CVE-2021-47515
Linux kernel Seg6 IPv6 socket control block NULL pointer dereference 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.
INFO
Published Date :
May 24, 2024, 3:15 p.m.
Last Modified :
Nov. 21, 2024, 6:36 a.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
Exploitability Score :
References to Advisories, Solutions, and Tools
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CVE-2021-47515.
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The following list is the news that have been mention
CVE-2021-47515 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-47515 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e Added Reference https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831 Added Reference https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1 Added Reference https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c Added Reference https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3 Added Reference https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 24, 2024
Action Type Old Value New Value Added 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. Added Reference kernel.org https://git.kernel.org/stable/c/b16d412e5f79734033df04e97d7ea2f50a8e9fe3 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/6431e71093f3da586a00c6d931481ffb0dc2db0e [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/ef8804e47c0a44ae106ead1740408af5ea6c6ee9 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/666521b3852d2b2f52d570f9122b1e4b50d96831 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/98adb2bbfa407c9290bda299d4c6f7a1c4ebd5e1 [No types assigned] Added Reference kernel.org https://git.kernel.org/stable/c/ae68d93354e5bf5191ee673982251864ea24dd5c [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-47515 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-47515
weaknesses.