| From bippy-7c5fe7eed585 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-2024-35910: tcp: properly terminate timers for kernel sockets |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| tcp: properly terminate timers for kernel sockets |
| |
| We had various syzbot reports about tcp timers firing after |
| the corresponding netns has been dismantled. |
| |
| Fortunately Josef Bacik could trigger the issue more often, |
| and could test a patch I wrote two years ago. |
| |
| When TCP sockets are closed, we call inet_csk_clear_xmit_timers() |
| to 'stop' the timers. |
| |
| inet_csk_clear_xmit_timers() can be called from any context, |
| including when socket lock is held. |
| This is the reason it uses sk_stop_timer(), aka del_timer(). |
| This means that ongoing timers might finish much later. |
| |
| For user sockets, this is fine because each running timer |
| holds a reference on the socket, and the user socket holds |
| a reference on the netns. |
| |
| For kernel sockets, we risk that the netns is freed before |
| timer can complete, because kernel sockets do not hold |
| reference on the netns. |
| |
| This patch adds inet_csk_clear_xmit_timers_sync() function |
| that using sk_stop_timer_sync() to make sure all timers |
| are terminated before the kernel socket is released. |
| Modules using kernel sockets close them in their netns exit() |
| handler. |
| |
| Also add sock_not_owned_by_me() helper to get LOCKDEP |
| support : inet_csk_clear_xmit_timers_sync() must not be called |
| while socket lock is held. |
| |
| It is very possible we can revert in the future commit |
| 3a58f13a881e ("net: rds: acquire refcount on TCP sockets") |
| which attempted to solve the issue in rds only. |
| (net/smc/af_smc.c and net/mptcp/subflow.c have similar code) |
| |
| We probably can remove the check_net() tests from |
| tcp_out_of_resources() and __tcp_close() in the future. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35910 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 4.19.312 with commit 93f0133b9d589cc6e865f254ad9be3e9d8133f50 |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 5.4.274 with commit 44e62f5d35678686734afd47c6a421ad30772e7f |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 5.10.215 with commit e3e27d2b446deb1f643758a0c4731f5c22492810 |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 5.15.154 with commit 2e43d8eba6edd1cf05a3a20fdd77688fa7ec16a4 |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 6.1.85 with commit 91b243de910a9ac8476d40238ab3dbfeedd5b7de |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 6.6.26 with commit c1ae4d1e76eacddaacb958b67cd942082f800c87 |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 6.8.5 with commit 899265c1389fe022802aae73dbf13ee08837a35a |
| Issue introduced in 4.2 with commit 26abe14379f8e2fa3fd1bcf97c9a7ad9364886fe and fixed in 6.9 with commit 151c9c724d05d5b0dd8acd3e11cb69ef1f2dbada |
| |
| 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-2024-35910 |
| 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: |
| include/net/inet_connection_sock.h |
| include/net/sock.h |
| net/ipv4/inet_connection_sock.c |
| net/ipv4/tcp.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/93f0133b9d589cc6e865f254ad9be3e9d8133f50 |
| https://git.kernel.org/stable/c/44e62f5d35678686734afd47c6a421ad30772e7f |
| https://git.kernel.org/stable/c/e3e27d2b446deb1f643758a0c4731f5c22492810 |
| https://git.kernel.org/stable/c/2e43d8eba6edd1cf05a3a20fdd77688fa7ec16a4 |
| https://git.kernel.org/stable/c/91b243de910a9ac8476d40238ab3dbfeedd5b7de |
| https://git.kernel.org/stable/c/c1ae4d1e76eacddaacb958b67cd942082f800c87 |
| https://git.kernel.org/stable/c/899265c1389fe022802aae73dbf13ee08837a35a |
| https://git.kernel.org/stable/c/151c9c724d05d5b0dd8acd3e11cb69ef1f2dbada |
