Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 3.14 11/37] openvswitch: fix panic with multiple vlan headers | Date | Mon, 13 Oct 2014 04:24:08 +0200 |
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3.14-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Benc <jbenc@redhat.com>
[ Upstream commit 2ba5af42a7b59ef01f9081234d8855140738defd ]
When there are multiple vlan headers present in a received frame, the first one is put into vlan_tci and protocol is set to ETH_P_8021Q. Anything in the skb beyond the VLAN TPID may be still non-linear, including the inner TCI and ethertype. While ovs_flow_extract takes care of IP and IPv6 headers, it does nothing with ETH_P_8021Q. Later, if OVS_ACTION_ATTR_POP_VLAN is executed, __pop_vlan_tci pulls the next vlan header into vlan_tci.
This leads to two things:
1. Part of the resulting ethernet header is in the non-linear part of the skb. When eth_type_trans is called later as the result of OVS_ACTION_ATTR_OUTPUT, kernel BUGs in __skb_pull. Also, __pop_vlan_tci is in fact accessing random data when it reads past the TPID.
2. network_header points into the ethernet header instead of behind it. mac_len is set to a wrong value (10), too.
Reported-by: Yulong Pei <ypei@redhat.com> Signed-off-by: Jiri Benc <jbenc@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/openvswitch/actions.c | 5 +++++ 1 file changed, 5 insertions(+)
--- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -42,6 +42,9 @@ static int do_execute_actions(struct dat static int make_writable(struct sk_buff *skb, int write_len) { + if (!pskb_may_pull(skb, write_len)) + return -ENOMEM; + if (!skb_cloned(skb) || skb_clone_writable(skb, write_len)) return 0; @@ -70,6 +73,8 @@ static int __pop_vlan_tci(struct sk_buff vlan_set_encap_proto(skb, vhdr); skb->mac_header += VLAN_HLEN; + if (skb_network_offset(skb) < ETH_HLEN) + skb_set_network_header(skb, ETH_HLEN); skb_reset_mac_len(skb); return 0;
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