Medium · published October 21, 2024
In the Linux kernel, the following vulnerability has been resolved:
net: add more sanity checks to qdisc_pkt_len_init()
One path takes care of SKB_GSO_DODGY, assuming
skb->len is bigger than hdr_len.
virtio_net_hdr_to_skb() does not fully dissect TCP headers,
it only make sure it is at least 20 bytes.
It is possible for an user to provide a malicious 'GSO' packet,
total length of 80 bytes.
- 20 bytes of IPv4 header
- 60 bytes TCP header
- a small gso_size like 8
virtio_net_hdr_to_skb() would declare this packet as a normal
GSO packet, because it would see 40 bytes of payload,
bigger than gso_size.
We need to make detect this case to not underflow
qdisc_skb_cb(skb)->pkt_len.
| Product | Versions | Fixed in |
|---|---|---|
| linux/linux_kernel | ≥ 3.9, < 4.19.323 | 4.19.323 |
| linux/linux_kernel | ≥ 4.20, < 5.4.285 | 5.4.285 |
| linux/linux_kernel | ≥ 5.5, < 5.10.227 | 5.10.227 |
| linux/linux_kernel | ≥ 5.11, < 5.15.168 | 5.15.168 |
| linux/linux_kernel | ≥ 5.16, < 6.1.113 | 6.1.113 |
| linux/linux_kernel | ≥ 6.2, < 6.6.55 | 6.6.55 |
| linux/linux_kernel | ≥ 6.7, < 6.10.14 | 6.10.14 |
| linux/linux_kernel | ≥ 6.11, < 6.11.3 | 6.11.3 |
| linux/linux_kernel | all versions | — |