1#include <linux/export.h>
2#include <linux/bug.h>
 
 
3#include <linux/uaccess.h>
 
4
5void copy_from_user_overflow(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6{
7	WARN(1, "Buffer overflow detected!\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8}
9EXPORT_SYMBOL(copy_from_user_overflow);

  1// SPDX-License-Identifier: GPL-2.0
  2#include <linux/bitops.h>
  3#include <linux/fault-inject-usercopy.h>
  4#include <linux/instrumented.h>
  5#include <linux/uaccess.h>
  6#include <linux/nospec.h>
  7
  8/* out-of-line parts */
  9
 10#ifndef INLINE_COPY_FROM_USER
 11unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
 12{
 13	unsigned long res = n;
 14	might_fault();
 15	if (!should_fail_usercopy() && likely(access_ok(from, n))) {
 16		/*
 17		 * Ensure that bad access_ok() speculation will not
 18		 * lead to nasty side effects *after* the copy is
 19		 * finished:
 20		 */
 21		barrier_nospec();
 22		instrument_copy_from_user_before(to, from, n);
 23		res = raw_copy_from_user(to, from, n);
 24		instrument_copy_from_user_after(to, from, n, res);
 25	}
 26	if (unlikely(res))
 27		memset(to + (n - res), 0, res);
 28	return res;
 29}
 30EXPORT_SYMBOL(_copy_from_user);
 31#endif
 32
 33#ifndef INLINE_COPY_TO_USER
 34unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n)
 35{
 36	might_fault();
 37	if (should_fail_usercopy())
 38		return n;
 39	if (likely(access_ok(to, n))) {
 40		instrument_copy_to_user(to, from, n);
 41		n = raw_copy_to_user(to, from, n);
 42	}
 43	return n;
 44}
 45EXPORT_SYMBOL(_copy_to_user);
 46#endif
 47
 48/**
 49 * check_zeroed_user: check if a userspace buffer only contains zero bytes
 50 * @from: Source address, in userspace.
 51 * @size: Size of buffer.
 52 *
 53 * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for
 54 * userspace addresses (and is more efficient because we don't care where the
 55 * first non-zero byte is).
 56 *
 57 * Returns:
 58 *  * 0: There were non-zero bytes present in the buffer.
 59 *  * 1: The buffer was full of zero bytes.
 60 *  * -EFAULT: access to userspace failed.
 61 */
 62int check_zeroed_user(const void __user *from, size_t size)
 63{
 64	unsigned long val;
 65	uintptr_t align = (uintptr_t) from % sizeof(unsigned long);
 66
 67	if (unlikely(size == 0))
 68		return 1;
 69
 70	from -= align;
 71	size += align;
 72
 73	if (!user_read_access_begin(from, size))
 74		return -EFAULT;
 75
 76	unsafe_get_user(val, (unsigned long __user *) from, err_fault);
 77	if (align)
 78		val &= ~aligned_byte_mask(align);
 79
 80	while (size > sizeof(unsigned long)) {
 81		if (unlikely(val))
 82			goto done;
 83
 84		from += sizeof(unsigned long);
 85		size -= sizeof(unsigned long);
 86
 87		unsafe_get_user(val, (unsigned long __user *) from, err_fault);
 88	}
 89
 90	if (size < sizeof(unsigned long))
 91		val &= aligned_byte_mask(size);
 92
 93done:
 94	user_read_access_end();
 95	return (val == 0);
 96err_fault:
 97	user_read_access_end();
 98	return -EFAULT;
 99}
100EXPORT_SYMBOL(check_zeroed_user);