Ubuntu: (CVE-2021-47515): linux vulnerability
Description
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.
Solution(s)
- ubuntu-upgrade-linux
- ubuntu-upgrade-linux-aws
- ubuntu-upgrade-linux-aws-5-4
- ubuntu-upgrade-linux-aws-hwe
- ubuntu-upgrade-linux-azure
- ubuntu-upgrade-linux-azure-4-15
- ubuntu-upgrade-linux-azure-5-4
- ubuntu-upgrade-linux-bluefield
- ubuntu-upgrade-linux-gcp
- ubuntu-upgrade-linux-gcp-4-15
- ubuntu-upgrade-linux-gcp-5-4
- ubuntu-upgrade-linux-gkeop
- ubuntu-upgrade-linux-hwe
- ubuntu-upgrade-linux-hwe-5-4
- ubuntu-upgrade-linux-ibm
- ubuntu-upgrade-linux-ibm-5-4
- ubuntu-upgrade-linux-kvm
- ubuntu-upgrade-linux-oracle
- ubuntu-upgrade-linux-oracle-5-4
- ubuntu-upgrade-linux-raspi
- ubuntu-upgrade-linux-raspi-5-4
- Lightweight Endpoint Agent
- Live Dashboards
- Real Risk Prioritization
- IT-Integrated Remediation Projects
- Cloud, Virtual, and Container Assessment
- Integrated Threat Feeds
- Easy-to-Use RESTful API
- Automation-Assisted Patching
- Automated Containment
With Rapid7 live dashboards, I have a clear view of all the assets on my network, which ones can be exploited, and what I need to do in order to reduce the risk in my environment in real-time. No other tool gives us that kind of value and insight.
– Scott Cheney, Manager of Information Security, Sierra View Medical Center