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usercopy: fold builtin_const check into inline function

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Instead of having each caller of check_object_size() need to remember to
check for a const size parameter, move the check into check_object_size()
itself. This actually matches the original implementation in PaX, though
this commit cleans up the now-redundant builtin_const() calls in the
various architectures.

Signed-off-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Kees Cook
2016-08-31 16:04:21 -07:00
parent e6971009a9
commit 81409e9e28
5 changed files with 19 additions and 31 deletions
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19
arch/powerpc/include/asm/uaccess.h
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@@ -311,14 +311,12 @@ static inline unsigned long copy_from_user(void *to,
unsigned long over;
if (access_ok(VERIFY_READ, from, n)) {
if (!__builtin_constant_p(n))
check_object_size(to, n, false);
check_object_size(to, n, false);
return __copy_tofrom_user((__force void __user *)to, from, n);
}
if ((unsigned long)from < TASK_SIZE) {
over = (unsigned long)from + n - TASK_SIZE;
if (!__builtin_constant_p(n - over))
check_object_size(to, n - over, false);
check_object_size(to, n - over, false);
return __copy_tofrom_user((__force void __user *)to, from,
n - over) + over;
}
@@ -331,14 +329,12 @@ static inline unsigned long copy_to_user(void __user *to,
unsigned long over;
if (access_ok(VERIFY_WRITE, to, n)) {
if (!__builtin_constant_p(n))
check_object_size(from, n, true);
check_object_size(from, n, true);
return __copy_tofrom_user(to, (__force void __user *)from, n);
}
if ((unsigned long)to < TASK_SIZE) {
over = (unsigned long)to + n - TASK_SIZE;
if (!__builtin_constant_p(n))
check_object_size(from, n - over, true);
check_object_size(from, n - over, true);
return __copy_tofrom_user(to, (__force void __user *)from,
n - over) + over;
}
@@ -383,8 +379,7 @@ static inline unsigned long __copy_from_user_inatomic(void *to,
return 0;
}
if (!__builtin_constant_p(n))
check_object_size(to, n, false);
check_object_size(to, n, false);
return __copy_tofrom_user((__force void __user *)to, from, n);
}
@@ -412,8 +407,8 @@ static inline unsigned long __copy_to_user_inatomic(void __user *to,
if (ret == 0)
return 0;
}
if (!__builtin_constant_p(n))
check_object_size(from, n, true);
check_object_size(from, n, true);
return __copy_tofrom_user(to, (__force const void __user *)from, n);
}