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copy_{from,to}_user(): move kasan checks and might_fault() out-of-line

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-06-29 21:39:54 -04:00
parent 2ea659a9ef
commit 9c5f6908de
2 changed files with 16 additions and 10 deletions
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16
include/linux/uaccess.h
View File

@ -109,8 +109,11 @@ static inline unsigned long
_copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
if (likely(access_ok(VERIFY_READ, from, n)))
might_fault();
if (likely(access_ok(VERIFY_READ, from, n))) {
kasan_check_write(to, n);
res = raw_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
@ -124,8 +127,11 @@ _copy_from_user(void *, const void __user *, unsigned long);
static inline unsigned long
_copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
might_fault();
if (access_ok(VERIFY_WRITE, to, n)) {
kasan_check_read(from, n);
n = raw_copy_to_user(to, from, n);
}
return n;
}
#else
@ -146,9 +152,6 @@ copy_from_user(void *to, const void __user *from, unsigned long n)
{
int sz = __compiletime_object_size(to);
might_fault();
kasan_check_write(to, n);
if (likely(sz < 0 || sz >= n)) {
check_object_size(to, n, false);
n = _copy_from_user(to, from, n);
@ -165,9 +168,6 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
{
int sz = __compiletime_object_size(from);
kasan_check_read(from, n);
might_fault();
if (likely(sz < 0 || sz >= n)) {
check_object_size(from, n, true);
n = _copy_to_user(to, from, n);

10
lib/usercopy.c
View File

@ -6,8 +6,11 @@
unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long res = n;
if (likely(access_ok(VERIFY_READ, from, n)))
might_fault();
if (likely(access_ok(VERIFY_READ, from, n))) {
kasan_check_write(to, n);
res = raw_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
@ -18,8 +21,11 @@ EXPORT_SYMBOL(_copy_from_user);
#ifndef INLINE_COPY_TO_USER
unsigned long _copy_to_user(void *to, const void __user *from, unsigned long n)
{
if (likely(access_ok(VERIFY_WRITE, to, n)))
might_fault();
if (likely(access_ok(VERIFY_WRITE, to, n))) {
kasan_check_read(from, n);
n = raw_copy_to_user(to, from, n);
}
return n;
}
EXPORT_SYMBOL(_copy_to_user);