linux-kernel - Re: [PATCH] x86: pad assembly functions with INT3

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <EF6BC538-EED3-4718-8AD2-DA2F60B580B1@zytor.com>
Date:   Mon, 07 May 2018 14:41:14 -0700
From:   hpa@...or.com
To:     Alexey Dobriyan <adobriyan@...il.com>, tglx@...utronix.de,
        mingo@...hat.com
CC:     linux-kernel@...r.kernel.org, x86@...nel.org
Subject: Re: [PATCH] x86: pad assembly functions with INT3

On May 7, 2018 2:37:55 PM PDT, Alexey Dobriyan <adobriyan@...il.com> wrote:
>Use INT3 instead of NOP. All that padding between functions is
>an illegal area, no legitimate code should jump into it.
>
>I've checked x86_64 allyesconfig disassembly, all changes looks sane:
>INT3 is only used after RET or unconditional JMP.
>
>Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
>---
>
> arch/x86/include/asm/linkage.h |    2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>--- a/arch/x86/include/asm/linkage.h
>+++ b/arch/x86/include/asm/linkage.h
>@@ -18,7 +18,7 @@
> 	name:
> 
> #if defined(CONFIG_X86_64) || defined(CONFIG_X86_ALIGNMENT_16)
>-#define __ALIGN		.p2align 4, 0x90
>+#define __ALIGN		.p2align 4, 0xCC
> #define __ALIGN_STR	__stringify(__ALIGN)
> #endif
> 

Acked-by: H. Peter Anvin <h.peter.anvin@in tel.com>
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.