On Tue, May 31, 2022 at 10:12:05AM +0800, Hangyu Hua wrote:Thanks for your explanation. I will be more careful in the future.
On 2022/5/30 18:37, Steffen Klassert wrote:
On Mon, May 30, 2022 at 06:20:46PM +0800, Hangyu Hua wrote:
xfrm_input needs to handle skb internally. But skb is not freed When
xo->flags & XFRM_GRO == 0 and decaps == 0.
Fixes: 7785bba299a8 ("esp: Add a software GRO codepath")
Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
---
net/xfrm/xfrm_input.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 144238a50f3d..6f9576352f30 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -742,7 +742,7 @@ int xfrm_input(struct sk_buff *skb, int nexthdr, __be32 spi, int encap_type)
gro_cells_receive(&gro_cells, skb);
return err;
}
-
+ kfree_skb(skb);
return err;
}
Did you test this? The function behind the 'afinfo->the transport_finish()'
pointer handles this skb and frees it in that case.
int xfrm4_transport_finish(struct sk_buff *skb, int async)
{
struct xfrm_offload *xo = xfrm_offload(skb);
struct iphdr *iph = ip_hdr(skb);
iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
#ifndef CONFIG_NETFILTER
if (!async)
return -iph->protocol; <--- [1]
#endif
...
NF_HOOK(NFPROTO_IPV4, NF_INET_PRE_ROUTING,
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
xfrm4_rcv_encap_finish); <--- [2]
return 0;
}
int xfrm6_transport_finish(struct sk_buff *skb, int async)
{
struct xfrm_offload *xo = xfrm_offload(skb);
int nhlen = skb->data - skb_network_header(skb);
skb_network_header(skb)[IP6CB(skb)->nhoff] =
XFRM_MODE_SKB_CB(skb)->protocol;
#ifndef CONFIG_NETFILTER
if (!async)
return 1; <--- [3]
#endif
...
NF_HOOK(NFPROTO_IPV6, NF_INET_PRE_ROUTING,
dev_net(skb->dev), NULL, skb, skb->dev, NULL,
xfrm6_transport_finish2);
return 0; <--- [4]
}
If transport_finish() return in [1] or [3], there will be a memory leak.
No, even in that case there is no memleak. Look for instance at the
IPv4 case, we return -iph->protocol here.
Then look at ip_protocol_deliver_rcu(). If the ipprot->handler (xfrm)
returns a negative value, this is interpreted as the protocol number
and the packet is resubmitted to the next protocol handler.
Please test your patches before you submit them in the future.