This is a note to let you know that I've just added the patch titled
veth: Ensure eth header is in skb's linear part
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
veth-ensure-eth-header-is-in-skb-s-linear-part.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 297c4ee054c011be247fd6275b603dcda92e7c9b
Author: Guillaume Nault <gnault@xxxxxxxxxx>
Date: Wed Apr 6 16:18:54 2022 +0200
veth: Ensure eth header is in skb's linear part
[ Upstream commit 726e2c5929de841fdcef4e2bf995680688ae1b87 ]
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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index ee7460ee3d05..57ff2fd95f75 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -114,7 +114,7 @@ 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;
}
