44 lines
1.2 KiB
Diff
44 lines
1.2 KiB
Diff
From 7dbc9b7dbfdfc853bcaf026a42c3b5385b472d1d Mon Sep 17 00:00:00 2001
|
|
From: Matthew Garrett <matthew.garrett@nebula.com>
|
|
Date: Fri, 8 Feb 2013 11:12:13 -0800
|
|
Subject: [PATCH] x86: Restrict MSR access when module loading is restricted
|
|
|
|
Writing to MSRs should not be allowed if module loading is restricted,
|
|
since it could lead to execution of arbitrary code in kernel mode. Based
|
|
on a patch by Kees Cook.
|
|
|
|
Cc: Kees Cook <keescook@chromium.org>
|
|
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
|
|
---
|
|
arch/x86/kernel/msr.c | 7 +++++++
|
|
1 file changed, 7 insertions(+)
|
|
|
|
diff --git a/arch/x86/kernel/msr.c b/arch/x86/kernel/msr.c
|
|
index c9603ac80de5..8bef43fc3f40 100644
|
|
--- a/arch/x86/kernel/msr.c
|
|
+++ b/arch/x86/kernel/msr.c
|
|
@@ -103,6 +103,9 @@ static ssize_t msr_write(struct file *file, const char __user *buf,
|
|
int err = 0;
|
|
ssize_t bytes = 0;
|
|
|
|
+ if (secure_modules())
|
|
+ return -EPERM;
|
|
+
|
|
if (count % 8)
|
|
return -EINVAL; /* Invalid chunk size */
|
|
|
|
@@ -150,6 +153,10 @@ static long msr_ioctl(struct file *file, unsigned int ioc, unsigned long arg)
|
|
err = -EBADF;
|
|
break;
|
|
}
|
|
+ if (secure_modules()) {
|
|
+ err = -EPERM;
|
|
+ break;
|
|
+ }
|
|
if (copy_from_user(®s, uregs, sizeof regs)) {
|
|
err = -EFAULT;
|
|
break;
|
|
--
|
|
1.9.3
|
|
|