usercopy: fold builtin_const check into inline function
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>
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index c1dc6c1..f1e3824 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -311,14 +311,12 @@
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 @@
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 @@
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 @@
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);
}