sparc: Use __builtin_object_size() to validate the buffer size for copy_from_user()

This mirrors x86 commit 9f0cf4adb6aa0bfccf675c938124e68f7f06349d
(x86: Use __builtin_object_size() to validate the buffer size for copy_from_user())

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 0 deletions

diff --git a/arch/sparc/include/asm/uaccess_32.h b/arch/sparc/include/asm/uaccess_32.h
index 8303ac481034..489d2ba92bcb 100644
--- a/arch/sparc/include/asm/uaccess_32.h
+++ b/arch/sparc/include/asm/uaccess_32.h
@@ -260,8 +260,23 @@ static inline unsigned long __copy_to_user(void __user *to, const void *from, un
 	return __copy_user(to, (__force void __user *) from, n);
 }
 
+extern void copy_from_user_overflow(void)
+#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
+	__compiletime_error("copy_from_user() buffer size is not provably correct")
+#else
+	__compiletime_warning("copy_from_user() buffer size is not provably correct")
+#endif
+;
+
 static inline unsigned long copy_from_user(void *to, const void __user *from, unsigned long n)
 {
+	int sz = __compiletime_object_size(to);
+
+	if (unlikely(sz != -1 && sz < n)) {
+		copy_from_user_overflow();
+		return -EFAULT;
+	}
+
 	if (n && __access_ok((unsigned long) from, n))
 		return __copy_user((__force void __user *) to, from, n);
 	else