}
 662
 663	return 0;
 664}
 665EXPORT_SYMBOL(copy_string_kernel);
 666
 667static int copy_strings_kernel(int argc, const char *const *argv,
 668			       struct linux_binprm *bprm)
 669{
 670	while (argc-- > 0) {
 671		int ret = copy_string_kernel(argv[argc], bprm);
 672		if (ret < 0)
 673			return ret;
 674		if (fatal_signal_pending(current))
 675			return -ERESTARTNOHAND;
 676		cond_resched();
 677	}
 678	return 0;
 679}
 680
 681#ifdef CONFIG_MMU
 682
 683/*
 684 * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX.  Once
 685 * the binfmt code determines where the new stack should reside, we shift it to
 686 * its final location.  The process proceeds as follows:
 687 *
 688 * 1) Use shift to calculate the new vma endpoints.
 689 * 2) Extend vma to cover both the old and new ranges.  This ensures the
 690 *    arguments passed to subsequent functions are consistent.
 691 * 3) Move vma's page tables to the new range.
 692 * 4) Free up any cleared pgd range.
 693 * 5) Shrink the vma to cover only the new range.
 694 */
 695static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 696{
 697	struct mm_struct *mm = vma->vm_mm;
 698	unsigned long old_start = vma->vm_start;
 699	unsigned long old_end = vma->vm_end;
 700	unsigned long length = old_end - old_start;
 701	unsigned long new_start = old_start - shift;
 702	unsigned long new_end = old_end - shift;
 703	VMA_ITERATOR(vmi, mm, new_start);
 704	struct vm_area_struct *next;
 705	struct mmu_gather tlb;
 706
 707	BUG_ON(new_start > new_end);
 708
 709	/*
 710	 * ensure there are no vmas between where we want to go
 711	 * and where we are
 712	 */
 713	if (vma != vma_next(&vmi))
 714		return -EFAULT;
 715
 716	vma_iter_prev_range(&vmi);
 717	/*
 718	 * cover the whole range: [new_start, old_end)
 719	 */
 720	if (vma_expand(&vmi, vma, new_start, old_end, vma->vm_pgoff, NULL))
 721		return -ENOMEM;
 722
 723	/*
 724	 * move the page tables downwards, on failure we rely on
 725	 * process cleanup to remove whatever mess we made.
 726	 */
 727	if (length != move_page_tables(vma, old_start,
 728				       vma, new_start, length, false, true))
 729		return -ENOMEM;
 730
 731	lru_add_drain();
 732	tlb_gather_mmu(&tlb, mm);
 733	next = vma_next(&vmi);
 734	if (new_end > old_start) {
 735		/*
 736		 * when the old and new regions overlap clear from new_end.
 737		 */
 738		free_pgd_range(&tlb, new_end, old_end, new_end,
 739			next ? next->vm_start : USER_PGTABLES_CEILING);
 740	} else {
 741		/*
 742		 * otherwise, clean from old_start; this is done to not touch
 743		 * the address space in [new_end, old_start) some architectures
 744		 * have constraints on va-space that make this illegal (IA64) -
 745		 * for the others its just a little faster.
 746		 */
 747		free_pgd_range(&tlb, old_start, old_end, new_end,
 748			next ? next->vm_start : USER_PGTABLES_CEILING);
 749	}
 750	tlb_finish_mmu(&tlb);
 751
 752	vma_prev(&vmi);
 753	/* Shrink the vma to just the new range */
 754	return vma_shrink(&vmi, vma, new_start, new_end, vma->vm_pgoff);
 755}
 756
 757/*
 758 * Finalizes the stack vm_area_struct. The flags and permissions are updated,
 759 * the stack is optionally relocated, and some extra space is added.
 760 */
 761int setup_arg_pages(struct linux_binprm *bprm,
 762		    unsigned long stack_top,
 763		    int executable_stack)
 764{
 765	unsigned long ret;
 766	unsigned long stack_shift;
 767	struct mm_struct *mm = current->mm;
 768	struct vm_area_struct *vma = bprm->vma;
 769	struct vm_area_struct *prev = NULL;
 770	unsigned long vm_flags;
 771	unsigned long stack_base;
 772	unsigned long stack_size;
 773	unsigned long stack_expand;
 774	unsigned long rlim_stack;
 775	struct mmu_gather tlb;
 776	struct vma_iterator vmi;
 777
 778#ifdef CONFIG_STACK_GROWSUP
 779	/* Limit stack size */
 780	stack_base = bprm->rlim_stack.rlim_max;
 781
 782	stack_base = calc_max_stack_size(stack_base);
 783
 784	/* Add space for stack randomization. */
 785	stack_base += (STACK_RND_MASK << PAGE_SHIFT);
 
 786
 787	/* Make sure we didn't let the argument array grow too large. */
 788	if (vma->vm_end - vma->vm_start > stack_base)
 789		return -ENOMEM;
 790
 791	stack_base = PAGE_ALIGN(stack_top - stack_base);
 792
 793	stack_shift = vma->vm_start - stack_base;
 794	mm->arg_start = bprm->p - stack_shift;
 795	bprm->p = vma->vm_end - stack_shift;
 796#else
 797	stack_top = arch_align_stack(stack_top);
 798	stack_top = PAGE_ALIGN(stack_top);
 799
 800	if (unlikely(stack_top < mmap_min_addr) ||
 801	    unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
 802		return -ENOMEM;
 803
 804	stack_shift = vma->vm_end - stack_top;
 805
 806	bprm->p -= stack_shift;
 807	mm->arg_start = bprm->p;
 808#endif
 809
 810	if (bprm->loader)
 811		bprm->loader -= stack_shift;
 812	bprm->exec -= stack_shift;
 813
 814	if (mmap_write_lock_killable(mm))
 815		return -EINTR;
 816
 817	vm_flags = VM_STACK_FLAGS;
 818
 819	/*
 820	 * Adjust stack execute permissions; explicitly enable for
 821	 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
 822	 * (arch default) otherwise.
 823	 */
 824	if (unlikely(executable_stack == EXSTACK_ENABLE_X))
 825		vm_flags |= VM_EXEC;
 826	else if (executable_stack == EXSTACK_DISABLE_X)
 827		vm_flags &= ~VM_EXEC;
 828	vm_flags |= mm->def_flags;
 829	vm_flags |= VM_STACK_INCOMPLETE_SETUP;
 830
 831	vma_iter_init(&vmi, mm, vma->vm_start);
 832
 833	tlb_gather_mmu(&tlb, mm);
 834	ret = mprotect_fixup(&vmi, &tlb, vma, &prev, vma->vm_start, vma->vm_end,
 835			vm_flags);
 836	tlb_finish_mmu(&tlb);
 837
 838	if (ret)
 839		goto out_unlock;
 840	BUG_ON(prev != vma);
 841
 842	if (unlikely(vm_flags & VM_EXEC)) {
 843		pr_warn_once("process '%pD4' started with executable stack\n",
 844			     bprm->file);
 845	}
 846
 847	/* Move stack pages down in memory. */
 848	if (stack_shift) {
 849		ret = shift_arg_pages(vma, stack_shift);
 
 
 
 
 
 850		if (ret)
 851			goto out_unlock;
 852	}
 853
 854	/* mprotect_fixup is overkill to remove the temporary stack flags */
 855	vm_flags_clear(vma, VM_STACK_INCOMPLETE_SETUP);
 856
 857	stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
 858	stack_size = vma->vm_end - vma->vm_start;
 859	/*
 860	 * Align this down to a page boundary as expand_stack
 861	 * will align it up.
 862	 */
 863	rlim_stack = bprm->rlim_stack.rlim_cur & PAGE_MASK;
 864
 865	stack_expand = min(rlim_stack, stack_size + stack_expand);
 866
 867#ifdef CONFIG_STACK_GROWSUP
 868	stack_base = vma->vm_start + stack_expand;
 869#else
 870	stack_base = vma->vm_end - stack_expand;
 871#endif
 872	current->mm->start_stack = bprm->p;
 873	ret = expand_stack_locked(vma, stack_base);
 874	if (ret)
 875		ret = -EFAULT;
 876
 877out_unlock:
 878	mmap_write_unlock(mm);
 879	return ret;
 880}
 881EXPORT_SYMBOL(setup_arg_pages);
 882
 883#else
 884
 885/*
 886 * Transfer the program arguments and environment from the holding pages
 887 * onto the stack. The provided stack pointer is adjusted accordingly.
 888 */
 889int transfer_args_to_stack(struct linux_binprm *bprm,
 890			   unsigned long *sp_location)
 891{
 892	unsigned long index, stop, sp;
 893	int ret = 0;
 894
 895	stop = bprm->p >> PAGE_SHIFT;
 896	sp = *sp_location;
 897
 898	for (index = MAX_ARG_PAGES - 1; index >= stop; index--) {
 899		unsigned int offset = index == stop ? bprm->p & ~PAGE_MASK : 0;
 900		char *src = kmap_local_page(bprm->page[index]) + offset;
 901		sp -= PAGE_SIZE - offset;
 902		if (copy_to_user((void *) sp, src, PAGE_SIZE - offset) != 0)
 903			ret = -EFAULT;
 904		kunmap_local(src);
 905		if (ret)
 906			goto out;
 907	}
 908
 909	bprm->exec += *sp_location - MAX_ARG_PAGES * PAGE_SIZE;
 910	*sp_location = sp;
 911
 912out:
 913	return ret;
 914}
 915EXPORT_SYMBOL(transfer_args_to_stack);
 916
 917#endif /* CONFIG_MMU */
 918
 919/*
 920 * On success, caller must call do_close_execat() on the returned
 921 * struct file to close it.
 922 */
 923static struct file *do_open_execat(int fd, struct filename *name, int flags)
 924{
 925	struct file *file;
 926	int err;
 
 927	struct open_flags open_exec_flags = {
 928		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
 929		.acc_mode = MAY_EXEC,
 930		.intent = LOOKUP_OPEN,
 931		.lookup_flags = LOOKUP_FOLLOW,
 932	};
 933
 934	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
 935		return ERR_PTR(-EINVAL);
 936	if (flags & AT_SYMLINK_NOFOLLOW)
 937		open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
 938	if (flags & AT_EMPTY_PATH)
 939		open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
 940
 941	file = do_filp_open(fd, name, &open_exec_flags);
 942	if (IS_ERR(file))
 943		goto out;
 944
 945	/*
 946	 * may_open() has already checked for this, so it should be
 947	 * impossible to trip now. But we need to be extra cautious
 948	 * and check again at the very end too.
 949	 */
 950	err = -EACCES;
 951	if (WARN_ON_ONCE(!S_ISREG(file_inode(file)->i_mode) ||
 952			 path_noexec(&file->f_path)))
 953		goto exit;
 954
 955	err = deny_write_access(file);
 956	if (err)
 957		goto exit;
 958
 959out:
 960	return file;
 961
 962exit:
 963	fput(file);
 964	return ERR_PTR(err);
 965}
 966
 967/**
 968 * open_exec - Open a path name for execution
 969 *
 970 * @name: path name to open with the intent of executing it.
 971 *
 972 * Returns ERR_PTR on failure or allocated struct file on success.
 973 *
 974 * As this is a wrapper for the internal do_open_execat(), callers
 975 * must call allow_write_access() before fput() on release. Also see
 976 * do_close_execat().
 977 */
 978struct file *open_exec(const char *name)
 979{
 980	struct filename *filename = getname_kernel(name);
 981	struct file *f = ERR_CAST(filename);
 982
 983	if (!IS_ERR(filename)) {
 984		f = do_open_execat(AT_FDCWD, filename, 0);
 985		putname(filename);
 986	}
 987	return f;
 988}
 989EXPORT_SYMBOL(open_exec);
 990
 991#if defined(CONFIG_BINFMT_FLAT) || defined(CONFIG_BINFMT_ELF_FDPIC)
 992ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
 993{
 994	ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
 995	if (res > 0)
 996		flush_icache_user_range(addr, addr + len);
 997	return res;
 998}
 999EXPORT_SYMBOL(read_code);
1000#endif
1001
1002/*
1003 * Maps the mm_struct mm into the current task struct.
1004 * On success, this function returns with exec_update_lock
1005 * held for writing.
1006 */
1007static int exec_mmap(struct mm_struct *mm)
1008{
1009	struct task_struct *tsk;
1010	struct mm_struct *old_mm, *active_mm;
1011	int ret;
1012
1013	/* Notify parent that we're no longer interested in the old VM */
1014	tsk = current;
1015	old_mm = current->mm;
1016	exec_mm_release(tsk, old_mm);
1017
1018	ret = down_write_killable(&tsk->signal->exec_update_lock);
1019	if (ret)
1020		return ret;
1021
1022	if (old_mm) {
1023		/*
1024		 * If there is a pending fatal signal perhaps a signal
1025		 * whose default action is to create a coredump get
1026		 * out and die instead of going through with the exec.
1027		 */
1028		ret = mmap_read_lock_killable(old_mm);
1029		if (ret) {
1030			up_write(&tsk->signal->exec_update_lock);
1031			return ret;
1032		}
1033	}
1034
1035	task_lock(tsk);
1036	membarrier_exec_mmap(mm);
1037
1038	local_irq_disable();
1039	active_mm = tsk->active_mm;
1040	tsk->active_mm = mm;
1041	tsk->mm = mm;
1042	mm_init_cid(mm);
1043	/*
1044	 * This prevents preemption while active_mm is being loaded and
1045	 * it and mm are being updated, which could cause problems for
1046	 * lazy tlb mm refcounting when these are updated by context
1047	 * switches. Not all architectures can handle irqs off over
1048	 * activate_mm yet.
1049	 */
1050	if (!IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
1051		local_irq_enable();
1052	activate_mm(active_mm, mm);
1053	if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
1054		local_irq_enable();
1055	lru_gen_add_mm(mm);
1056	task_unlock(tsk);
1057	lru_gen_use_mm(mm);
1058	if (old_mm) {
1059		mmap_read_unlock(old_mm);
1060		BUG_ON(active_mm != old_mm);
1061		setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm);
1062		mm_update_next_owner(old_mm);
1063		mmput(old_mm);
1064		return 0;
1065	}
1066	mmdrop_lazy_tlb(active_mm);
1067	return 0;
1068}
1069
1070static int de_thread(struct task_struct *tsk)
1071{
1072	struct signal_struct *sig = tsk->signal;
1073	struct sighand_struct *oldsighand = tsk->sighand;
1074	spinlock_t *lock = &oldsighand->siglock;
1075
1076	if (thread_group_empty(tsk))
1077		goto no_thread_group;
1078
1079	/*
1080	 * Kill all other threads in the thread group.
1081	 */
1082	spin_lock_irq(lock);
1083	if ((sig->flags & SIGNAL_GROUP_EXIT) || sig->group_exec_task) {
1084		/*
1085		 * Another group action in progress, just
1086		 * return so that the signal is processed.
1087		 */
1088		spin_unlock_irq(lock);
1089		return -EAGAIN;
1090	}
1091
1092	sig->group_exec_task = tsk;
1093	sig->notify_count = zap_other_threads(tsk);
1094	if (!thread_group_leader(tsk))
1095		sig->notify_count--;
1096
1097	while (sig->notify_count) {
1098		__set_current_state(TASK_KILLABLE);
1099		spin_unlock_irq(lock);
1100		schedule();
1101		if (__fatal_signal_pending(tsk))
1102			goto killed;
1103		spin_lock_irq(lock);
1104	}
1105	spin_unlock_irq(lock);
1106
1107	/*
1108	 * At this point all other threads have exited, all we have to
1109	 * do is to wait for the thread group leader to become inactive,
1110	 * and to assume its PID:
1111	 */
1112	if (!thread_group_leader(tsk)) {
1113		struct task_struct *leader = tsk->group_leader;
1114
1115		for (;;) {
1116			cgroup_threadgroup_change_begin(tsk);
1117			write_lock_irq(&tasklist_lock);
1118			/*
1119			 * Do this under tasklist_lock to ensure that
1120			 * exit_notify() can't miss ->group_exec_task
1121			 */
1122			sig->notify_count = -1;
1123			if (likely(leader->exit_state))
1124				break;
1125			__set_current_state(TASK_KILLABLE);
1126			write_unlock_irq(&tasklist_lock);
1127			cgroup_threadgroup_change_end(tsk);
1128			schedule();
1129			if (__fatal_signal_pending(tsk))
1130				goto killed;
1131		}
1132
1133		/*
1134		 * The only record we have of the real-time age of a
1135		 * process, regardless of execs it's done, is start_time.
1136		 * All the past CPU time is accumulated in signal_struct
1137		 * from sister threads now dead.  But in this non-leader
1138		 * exec, nothing survives from the original leader thread,
1139		 * whose birth marks the true age of this process now.
1140		 * When we take on its identity by switching to its PID, we
1141		 * also take its birthdate (always earlier than our own).
1142		 */
1143		tsk->start_time = leader->start_time;
1144		tsk->start_boottime = leader->start_boottime;
1145
1146		BUG_ON(!same_thread_group(leader, tsk));
1147		/*
1148		 * An exec() starts a new thread group with the
1149		 * TGID of the previous thread group. Rehash the
1150		 * two threads with a switched PID, and release
1151		 * the former thread group leader:
1152		 */
1153
1154		/* Become a process group leader with the old leader's pid.
1155		 * The old leader becomes a thread of the this thread group.
1156		 */
1157		exchange_tids(tsk, leader);
1158		transfer_pid(leader, tsk, PIDTYPE_TGID);
1159		transfer_pid(leader, tsk, PIDTYPE_PGID);
1160		transfer_pid(leader, tsk, PIDTYPE_SID);
1161
1162		list_replace_rcu(&leader->tasks, &tsk->tasks);
1163		list_replace_init(&leader->sibling, &tsk->sibling);
1164
1165		tsk->group_leader = tsk;
1166		leader->group_leader = tsk;
1167
1168		tsk->exit_signal = SIGCHLD;
1169		leader->exit_signal = -1;
1170
1171		BUG_ON(leader->exit_state != EXIT_ZOMBIE);
1172		leader->exit_state = EXIT_DEAD;
1173		/*
1174		 * We are going to release_task()->ptrace_unlink() silently,
1175		 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
1176		 * the tracer won't block again waiting for this thread.
1177		 */
1178		if (unlikely(leader->ptrace))
1179			__wake_up_parent(leader, leader->parent);
1180		write_unlock_irq(&tasklist_lock);
1181		cgroup_threadgroup_change_end(tsk);
1182
1183		release_task(leader);
1184	}
1185
1186	sig->group_exec_task = NULL;
1187	sig->notify_count = 0;
1188
1189no_thread_group:
1190	/* we have changed execution domain */
1191	tsk->exit_signal = SIGCHLD;
1192
1193	BUG_ON(!thread_group_leader(tsk));
1194	return 0;
1195
1196killed:
1197	/* protects against exit_notify() and __exit_signal() */
1198	read_lock(&tasklist_lock);
1199	sig->group_exec_task = NULL;
1200	sig->notify_count = 0;
1201	read_unlock(&tasklist_lock);
1202	return -EAGAIN;
1203}
1204
1205
1206/*
1207 * This function makes sure the current process has its own signal table,
1208 * so that flush_signal_handlers can later reset the handlers without
1209 * disturbing other processes.  (Other processes might share the signal
1210 * table via the CLONE_SIGHAND option to clone().)
1211 */
1212static int unshare_sighand(struct task_struct *me)
1213{
1214	struct sighand_struct *oldsighand = me->sighand;
1215
1216	if (refcount_read(&oldsighand->count) != 1) {
1217		struct sighand_struct *newsighand;
1218		/*
1219		 * This ->sighand is shared with the CLONE_SIGHAND
1220		 * but not CLONE_THREAD task, switch to the new one.
1221		 */
1222		newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
1223		if (!newsighand)
1224			return -ENOMEM;
1225
1226		refcount_set(&newsighand->count, 1);
1227
1228		write_lock_irq(&tasklist_lock);
1229		spin_lock(&oldsighand->siglock);
1230		memcpy(newsighand->action, oldsighand->action,
1231		       sizeof(newsighand->action));
1232		rcu_assign_pointer(me->sighand, newsighand);
1233		spin_unlock(&oldsighand->siglock);
1234		write_unlock_irq(&tasklist_lock);
1235
1236		__cleanup_sighand(oldsighand);
1237	}
1238	return 0;
1239}
1240
1241char *__get_task_comm(char *buf, size_t buf_size, struct task_struct *tsk)
1242{
1243	task_lock(tsk);
1244	/* Always NUL terminated and zero-padded */
1245	strscpy_pad(buf, tsk->comm, buf_size);
1246	task_unlock(tsk);
1247	return buf;
1248}
1249EXPORT_SYMBOL_GPL(__get_task_comm);
1250
1251/*
1252 * These functions flushes out all traces of the currently running executable
1253 * so that a new one can be started
1254 */
1255
1256void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
1257{
1258	task_lock(tsk);
1259	trace_task_rename(tsk, buf);
1260	strscpy_pad(tsk->comm, buf, sizeof(tsk->comm));
1261	task_unlock(tsk);
1262	perf_event_comm(tsk, exec);
1263}
1264
1265/*
1266 * Calling this is the point of no return. None of the failures will be
1267 * seen by userspace since either the process is already taking a fatal
1268 * signal (via de_thread() or coredump), or will have SEGV raised
1269 * (after exec_mmap()) by search_binary_handler (see below).
1270 */
1271int begin_new_exec(struct linux_binprm * bprm)
1272{
1273	struct task_struct *me = current;
1274	int retval;
1275
1276	/* Once we are committed compute the creds */
1277	retval = bprm_creds_from_file(bprm);
1278	if (retval)
1279		return retval;
1280
1281	/*
 
 
 
 
 
 
 
 
1282	 * Ensure all future errors are fatal.
1283	 */
1284	bprm->point_of_no_return = true;
1285
1286	/*
1287	 * Make this the only thread in the thread group.
1288	 */
1289	retval = de_thread(me);
1290	if (retval)
1291		goto out;
1292
1293	/*
1294	 * Cancel any io_uring activity across execve
1295	 */
1296	io_uring_task_cancel();
1297
1298	/* Ensure the files table is not shared. */
1299	retval = unshare_files();
1300	if (retval)
1301		goto out;
1302
1303	/*
1304	 * Must be called _before_ exec_mmap() as bprm->mm is
1305	 * not visible until then. Doing it here also ensures
1306	 * we don't race against replace_mm_exe_file().
1307	 */
1308	retval = set_mm_exe_file(bprm->mm, bprm->file);
1309	if (retval)
1310		goto out;
1311
1312	/* If the binary is not readable then enforce mm->dumpable=0 */
1313	would_dump(bprm, bprm->file);
1314	if (bprm->have_execfd)
1315		would_dump(bprm, bprm->executable);
1316
1317	/*
1318	 * Release all of the old mmap stuff
1319	 */
1320	acct_arg_size(bprm, 0);
1321	retval = exec_mmap(bprm->mm);
1322	if (retval)
1323		goto out;
1324
1325	bprm->mm = NULL;
1326
1327	retval = exec_task_namespaces();
1328	if (retval)
1329		goto out_unlock;
1330
1331#ifdef CONFIG_POSIX_TIMERS
1332	spin_lock_irq(&me->sighand->siglock);
1333	posix_cpu_timers_exit(me);
1334	spin_unlock_irq(&me->sighand->siglock);
1335	exit_itimers(me);
1336	flush_itimer_signals();
1337#endif
1338
1339	/*
1340	 * Make the signal table private.
1341	 */
1342	retval = unshare_sighand(me);
1343	if (retval)
1344		goto out_unlock;
1345
1346	me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC |
1347					PF_NOFREEZE | PF_NO_SETAFFINITY);
1348	flush_thread();
1349	me->personality &= ~bprm->per_clear;
1350
1351	clear_syscall_work_syscall_user_dispatch(me);
1352
1353	/*
1354	 * We have to apply CLOEXEC before we change whether the process is
1355	 * dumpable (in setup_new_exec) to avoid a race with a process in userspace
1356	 * trying to access the should-be-closed file descriptors of a process
1357	 * undergoing exec(2).
1358	 */
1359	do_close_on_exec(me->files);
1360
1361	if (bprm->secureexec) {
1362		/* Make sure parent cannot signal privileged process. */
1363		me->pdeath_signal = 0;
1364
1365		/*
1366		 * For secureexec, reset the stack limit to sane default to
1367		 * avoid bad behavior from the prior rlimits. This has to
1368		 * happen before arch_pick_mmap_layout(), which examines
1369		 * RLIMIT_STACK, but after the point of no return to avoid
1370		 * needing to clean up the change on failure.
1371		 */
1372		if (bprm->rlim_stack.rlim_cur > _STK_LIM)
1373			bprm->rlim_stack.rlim_cur = _STK_LIM;
1374	}
1375
1376	me->sas_ss_sp = me->sas_ss_size = 0;
1377
1378	/*
1379	 * Figure out dumpability. Note that this checking only of current
1380	 * is wrong, but userspace depends on it. This should be testing
1381	 * bprm->secureexec instead.
1382	 */
1383	if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP ||
1384	    !(uid_eq(current_euid(), current_uid()) &&
1385	      gid_eq(current_egid(), current_gid())))
1386		set_dumpable(current->mm, suid_dumpable);
1387	else
1388		set_dumpable(current->mm, SUID_DUMP_USER);
1389
1390	perf_event_exec();
1391	__set_task_comm(me, kbasename(bprm->filename), true);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1392
1393	/* An exec changes our domain. We are no longer part of the thread
1394	   group */
1395	WRITE_ONCE(me->self_exec_id, me->self_exec_id + 1);
1396	flush_signal_handlers(me, 0);
1397
1398	retval = set_cred_ucounts(bprm->cred);
1399	if (retval < 0)
1400		goto out_unlock;
1401
1402	/*
1403	 * install the new credentials for this executable
1404	 */
1405	security_bprm_committing_creds(bprm);
1406
1407	commit_creds(bprm->cred);
1408	bprm->cred = NULL;
1409
1410	/*
1411	 * Disable monitoring for regular users
1412	 * when executing setuid binaries. Must
1413	 * wait until new credentials are committed
1414	 * by commit_creds() above
1415	 */
1416	if (get_dumpable(me->mm) != SUID_DUMP_USER)
1417		perf_event_exit_task(me);
1418	/*
1419	 * cred_guard_mutex must be held at least to this point to prevent
1420	 * ptrace_attach() from altering our determination of the task's
1421	 * credentials; any time after this it may be unlocked.
1422	 */
1423	security_bprm_committed_creds(bprm);
1424
1425	/* Pass the opened binary to the interpreter. */
1426	if (bprm->have_execfd) {
1427		retval = get_unused_fd_flags(0);
1428		if (retval < 0)
1429			goto out_unlock;
1430		fd_install(retval, bprm->executable);
1431		bprm->executable = NULL;
1432		bprm->execfd = retval;
1433	}
1434	return 0;
1435
1436out_unlock:
1437	up_write(&me->signal->exec_update_lock);
1438	if (!bprm->cred)
1439		mutex_unlock(&me->signal->cred_guard_mutex);
1440
1441out:
1442	return retval;
1443}
1444EXPORT_SYMBOL(begin_new_exec);
1445
1446void would_dump(struct linux_binprm *bprm, struct file *file)
1447{
1448	struct inode *inode = file_inode(file);
1449	struct mnt_idmap *idmap = file_mnt_idmap(file);
1450	if (inode_permission(idmap, inode, MAY_READ) < 0) {
1451		struct user_namespace *old, *user_ns;
1452		bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
1453
1454		/* Ensure mm->user_ns contains the executable */
1455		user_ns = old = bprm->mm->user_ns;
1456		while ((user_ns != &init_user_ns) &&
1457		       !privileged_wrt_inode_uidgid(user_ns, idmap, inode))
1458			user_ns = user_ns->parent;
1459
1460		if (old != user_ns) {
1461			bprm->mm->user_ns = get_user_ns(user_ns);
1462			put_user_ns(old);
1463		}
1464	}
1465}
1466EXPORT_SYMBOL(would_dump);
1467
1468void setup_new_exec(struct linux_binprm * bprm)
1469{
1470	/* Setup things that can depend upon the personality */
1471	struct task_struct *me = current;
1472
1473	arch_pick_mmap_layout(me->mm, &bprm->rlim_stack);
1474
1475	arch_setup_new_exec();
1476
1477	/* Set the new mm task size. We have to do that late because it may
1478	 * depend on TIF_32BIT which is only updated in flush_thread() on
1479	 * some architectures like powerpc
1480	 */
1481	me->mm->task_size = TASK_SIZE;
1482	up_write(&me->signal->exec_update_lock);
1483	mutex_unlock(&me->signal->cred_guard_mutex);
1484}
1485EXPORT_SYMBOL(setup_new_exec);
1486
1487/* Runs immediately before start_thread() takes over. */
1488void finalize_exec(struct linux_binprm *bprm)
1489{
1490	/* Store any stack rlimit changes before starting thread. */
1491	task_lock(current->group_leader);
1492	current->signal->rlim[RLIMIT_STACK] = bprm->rlim_stack;
1493	task_unlock(current->group_leader);
1494}
1495EXPORT_SYMBOL(finalize_exec);
1496
1497/*
1498 * Prepare credentials and lock ->cred_guard_mutex.
1499 * setup_new_exec() commits the new creds and drops the lock.
1500 * Or, if exec fails before, free_bprm() should release ->cred
1501 * and unlock.
1502 */
1503static int prepare_bprm_creds(struct linux_binprm *bprm)
1504{
1505	if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
1506		return -ERESTARTNOINTR;
1507
1508	bprm->cred = prepare_exec_creds();
1509	if (likely(bprm->cred))
1510		return 0;
1511
1512	mutex_unlock(&current->signal->cred_guard_mutex);
1513	return -ENOMEM;
1514}
1515
1516/* Matches do_open_execat() */
1517static void do_close_execat(struct file *file)
1518{
1519	if (!file)
1520		return;
1521	allow_write_access(file);
1522	fput(file);
1523}
1524
1525static void free_bprm(struct linux_binprm *bprm)
1526{
1527	if (bprm->mm) {
1528		acct_arg_size(bprm, 0);
1529		mmput(bprm->mm);
1530	}
1531	free_arg_pages(bprm);
1532	if (bprm->cred) {
1533		mutex_unlock(&current->signal->cred_guard_mutex);
1534		abort_creds(bprm->cred);
1535	}
1536	do_close_execat(bprm->file);
1537	if (bprm->executable)
1538		fput(bprm->executable);
1539	/* If a binfmt changed the interp, free it. */
1540	if (bprm->interp != bprm->filename)
1541		kfree(bprm->interp);
1542	kfree(bprm->fdpath);
1543	kfree(bprm);
1544}
1545
1546static struct linux_binprm *alloc_bprm(int fd, struct filename *filename, int flags)
1547{
1548	struct linux_binprm *bprm;
1549	struct file *file;
1550	int retval = -ENOMEM;
1551
1552	file = do_open_execat(fd, filename, flags);
1553	if (IS_ERR(file))
1554		return ERR_CAST(file);
1555
1556	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
1557	if (!bprm) {
1558		do_close_execat(file);
1559		return ERR_PTR(-ENOMEM);
1560	}
1561
1562	bprm->file = file;
1563
1564	if (fd == AT_FDCWD || filename->name[0] == '/') {
1565		bprm->filename = filename->name;
1566	} else {
1567		if (filename->name[0] == '\0')
1568			bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d", fd);
1569		else
 
1570			bprm->fdpath = kasprintf(GFP_KERNEL, "/dev/fd/%d/%s",
1571						  fd, filename->name);
 
1572		if (!bprm->fdpath)
1573			goto out_free;
1574
1575		/*
1576		 * Record that a name derived from an O_CLOEXEC fd will be
1577		 * inaccessible after exec.  This allows the code in exec to
1578		 * choose to fail when the executable is not mmaped into the
1579		 * interpreter and an open file descriptor is not passed to
1580		 * the interpreter.  This makes for a better user experience
1581		 * than having the interpreter start and then immediately fail
1582		 * when it finds the executable is inaccessible.
1583		 */
1584		if (get_close_on_exec(fd))
1585			bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
1586
1587		bprm->filename = bprm->fdpath;
1588	}
1589	bprm->interp = bprm->filename;
1590
1591	retval = bprm_mm_init(bprm);
1592	if (!retval)
1593		return bprm;
1594
1595out_free:
1596	free_bprm(bprm);
1597	return ERR_PTR(retval);
1598}
1599
1600int bprm_change_interp(const char *interp, struct linux_binprm *bprm)
1601{
1602	/* If a binfmt changed the interp, free it first. */
1603	if (bprm->interp != bprm->filename)
1604		kfree(bprm->interp);
1605	bprm->interp = kstrdup(interp, GFP_KERNEL);
1606	if (!bprm->interp)
1607		return -ENOMEM;
1608	return 0;
1609}
1610EXPORT_SYMBOL(bprm_change_interp);
1611
1612/*
1613 * determine how safe it is to execute the proposed program
1614 * - the caller must hold ->cred_guard_mutex to protect against
1615 *   PTRACE_ATTACH or seccomp thread-sync
1616 */
1617static void check_unsafe_exec(struct linux_binprm *bprm)
1618{
1619	struct task_struct *p = current, *t;
1620	unsigned n_fs;
1621
1622	if (p->ptrace)
1623		bprm->unsafe |= LSM_UNSAFE_PTRACE;
1624
1625	/*
1626	 * This isn't strictly necessary, but it makes it harder for LSMs to
1627	 * mess up.
1628	 */
1629	if (task_no_new_privs(current))
1630		bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
1631
1632	/*
1633	 * If another task is sharing our fs, we cannot safely
1634	 * suid exec because the differently privileged task
1635	 * will be able to manipulate the current directory, etc.
1636	 * It would be nice to force an unshare instead...
1637	 */
1638	n_fs = 1;
1639	spin_lock(&p->fs->lock);
1640	rcu_read_lock();
1641	for_other_threads(p, t) {
1642		if (t->fs == p->fs)
1643			n_fs++;
1644	}
1645	rcu_read_unlock();
1646
1647	/* "users" and "in_exec" locked for copy_fs() */
1648	if (p->fs->users > n_fs)
1649		bprm->unsafe |= LSM_UNSAFE_SHARE;
1650	else
1651		p->fs->in_exec = 1;
1652	spin_unlock(&p->fs->lock);
1653}
1654
1655static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)
1656{
1657	/* Handle suid and sgid on files */
1658	struct mnt_idmap *idmap;
1659	struct inode *inode = file_inode(file);
1660	unsigned int mode;
1661	vfsuid_t vfsuid;
1662	vfsgid_t vfsgid;
 
1663
1664	if (!mnt_may_suid(file->f_path.mnt))
1665		return;
1666
1667	if (task_no_new_privs(current))
1668		return;
1669
1670	mode = READ_ONCE(inode->i_mode);
1671	if (!(mode & (S_ISUID|S_ISGID)))
1672		return;
1673
1674	idmap = file_mnt_idmap(file);
1675
1676	/* Be careful if suid/sgid is set */
1677	inode_lock(inode);
1678
1679	/* reload atomically mode/uid/gid now that lock held */
1680	mode = inode->i_mode;
1681	vfsuid = i_uid_into_vfsuid(idmap, inode);
1682	vfsgid = i_gid_into_vfsgid(idmap, inode);
 
1683	inode_unlock(inode);
1684
 
 
 
 
1685	/* We ignore suid/sgid if there are no mappings for them in the ns */
1686	if (!vfsuid_has_mapping(bprm->cred->user_ns, vfsuid) ||
1687	    !vfsgid_has_mapping(bprm->cred->user_ns, vfsgid))
1688		return;
1689
1690	if (mode & S_ISUID) {
1691		bprm->per_clear |= PER_CLEAR_ON_SETID;
1692		bprm->cred->euid = vfsuid_into_kuid(vfsuid);
1693	}
1694
1695	if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
1696		bprm->per_clear |= PER_CLEAR_ON_SETID;
1697		bprm->cred->egid = vfsgid_into_kgid(vfsgid);
1698	}
1699}
1700
1701/*
1702 * Compute brpm->cred based upon the final binary.
1703 */
1704static int bprm_creds_from_file(struct linux_binprm *bprm)
1705{
1706	/* Compute creds based on which file? */
1707	struct file *file = bprm->execfd_creds ? bprm->executable : bprm->file;
1708
1709	bprm_fill_uid(bprm, file);
1710	return security_bprm_creds_from_file(bprm, file);
1711}
1712
1713/*
1714 * Fill the binprm structure from the inode.
1715 * Read the first BINPRM_BUF_SIZE bytes
1716 *
1717 * This may be called multiple times for binary chains (scripts for example).
1718 */
1719static int prepare_binprm(struct linux_binprm *bprm)
1720{
1721	loff_t pos = 0;
1722
1723	memset(bprm->buf, 0, BINPRM_BUF_SIZE);
1724	return kernel_read(bprm->file, bprm->buf, BINPRM_BUF_SIZE, &pos);
1725}
1726
1727/*
1728 * Arguments are '\0' separated strings found at the location bprm->p
1729 * points to; chop off the first by relocating brpm->p to right after
1730 * the first '\0' encountered.
1731 */
1732int remove_arg_zero(struct linux_binprm *bprm)
1733{
1734	unsigned long offset;
1735	char *kaddr;
1736	struct page *page;
1737
1738	if (!bprm->argc)
1739		return 0;
1740
1741	do {
1742		offset = bprm->p & ~PAGE_MASK;
1743		page = get_arg_page(bprm, bprm->p, 0);
1744		if (!page)
1745			return -EFAULT;
1746		kaddr = kmap_local_page(page);
1747
1748		for (; offset < PAGE_SIZE && kaddr[offset];
1749				offset++, bprm->p++)
1750			;
1751
1752		kunmap_local(kaddr);
1753		put_arg_page(page);
1754	} while (offset == PAGE_SIZE);
1755
1756	bprm->p++;
1757	bprm->argc--;
1758
1759	return 0;
1760}
1761EXPORT_SYMBOL(remove_arg_zero);
1762
1763#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
1764/*
1765 * cycle the list of binary formats handler, until one recognizes the image
1766 */
1767static int search_binary_handler(struct linux_binprm *bprm)
1768{
1769	bool need_retry = IS_ENABLED(CONFIG_MODULES);
1770	struct linux_binfmt *fmt;
1771	int retval;
1772
1773	retval = prepare_binprm(bprm);
1774	if (retval < 0)
1775		return retval;
1776
1777	retval = security_bprm_check(bprm);
1778	if (retval)
1779		return retval;
1780
1781	retval = -ENOENT;
1782 retry:
1783	read_lock(&binfmt_lock);
1784	list_for_each_entry(fmt, &formats, lh) {
1785		if (!try_module_get(fmt->module))
1786			continue;
1787		read_unlock(&binfmt_lock);
1788
1789		retval = fmt->load_binary(bprm);
1790
1791		read_lock(&binfmt_lock);
1792		put_binfmt(fmt);
1793		if (bprm->point_of_no_return || (retval != -ENOEXEC)) {
1794			read_unlock(&binfmt_lock);
1795			return retval;
1796		}
1797	}
1798	read_unlock(&binfmt_lock);
1799
1800	if (need_retry) {
1801		if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
1802		    printable(bprm->buf[2]) && printable(bprm->buf[3]))
1803			return retval;
1804		if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
1805			return retval;
1806		need_retry = false;
1807		goto retry;
1808	}
1809
1810	return retval;
1811}
1812
1813/* binfmt handlers will call back into begin_new_exec() on success. */
1814static int exec_binprm(struct linux_binprm *bprm)
1815{
1816	pid_t old_pid, old_vpid;
1817	int ret, depth;
1818
1819	/* Need to fetch pid before load_binary changes it */
1820	old_pid = current->pid;
1821	rcu_read_lock();
1822	old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
1823	rcu_read_unlock();
1824
1825	/* This allows 4 levels of binfmt rewrites before failing hard. */
1826	for (depth = 0;; depth++) {
1827		struct file *exec;
1828		if (depth > 5)
1829			return -ELOOP;
1830
1831		ret = search_binary_handler(bprm);
1832		if (ret < 0)
1833			return ret;
1834		if (!bprm->interpreter)
1835			break;
1836
1837		exec = bprm->file;
1838		bprm->file = bprm->interpreter;
1839		bprm->interpreter = NULL;
1840
1841		allow_write_access(exec);
1842		if (unlikely(bprm->have_execfd)) {
1843			if (bprm->executable) {
1844				fput(exec);
1845				return -ENOEXEC;
1846			}
1847			bprm->executable = exec;
1848		} else
1849			fput(exec);
1850	}
1851
1852	audit_bprm(bprm);
1853	trace_sched_process_exec(current, old_pid, bprm);
1854	ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
1855	proc_exec_connector(current);
1856	return 0;
1857}
1858
1859static int bprm_execve(struct linux_binprm *bprm)
1860{
1861	int retval;
1862
1863	retval = prepare_bprm_creds(bprm);
1864	if (retval)
1865		return retval;
1866
1867	/*
1868	 * Check for unsafe execution states before exec_binprm(), which
1869	 * will call back into begin_new_exec(), into bprm_creds_from_file(),
1870	 * where setuid-ness is evaluated.
1871	 */
1872	check_unsafe_exec(bprm);
1873	current->in_execve = 1;
1874	sched_mm_cid_before_execve(current);
1875
1876	sched_exec();
1877
1878	/* Set the unchanging part of bprm->cred */
1879	retval = security_bprm_creds_for_exec(bprm);
1880	if (retval)
1881		goto out;
1882
1883	retval = exec_binprm(bprm);
1884	if (retval < 0)
1885		goto out;
1886
1887	sched_mm_cid_after_execve(current);
1888	/* execve succeeded */
1889	current->fs->in_exec = 0;
1890	current->in_execve = 0;
1891	rseq_execve(current);
1892	user_events_execve(current);
1893	acct_update_integrals(current);
1894	task_numa_free(current, false);
1895	return retval;
1896
1897out:
1898	/*
1899	 * If past the point of no return ensure the code never
1900	 * returns to the userspace process.  Use an existing fatal
1901	 * signal if present otherwise terminate the process with
1902	 * SIGSEGV.
1903	 */
1904	if (bprm->point_of_no_return && !fatal_signal_pending(current))
1905		force_fatal_sig(SIGSEGV);
1906
1907	sched_mm_cid_after_execve(current);
1908	current->fs->in_exec = 0;
1909	current->in_execve = 0;
1910
1911	return retval;
1912}
1913
1914static int do_execveat_common(int fd, struct filename *filename,
1915			      struct user_arg_ptr argv,
1916			      struct user_arg_ptr envp,
1917			      int flags)
1918{
1919	struct linux_binprm *bprm;
1920	int retval;
1921
1922	if (IS_ERR(filename))
1923		return PTR_ERR(filename);
1924
1925	/*
1926	 * We move the actual failure in case of RLIMIT_NPROC excess from
1927	 * set*uid() to execve() because too many poorly written programs
1928	 * don't check setuid() return code.  Here we additionally recheck
1929	 * whether NPROC limit is still exceeded.
1930	 */
1931	if ((current->flags & PF_NPROC_EXCEEDED) &&
1932	    is_rlimit_overlimit(current_ucounts(), UCOUNT_RLIMIT_NPROC, rlimit(RLIMIT_NPROC))) {
1933		retval = -EAGAIN;
1934		goto out_ret;
1935	}
1936
1937	/* We're below the limit (still or again), so we don't want to make
1938	 * further execve() calls fail. */
1939	current->flags &= ~PF_NPROC_EXCEEDED;
1940
1941	bprm = alloc_bprm(fd, filename, flags);
1942	if (IS_ERR(bprm)) {
1943		retval = PTR_ERR(bprm);
1944		goto out_ret;
1945	}
1946
1947	retval = count(argv, MAX_ARG_STRINGS);
1948	if (retval == 0)
1949		pr_warn_once("process '%s' launched '%s' with NULL argv: empty string added\n",
1950			     current->comm, bprm->filename);
1951	if (retval < 0)
1952		goto out_free;
1953	bprm->argc = retval;
1954
1955	retval = count(envp, MAX_ARG_STRINGS);
1956	if (retval < 0)
1957		goto out_free;
1958	bprm->envc = retval;
1959
1960	retval = bprm_stack_limits(bprm);
1961	if (retval < 0)
1962		goto out_free;
1963
1964	retval = copy_string_kernel(bprm->filename, bprm);
1965	if (retval < 0)
1966		goto out_free;
1967	bprm->exec = bprm->p;
1968
1969	retval = copy_strings(bprm->envc, envp, bprm);
1970	if (retval < 0)
1971		goto out_free;
1972
1973	retval = copy_strings(bprm->argc, argv, bprm);
1974	if (retval < 0)
1975		goto out_free;
1976
1977	/*
1978	 * When argv is empty, add an empty string ("") as argv[0] to
1979	 * ensure confused userspace programs that start processing
1980	 * from argv[1] won't end up walking envp. See also
1981	 * bprm_stack_limits().
1982	 */
1983	if (bprm->argc == 0) {
1984		retval = copy_string_kernel("", bprm);
1985		if (retval < 0)
1986			goto out_free;
1987		bprm->argc = 1;
1988	}
1989
1990	retval = bprm_execve(bprm);
1991out_free:
1992	free_bprm(bprm);
1993
1994out_ret:
1995	putname(filename);
1996	return retval;
1997}
1998
1999int kernel_execve(const char *kernel_filename,
2000		  const char *const *argv, const char *const *envp)
2001{
2002	struct filename *filename;
2003	struct linux_binprm *bprm;
2004	int fd = AT_FDCWD;
2005	int retval;
2006
2007	/* It is non-sense for kernel threads to call execve */
2008	if (WARN_ON_ONCE(current->flags & PF_KTHREAD))
2009		return -EINVAL;
2010
2011	filename = getname_kernel(kernel_filename);
2012	if (IS_ERR(filename))
2013		return PTR_ERR(filename);
2014
2015	bprm = alloc_bprm(fd, filename, 0);
2016	if (IS_ERR(bprm)) {
2017		retval = PTR_ERR(bprm);
2018		goto out_ret;
2019	}
2020
2021	retval = count_strings_kernel(argv);
2022	if (WARN_ON_ONCE(retval == 0))
2023		retval = -EINVAL;
2024	if (retval < 0)
2025		goto out_free;
2026	bprm->argc = retval;
2027
2028	retval = count_strings_kernel(envp);
2029	if (retval < 0)
2030		goto out_free;
2031	bprm->envc = retval;
2032
2033	retval = bprm_stack_limits(bprm);
2034	if (retval < 0)
2035		goto out_free;
2036
2037	retval = copy_string_kernel(bprm->filename, bprm);
2038	if (retval < 0)
2039		goto out_free;
2040	bprm->exec = bprm->p;
2041
2042	retval = copy_strings_kernel(bprm->envc, envp, bprm);
2043	if (retval < 0)
2044		goto out_free;
2045
2046	retval = copy_strings_kernel(bprm->argc, argv, bprm);
2047	if (retval < 0)
2048		goto out_free;
2049
2050	retval = bprm_execve(bprm);
2051out_free:
2052	free_bprm(bprm);
2053out_ret:
2054	putname(filename);
2055	return retval;
2056}
2057
2058static int do_execve(struct filename *filename,
2059	const char __user *const __user *__argv,
2060	const char __user *const __user *__envp)
2061{
2062	struct user_arg_ptr argv = { .ptr.native = __argv };
2063	struct user_arg_ptr envp = { .ptr.native = __envp };
2064	return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
2065}
2066
2067static int do_execveat(int fd, struct filename *filename,
2068		const char __user *const __user *__argv,
2069		const char __user *const __user *__envp,
2070		int flags)
2071{
2072	struct user_arg_ptr argv = { .ptr.native = __argv };
2073	struct user_arg_ptr envp = { .ptr.native = __envp };
2074
2075	return do_execveat_common(fd, filename, argv, envp, flags);
2076}
2077
2078#ifdef CONFIG_COMPAT
2079static int compat_do_execve(struct filename *filename,
2080	const compat_uptr_t __user *__argv,
2081	const compat_uptr_t __user *__envp)
2082{
2083	struct user_arg_ptr argv = {
2084		.is_compat = true,
2085		.ptr.compat = __argv,
2086	};
2087	struct user_arg_ptr envp = {
2088		.is_compat = true,
2089		.ptr.compat = __envp,
2090	};
2091	return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
2092}
2093
2094static int compat_do_execveat(int fd, struct filename *filename,
2095			      const compat_uptr_t __user *__argv,
2096			      const compat_uptr_t __user *__envp,
2097			      int flags)
2098{
2099	struct user_arg_ptr argv = {
2100		.is_compat = true,
2101		.ptr.compat = __argv,
2102	};
2103	struct user_arg_ptr envp = {
2104		.is_compat = true,
2105		.ptr.compat = __envp,
2106	};
2107	return do_execveat_common(fd, filename, argv, envp, flags);
2108}
2109#endif
2110
2111void set_binfmt(struct linux_binfmt *new)
2112{
2113	struct mm_struct *mm = current->mm;
2114
2115	if (mm->binfmt)
2116		module_put(mm->binfmt->module);
2117
2118	mm->binfmt = new;
2119	if (new)
2120		__module_get(new->module);
2121}
2122EXPORT_SYMBOL(set_binfmt);
2123
2124/*
2125 * set_dumpable stores three-value SUID_DUMP_* into mm->flags.
2126 */
2127void set_dumpable(struct mm_struct *mm, int value)
2128{
2129	if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
2130		return;
2131
2132	set_mask_bits(&mm->flags, MMF_DUMPABLE_MASK, value);
2133}
2134
2135SYSCALL_DEFINE3(execve,
2136		const char __user *, filename,
2137		const char __user *const __user *, argv,
2138		const char __user *const __user *, envp)
2139{
2140	return do_execve(getname(filename), argv, envp);
2141}
2142
2143SYSCALL_DEFINE5(execveat,
2144		int, fd, const char __user *, filename,
2145		const char __user *const __user *, argv,
2146		const char __user *const __user *, envp,
2147		int, flags)
2148{
2149	return do_execveat(fd,
2150			   getname_uflags(filename, flags),
2151			   argv, envp, flags);
2152}
2153
2154#ifdef CONFIG_COMPAT
2155COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
2156	const compat_uptr_t __user *, argv,
2157	const compat_uptr_t __user *, envp)
2158{
2159	return compat_do_execve(getname(filename), argv, envp);
2160}
2161
2162COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
2163		       const char __user *, filename,
2164		       const compat_uptr_t __user *, argv,
2165		       const compat_uptr_t __user *, envp,
2166		       int,  flags)
2167{
2168	return compat_do_execveat(fd,
2169				  getname_uflags(filename, flags),
2170				  argv, envp, flags);
2171}
2172#endif
2173
2174#ifdef CONFIG_SYSCTL
2175
2176static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write,
2177		void *buffer, size_t *lenp, loff_t *ppos)
2178{
2179	int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
2180
2181	if (!error)
2182		validate_coredump_safety();
2183	return error;
2184}
2185
2186static struct ctl_table fs_exec_sysctls[] = {
2187	{
2188		.procname	= "suid_dumpable",
2189		.data		= &suid_dumpable,
2190		.maxlen		= sizeof(int),
2191		.mode		= 0644,
2192		.proc_handler	= proc_dointvec_minmax_coredump,
2193		.extra1		= SYSCTL_ZERO,
2194		.extra2		= SYSCTL_TWO,
2195	},
2196};
2197
2198static int __init init_fs_exec_sysctls(void)
2199{
2200	register_sysctl_init("fs", fs_exec_sysctls);
2201	return 0;
2202}
2203
2204fs_initcall(init_fs_exec_sysctls);
2205#endif /* CONFIG_SYSCTL */