4.9-stable review patch. If anyone has any objections, please let me know.
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From: Stefano Brivio sbrivio@redhat.com
[ Upstream commit ee1abcf689353f36d9322231b4320926096bdee0 ]
Commit a61bbcf28a8c ("[NET]: Store skb->timestamp as offset to a base timestamp") introduces a neighbour control buffer and zeroes it out in ndisc_rcv(), as ndisc_recv_ns() uses it.
Commit f2776ff04722 ("[IPV6]: Fix address/interface handling in UDP and DCCP, according to the scoping architecture.") introduces the usage of the IPv6 control buffer in protocol error handlers (e.g. inet6_iif() in present-day __udp6_lib_err()).
Now, with commit b94f1c0904da ("ipv6: Use icmpv6_notify() to propagate redirect, instead of rt6_redirect()."), we call protocol error handlers from ndisc_redirect_rcv(), after the control buffer is already stolen and some parts are already zeroed out. This implies that inet6_iif() on this path will always return zero.
This gives unexpected results on UDP socket lookup in __udp6_lib_err(), as we might actually need to match sockets for a given interface.
Instead of always claiming the control buffer in ndisc_rcv(), do that only when needed.
Fixes: b94f1c0904da ("ipv6: Use icmpv6_notify() to propagate redirect, instead of rt6_redirect().") Signed-off-by: Stefano Brivio sbrivio@redhat.com Reviewed-by: Sabrina Dubroca sd@queasysnail.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ndisc.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1692,10 +1692,9 @@ int ndisc_rcv(struct sk_buff *skb) return 0; }
- memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); - switch (msg->icmph.icmp6_type) { case NDISC_NEIGHBOUR_SOLICITATION: + memset(NEIGH_CB(skb), 0, sizeof(struct neighbour_cb)); ndisc_recv_ns(skb); break;