| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-49697: bpf: Fix request_sock leak in sk lookup helpers |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2022-49697 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.2 with commit edbf8c01de5a104a71ed6df2bf6421ceb2836a8e and fixed in 5.4.202 with commit 8ffe2e50e9678c8373027492035f094b130437f1 |
| Issue introduced in 5.2 with commit edbf8c01de5a104a71ed6df2bf6421ceb2836a8e and fixed in 5.10.127 with commit 516760f1d2979903eaad5b437256913c5cd98416 |
| Issue introduced in 5.2 with commit edbf8c01de5a104a71ed6df2bf6421ceb2836a8e and fixed in 5.15.51 with commit b03607437ea81b850599f705096b05b85e7a4a71 |
| Issue introduced in 5.2 with commit edbf8c01de5a104a71ed6df2bf6421ceb2836a8e and fixed in 5.18.8 with commit 5a62b5ba4c0ce8315b6382cd4ace81b48cd121cd |
| Issue introduced in 5.2 with commit edbf8c01de5a104a71ed6df2bf6421ceb2836a8e and fixed in 5.19 with commit 3046a827316c0e55fc563b4fb78c93b9ca5c7c37 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2022-49697 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| net/core/filter.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/8ffe2e50e9678c8373027492035f094b130437f1 |
| https://git.kernel.org/stable/c/516760f1d2979903eaad5b437256913c5cd98416 |
| https://git.kernel.org/stable/c/b03607437ea81b850599f705096b05b85e7a4a71 |
| https://git.kernel.org/stable/c/5a62b5ba4c0ce8315b6382cd4ace81b48cd121cd |
| https://git.kernel.org/stable/c/3046a827316c0e55fc563b4fb78c93b9ca5c7c37 |
