Bug 207307 - CVE-2006-4997 IP over ATM clip_mkip dereference freed pointer
Summary: CVE-2006-4997 IP over ATM clip_mkip dereference freed pointer
Alias: None
Product: Red Hat Enterprise Linux 2.1
Classification: Red Hat
Component: kernel   
(Show other bugs)
Version: 2.1
Hardware: ia64
OS: Linux
Target Milestone: ---
Assignee: Don Howard
QA Contact: Brian Brock
Whiteboard: impact=moderate,reported=20060912,sou...
Keywords: Security
Depends On:
TreeView+ depends on / blocked
Reported: 2006-09-20 15:57 UTC by Marcel Holtmann
Modified: 2007-11-30 22:06 UTC (History)
1 user (show)

Fixed In Version: RHSA-2007-0012
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2007-01-17 10:51:31 UTC
Type: ---
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

Attachments (Terms of Use)

External Trackers
Tracker ID Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2007:0012 normal SHIPPED_LIVE Moderate: kernel security update 2007-01-17 10:51:04 UTC

Description Marcel Holtmann 2006-09-20 15:57:34 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;
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 4 Mike Gahagan 2006-12-19 23:03:32 UTC
verified... fix is present in linux-2.4.18-smallpatches.patch and is being
applied to the 2.4.18-e.64 source tree.

Comment 6 Red Hat Bugzilla 2007-01-17 10:51:31 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.


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