CVE-2024-35839
netfilter: bridge: replace physindev with physinif in nf_bridge_info
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
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.
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: bridge: reemplace physindev con physinif en nf_bridge_info. Se puede agregar un skb a neigh->arp_queue mientras se espera una respuesta de arp. Donde skb->dev del skb original puede ser diferente al neigh->dev de neigh. Por ejemplo, en el caso de unir un skb designado de un veth a otro, el skb se agregaría a un vecino->arp_queue del puente. Como skb->dev se puede restablecer a nf_bridge->physindev y usarse, y como no existe un mecanismo explícito que impida que este physindev se libere bajo nuestra responsabilidad (por ejemplo, neigh_flush_dev no limpia skbs de la cola vecina de diferentes dispositivos), podemos crashear, por ejemplo, en esta pila: 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 Usemos ifindex simple en lugar de enlace net_device. Para echar un vistazo al net_device original usaremos dev_get_by_index_rcu(). Por lo tanto, o obtenemos el dispositivo y podemos usarlo con seguridad o no lo obtenemos y eliminamos skb.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-17 CVE Reserved
- 2024-05-17 CVE Published
- 2024-05-18 EPSS Updated
- 2024-08-02 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (7)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/c4e70a87d975d1f561a00abfe2d3cefa2a486c95 | Vuln. Introduced |
| URL | Date | SRC |
|---|
| URL | Date | SRC |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2024-35839 | 2024-09-04 | |
| https://bugzilla.redhat.com/show_bug.cgi?id=2281284 | 2024-09-04 |
Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.2 < 6.1.75 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.1.75" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.2 < 6.6.14 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.6.14" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.2 < 6.7.2 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.7.2" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.2 < 6.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.2 < 6.8" | en |
Affected
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