From: Peter Oskolkov <posk@google.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
netdev@vger.kernel.org
Cc: Peter Oskolkov <posk@posk.io>, David Ahern <dsahern@gmail.com>,
Willem de Bruijn <willemb@google.com>,
Peter Oskolkov <posk@google.com>
Subject: [PATCH bpf-next v2] bpf: fix memory leak in bpf_lwt_xmit_reroute
Date: Thu, 14 Feb 2019 10:39:31 -0800 [thread overview]
Message-ID: <20190214183931.20293-1-posk@google.com> (raw)
On error the skb should be freed. Tested with diff/steps
provided by David Ahern.
v2: surface routing errors to the user instead of a generic EINVAL,
as suggested by David Ahern.
Reported-by: David Ahern <dsahern@gmail.com>
Fixes: 3bd0b15281af ("bpf: add handling of BPF_LWT_REROUTE to lwt_bpf.c")
Signed-off-by: Peter Oskolkov <posk@google.com>
---
net/core/lwt_bpf.c | 29 ++++++++++++++++++++---------
1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/net/core/lwt_bpf.c b/net/core/lwt_bpf.c
index 32251f3fcda0..a5c8c79d468a 100644
--- a/net/core/lwt_bpf.c
+++ b/net/core/lwt_bpf.c
@@ -179,17 +179,17 @@ 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;
sk = sk_to_full_sk(skb->sk);
if (sk) {
@@ -215,8 +215,10 @@ static int bpf_lwt_xmit_reroute(struct sk_buff *skb)
fl4.saddr = iph->saddr;
rt = ip_route_output_key(net, &fl4);
- if (IS_ERR(rt))
- return -EINVAL;
+ if (IS_ERR(rt)) {
+ err = PTR_ERR(rt);
+ goto err;
+ }
dst = &rt->dst;
} else {
struct ipv6hdr *iph6 = ipv6_hdr(skb);
@@ -231,12 +233,17 @@ 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 (unlikely(err))
+ goto err;
+ if (IS_ERR(dst)) {
+ err = PTR_ERR(dst);
+ goto err;
+ }
}
if (unlikely(dst->error)) {
+ err = dst->error;
dst_release(dst);
- return -EINVAL;
+ goto err;
}
/* Although skb header was reserved in bpf_lwt_push_ip_encap(), it
@@ -246,17 +253,21 @@ 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
next reply other threads:[~2019-02-14 18:39 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-14 18:39 Peter Oskolkov [this message]
2019-02-14 19:04 ` [PATCH bpf-next v2] bpf: fix memory leak in bpf_lwt_xmit_reroute David Ahern
2019-02-14 23:33 ` Alexei Starovoitov
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