Commit 8e822a0f authored by Eric Dumazet's avatar Eric Dumazet Committed by Ben Hutchings

net/llc: avoid BUG_ON() in skb_orphan()

commit 8b74d439 upstream.

It seems nobody used LLC since linux-3.12.

Fortunately fuzzers like syzkaller still know how to run this code,
otherwise it would be no fun.

Setting skb->sk without skb->destructor leads to all kinds of
bugs, we now prefer to be very strict about it.

Ideally here we would use skb_set_owner() but this helper does not exist yet,
only CAN seems to have a private helper for that.

Fixes: 376c7311 ("net: add a temporary sanity check in skb_orphan()")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reported-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 8f1a8602
......@@ -821,7 +821,10 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
* another trick required to cope with how the PROCOM state
* machine works. -acme
*/
skb_orphan(skb);
sock_hold(sk);
skb->sk = sk;
skb->destructor = sock_efree;
}
if (!sock_owned_by_user(sk))
llc_conn_rcv(sk, skb);
......
......@@ -290,7 +290,10 @@ static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
ev->type = LLC_SAP_EV_TYPE_PDU;
ev->reason = 0;
skb_orphan(skb);
sock_hold(sk);
skb->sk = sk;
skb->destructor = sock_efree;
llc_sap_state_process(sap, skb);
}
......
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