bpf: Fix request_sock leak in sk lookup helpers
Published Feb 26, 2025
5.5
MEDIUMCVSS 3.1
EPSS 0.27%
Description
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.
Affected products
-
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version
-
- Version 5.2StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<5.2
- Version 5.10.127StatusunaffectedConstraints<=5.10.*
- Version 5.15.51StatusunaffectedConstraints<=5.15.*
- Version 5.18.8StatusunaffectedConstraints<=5.18.*
- Version 5.19StatusunaffectedConstraints<=*
- Version 5.4.202StatusunaffectedConstraints<=5.4.*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
| ||||||||||||||||||||||||
| Linux | Linux | affected |
|
- ≥ 5.2 · < 5.4.202
- ≥ 5.5 · < 5.10.127
- ≥ 5.11 · < 5.15.51
- ≥ 5.16 · < 5.18.8
- 5.19
- 5.19
- 5.19
No data.
Red Hat Enterprise Linux 8
kernel-0:4.18.0-425.3.1.el8
Fixed · RHSA-2022:7683
Red Hat Enterprise Linux 9
kernel-0:5.14.0-162.6.1.el9_1
Fixed · RHSA-2022:8267
Red Hat Enterprise Linux 9
kernel-0:5.14.0-162.6.1.el9_1
Fixed · RHSA-2022:8267
Red Hat Enterprise Linux 10
kernel
Not affected
Red Hat Enterprise Linux 6
kernel
Out of support scope
Red Hat Enterprise Linux 7
kernel
Out of support scope
Red Hat Enterprise Linux 7
kernel-rt
Out of support scope
Red Hat Enterprise Linux 8
kernel-rt
Out of support scope
Red Hat Enterprise Linux 9
kernel-rt
Affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 8 | kernel-0:4.18.0-425.3.1.el8 | Fixed | RHSA-2022:7683 |
| Red Hat Enterprise Linux 9 | kernel-0:5.14.0-162.6.1.el9_1 | Fixed | RHSA-2022:8267 |
| Red Hat Enterprise Linux 9 | kernel-0:5.14.0-162.6.1.el9_1 | Fixed | RHSA-2022:8267 |
| Red Hat Enterprise Linux 10 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | kernel | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Out of support scope | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Out of support scope | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (11)
- https://access.redhat.com/security/cve/CVE-2022-49697 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2347938 Issue Tracking
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2022-54538 Advisory
- https://git.kernel.org/stable/c/3046a827316c0e55fc563b4fb78c93b9ca5c7c37 Patch
- https://git.kernel.org/stable/c/516760f1d2979903eaad5b437256913c5cd98416 Patch
- https://git.kernel.org/stable/c/5a62b5ba4c0ce8315b6382cd4ace81b48cd121cd Patch
- https://git.kernel.org/stable/c/8ffe2e50e9678c8373027492035f094b130437f1 Patch
- https://git.kernel.org/stable/c/b03607437ea81b850599f705096b05b85e7a4a71 Patch
- https://lore.kernel.org/linux-cve-announce/2025022628-CVE-2022-49697-db0b@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2022-49697
- https://www.cve.org/CVERecord?id=CVE-2022-49697
Change history (0)
No recorded changes yet.