X-Git-Url: https://git.kernelconcepts.de/?p=karo-tx-linux.git;a=blobdiff_plain;f=include%2Flinux%2Fthread_info.h;h=250a27614328471e4a805884a952881116a14c3e;hp=d7d3ea637dd0a500875cbe64c00eb5e0188acd41;hb=47d2f3cc737ba183a27901faf4048f422aa7c010;hpb=079c1812a2848539b61351fe4b08902187e19019

diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h
index d7d3ea637dd0..250a27614328 100644
--- a/include/linux/thread_info.h
+++ b/include/linux/thread_info.h
@@ -113,6 +113,33 @@ static inline void check_object_size(const void *ptr, unsigned long n,
 { }
 #endif /* CONFIG_HARDENED_USERCOPY */
 
+extern void __compiletime_error("copy source size is too small")
+__bad_copy_from(void);
+extern void __compiletime_error("copy destination size is too small")
+__bad_copy_to(void);
+
+static inline void copy_overflow(int size, unsigned long count)
+{
+	WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
+}
+
+static __always_inline bool
+check_copy_size(const void *addr, size_t bytes, bool is_source)
+{
+	int sz = __compiletime_object_size(addr);
+	if (unlikely(sz >= 0 && sz < bytes)) {
+		if (!__builtin_constant_p(bytes))
+			copy_overflow(sz, bytes);
+		else if (is_source)
+			__bad_copy_from();
+		else
+			__bad_copy_to();
+		return false;
+	}
+	check_object_size(addr, bytes, is_source);
+	return true;
+}
+
 #ifndef arch_setup_new_exec
 static inline void arch_setup_new_exec(void) { }
 #endif