From a829b13986d556ab3aeb52668129fe4b13a1f24f Mon Sep 17 00:00:00 2001 From: Damjan Marion Date: Wed, 24 Apr 2019 23:39:16 +0200 Subject: [PATCH] ipsec: drop runts in esp-decrypt Change-Id: Id7fcaf8590f9f2dcccdebea0ad31c7ecd1cbc8af Signed-off-by: Damjan Marion --- src/vnet/ipsec/esp_decrypt.c | 8 ++++++++ test/template_ipsec.py | 24 ++++++++++++++++++++++-- 2 files changed, 30 insertions(+), 2 deletions(-) diff --git a/src/vnet/ipsec/esp_decrypt.c b/src/vnet/ipsec/esp_decrypt.c index 5d1f20604d5..dfc86d47ace 100644 --- a/src/vnet/ipsec/esp_decrypt.c +++ b/src/vnet/ipsec/esp_decrypt.c @@ -44,6 +44,7 @@ typedef enum _(INTEG_ERROR, "Integrity check failed") \ _(CRYPTO_ENGINE_ERROR, "crypto engine error (packet dropped)") \ _(REPLAY, "SA replayed packet") \ + _(RUNT, "undersized packet") \ _(CHAINED_BUFFER, "chained buffers (packet dropped)") \ _(OVERSIZED_HEADER, "buffer with oversized header (dropped)") \ _(NO_TAIL_SPACE, "no enough buffer tail space (dropped)") @@ -193,6 +194,13 @@ esp_decrypt_inline (vlib_main_t * vm, goto next; } + if (pd->current_length < cpd.icv_sz + esp_sz + cpd.iv_sz) + { + b[0]->error = node->errors[ESP_DECRYPT_ERROR_RUNT]; + next[0] = ESP_DECRYPT_NEXT_DROP; + goto next; + } + len = pd->current_length - cpd.icv_sz; current_sa_pkts += 1; current_sa_bytes += pd->current_length; diff --git a/test/template_ipsec.py b/test/template_ipsec.py index 3a978205b1e..c623d6a4d9b 100644 --- a/test/template_ipsec.py +++ b/test/template_ipsec.py @@ -3,7 +3,7 @@ import socket import struct from scapy.layers.inet import IP, ICMP, TCP, UDP -from scapy.layers.ipsec import SecurityAssociation +from scapy.layers.ipsec import SecurityAssociation, ESP from scapy.layers.l2 import Ether, Raw from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest @@ -308,7 +308,11 @@ class IpsecTra4(object): # a packet that does not decrypt does not move the window forward bogus_sa = SecurityAssociation(self.encryption_type, - p.vpp_tra_spi) + p.vpp_tra_spi, + crypt_algo=p.crypt_algo, + crypt_key=p.crypt_key[::-1], + auth_algo=p.auth_algo, + auth_key=p.auth_key[::-1]) pkt = (Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac) / bogus_sa.encrypt(IP(src=self.tra_if.remote_ip4, @@ -320,6 +324,22 @@ class IpsecTra4(object): self.assert_packet_counter_equal( '/err/%s/Integrity check failed' % self.tra4_decrypt_node_name, 17) + # a malformed 'runt' packet + # created by a mis-constructed SA + if (ESP == self.encryption_type): + bogus_sa = SecurityAssociation(self.encryption_type, + p.vpp_tra_spi) + pkt = (Ether(src=self.tra_if.remote_mac, + dst=self.tra_if.local_mac) / + bogus_sa.encrypt(IP(src=self.tra_if.remote_ip4, + dst=self.tra_if.local_ip4) / + ICMP(), + seq_num=350)) + self.send_and_assert_no_replies(self.tra_if, pkt * 17) + + self.assert_packet_counter_equal( + '/err/%s/undersized packet' % self.tra4_decrypt_node_name, 17) + # which we can determine since this packet is still in the window pkt = (Ether(src=self.tra_if.remote_mac, dst=self.tra_if.local_mac) / -- 2.16.6