| Message ID | b09b089827f128f65e9974c1dccdbbd06591f59a.1649254421.git.gnault@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 726e2c5929de841fdcef4e2bf995680688ae1b87 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] veth: Ensure eth header is in skb's linear part | expand |
Hello: This patch was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Wed, 6 Apr 2022 16:18:54 +0200 you wrote: > 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. > > [...] Here is the summary with links: - [net] veth: Ensure eth header is in skb's linear part https://git.kernel.org/netdev/net/c/726e2c5929de You are awesome, thank you!
diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 1b5714926d81..eb0121a64d6d 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -320,7 +320,7 @@ static netdev_tx_t veth_xmit(struct sk_buff *skb, struct net_device *dev) rcu_read_lock(); rcv = rcu_dereference(priv->peer); - if (unlikely(!rcv)) { + if (unlikely(!rcv) || !pskb_may_pull(skb, ETH_HLEN)) { kfree_skb(skb); goto drop; }
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: <IRQ> __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 Fixes: e314dbdc1c0d ("[NET]: Virtual ethernet device driver.") Signed-off-by: Guillaume Nault <gnault@redhat.com> --- drivers/net/veth.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)