| 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-2024-35839: netfilter: bridge: replace physindev with physinif in nf_bridge_info |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| netfilter: bridge: replace physindev with physinif in nf_bridge_info |
| |
| An skb can be added to a neigh->arp_queue while waiting for an arp |
| reply. Where original skb's skb->dev can be different to neigh's |
| neigh->dev. For instance in case of bridging dnated skb from one veth to |
| another, the skb would be added to a neigh->arp_queue of the bridge. |
| |
| As skb->dev can be reset back to nf_bridge->physindev and used, and as |
| there is no explicit mechanism that prevents this physindev from been |
| freed under us (for instance neigh_flush_dev doesn't cleanup skbs from |
| different device's neigh queue) we can crash on e.g. this stack: |
| |
| arp_process |
| neigh_update |
| skb = __skb_dequeue(&neigh->arp_queue) |
| neigh_resolve_output(..., skb) |
| ... |
| br_nf_dev_xmit |
| br_nf_pre_routing_finish_bridge_slow |
| skb->dev = nf_bridge->physindev |
| br_handle_frame_finish |
| |
| Let's use plain ifindex instead of net_device link. To peek into the |
| original net_device we will use dev_get_by_index_rcu(). Thus either we |
| get device and are safe to use it or we don't get it and drop skb. |
| |
| The Linux kernel CVE team has assigned CVE-2024-35839 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.2 with commit c4e70a87d975d1f561a00abfe2d3cefa2a486c95 and fixed in 6.1.75 with commit 7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97b |
| Issue introduced in 4.2 with commit c4e70a87d975d1f561a00abfe2d3cefa2a486c95 and fixed in 6.6.14 with commit 9325e3188a9cf3f69fc6f32af59844bbc5b90547 |
| Issue introduced in 4.2 with commit c4e70a87d975d1f561a00abfe2d3cefa2a486c95 and fixed in 6.7.2 with commit 544add1f1cfb78c3dfa3e6edcf4668f6be5e730c |
| Issue introduced in 4.2 with commit c4e70a87d975d1f561a00abfe2d3cefa2a486c95 and fixed in 6.8 with commit 9874808878d9eed407e3977fd11fee49de1e1d86 |
| |
| 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-2024-35839 |
| 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/linux/netfilter_bridge.h |
| include/linux/skbuff.h |
| net/bridge/br_netfilter_hooks.c |
| net/bridge/br_netfilter_ipv6.c |
| net/ipv4/netfilter/nf_reject_ipv4.c |
| net/ipv6/netfilter/nf_reject_ipv6.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/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97b |
| https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547 |
| https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730c |
| https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86 |
