45 lines
1.2 KiB
Diff
45 lines
1.2 KiB
Diff
From c076ed5eed97cba612d7efec41359815c5547f4c 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 09/20] 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 113e70784854..26c2f83fc470 100644
|
|
--- a/arch/x86/kernel/msr.c
|
|
+++ b/arch/x86/kernel/msr.c
|
|
@@ -105,6 +105,9 @@ 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 */
|
|
|
|
@@ -152,6 +155,10 @@ 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;
|
|
--
|
|
2.4.3
|
|
|