netfilter: flowtable: validate pppoe header
[ Upstream commit 87b3593bed1868b2d9fe096c01bcdf0ea86cbebf ]
Ensure there is sufficient room to access the protocol field of the
PPPoe header. Validate it once before the flowtable lookup, then use a
helper function to access protocol field.
Reported-by: syzbot+b6f07e1c07ef40199081@syzkaller.appspotmail.com
Fixes: 72efd585f7
("netfilter: flowtable: add pppoe support")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
parent
ebf7c9746f
commit
a2471d2710
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@ -335,7 +335,7 @@ int nf_flow_rule_route_ipv6(struct net *net, struct flow_offload *flow,
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int nf_flow_table_offload_init(void);
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int nf_flow_table_offload_init(void);
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void nf_flow_table_offload_exit(void);
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void nf_flow_table_offload_exit(void);
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static inline __be16 nf_flow_pppoe_proto(const struct sk_buff *skb)
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static inline __be16 __nf_flow_pppoe_proto(const struct sk_buff *skb)
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{
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{
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__be16 proto;
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__be16 proto;
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@ -351,6 +351,16 @@ static inline __be16 nf_flow_pppoe_proto(const struct sk_buff *skb)
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return 0;
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return 0;
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}
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}
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static inline bool nf_flow_pppoe_proto(struct sk_buff *skb, __be16 *inner_proto)
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{
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if (!pskb_may_pull(skb, PPPOE_SES_HLEN))
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return false;
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*inner_proto = __nf_flow_pppoe_proto(skb);
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return true;
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}
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#define NF_FLOW_TABLE_STAT_INC(net, count) __this_cpu_inc((net)->ft.stat->count)
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#define NF_FLOW_TABLE_STAT_INC(net, count) __this_cpu_inc((net)->ft.stat->count)
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#define NF_FLOW_TABLE_STAT_DEC(net, count) __this_cpu_dec((net)->ft.stat->count)
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#define NF_FLOW_TABLE_STAT_DEC(net, count) __this_cpu_dec((net)->ft.stat->count)
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#define NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count) \
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#define NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count) \
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@ -21,7 +21,8 @@ nf_flow_offload_inet_hook(void *priv, struct sk_buff *skb,
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proto = veth->h_vlan_encapsulated_proto;
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proto = veth->h_vlan_encapsulated_proto;
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break;
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break;
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case htons(ETH_P_PPP_SES):
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case htons(ETH_P_PPP_SES):
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proto = nf_flow_pppoe_proto(skb);
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if (!nf_flow_pppoe_proto(skb, &proto))
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return NF_ACCEPT;
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break;
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break;
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default:
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default:
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proto = skb->protocol;
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proto = skb->protocol;
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@ -273,10 +273,11 @@ static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
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return NF_STOLEN;
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return NF_STOLEN;
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}
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}
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static bool nf_flow_skb_encap_protocol(const struct sk_buff *skb, __be16 proto,
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static bool nf_flow_skb_encap_protocol(struct sk_buff *skb, __be16 proto,
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u32 *offset)
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u32 *offset)
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{
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{
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struct vlan_ethhdr *veth;
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struct vlan_ethhdr *veth;
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__be16 inner_proto;
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switch (skb->protocol) {
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switch (skb->protocol) {
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case htons(ETH_P_8021Q):
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case htons(ETH_P_8021Q):
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@ -287,7 +288,8 @@ static bool nf_flow_skb_encap_protocol(const struct sk_buff *skb, __be16 proto,
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}
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}
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break;
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break;
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case htons(ETH_P_PPP_SES):
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case htons(ETH_P_PPP_SES):
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if (nf_flow_pppoe_proto(skb) == proto) {
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if (nf_flow_pppoe_proto(skb, &inner_proto) &&
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inner_proto == proto) {
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*offset += PPPOE_SES_HLEN;
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*offset += PPPOE_SES_HLEN;
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return true;
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return true;
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}
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}
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@ -316,7 +318,7 @@ static void nf_flow_encap_pop(struct sk_buff *skb,
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skb_reset_network_header(skb);
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skb_reset_network_header(skb);
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break;
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break;
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case htons(ETH_P_PPP_SES):
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case htons(ETH_P_PPP_SES):
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skb->protocol = nf_flow_pppoe_proto(skb);
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skb->protocol = __nf_flow_pppoe_proto(skb);
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skb_pull(skb, PPPOE_SES_HLEN);
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skb_pull(skb, PPPOE_SES_HLEN);
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skb_reset_network_header(skb);
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skb_reset_network_header(skb);
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break;
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break;
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