Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
ipv4: Fix fib_nlmsg_size() for RTA_VIA nexthops
fib_nlmsg_size() still estimates nexthop space as if every gateway is encoded as an IPv4 RTA_GATEWAY attribute. IPv4 routes can also carry an IPv6 gateway, which fib_nexthop_info() dumps as RTA_VIA.
As a result, route notifications can allocate an skb that is too small. fib_dump_info() then fails with -EMSGSIZE and rtmsg_fib() hits the WARN_ON() that marks such failures as a fib_nlmsg_size() bug. With panic_on_warn set, this becomes a kernel panic.
Mirror the actual nexthop dump layout in fib_nlmsg_size(): account for IPv6 nexthop gateways dumped as RTA_VIA, for the no-header rtnexthop layout used inside RTA_MULTIPATH, and for RTA_FLOW only when it is actually present.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 4.19.0 (+7 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9.2 ESU | In Rollout |
36 kernels
|
| Debian 12 | Released |
43 kernels
|
| Debian 13 | Released |
15 kernels
|
| Oracle Linux 8 UEK 7 | Released |
112 kernels
|
| Oracle Linux 9 UEK 7 | Released |
112 kernels
|
| Proxmox VE 7 5.15 | In Rollout |
47 kernels
|
| Ubuntu 20.04 HWE AWS | In Rollout |
57 kernels
|
| Ubuntu 22.04 | Released |
102 kernels
|
| Ubuntu 22.04 AWS | Released |
93 kernels
|
| Ubuntu 22.04 Azure | Released |
83 kernels
|