ipv6: accept 64k - 1 packet length in ip6_find_1stfragopt()
commit6eb7ae1223f75fe19de8e75df80ac78ab6b7c39d
authorStefano Brivio <sbrivio@redhat.com>
Fri, 18 Aug 2017 12:40:53 +0000 (18 14:40 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 27 Sep 2017 09:00:10 +0000 (27 11:00 +0200)
treea79c51ef47df4b24eda14393f540311f6cfdda37
parentb52c9082f2eb3a6f7fbbc86fad3eaa2a1725da66
ipv6: accept 64k - 1 packet length in ip6_find_1stfragopt()

[ Upstream commit 3de33e1ba0506723ab25734e098cf280ecc34756 ]

A packet length of exactly IPV6_MAXPLEN is allowed, we should
refuse parsing options only if the size is 64KiB or more.

While at it, remove one extra variable and one assignment which
were also introduced by the commit that introduced the size
check. Checking the sum 'offset + len' and only later adding
'len' to 'offset' doesn't provide any advantage over directly
summing to 'offset' and checking it.

Fixes: 6399f1fae4ec ("ipv6: avoid overflow of offset in ip6_find_1stfragopt")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/ipv6/output_core.c