From 4a3127693001c61a21d1ce680db6340623f52e93 Mon Sep 17 00:00:00 2001 From: Arjan van de Ven Date: Wed, 30 Sep 2009 13:05:23 +0200 Subject: x86: Turn the copy_from_user check into an (optional) compile time warning A previous patch added the buffer size check to copy_from_user(). One of the things learned from analyzing the result of the previous patch is that in general, gcc is really good at proving that the code contains sufficient security checks to not need to do a runtime check. But that for those cases where gcc could not prove this, there was a relatively high percentage of real security issues. This patch turns the case of "gcc cannot prove" into a compile time warning, as long as a sufficiently new gcc is in use that supports this. The objective is that these warnings will trigger developers checking new cases out before a security hole enters a linux kernel release. Signed-off-by: Arjan van de Ven Cc: Linus Torvalds Cc: "David S. Miller" Cc: James Morris Cc: Jan Beulich LKML-Reference: <20090930130523.348ae6c4@infradead.org> Signed-off-by: Ingo Molnar --- include/linux/compiler-gcc4.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux/compiler-gcc4.h') diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h index a3aef5d55dba..f1709c1f9eae 100644 --- a/include/linux/compiler-gcc4.h +++ b/include/linux/compiler-gcc4.h @@ -39,3 +39,6 @@ #endif #define __compiletime_object_size(obj) __builtin_object_size(obj, 0) +#if __GNUC_MINOR__ >= 4 +#define __compiletime_warning(message) __attribute__((warning(message))) +#endif -- cgit v1.2.3