diff options
| author | Florian Westphal <fw@strlen.de> | 2019-10-29 01:44:04 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-10-29 17:54:29 -0700 |
| commit | 51210ad5a558dcc7511d0c083f5cd796077b4e4d (patch) | |
| tree | 50f32514dcef0f73374301a8044e6f976d5645df | |
| parent | acda6180e86ba9e0026287d65f30d1e2b0c8882a (diff) | |
inet: do not call sublist_rcv on empty list
syzbot triggered struct net NULL deref in NF_HOOK_LIST:
RIP: 0010:NF_HOOK_LIST include/linux/netfilter.h:331 [inline]
RIP: 0010:ip6_sublist_rcv+0x5c9/0x930 net/ipv6/ip6_input.c:292
ipv6_list_rcv+0x373/0x4b0 net/ipv6/ip6_input.c:328
__netif_receive_skb_list_ptype net/core/dev.c:5274 [inline]
Reason:
void ipv6_list_rcv(struct list_head *head, struct packet_type *pt,
struct net_device *orig_dev)
[..]
list_for_each_entry_safe(skb, next, head, list) {
/* iterates list */
skb = ip6_rcv_core(skb, dev, net);
/* ip6_rcv_core drops skb -> NULL is returned */
if (skb == NULL)
continue;
[..]
}
/* sublist is empty -> curr_net is NULL */
ip6_sublist_rcv(&sublist, curr_dev, curr_net);
Before the recent change NF_HOOK_LIST did a list iteration before
struct net deref, i.e. it was a no-op in the empty list case.
List iteration now happens after *net deref, causing crash.
Follow the same pattern as the ip(v6)_list_rcv loop and add a list_empty
test for the final sublist dispatch too.
Cc: Edward Cree <ecree@solarflare.com>
Reported-by: syzbot+c54f457cad330e57e967@syzkaller.appspotmail.com
Fixes: ca58fbe06c54 ("netfilter: add and use nf_hook_slow_list()")
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Leon Romanovsky <leonro@mellanox.com>
Tested-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv4/ip_input.c | 3 | ||||
| -rw-r--r-- | net/ipv6/ip6_input.c | 3 |
2 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c index c59a78a267c3..24a95126e698 100644 --- a/net/ipv4/ip_input.c +++ b/net/ipv4/ip_input.c @@ -611,5 +611,6 @@ void ip_list_rcv(struct list_head *head, struct packet_type *pt, list_add_tail(&skb->list, &sublist); } /* dispatch final sublist */ - ip_sublist_rcv(&sublist, curr_dev, curr_net); + if (!list_empty(&sublist)) + ip_sublist_rcv(&sublist, curr_dev, curr_net); } diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c index 3d71c7d6102c..ef7f707d9ae3 100644 --- a/net/ipv6/ip6_input.c +++ b/net/ipv6/ip6_input.c @@ -325,7 +325,8 @@ void ipv6_list_rcv(struct list_head *head, struct packet_type *pt, list_add_tail(&skb->list, &sublist); } /* dispatch final sublist */ - ip6_sublist_rcv(&sublist, curr_dev, curr_net); + if (!list_empty(&sublist)) + ip6_sublist_rcv(&sublist, curr_dev, curr_net); } INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *)); |