kernel/x86-Restrict-MSR-access-when-module-loading-is-restr.patch
Josh Boyer efcd02beae Linux v3.17-rc1-231-g7be141d05549
- Add patch to fix NFS oops on /proc removal (rhbz 1132368)
2014-08-25 10:33:49 -04:00

44 lines
1.2 KiB
Diff

From e937c26ad4a50a642ecd53803e119dd21cb6d94a 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(&regs, uregs, sizeof regs)) {
err = -EFAULT;
break;
--
1.9.3