| From aa86c10f86a6518c76d80c51cd2da1b08b892bef Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Sun, 12 Feb 2017 14:03:52 -0800 |
| Subject: [PATCH] net/llc: avoid BUG_ON() in skb_orphan() |
| |
| commit 8b74d439e1697110c5e5c600643e823eb1dd0762 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: 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> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c |
| index 3e821daf9dd4..8bc5a1bd2d45 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 d0e1e804ebd7..5404d0d195cc 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); |
| } |
| |
| -- |
| 2.12.0 |
| |