Xen devel - Oct 2006 - [PATCH] Don''t allow MICROCODE built as a modul

Hi;

Attached patch [against xen-3.0.3-testing.hg] 
fixes "/lib/modules/2.6.12.6-xen/kernel/arch/xen/i386/kernel/microcode.ko
needs unknown symbol sys_munlock" problem by not allowing microcode as a 
module.

Cheers
-- 
S.Çağlar Onur <caglar@pardus.org.tr>
http://cekirdek.pardus.org.tr/~caglar/

Linux is like living in a teepee. No Windows, no Gates and an Apache in house!



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On 17/10/06 8:10 pm, "S.Çağlar Onur" <caglar@pardus.org.tr>
wrote:
> Hi;
> 
> Attached patch [against xen-3.0.3-testing.hg]
> fixes
"/lib/modules/2.6.12.6-xen/kernel/arch/xen/i386/kernel/microcode.ko
> needs unknown symbol sys_munlock" problem by not allowing microcode as
a
> module.
That''s not fixing the underlying problem. Why would the microcode
driver
require sys_munlock()? I''m sure one of the distros would have provided
a
patch already if they were seeing this problem.

 -- Keir



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On 17/10/06 9:20 pm, "S.Çağlar Onur" <caglar@pardus.org.tr>
wrote:
> 17 Eki 2006 Sal 22:54 tarihinde, Keir Fraser şunları yazmıştı:
>> That''s not fixing the underlying problem. Why would the
microcode driver
>> require sys_munlock()? I''m sure one of the distros would have
provided a
>> patch already if they were seeing this problem.
> 
> Hmm, a little google search shows SUSE already has [1], im not sure
original
> author submits or not but here it is [2]
> 
> [1] http://lists.opensuse.org/opensuse-commit/2006-04/msg00962.html
> [2] http://cekirdek.pardus.org.tr/~caglar/xen-microcode-modular
Ah yes, that looks sensible. Perhaps if we ask nicely Jan will post it to
the list with a signed-off-by attribution. :-)

 -- Keir



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17 Eki 2006 Sal 22:54 tarihinde, Keir Fraser şunları yazmıştı:
> That''s not fixing the underlying problem. Why would the microcode
driver
> require sys_munlock()? I''m sure one of the distros would have
provided a
> patch already if they were seeing this problem.
Hmm, a little google search shows SUSE already has [1], im not sure original 
author submits or not but here it is [2]

[1] http://lists.opensuse.org/opensuse-commit/2006-04/msg00962.html
[2] http://cekirdek.pardus.org.tr/~caglar/xen-microcode-modular

-- 
S.Çağlar Onur <caglar@pardus.org.tr>
http://cekirdek.pardus.org.tr/~caglar/

Linux is like living in a teepee. No Windows, no Gates and an Apache in house!


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>>> Keir Fraser <Keir.Fraser@cl.cam.ac.uk> 17.10.06 22:19
>>>
>On 17/10/06 9:20 pm, "S.Ça*lar Onur" <caglar@pardus.org.tr>
wrote:
>
>> 17 Eki 2006 Sal 22:54 tarihinde, Keir Fraser *unlar* yazm**t*:
>>> That''s not fixing the underlying problem. Why would the
microcode driver
>>> require sys_munlock()? I''m sure one of the distros would
have provided a
>>> patch already if they were seeing this problem.
>> 
>> Hmm, a little google search shows SUSE already has [1], im not sure
original
>> author submits or not but here it is [2]
>> 
>> [1] http://lists.opensuse.org/opensuse-commit/2006-04/msg00962.html 
>> [2] http://cekirdek.pardus.org.tr/~caglar/xen-microcode-modular 
>
>Ah yes, that looks sensible. Perhaps if we ask nicely Jan will post it to
>the list with a signed-off-by attribution. :-)
Eliminating the dependency on sys_m{,un}lock as well as the needless use of
static variables.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

Index: sle10-sp1-2006-10-05/arch/i386/kernel/microcode-xen.c
==================================================================---
sle10-sp1-2006-10-05.orig/arch/i386/kernel/microcode-xen.c	2006-10-05
12:23:01.000000000 +0200
+++ sle10-sp1-2006-10-05/arch/i386/kernel/microcode-xen.c	2006-10-05
13:37:27.000000000 +0200
@@ -50,9 +50,6 @@ MODULE_LICENSE("GPL");
 
 /* no concurrent ->write()s are allowed on /dev/cpu/microcode */
 static DECLARE_MUTEX(microcode_sem);
-
-static void __user *user_buffer;	/* user area microcode data buffer */
-static unsigned int user_buffer_size;	/* it''s size */
 				
 static int microcode_open (struct inode *unused1, struct file *unused2)
 {
@@ -60,21 +57,26 @@ static int microcode_open (struct inode 
 }
 
 
-static int do_microcode_update (void)
+static int do_microcode_update (const void __user *ubuf, size_t len)
 {
 	int err;
-	dom0_op_t op;
+	void *kbuf;
 
-	err = sys_mlock((unsigned long)user_buffer, user_buffer_size);
-	if (err != 0)
-		return err;
-
-	op.cmd = DOM0_MICROCODE;
-	set_xen_guest_handle(op.u.microcode.data, user_buffer);
-	op.u.microcode.length = user_buffer_size;
-	err = HYPERVISOR_dom0_op(&op);
+	kbuf = vmalloc(len);
+	if (!kbuf)
+		return -ENOMEM;
+
+	if (copy_from_user(kbuf, ubuf, len) == 0) {
+		dom0_op_t op;
+
+		op.cmd = DOM0_MICROCODE;
+		set_xen_guest_handle(op.u.microcode.data, kbuf);
+		op.u.microcode.length = len;
+		err = HYPERVISOR_dom0_op(&op);
+	} else
+		err = -EFAULT;
 
-	(void)sys_munlock((unsigned long)user_buffer, user_buffer_size);
+	vfree(kbuf);
 
 	return err;
 }
@@ -88,17 +90,9 @@ static ssize_t microcode_write (struct f
 		return -EINVAL;
 	}
 
-	if ((len >> PAGE_SHIFT) > num_physpages) {
-		printk(KERN_ERR "microcode: too much data (max %ld pages)\n",
num_physpages);
-		return -EINVAL;
-	}
-
 	down(&microcode_sem);
 
-	user_buffer = (void __user *) buf;
-	user_buffer_size = (int) len;
-
-	ret = do_microcode_update();
+	ret = do_microcode_update(buf, len);
 	if (!ret)
 		ret = (ssize_t)len;
 



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