2017-10-31 13:24:35 -04:00
|
|
|
From 8b74d439e1697110c5e5c600643e823eb1dd0762 Mon Sep 17 00:00:00 2001
|
|
|
|
|
From: Eric Dumazet <edumazet@google.com>
|
|
|
|
|
Date: Sun, 12 Feb 2017 14:03:52 -0800
|
|
|
|
|
Subject: net/llc: avoid BUG_ON() in skb_orphan()
|
|
|
|
|
|
|
|
|
|
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: 376c7311bdb6 ("net: add a temporary sanity check in skb_orphan()")
|
|
|
|
|
Signed-off-by: Eric Dumazet <edumazet@google.com>
|
|
|
|
|
Reported-by: Andrey Konovalov <andreyknvl@google.com>
|
|
|
|
|
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
|
|
|
---
|
|
|
|
|
net/llc/llc_conn.c | 3 +++
|
|
|
|
|
net/llc/llc_sap.c | 3 +++
|
|
|
|
|
2 files changed, 6 insertions(+)
|
|
|
|
|
|
|
|
|
|
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
|
|
|
|
|
index 3e821da..8bc5a1b 100644
|
|
|
|
|
--- a/net/llc/llc_conn.c
|
|
|
|
|
+++ b/net/llc/llc_conn.c
|
|
|
|
|
@@ -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);
|
|
|
|
|
diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
|
|
|
|
|
index d0e1e80..5404d0d 100644
|
|
|
|
|
--- a/net/llc/llc_sap.c
|
|
|
|
|
+++ b/net/llc/llc_sap.c
|
|
|
|
|
@@ -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);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
--
|
|
|
|
|
cgit v1.1
|
|
|
|
|
|
