Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bonding: refuse to enslave CAN devices syzbot reported a kernel paging request crash in can_rx_unregister() inside net/can/af_can.c. The crash occurs because a virtual CAN device (vxcan) is being enslaved to a bonding master. During the enslavement process, the bonding driver mutates and modifies the network device states to fit an Ethernet-like aggregation model. However, CAN devices operate on a completely different Layer 2 architecture, relying on the CAN mid-layer private data structure (can_ml_priv) instead of standard Ethernet structures. Since bonding does not initialize or maintain these CAN structures, subsequent operations on the half-enslaved interface (such as closing associated sockets via isotp_release) lead to a null-pointer dereference when accessing the CAN receiver lists. Bonding CAN interfaces is architecturally invalid as CAN lacks MAC addresses, ARP capabilities, and standard Ethernet link-layer mechanisms. While generic loopback devices are blocked globally in net/core/dev.c, virtual CAN devices bypass this check because they do not carry the IFF_LOOPBACK flag, despite acting as local software-loopbacks. Fix this by explicitly blocking network devices of type ARPHRD_CAN from being enslaved at the very beginning of bond_enslave(). This prevents illegal state mutations, eliminates the resulting KASAN crashes, and avoids potential memory leaks from incomplete socket cleanups. As the CAN support has been added a long time after bonding the Fixes-tag points to the introduction of ARPHRD_CAN that would have needed a specific handling in bonding_main.c.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 69b78b5f3033272e53a2dc2dad675962654a5b38; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 41e8478c4cd896d3abbe33d41afc90c84ac66602; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before f4d78a81f57df82e9d82a2c07471fed1a1235893; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 02f1c87ded33b43d48b4a1d665da15f2157b30d8; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 9ea8a648d9120f7652bcde1ce2c4ad66871af707; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 563090e5d450c665f70d955a39f9587afc7842eb; affected cd05acfe65ed2cf2db683fa9a6adb8d35635263b before 8ba68464e4787b6a7ec938826e16124df20fd23d |
| Linux / Linux | affected 2.6.25; unaffected 0 before 2.6.25; unaffected 5.15.210 through 5.15.*; unaffected 6.1.176 through 6.1.*; unaffected 6.6.143 through 6.6.*; unaffected 6.12.93 through 6.12.*; unaffected 6.18.35 through 6.18.*; unaffected 7.0.12 through 7.0.*; unaffected 7.1 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/69b78b5f3033272e53a2dc2dad675962654a5b38
- https://git.kernel.org/stable/c/41e8478c4cd896d3abbe33d41afc90c84ac66602
- https://git.kernel.org/stable/c/f4d78a81f57df82e9d82a2c07471fed1a1235893
- https://git.kernel.org/stable/c/02f1c87ded33b43d48b4a1d665da15f2157b30d8
- https://git.kernel.org/stable/c/9ea8a648d9120f7652bcde1ce2c4ad66871af707
- https://git.kernel.org/stable/c/563090e5d450c665f70d955a39f9587afc7842eb
- https://git.kernel.org/stable/c/8ba68464e4787b6a7ec938826e16124df20fd23d