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CVE-2022-49697

MEDIUMCVSS 5.5/10EPSS 0.26%

Last modified

CVE-2022-49697 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: bpf: Fix request_sock leak in sk lookup helpers A customer reported a request_socket leak in a Calico cloud environment. We found that a BPF program was doing a socket lookup with takes a refcnt on the socket and that it was finding the request_socket but returning the parent LISTEN socket via sk_to_full_sk() without decrementing the child request socket 1st, resulting in request_sock slab object leak. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix request_sock leak in sk lookup helpers A customer reported a request_socket leak in a Calico cloud environment. We found that a BPF program was doing a socket lookup with takes a refcnt on the socket and that it was finding the request_socket but returning the parent LISTEN socket via sk_to_full_sk() without decrementing the child request socket 1st, resulting in request_sock slab object leak. This patch retains the existing behaviour of returning full socks to the caller but it also decrements the child request_socket if one is present before doing so to prevent the leak. Thanks to Curtis Taylor for all the help in diagnosing and testing this. And thanks to Antoine Tenart for the reproducer and patch input. v2 of this patch contains, refactor as per Daniel Borkmann's suggestions to validate RCU flags on the listen socket so that it balances with bpf_sk_release() and update comments as per Martin KaFai Lau's suggestion. One small change to Daniels suggestion, put "sk = sk2" under "if (sk2 != sk)" to avoid an extra instruction.

Metrics

CVSS 3.1
5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
0.26%

17.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersionsUpdate
LinuxLinux Kernel>= 5.2, < 5.4.202—
LinuxLinux Kernel>= 5.5, < 5.10.127—
LinuxLinux Kernel>= 5.11, < 5.15.51—
LinuxLinux Kernel>= 5.16, < 5.18.8—
LinuxLinux Kernel5.19Rc1

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2022-49697?
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix request_sock leak in sk lookup helpers A customer reported a request_socket leak in a Calico cloud environment. We found that a BPF program was doing a socket lookup with takes a refcnt on the socket and that it was finding the request_socket but returning the parent LISTEN socket via sk_to_full_sk() without decrementing the child request socket 1st, resulting in request_sock slab object leak. This patch retains the existing behaviour of returning full socks to the caller but it also decrements the child request_socket if one is present before doing so to prevent the leak. Thanks to Curtis Taylor for all the help in diagnosing and testing this. And thanks to Antoine Tenart for the reproducer and patch input. v2 of this patch contains, refactor as per Daniel Borkmann's suggestions to validate RCU flags on the listen socket so that it balances with bpf_sk_release() and update comments as per Martin KaFai Lau's suggestion. One small change to Daniels suggestion, put "sk = sk2" under "if (sk2 != sk)" to avoid an extra instruction.
How severe is CVE-2022-49697?
CVE-2022-49697 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.
How do I fix CVE-2022-49697?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-49697?

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Source: NVD / NIST