Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
nvmet-tcp: Do not WARN on remotely-controlled oversized SGL allocations
When fuzzing the nvme target code, I tripped a kernel warning in nvmet_tcp_map_data() because the length passed into the allocator is controlled by the remote initiator.
A remote initiator that sends a command with an SGL claiming a huge number, can create a scatterlist and iovec allocation of over 1 million entries, which causes the backing kmalloc call to exceed MAX_PAGE_ORDER and then the page allocator will trip on a WARN_ON_ONCE_GFP() message:
WARNING: mm/page_alloc.c:5280 __alloc_frozen_pages_noprof Workqueue: nvmet_tcp_wq nvmet_tcp_io_work … sgl_alloc_order nvmet_tcp_map_data nvmet_tcp_try_recv_pdu
As it’s never good to trip a kernel warning remotely due to many systems having panic-on-warn enabled, let’s silence it by just add GFP_NOWARN to the allocation flags.
Details
- Affected product:
- Debian 11 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.10.259 (+1 more)
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 12 | Planned | — |