sctp: fix src address selection if using secondary addresses for ipv6

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[ Upstream commit dbc2b5e9a0 ]

Commit 0ca50d12fe ("sctp: fix src address selection if using secondary
addresses") has fixed a src address selection issue when using secondary
addresses for ipv4.

Now sctp ipv6 also has the similar issue. When using a secondary address,
sctp_v6_get_dst tries to choose the saddr which has the most same bits
with the daddr by sctp_v6_addr_match_len. It may make some cases not work
as expected.

hostA:
  [1] fd21:356b:459a:cf10::11 (eth1)
  [2] fd21:356b:459a:cf20::11 (eth2)

hostB:
  [a] fd21:356b:459a:cf30::2  (eth1)
  [b] fd21:356b:459a:cf40::2  (eth2)

route from hostA to hostB:
  fd21:356b:459a:cf30::/64 dev eth1  metric 1024  mtu 1500

The expected path should be:
  fd21:356b:459a:cf10::11 <-> fd21:356b:459a:cf30::2
But addr[2] matches addr[a] more bits than addr[1] does, according to
sctp_v6_addr_match_len. It causes the path to be:
  fd21:356b:459a:cf20::11 <-> fd21:356b:459a:cf30::2

This patch is to fix it with the same way as Marcelo's fix for sctp ipv4.
As no ip_dev_find for ipv6, this patch is to use ipv6_chk_addr to check
if the saddr is in a dev instead.

Note that for backwards compatibility, it will still do the addr_match_len
check here when no optimal is found.

Reported-by: Patrick Talbert <ptalbert@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Xin Long 2017-05-12 14:39:52 +08:00 • committed by Greg Kroah-Hartman

parent 8d625242e8

commit eb7f6d6989

1 changed files with 29 additions and 17 deletions

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net/sctp/ipv6.c

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