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>

2 files changed, 6 insertions, 10 deletions

diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h
index 341a5a133f48..e722c510bb1b 100644
--- a/arch/sparc/include/asm/uaccess_32.h
+++ b/arch/sparc/include/asm/uaccess_32.h
@@ -249,8 +249,7 @@ unsigned long __copy_user(void __user *to, const void __user *from, unsigned lon
 static inline unsigned long copy_to_user(void __user *to, const void *from, unsigned long n)
 {
 	if (n && __access_ok((unsigned long) to, n)) {
-		if (!__builtin_constant_p(n))
-			check_object_size(from, n, true);
+		check_object_size(from, n, true);
 		return __copy_user(to, (__force void __user *) from, n);
 	} else
 		return n;
@@ -258,16 +257,14 @@ static inline unsigned long copy_to_user(void __user *to, const void *from, unsi
 
 static inline unsigned long __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (!__builtin_constant_p(n))
-		check_object_size(from, n, true);
+	check_object_size(from, n, true);
 	return __copy_user(to, (__force void __user *) from, n);
 }
 
 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 {
 	if (n && __access_ok((unsigned long) from, n)) {
-		if (!__builtin_constant_p(n))
-			check_object_size(to, n, false);
+		check_object_size(to, n, false);
 		return __copy_user((__force void __user *) to, from, n);
 	} else
 		return n;
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index 8bda94fab8e8..37a315d0ddd4 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -212,8 +212,7 @@ copy_from_user(void *to, const void __user *from, unsigned long size)
 {
 	unsigned long ret;
 
-	if (!__builtin_constant_p(size))
-		check_object_size(to, size, false);
+	check_object_size(to, size, false);
 
 	ret = ___copy_from_user(to, from, size);
 	if (unlikely(ret))
@@ -233,8 +232,8 @@ copy_to_user(void __user *to, const void *from, unsigned long size)
 {
 	unsigned long ret;
 
-	if (!__builtin_constant_p(size))
-		check_object_size(from, size, true);
+	check_object_size(from, size, true);
+
 	ret = ___copy_to_user(to, from, size);
 	if (unlikely(ret))
 		ret = copy_to_user_fixup(to, from, size);