linux-kernel - [PATCH] livepatch: x86: bugfix about kASLR

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-next>] [day] [month] [year] [list]

Date:	Wed, 4 Nov 2015 17:32:12 +0800
From:	Zhou Chengming <zhouchengming1@...wei.com>
To:	<jpoimboe@...hat.com>, <sjenning@...hat.com>, <jkosina@...e.cz>,
	<vojtech@...e.cz>
CC:	<live-patching@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<guohanjun@...wei.com>, <huawei.libin@...wei.com>,
	<xiexiuqi@...wei.com>, <cbay@...aysdata.com>
Subject: [PATCH] livepatch: x86: bugfix about kASLR

When enable KASLR, func->old_addr will be set to zero
and livepatch will find the right old address.
But for reloc, livepatch just verify it using reloc->val
(old addr from user), so verify failed and report
"kernel mismatch" error.

Reported-by: Cyril B. <cbay@...aysdata.com>
Signed-off-by: Zhou Chengming <zhouchengming1@...wei.com>
---
 kernel/livepatch/core.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 53196e2..c8885c6 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -311,7 +311,12 @@ static int klp_write_object_relocations(struct module *pmod,
 		return -EINVAL;
 
 	for (reloc = obj->relocs; reloc->name; reloc++) {
-		if (!klp_is_module(obj)) {
+
+#if defined(CONFIG_RANDOMIZE_BASE)
+		/* KASLR is enabled, disregard old_addr from user */
+		reloc->val = 0;
+#endif
+		if (reloc->val && !klp_is_module(obj)) {
 			ret = klp_verify_vmlinux_symbol(reloc->name,
 							reloc->val);
 			if (ret)
-- 
1.7.7

--
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/