CVE-2021-47515 Affecting kernel-zfcpdump-modules-internal package, versions *
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Test your applications- Snyk ID SNYK-RHEL9-KERNELZFCPDUMPMODULESINTERNAL-7122019
- published 27 May 2024
- disclosed 24 May 2024
How to fix?
There is no fixed version for RHEL:9 kernel-zfcpdump-modules-internal.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-modules-internal package and not the kernel-zfcpdump-modules-internal package as distributed by RHEL.
See How to fix? for RHEL:9 relevant fixed versions and status.
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.
References
- https://access.redhat.com/security/cve/CVE-2021-47515
- https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e
- https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831
- https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1
- https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c
- https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3
- https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9