Merge tag 'net-6.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Paolo Abeni:
 "Including fixes from netfilter.

  Current release - regressions:

   - sched: sch_taprio: do not schedule in taprio_reset()

  Previous releases - regressions:

   - core: fix UaF in netns ops registration error path

   - ipv4: prevent potential spectre v1 gadgets

   - ipv6: fix reachability confirmation with proxy_ndp

   - netfilter: fix for the set rbtree

   - eth: fec: use page_pool_put_full_page when freeing rx buffers

   - eth: iavf: fix temporary deadlock and failure to set MAC address

  Previous releases - always broken:

   - netlink: prevent potential spectre v1 gadgets

   - netfilter: fixes for SCTP connection tracking

   - mctp: struct sock lifetime fixes

   - eth: ravb: fix possible hang if RIS2_QFF1 happen

   - eth: tg3: resolve deadlock in tg3_reset_task() during EEH

  Misc:

   - Mat stepped out as MPTCP co-maintainer"

* tag 'net-6.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (40 commits)
  net: mdio-mux-meson-g12a: force internal PHY off on mux switch
  docs: networking: Fix bridge documentation URL
  tsnep: Fix TX queue stop/wake for multiple queues
  net/tg3: resolve deadlock in tg3_reset_task() during EEH
  net: mctp: mark socks as dead on unhash, prevent re-add
  net: mctp: hold key reference when looking up a general key
  net: mctp: move expiry timer delete to unhash
  net: mctp: add an explicit reference from a mctp_sk_key to sock
  net: ravb: Fix possible hang if RIS2_QFF1 happen
  net: ravb: Fix lack of register setting after system resumed for Gen3
  net/x25: Fix to not accept on connected socket
  ice: move devlink port creation/deletion
  sctp: fail if no bound addresses can be used for a given scope
  net/sched: sch_taprio: do not schedule in taprio_reset()
  Revert "Merge branch 'ethtool-mac-merge'"
  netrom: Fix use-after-free of a listening socket.
  netfilter: conntrack: unify established states for SCTP paths
  Revert "netfilter: conntrack: add sctp DATA_SENT state"
  netfilter: conntrack: fix bug in for_each_sctp_chunk
  netfilter: conntrack: fix vtag checks for ABORT/SHUTDOWN_COMPLETE
  ...

1 files changed, 14 insertions, 1 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 60fd91bb5171..c314fdde0097 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -547,7 +547,20 @@ int ip6_forward(struct sk_buff *skb)
 	    pneigh_lookup(&nd_tbl, net, &hdr->daddr, skb->dev, 0)) {
 		int proxied = ip6_forward_proxy_check(skb);
 		if (proxied > 0) {
-			hdr->hop_limit--;
+			/* It's tempting to decrease the hop limit
+			 * here by 1, as we do at the end of the
+			 * function too.
+			 *
+			 * But that would be incorrect, as proxying is
+			 * not forwarding.  The ip6_input function
+			 * will handle this packet locally, and it
+			 * depends on the hop limit being unchanged.
+			 *
+			 * One example is the NDP hop limit, that
+			 * always has to stay 255, but other would be
+			 * similar checks around RA packets, where the
+			 * user can even change the desired limit.
+			 */
 			return ip6_input(skb);
 		} else if (proxied < 0) {
 			__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);