CVE-2022-49066

In the Linux kernel, the following vulnerability has been resolved:

veth: Ensure eth header is in skbs linear part

After feeding a decapsulated packet to a veth device with act_mirred, skb_headlen() may be 0. But veth_xmit() calls __dev_forward_skb(), which expects at least ETH_HLEN byte of linear data (as __dev_forward_skb2() calls eth_type_trans(), which pulls ETH_HLEN bytes unconditionally).

Use pskb_may_pull() to ensure veth_xmit() respects this constraint.

kernel BUG at include/linux/skbuff.h:2328! RIP: 0010:eth_type_trans+0xcf/0x140 Call Trace: __dev_forward_skb2+0xe3/0x160 veth_xmit+0x6e/0x250 [veth] dev_hard_start_xmit+0xc7/0x200 __dev_queue_xmit+0x47f/0x520 ? skb_ensure_writable+0x85/0xa0 ? skb_mpls_pop+0x98/0x1c0 tcf_mirred_act+0x442/0x47e [act_mirred] tcf_action_exec+0x86/0x140 fl_classify+0x1d8/0x1e0 [cls_flower] ? dma_pte_clear_level+0x129/0x1a0 ? dma_pte_clear_level+0x129/0x1a0 ? prb_fill_curr_block+0x2f/0xc0 ? skb_copy_bits+0x11a/0x220 __tcf_classify+0x58/0x110 tcf_classify_ingress+0x6b/0x140 __netif_receive_skb_core.constprop.0+0x47d/0xfd0 ? __iommu_dma_unmap_swiotlb+0x44/0x90 __netif_receive_skb_one_core+0x3d/0xa0 netif_receive_skb+0x116/0x170 be_process_rx+0x22f/0x330 [be2net] be_poll+0x13c/0x370 [be2net] __napi_poll+0x2a/0x170 net_rx_action+0x22f/0x2f0 __do_softirq+0xca/0x2a8 __irq_exit_rcu+0xc1/0xe0 common_interrupt+0x83/0xa0

Affected Software

References

• https://git.kernel.org/stable/c/1ef0088e43af1de4e3b365218c4d3179d9a37eec
• https://git.kernel.org/stable/c/2fd90b86dff413fbf8128780c04ea9c6849c16e2
• https://git.kernel.org/stable/c/3de2a02b60a4ef0ab76263216f08c7d095fc7c42
• https://git.kernel.org/stable/c/46bc359fec0c6d87b70d7a008bcd9a5e30dd6f27
• https://git.kernel.org/stable/c/726e2c5929de841fdcef4e2bf995680688ae1b87
• https://git.kernel.org/stable/c/93940fc4cb81840dc0fa202de48cccb949a0261d
• https://git.kernel.org/stable/c/d417a859221f127e8edf09c14b76ab50f825e171
• https://git.kernel.org/stable/c/d67c900f1947d64ba8a64f693504bcaab8d9000c