ghsa-gw6v-2949-7c2m
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2024-35839"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-17T15:15:21Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: bridge: replace physindev with physinif in nf_bridge_info\n\nAn skb can be added to a neigh-\u003earp_queue while waiting for an arp\nreply. Where original skb\u0027s skb-\u003edev can be different to neigh\u0027s\nneigh-\u003edev. For instance in case of bridging dnated skb from one veth to\nanother, the skb would be added to a neigh-\u003earp_queue of the bridge.\n\nAs skb-\u003edev can be reset back to nf_bridge-\u003ephysindev and used, and as\nthere is no explicit mechanism that prevents this physindev from been\nfreed under us (for instance neigh_flush_dev doesn\u0027t cleanup skbs from\ndifferent device\u0027s neigh queue) we can crash on e.g. this stack:\n\narp_process\n neigh_update\n skb = __skb_dequeue(\u0026neigh-\u003earp_queue)\n neigh_resolve_output(..., skb)\n ...\n br_nf_dev_xmit\n br_nf_pre_routing_finish_bridge_slow\n skb-\u003edev = nf_bridge-\u003ephysindev\n br_handle_frame_finish\n\nLet\u0027s use plain ifindex instead of net_device link. To peek into the\noriginal net_device we will use dev_get_by_index_rcu(). Thus either we\nget device and are safe to use it or we don\u0027t get it and drop skb.",
"id": "GHSA-gw6v-2949-7c2m",
"modified": "2024-05-17T15:31:12Z",
"published": "2024-05-17T15:31:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-35839"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/544add1f1cfb78c3dfa3e6edcf4668f6be5e730c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7ae19ee81ca56b13c50a78de6c47d5b8fdc9d97b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9325e3188a9cf3f69fc6f32af59844bbc5b90547"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9874808878d9eed407e3977fd11fee49de1e1d86"
}
],
"schema_version": "1.4.0",
"severity": []
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.