x86: Use __builtin_object_size() to validate the buffer size for copy_from_user()

[mv-sheeva.git] / arch / x86 / include / asm / uaccess_32.h

diff --git a/arch/x86/include/asm/uaccess_32.h b/arch/x86/include/asm/uaccess_32.h
index 632fb44b4cb547fe126830a76945d8b9fc6727bd..582d6aef7417e8de12af450afc278e182d5093ef 100644 (file)
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -187,9 +187,26 @@ __copy_from_user_inatomic_nocache(void *to, const void __user *from,
 
 unsigned long __must_check copy_to_user(void __user *to,
                                        const void *from, unsigned long n);
-unsigned long __must_check copy_from_user(void *to,
+unsigned long __must_check _copy_from_user(void *to,
                                          const void __user *from,
                                          unsigned long n);
+
+static inline unsigned long __must_check copy_from_user(void *to,
+                                         const void __user *from,
+                                         unsigned long n)
+{
+       int sz = __compiletime_object_size(to);
+       int ret = -EFAULT;
+
+       if (likely(sz == -1 || sz >= n))
+               ret = _copy_from_user(to, from, n);
+#ifdef CONFIG_DEBUG_VM
+       else
+               WARN(1, "Buffer overflow detected!\n");
+#endif
+       return ret;
+}
+
 long __must_check strncpy_from_user(char *dst, const char __user *src,
                                    long count);
 long __must_check __strncpy_from_user(char *dst,