From 8f7d302fd5a81a6282dcc2af33cea9f76680d0a1 Mon Sep 17 00:00:00 2001 From: Victor Orlikowski Date: Sun, 31 Jan 2016 14:54:06 +0900 Subject: packet: Better validate parameters to constructors better icmp MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit According to RFC 4884 (which supersedes RFC 792), the Destination Unreachable and Time Exceeded ICMP message get a new “length” field. This length field, for ICMPv4, is interpreted in 32 bit units. In the constructor, we cannot validate that the length specified matches the length of the data passed; the length may need to be larger (in 32 bit units) in order to accommodate the data that is actually being sent. We *should*, however, ensure that the data_len parameter passed fits into a single byte. It may make sense to document the fact that the length is specified 32 bit units, for when users of the icmp class get a ValueError back from these constructors. Signed-off-by: Victor J. Orlikowski Signed-off-by: FUJITA Tomonori --- ryu/lib/packet/icmp.py | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/ryu/lib/packet/icmp.py b/ryu/lib/packet/icmp.py index 57b153c4..1a6cd76f 100644 --- a/ryu/lib/packet/icmp.py +++ b/ryu/lib/packet/icmp.py @@ -214,7 +214,12 @@ class dest_unreach(stringify.StringifyMixin): def __init__(self, data_len=0, mtu=0, data=None): super(dest_unreach, self).__init__() - self.data_len = data_len + + if ((data_len >= 0) and (data_len <= 255)): + self.data_len = data_len + else: + raise ValueError('Specified data length (%d) is invalid.' % data_len) + self.mtu = mtu self.data = data @@ -273,7 +278,11 @@ class TimeExceeded(stringify.StringifyMixin): _MIN_LEN = struct.calcsize(_PACK_STR) def __init__(self, data_len=0, data=None): - self.data_len = data_len + if ((data_len >= 0) and (data_len <= 255)): + self.data_len = data_len + else: + raise ValueError('Specified data length (%d) is invalid.' % data_len) + self.data = data @classmethod -- cgit v1.2.3