[PATCH bpf-next] bpf: fix memory leak in bpf_lwt_xmit_reroute
From: Peter Oskolkov <hidden>
Date: 2019-02-14 06:09:54
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
On error the skb should be freed. Tested with diff/steps
provided by David Ahern.
Reported-by: David Ahern <redacted>
Fixes: 3bd0b15281af ("bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c")
Signed-off-by: Peter Oskolkov <redacted>
---
net/core/lwt_bpf.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 32251f3fcda0..f3273cbb6b22 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c@@ -179,18 +179,19 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb) struct net_device *l3mdev = l3mdev_master_dev_rcu(skb_dst(skb)->dev); int oif = l3mdev ? l3mdev->ifindex : 0; struct dst_entry *dst = NULL; + int err = -EAFNOSUPPORT; struct sock *sk; struct net *net; bool ipv4; - int err; if (skb->protocol == htons(ETH_P_IP)) ipv4 = true; else if (skb->protocol == htons(ETH_P_IPV6)) ipv4 = false; else - return -EAFNOSUPPORT; + goto err; + err = -EINVAL; sk = sk_to_full_sk(skb->sk); if (sk) { if (sk->sk_bound_dev_if)
@@ -216,7 +217,7 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb) rt = ip_route_output_key(net, &fl4); if (IS_ERR(rt)) - return -EINVAL; + goto err; dst = &rt->dst; } else { struct ipv6hdr *iph6 = ipv6_hdr(skb);
@@ -231,12 +232,15 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb) fl6.saddr = iph6->saddr; err = ipv6_stub->ipv6_dst_lookup(net, skb->sk, &dst, &fl6); - if (err || IS_ERR(dst)) - return -EINVAL; + if (err || IS_ERR(dst)) { + err = -EINVAL; + goto err; + } } if (unlikely(dst->error)) { dst_release(dst); - return -EINVAL; + err = -EINVAL; + goto err; } /* Although skb header was reserved in bpf_lwt_push_ip_encap(), it
@@ -246,17 +250,21 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb) */ err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev)); if (unlikely(err)) - return err; + goto err; skb_dst_drop(skb); skb_dst_set(skb, dst); err = dst_output(dev_net(skb_dst(skb)->dev), skb->sk, skb); if (unlikely(err)) - return err; + goto err; /* ip[6]_finish_output2 understand LWTUNNEL_XMIT_DONE */ return LWTUNNEL_XMIT_DONE; + +err: + kfree_skb(skb); + return err; } static int bpf_xmit(struct sk_buff *skb)
--
2.21.0.rc0.258.g878e2cd30e-goog