Description

In the Linux kernel, the following vulnerability has been resolved: tun: free page on short-frame rejection in tun_xdp_one() tun_xdp_one() returns -EINVAL on a frame shorter than ETH_HLEN without freeing the page that vhost_net_build_xdp() allocated for it. tun_sendmsg() discards that -EINVAL and still returns total_len, so vhost_tx_batch() takes the success path and never frees the page; each short frame in a batch leaks one page-frag chunk. A local process that can open /dev/net/tun and /dev/vhost-net can hit this path: it attaches a tun/tap device as the vhost-net backend and feeds TX descriptors whose length minus the virtio-net header is below ETH_HLEN. Each kick leaks the page-frag chunks for that batch, and a tight submission loop exhausts host memory and triggers an OOM panic. Free the page before returning -EINVAL, matching the XDP-program error path in the same function.

References 8

• git.kernel.org https://git.kernel.org/stable/c/0a6f46a9332ad6958992d64d3b3a81a80b2ca940
• git.kernel.org https://git.kernel.org/stable/c/0e8211fcf9426f5adddf32516ba0f400ceb9544d
• git.kernel.org https://git.kernel.org/stable/c/37a1c268c2c8090bf4dc552d732bd23ba36f8eb0
• git.kernel.org https://git.kernel.org/stable/c/5b34f9e4fe2f203724a6e893d6df0316b9670057
• git.kernel.org https://git.kernel.org/stable/c/69863ff2720a0e9871f1a5710f2a33a94217fee0
• git.kernel.org https://git.kernel.org/stable/c/98c67be9eb9de72465a071949e84a3cdb8fab5a3
• git.kernel.org https://git.kernel.org/stable/c/e915445942af6dcea628bf66d6241641201a0c41
• git.kernel.org https://git.kernel.org/stable/c/f4feb1e20058e407cb00f45aff47f5b7e19a6bbf

Remediation