linux-kernel - [PATCH][RESEND] kprobes: x86: mark 2 bytes NOP as boostable.

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]

Date:	Tue, 10 Feb 2015 09:34:05 +0800
From:	Wang Nan <wangnan0@...wei.com>
To:	<masami.hiramatsu.pt@...achi.com>, <mingo@...hat.com>
CC:	<tglx@...utronix.de>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>, <lizefan@...wei.com>
Subject: [PATCH][RESEND] kprobes: x86: mark 2 bytes NOP as boostable.

Currently, x86 kprobes is unable to boost 2 bytes nop like:

nopl 0x0(%rax,%rax,1)

which is 0x0f 0x1f 0x44 0x00 0x00.

Such nops have exactly 5 bytes to hold a relative jmp instruction.
Boosting them should be obviously safe.

This patch enable boosting such nops by simply updating
twobyte_is_boostable[] array.

Signed-off-by: Wang Nan <wangnan0@...wei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
---
 arch/x86/kernel/kprobes/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 98f654d..6a1146e 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -84,7 +84,7 @@ static volatile u32 twobyte_is_boostable[256 / 32] = {
 	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
 	/*      ----------------------------------------------          */
 	W(0x00, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 0, 0) | /* 00 */
-	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 10 */
+	W(0x10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1) , /* 10 */
 	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 20 */
 	W(0x30, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 30 */
 	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 40 */
-- 
1.8.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/