From f99a93352471791351d67b4f56a7ac891ec1b6aa Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 3 May 2019 08:24:44 -0700 Subject: [PATCH] ip6: fix skb leak in ip6frag_expire_frag_queue() commit 47d3d7fdb10a21c223036b58bd70ffdc24a472c4 upstream. Since ip6frag_expire_frag_queue() now pulls the head skb from frag queue, we should no longer use skb_get(), since this leads to an skb leak. Stefan Bader initially reported a problem in 4.4.stable [1] caused by the skb_get(), so this patch should also fix this issue. 296583.091021] kernel BUG at /build/linux-6VmqmP/linux-4.4.0/net/core/skbuff.c:1207! [296583.091734] Call Trace: [296583.091749] [] __pskb_pull_tail+0x50/0x350 [296583.091764] [] _decode_session6+0x26a/0x400 [296583.091779] [] __xfrm_decode_session+0x39/0x50 [296583.091795] [] icmpv6_route_lookup+0xf0/0x1c0 [296583.091809] [] icmp6_send+0x5e1/0x940 [296583.091823] [] ? __netif_receive_skb+0x18/0x60 [296583.091838] [] ? netif_receive_skb_internal+0x32/0xa0 [296583.091858] [] ? ixgbe_clean_rx_irq+0x594/0xac0 [ixgbe] [296583.091876] [] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6] [296583.091893] [] icmpv6_send+0x21/0x30 [296583.091906] [] ip6_expire_frag_queue+0xe0/0x120 [296583.091921] [] nf_ct_frag6_expire+0x1f/0x30 [nf_defrag_ipv6] [296583.091938] [] call_timer_fn+0x37/0x140 [296583.091951] [] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6] [296583.091968] [] run_timer_softirq+0x234/0x330 [296583.091982] [] __do_softirq+0x109/0x2b0 Fixes: d4289fcc9b16 ("net: IP6 defrag: use rbtrees for IPv6 defrag") Signed-off-by: Eric Dumazet Reported-by: Stefan Bader Cc: Peter Oskolkov Cc: Florian Westphal Signed-off-by: David S. Miller Signed-off-by: Baolin Wang Signed-off-by: Greg Kroah-Hartman --- include/net/ipv6_frag.h | 1 - 1 file changed, 1 deletion(-) diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h index 28aa9b30aece..1f77fb4dc79d 100644 --- a/include/net/ipv6_frag.h +++ b/include/net/ipv6_frag.h @@ -94,7 +94,6 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq) goto out; head->dev = dev; - skb_get(head); spin_unlock(&fq->q.lock); icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0); -- 2.20.1