From 9af86f9338949a9369bda5e6fed69347d1813054 Mon Sep 17 00:00:00 2001 From: Edward Cree Date: Mon, 9 Jul 2018 18:10:19 +0100 Subject: [PATCH] net: core: fix use-after-free in __netif_receive_skb_list_core __netif_receive_skb_core can free the skb, so we have to use the dequeue- enqueue model when calling it from __netif_receive_skb_list_core. Fixes: 88eb1944e18c ("net: core: propagate SKB lists through packet_type lookup") Signed-off-by: Edward Cree Signed-off-by: David S. Miller --- net/core/dev.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index ce4583564e00..d13cddcac41f 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4830,23 +4830,28 @@ static void __netif_receive_skb_list_core(struct list_head *head, bool pfmemallo struct list_head sublist; struct sk_buff *skb, *next; + INIT_LIST_HEAD(&sublist); list_for_each_entry_safe(skb, next, head, list) { struct net_device *orig_dev = skb->dev; struct packet_type *pt_prev = NULL; + list_del(&skb->list); __netif_receive_skb_core(skb, pfmemalloc, &pt_prev); + if (!pt_prev) + continue; if (pt_curr != pt_prev || od_curr != orig_dev) { /* dispatch old sublist */ - list_cut_before(&sublist, head, &skb->list); __netif_receive_skb_list_ptype(&sublist, pt_curr, od_curr); /* start new sublist */ + INIT_LIST_HEAD(&sublist); pt_curr = pt_prev; od_curr = orig_dev; } + list_add_tail(&skb->list, &sublist); } /* dispatch final sublist */ - __netif_receive_skb_list_ptype(head, pt_curr, od_curr); + __netif_receive_skb_list_ptype(&sublist, pt_curr, od_curr); } static int __netif_receive_skb(struct sk_buff *skb) -- 2.30.2