| 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-2023-53020: l2tp: close all race conditions in l2tp_tunnel_register() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| l2tp: close all race conditions in l2tp_tunnel_register() |
| |
| The code in l2tp_tunnel_register() is racy in several ways: |
| |
| 1. It modifies the tunnel socket _after_ publishing it. |
| |
| 2. It calls setup_udp_tunnel_sock() on an existing socket without |
| locking. |
| |
| 3. It changes sock lock class on fly, which triggers many syzbot |
| reports. |
| |
| This patch amends all of them by moving socket initialization code |
| before publishing and under sock lock. As suggested by Jakub, the |
| l2tp lockdep class is not necessary as we can just switch to |
| bh_lock_sock_nested(). |
| |
| The Linux kernel CVE team has assigned CVE-2023-53020 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 3.6 with commit 37159ef2c1ae1e696b24b260b241209a19f92c60 and fixed in 5.10.166 with commit 2d77e5c0ad79004b5ef901895437e9cce6dfcc7e |
| Issue introduced in 3.6 with commit 37159ef2c1ae1e696b24b260b241209a19f92c60 and fixed in 5.15.91 with commit 77e8ed776cdb1a24b2aab8fe7c6f1f154235e1ce |
| Issue introduced in 3.6 with commit 37159ef2c1ae1e696b24b260b241209a19f92c60 and fixed in 6.1.9 with commit cef0845b6dcfa2f6c2c832e7f9622551456c741d |
| Issue introduced in 3.6 with commit 37159ef2c1ae1e696b24b260b241209a19f92c60 and fixed in 6.2 with commit 0b2c59720e65885a394a017d0cf9cab118914682 |
| |
| 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-2023-53020 |
| 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/l2tp/l2tp_core.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/2d77e5c0ad79004b5ef901895437e9cce6dfcc7e |
| https://git.kernel.org/stable/c/77e8ed776cdb1a24b2aab8fe7c6f1f154235e1ce |
| https://git.kernel.org/stable/c/cef0845b6dcfa2f6c2c832e7f9622551456c741d |
| https://git.kernel.org/stable/c/0b2c59720e65885a394a017d0cf9cab118914682 |
