path: root/net/llc
diff options
authorEric Dumazet <edumazet@google.com>2017-02-12 14:03:52 -0800
committerDavid S. Miller <davem@davemloft.net>2017-02-12 22:14:49 -0500
commit8b74d439e1697110c5e5c600643e823eb1dd0762 (patch)
treeedfcfac1f41af2d3c3397eea8a66ae9b53f29ab3 /net/llc
parentbpf: introduce BPF_F_ALLOW_OVERRIDE flag (diff)
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>
Diffstat (limited to 'net/llc')
2 files changed, 6 insertions, 0 deletions
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);