net: __skb_flow_dissect() must cap its return value
After Tom patch, thoff field could point past the end of the buffer,
this could fool some callers.
If an skb was provided, skb->len should be the upper limit.
If not, hlen is supposed to be the upper limit.
Fixes: a6e544b0a8
("flow_dissector: Jump to exit code in __skb_flow_dissect")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Yibin Yang <yibyang@cisco.com
Acked-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
79774d6bfa
commit
34fad54c25
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@ -122,7 +122,7 @@ bool __skb_flow_dissect(const struct sk_buff *skb,
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struct flow_dissector_key_keyid *key_keyid;
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struct flow_dissector_key_keyid *key_keyid;
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bool skip_vlan = false;
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bool skip_vlan = false;
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u8 ip_proto = 0;
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u8 ip_proto = 0;
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bool ret = false;
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bool ret;
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if (!data) {
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if (!data) {
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data = skb->data;
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data = skb->data;
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@ -549,12 +549,17 @@ ip_proto_again:
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out_good:
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out_good:
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ret = true;
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ret = true;
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out_bad:
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key_control->thoff = (u16)nhoff;
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out:
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key_basic->n_proto = proto;
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key_basic->n_proto = proto;
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key_basic->ip_proto = ip_proto;
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key_basic->ip_proto = ip_proto;
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key_control->thoff = (u16)nhoff;
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return ret;
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return ret;
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out_bad:
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ret = false;
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key_control->thoff = min_t(u16, nhoff, skb ? skb->len : hlen);
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goto out;
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}
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}
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EXPORT_SYMBOL(__skb_flow_dissect);
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EXPORT_SYMBOL(__skb_flow_dissect);
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