In the Linux kernel, the following vulnerability has been resolved:
seg6: fix the iif in the IPv6 socket control block
When an IPv4 packet is received, the ip_rcv_core(...) sets the receiving
interface index into the IPv4 socket control block (v5.16-rc4,
net/ipv4/ip_input.c line 510):
IPCB(skb)->iif = skb->skb_iif;
If that IPv4 packet is meant to be encapsulated in an outer IPv6+SRH
header, the seg6_do_srh_encap(...) performs the required encapsulation.
In this case, the seg6_do_srh_encap function clears the IPv6 socket control
block (v5.16-rc4 net/ipv6/seg6_iptunnel.c line 163):
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
The memset(...) was introduced in commit ef489749aae5 ("ipv6: sr: clear
IP6CB(skb) on SRH ip4ip6 encapsulation") a long time ago (2019-01-29).
Since the IPv6 socket control block and the IPv4 socket control block share
the same memory area (skb->cb), the receiving interface index info is lost
(IP6CB(skb)->iif is set to zero).
As a side effect, that condition triggers a NULL pointer dereference if
commit 0857d6f8c759 ("ipv6: When forwarding count rx stats on the orig
netdev") is applied.
To fix that issue, we set the IP6CB(skb)->iif with the index of the
receiving interface once again.
Metrics
Affected Vendors & Products
References
History
Thu, 12 Sep 2024 08:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
ssvc
|
Wed, 11 Sep 2024 13:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
ssvc
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-05-24T15:09:29.334Z
Updated: 2024-09-11T17:32:52.378Z
Reserved: 2024-05-24T15:02:54.824Z
Link: CVE-2021-47515
Vulnrichment
Updated: 2024-08-04T05:39:59.755Z
NVD
Status : Awaiting Analysis
Published: 2024-05-24T15:15:12.937
Modified: 2024-05-24T18:09:20.027
Link: CVE-2021-47515
Redhat