Bug 206270

Summary: CVE-2006-4997 IP over ATM clip_mkip dereference freed pointer
Product: Red Hat Enterprise Linux 3 Reporter: Marcel Holtmann <holtmann>
Component: kernelAssignee: Thomas Graf <tgraf>
Status: CLOSED ERRATA QA Contact: Brian Brock <bbrock>
Severity: medium Docs Contact:
Priority: medium    
Version: 3.0CC: lwang, petrides, rkhan, security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,reported=20060912,source=lkml,public=20060912
Fixed In Version: RHSA-2006-0710 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2006-10-19 12:46:07 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Attachments:
Description Flags
proposed patch none

Description Marcel Holtmann 2006-09-13 12:43:16 UTC
Reported by ADLab, Venustech info Ltd CHINA:

There is a vulnerability in function clip_mkip() in net/atm/clip.c. When
re-processing received data, a struct sk_buff pointer skb may be dereferenced
after a free operation. It will lead to a kernel panic and denying further service.
 
clip_mkip (clip.c):

502         while ((skb = skb_dequeue(&copy)) != NULL)
503                 if (!clip_devs) {
504                         atm_return(vcc,skb->truesize);
505                         kfree_skb(skb);
506                 }
507                 else {
508                         unsigned int len = skb->len;
509
510                         clip_push(vcc,skb);
511                         PRIV(skb->dev)->stats.rx_packets--;
512                         PRIV(skb->dev)->stats.rx_bytes -= len;
513                 }
 
At line 511, PRIV(skb->dev) reference skb->dev; but after call clip_push at line
510, skb may be freed.
 
clip_push (clip.c):

198 static void clip_push(struct atm_vcc *vcc,struct sk_buff *skb)
199 {

	......

234         memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
235         netif_rx(skb);
236 }
 
netif_rx (dev.c):

1392 int netif_rx(struct sk_buff *skb)
1393 {

	......

1428         kfree_skb(skb);	//drop skb
1429         return NET_RX_DROP;
1430 }

In netif_rx(), skb may be dropped during processing for congestion control or by
the protocol layers; the return value NET_RX_DROP is used to identify skb
pointer arg is dropped(freed).

Comment 2 Thomas Graf 2006-10-02 17:25:31 UTC
Created attachment 137572 [details]
proposed patch

Comment 3 RHEL Program Management 2006-10-09 15:18:40 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Comment 4 Jay Turner 2006-10-10 12:10:55 UTC
QE ack for U9.

Comment 5 Ernie Petrides 2006-10-10 22:20:30 UTC
A fix for this problem has just been committed to the RHEL3 U9
patch pool this evening (in kernel version 2.4.21-47.2.EL).


Comment 6 Ernie Petrides 2006-10-13 21:51:46 UTC
A fix for this problem has also been committed to the RHEL3 E9
patch pool this evening (in kernel version 2.4.21-47.0.1.EL).


Comment 9 Red Hat Bugzilla 2006-10-19 12:46:09 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2006-0710.html