CVE - CVE-2021-47515

CVE-ID
CVE-2021-47515	Learn more at National Vulnerability Database (NVD) • CVSS Severity Rating • Fix Information • Vulnerable Software Versions • SCAP Mappings • CPE Information
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.
References
Note: References are provided for the convenience of the reader to help distinguish between vulnerabilities. The list is not intended to be complete.
MISC:https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e URL:https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e MISC:https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831 URL:https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831 MISC:https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1 URL:https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1 MISC:https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c URL:https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c MISC:https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3 URL:https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3 MISC:https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9 URL:https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9
Assigning CNA
kernel.org
Date Record Created
20240524	Disclaimer: The record creation date may reflect when the CVE ID was allocated or reserved, and does not necessarily indicate when this vulnerability was discovered, shared with the affected vendor, publicly disclosed, or updated in CVE.
Phase (Legacy)
Assigned (20240524)
Votes (Legacy)

Comments (Legacy)

Proposed (Legacy)
N/A
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