9874808878
An skb can be added to a neigh->arp_queue while waiting for an arp
reply. Where original skb's skb->dev can be different to neigh's
neigh->dev. For instance in case of bridging dnated skb from one veth to
another, the skb would be added to a neigh->arp_queue of the bridge.
As skb->dev can be reset back to nf_bridge->physindev and used, and as
there is no explicit mechanism that prevents this physindev from been
freed under us (for instance neigh_flush_dev doesn't cleanup skbs from
different device's neigh queue) we can crash on e.g. this stack:
arp_process
neigh_update
skb = __skb_dequeue(&neigh->arp_queue)
neigh_resolve_output(..., skb)
...
br_nf_dev_xmit
br_nf_pre_routing_finish_bridge_slow
skb->dev = nf_bridge->physindev
br_handle_frame_finish
Let's use plain ifindex instead of net_device link. To peek into the
original net_device we will use dev_get_by_index_rcu(). Thus either we
get device and are safe to use it or we don't get it and drop skb.
Fixes:
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.. | ||
ip6_tables.c | ||
ip6t_ah.c | ||
ip6t_eui64.c | ||
ip6t_frag.c | ||
ip6t_hbh.c | ||
ip6t_ipv6header.c | ||
ip6t_mh.c | ||
ip6t_NPT.c | ||
ip6t_REJECT.c | ||
ip6t_rpfilter.c | ||
ip6t_rt.c | ||
ip6t_srh.c | ||
ip6t_SYNPROXY.c | ||
ip6table_filter.c | ||
ip6table_mangle.c | ||
ip6table_nat.c | ||
ip6table_raw.c | ||
ip6table_security.c | ||
Kconfig | ||
Makefile | ||
nf_conntrack_reasm.c | ||
nf_defrag_ipv6_hooks.c | ||
nf_dup_ipv6.c | ||
nf_reject_ipv6.c | ||
nf_socket_ipv6.c | ||
nf_tproxy_ipv6.c | ||
nft_dup_ipv6.c | ||
nft_fib_ipv6.c | ||
nft_reject_ipv6.c |