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copy_{to,from}_user(): consolidate object size checks

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... and move them into thread_info.h, next to check_object_size()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2017-06-29 21:42:43 -04:00
parent 9c5f6908de
commit b0377fedb6
2 changed files with 29 additions and 26 deletions
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28
include/linux/uaccess.h
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@@ -139,43 +139,19 @@ extern unsigned long
_copy_to_user(void __user *, const void *, unsigned long);
#endif
extern void __compiletime_error("usercopy buffer size is too small")
__bad_copy_user(void);
static inline void copy_user_overflow(int size, unsigned long count)
{
WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
}
static __always_inline unsigned long __must_check
copy_from_user(void *to, const void __user *from, unsigned long n)
{
int sz = __compiletime_object_size(to);
if (likely(sz < 0 || sz >= n)) {
check_object_size(to, n, false);
if (likely(check_copy_size(to, n, false)))
n = _copy_from_user(to, from, n);
} else if (!__builtin_constant_p(n))
copy_user_overflow(sz, n);
else
__bad_copy_user();
return n;
}
static __always_inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
int sz = __compiletime_object_size(from);
if (likely(sz < 0 || sz >= n)) {
check_object_size(from, n, true);
if (likely(check_copy_size(from, n, true)))
n = _copy_to_user(to, from, n);
} else if (!__builtin_constant_p(n))
copy_user_overflow(sz, n);
else
__bad_copy_user();
return n;
}
#ifdef CONFIG_COMPAT