| 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-2022-48974: netfilter: conntrack: fix using __this_cpu_add in preemptible |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfilter: conntrack: fix using __this_cpu_add in preemptible |
| |
| Currently in nf_conntrack_hash_check_insert(), when it fails in |
| nf_ct_ext_valid_pre/post(), NF_CT_STAT_INC() will be called in the |
| preemptible context, a call trace can be triggered: |
| |
| BUG: using __this_cpu_add() in preemptible [00000000] code: conntrack/1636 |
| caller is nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] |
| Call Trace: |
| <TASK> |
| dump_stack_lvl+0x33/0x46 |
| check_preemption_disabled+0xc3/0xf0 |
| nf_conntrack_hash_check_insert+0x45/0x430 [nf_conntrack] |
| ctnetlink_create_conntrack+0x3cd/0x4e0 [nf_conntrack_netlink] |
| ctnetlink_new_conntrack+0x1c0/0x450 [nf_conntrack_netlink] |
| nfnetlink_rcv_msg+0x277/0x2f0 [nfnetlink] |
| netlink_rcv_skb+0x50/0x100 |
| nfnetlink_rcv+0x65/0x144 [nfnetlink] |
| netlink_unicast+0x1ae/0x290 |
| netlink_sendmsg+0x257/0x4f0 |
| sock_sendmsg+0x5f/0x70 |
| |
| This patch is to fix it by changing to use NF_CT_STAT_INC_ATOMIC() for |
| nf_ct_ext_valid_pre/post() check in nf_conntrack_hash_check_insert(), |
| as well as nf_ct_ext_valid_post() in __nf_conntrack_confirm(). |
| |
| Note that nf_ct_ext_valid_pre() check in __nf_conntrack_confirm() is |
| safe to use NF_CT_STAT_INC(), as it's under local_bh_disable(). |
| |
| The Linux kernel CVE team has assigned CVE-2022-48974 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19 with commit c56716c69ce1ac320432fb1ea5654196ba24d2f8 and fixed in 6.0.13 with commit d9bf1138a5db419db13bd9fcd3a7178d6bb20f7c |
| Issue introduced in 5.19 with commit c56716c69ce1ac320432fb1ea5654196ba24d2f8 and fixed in 6.1 with commit 9464d0b68f11a9bc768370c3260ec02b3550447b |
| |
| 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-2022-48974 |
| 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_conntrack_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/d9bf1138a5db419db13bd9fcd3a7178d6bb20f7c |
| https://git.kernel.org/stable/c/9464d0b68f11a9bc768370c3260ec02b3550447b |
