Openwall GNU/*/Linux - a small security-enhanced Linux distro for servers
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Mon,  2 Oct 2017 12:20:05 -0700
From: Kees Cook <keescook@...omium.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Kees Cook <keescook@...omium.org>,
	Yoshinori Sato <ysato@...rs.sourceforge.jp>,
	Rich Felker <dalias@...c.org>,
	linux-sh@...r.kernel.org,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Michal Marek <mmarek@...e.com>,
	Ingo Molnar <mingo@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Nicholas Piggin <npiggin@...il.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Laura Abbott <labbott@...hat.com>,
	linux-kbuild@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	kernel-hardening@...ts.openwall.com
Subject: [PATCH 1/3] sh/boot: Add static stack-protector to pre-kernel

The sh decompressor code triggers stack-protector code generation when
using CONFIG_CC_STACKPROTECTOR_STRONG. As done for arm and mips, add a
simple static stack-protector canary. As this wasn't protected before, the
risk of using a weak canary is minimized. Once the kernel is actually up,
a better canary is chosen.

Cc: Yoshinori Sato <ysato@...rs.sourceforge.jp>
Cc: Rich Felker <dalias@...c.org>
Cc: linux-sh@...r.kernel.org
Signed-off-by: Kees Cook <keescook@...omium.org>
---
 arch/sh/boot/compressed/misc.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/arch/sh/boot/compressed/misc.c b/arch/sh/boot/compressed/misc.c
index ae1dfdb0013b..f4bdc5d00c04 100644
--- a/arch/sh/boot/compressed/misc.c
+++ b/arch/sh/boot/compressed/misc.c
@@ -103,6 +103,18 @@ static void error(char *x)
 	while(1);	/* Halt */
 }
 
+unsigned long __stack_chk_guard;
+
+void __stack_chk_guard_setup(void)
+{
+	__stack_chk_guard = 0x000a0dff;
+}
+
+void __stack_chk_fail(void)
+{
+	error("stack-protector: Kernel stack is corrupted\n");
+}
+
 #ifdef CONFIG_SUPERH64
 #define stackalign	8
 #else
@@ -117,6 +129,8 @@ void decompress_kernel(void)
 {
 	unsigned long output_addr;
 
+	__stack_chk_guard_setup();
+
 #ifdef CONFIG_SUPERH64
 	output_addr = (CONFIG_MEMORY_START + 0x2000);
 #else
-- 
2.7.4

Powered by blists - more mailing lists

Your e-mail address:

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.