| 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-2021-47132: mptcp: fix sk_forward_memory corruption on retransmission |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| mptcp: fix sk_forward_memory corruption on retransmission |
| |
| MPTCP sk_forward_memory handling is a bit special, as such field |
| is protected by the msk socket spin_lock, instead of the plain |
| socket lock. |
| |
| Currently we have a code path updating such field without handling |
| the relevant lock: |
| |
| __mptcp_retrans() -> __mptcp_clean_una_wakeup() |
| |
| Several helpers in __mptcp_clean_una_wakeup() will update |
| sk_forward_alloc, possibly causing such field corruption, as reported |
| by Matthieu. |
| |
| Address the issue providing and using a new variant of blamed function |
| which explicitly acquires the msk spin lock. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47132 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.12 with commit 64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 and fixed in 5.12.10 with commit b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3 |
| Issue introduced in 5.12 with commit 64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 and fixed in 5.13 with commit b5941f066b4ca331db225a976dae1d6ca8cf0ae3 |
| Issue introduced in 5.11.4 with commit 96db8ffef07516a6d7414b6988f2a4298a839977 |
| |
| 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-2021-47132 |
| 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/mptcp/protocol.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/b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3 |
| https://git.kernel.org/stable/c/b5941f066b4ca331db225a976dae1d6ca8cf0ae3 |
