CVE-2024-35839
Assigner: Linux
Published: 2024-05-17T14:27:30.524Z
State: PUBLISHED
descriptions: value: 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: product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: c4e70a87d975
lessThan: 7ae19ee81ca5
status: affected
versionType: git
version: c4e70a87d975
lessThan: 9325e3188a9c
status: affected
versionType: git
version: c4e70a87d975
lessThan: 544add1f1cfb
status: affected
versionType: git
version: c4e70a87d975
lessThan: 9874808878d9
status: affected
versionType: git
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions: version: 4.2
status: affected
version: 0
lessThan: 4.2
status: unaffected
versionType: custom
version: 6.1.75
lessThanOrEqual: 6.1.*
status: unaffected
versionType: custom
version: 6.6.14
lessThanOrEqual: 6.6.*
status: unaffected
versionType: custom
version: 6.7.2
lessThanOrEqual: 6.7.*
status: unaffected
versionType: custom
version: 6.8
lessThanOrEqual: *
status: unaffected
versionType: original_commit_for_fix
title: netfilter: bridge: replace physindev with physinif in nf_bridge_info
x_generator: engine: bippy-d175d3acf727