| 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-2022-48976: netfilter: flowtable_offload: fix using __this_cpu_add in preemptible |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfilter: flowtable_offload: fix using __this_cpu_add in preemptible |
| |
| flow_offload_queue_work() can be called in workqueue without |
| bh disabled, like the call trace showed in my act_ct testing, |
| calling NF_FLOW_TABLE_STAT_INC() there would cause a call |
| trace: |
| |
| BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u4:0/138560 |
| caller is flow_offload_queue_work+0xec/0x1b0 [nf_flow_table] |
| Workqueue: act_ct_workqueue tcf_ct_flow_table_cleanup_work [act_ct] |
| Call Trace: |
| <TASK> |
| dump_stack_lvl+0x33/0x46 |
| check_preemption_disabled+0xc3/0xf0 |
| flow_offload_queue_work+0xec/0x1b0 [nf_flow_table] |
| nf_flow_table_iterate+0x138/0x170 [nf_flow_table] |
| nf_flow_table_free+0x140/0x1a0 [nf_flow_table] |
| tcf_ct_flow_table_cleanup_work+0x2f/0x2b0 [act_ct] |
| process_one_work+0x6a3/0x1030 |
| worker_thread+0x8a/0xdf0 |
| |
| This patch fixes it by using NF_FLOW_TABLE_STAT_INC_ATOMIC() |
| instead in flow_offload_queue_work(). |
| |
| Note that for FLOW_CLS_REPLACE branch in flow_offload_queue_work(), |
| it may not be called in preemptible path, but it's good to use |
| NF_FLOW_TABLE_STAT_INC_ATOMIC() for all cases in |
| flow_offload_queue_work(). |
| |
| The Linux kernel CVE team has assigned CVE-2022-48976 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.0 with commit b038177636f83bbf87c2b238706474145dd2cd04 and fixed in 6.0.13 with commit a220a11fda012fba506b35929672374c2723ae6d |
| Issue introduced in 6.0 with commit b038177636f83bbf87c2b238706474145dd2cd04 and fixed in 6.1 with commit a81047154e7ce4eb8769d5d21adcbc9693542a79 |
| Issue introduced in 5.15.157 with commit 5345d78ae64d5a760c211cd2da995dc71c5b29e4 |
| |
| 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-2022-48976 |
| 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/netfilter/nf_flow_table_offload.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/a220a11fda012fba506b35929672374c2723ae6d |
| https://git.kernel.org/stable/c/a81047154e7ce4eb8769d5d21adcbc9693542a79 |
