/usr/lib/opendnssec/kasp_auditor/key_tracker.rb is in opendnssec-auditor 1.3.4-1ubuntu1.
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# $Id$
#
# Copyright (c) 2009 Nominet UK. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
# IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
# IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
module KASPAuditor
# This class manages the caches that are used to track the lifecycle
# of keys used to sign the zone.
# We need to store all the keys that we see for each zone that we audit.
# We need the following states : pre-published, in-use, retired, and dead.
# REVOKED will indicate retired for RFC5011 keys, but non-5011 keys may
# go through a "present, but not used" retirement phase. Keys may also move
# straight to dead. Once dead, keys are no longer tracked.
# As we start to track a non-RFC5011 zone, we may have problems differentiating
# between pre-published and retired keys. Thus some keys may go directly from
# pre-published to dead.
#
# FILE : have one file cache for each zone which is tracked :
# (<workingdirectory>/tracking/<zone_name>
# The file will consist of a list of [key, status, timestamp] tuples,
# where status is one of :
# PREPUBLISHED, INUSE, RETIRED, DEAD
# DEAD keys may be purged from the file (and may indeed never appear).
# The key_tag will be the PRE-REVOKED key_tag (even for revoked keys).
# The timestamp field records the time the key first entered the new state.
# The file starts with two records - one for the timestamp at which the file
# was originally created, and one for the last SOA serial that was seen.
#
class KeyTracker
class Status < Dnsruby::CodeMapper
PREPUBLISHED = 1
INUSE = 2
RETIRED = 4
update
end
SEPARATOR = "\0\0$~$~$~\0\0"
# The Cache holds the data for each of the Status levels.
# It is dynamically generated from the Status levels.
# The dynamic methods created here will not show up in RDoc,
# but consist of methods to add, remove and find keys in
# different states. Timestamps are also held here.
class Cache
# Set up add_inuse_key, etc.
Status.strings.each {|s| eval "attr_reader :#{s.downcase}"}
Status.strings.each {|s| eval "def add_#{s.downcase}_key(key)
if (!include_#{s.downcase}_key?key)
new_key = key.clone
new_key.public_key
@#{s.downcase}[new_key]=[Time.now.to_i, Time.now.to_i]
end
end"}
# Set up add_inuse_key_with_time, etc.
Status.strings.each {|s| eval "def add_#{s.downcase}_key_with_time(key, time, first_time)
if (!include_#{s.downcase}_key?key)
new_key = key.clone
new_key.public_key
@#{s.downcase}[new_key]=[time, first_time]
end
end"}
# Set up include_inuse_key?, etc.
Status.strings.each {|s| eval "def include_#{s.downcase}_key?(key)
key.public_key
@#{s.downcase}.each {|k,v|
if ((k == key) || (k.key_tag_pre_revoked ==
key.key_tag_pre_revoked))
return v
end
}
return false
end"}
# Set up delete_inuse_key, etc.
Status.strings.each {|s| eval "def delete_#{s.downcase}_key(key)
key.public_key
@#{s.downcase}.delete_if {|k, temp|
((k==key) || (k.key_tag_pre_revoked == key.key_tag_pre_revoked))
}
end"}
def include_key?(key)
Status.strings.each {|s| eval "return true if include_#{s.downcase}_key?(key)"}
return false
end
def initialize
Status.strings.each {|s| eval "@#{s.downcase} = {}"}
end
end
attr_reader :cache
attr_accessor :last_soa_serial
# Each run, the auditor needs to load the key caches for the zone, then
# audit the zone, keeping track of which keys are used. The key caches are
# then updated. The auditor needs to run the lifetime, numStandby checks
# on the keys as well.
#
# If the key caches can't be found, then create new ones.
#
# These files, once started for a zone, will never be deleted.
def initialize(working_directory, zone_name, parent, config, enforcer_interval, validity)
@working = working_directory
@zone = zone_name
@parent = parent
@config = config
@enforcer_interval = enforcer_interval
@last_soa_serial = nil
@initial_timestamp = Time.now.to_i
@validity = validity
@cache = load_tracker_cache()
end
# Load the cache for the zone from the workingdirectory. Create a new
# cache if one can't be found. Also defaults to reloading the SOA serial
# for the zone.
def load_tracker_cache(load_soa_serial = true)
# Need to store the time that the state change was first noticed.
# Need to load this from file, store in cache, add to new cache values,
# and write back to file.
cache = Cache.new
filename = get_tracker_filename
dir = File.dirname(filename)
begin
Dir.mkdir(dir) unless File.directory?(dir)
rescue Errno::ENOENT
@parent.log(LOG_ERR, "Can't create working folder : #{dir}")
KASPAuditor.exit("Can't create working folder : #{dir}", 1)
end
File.open(filename, File::CREAT) { |f|
# Now load the cache
# Is there an initial timestamp and a current SOA serial to load?
count = 0
while (line = f.gets)
count += 1
if (count == 1)
@initial_timestamp = line.chomp.to_i
next
elsif (count == 2)
if (load_soa_serial)
@last_soa_serial = line.chomp.to_i
end
next
end
key_string, status_string, time, first_time = line.split(SEPARATOR)
if (!first_time)
first_time = time
end
key = RR.create(key_string)
eval "cache.add_#{status_string.downcase}_key_with_time(key, time.to_i, first_time.to_i)".untaint
end
}
return cache
end
# Store the data back to the file
def save_tracker_cache
# These values should only be written if the audit has been successful!!
# Best to write it back to a new file - then move the new file to the
# original location (overwriting the original)
return if @parent.ret_val == 3
tracker_file = get_tracker_filename
File.open(tracker_file + ".temp", 'w') { |f|
# First, save the initial timestamp and the current SOA serial
f.puts(@initial_timestamp.to_s)
f.puts(@last_soa_serial.to_s)
# Now save the cache!!
Status.strings.each {|s|
status = s.downcase
eval "@cache.#{status}.each {|key, time|
write_key_to_file(f, key.to_s, status, time[0], time[1])
}".untaint
}
}
# Now move the .temp file over the original
File.delete(tracker_file)
File.rename(tracker_file+".temp", tracker_file)
end
def write_key_to_file(f, key, status, time, first_time)
f.puts("#{key}#{SEPARATOR}#{status}#{SEPARATOR}#{time}#{SEPARATOR}#{first_time}")
end
def get_tracker_filename
zone = @zone
if ((zone.to_s == ".") || (zone.to_s==""))
zone = "root.zone"
end
return @working + "#{File::SEPARATOR}tracker#{File::SEPARATOR}" + zone
end
#Compare two serials according to RFC 1982. Return 0 if equal,
#-1 if s1 is bigger, 1 if s1 is smaller.
def compare_serial(s1, s2)
if s1 == s2
return 0
end
if s1 < s2 and (s2 - s1) < (2**31)
return 1
end
if s1 > s2 and (s1 - s2) > (2**31)
return 1
end
if s1 < s2 and (s2 - s1) > (2**31)
return -1
end
if s1 > s2 and (s1 - s2) < (2**31)
return -1
end
return 0
end
# The auditor calls this method at the end of the auditing run.
# This is the only public method in this class.
# It passes in all the keys it has seen, and the keys it has seen used.
# keys is a list of DNSKeys, and keys_used is a list of the key_tags
# used to sign RRSIGs in the zone.
# The data is then used to track the lifecycle of zone keys, and perform
# associated auditing checks
def process_key_data(keys, keys_used, soa_serial, key_ttl)
update_cache(keys, keys_used)
if (@last_soa_serial)
if (compare_serial(soa_serial, @last_soa_serial) == 1)
@parent.log(LOG_ERR, "SOA serial has decreased - used to be #{@last_soa_serial} but is now #{soa_serial}")
end
else
@last_soa_serial = soa_serial
end
@last_soa_serial = soa_serial
run_checks(key_ttl)
# Then we need to save the data
save_tracker_cache
end
# run the checks on the new zone data - called internally
def run_checks(key_ttl)
# We also need to perform the auditing checks against the config
# Checks to be performed :
# b) Warn if number of prepublished ZSKs < ZSK:Standby
# Do this by [alg, alg_length] - so only select those keys which match the config
@config.keys.zsks.each {|zsk|
prepublished_zsk_count = @cache.prepublished.keys.select {|k|
k.zone_key? && !k.sep_key? && (k.algorithm == zsk.algorithm) &&
(k.key_length == zsk.alg_length)
}.length
if (prepublished_zsk_count < zsk.standby)
msg = "Not enough prepublished ZSKs! Should be #{zsk.standby} but have #{prepublished_zsk_count}"
@parent.log(LOG_WARNING, msg)
end
}
@cache.inuse.each {|key, time|
timestamp = time[0]
first_timestamp = time[1]
# Ignore this check if the key was already in use at the time at which the lifetime policy was changed.
# How do we know to which AnyKey group this key belongs? Can only take a guess by [algorithm, alg_length] tuple
# Also going to have to put checks in place where key protocol/algorithm is checked against policy :-(
# - no we don't! These are only checked when we are loading a new key - not one we've seen before.
# and of course, a new key should be created with the correct values!
key_group_policy_changed = false
# First, find all the key groups which this key could belong to
keys = @config.changed_config.zsks
if (key.sep_key?)
keys = @config.changed_config.ksks
end
possible_groups = keys.select{|k| (k.algorithm == key.algorithm) &&
(k.alg_length == key.key_length)}
# Then, find the latest timestamp (other than 0)
key_group_policy_changed_time = 0
if (possible_groups.length == 0)
# Can't find the group this key belongs to
if (@config.changed_config.kasp_timestamp < first_timestamp)
# @TODO@ o if there has been no change in any of the configured keys then error (the key shouldn't exist)
# Shouldn't this be caught by something else?
end
# o if there has been a change since the key was first seen, then don't raise any errors for this key
else
possible_groups.each {|g|
if (g.timestamp > key_group_policy_changed_time)
key_group_policy_changed_time = g.timestamp
key_group_policy_changed = true
end
}
next if (key_group_policy_changed && (first_timestamp < key_group_policy_changed_time))
end
if (key.zone_key? && !key.sep_key?)
# d) Warn if ZSK inuse longer than ZSK:Lifetime + Enforcer:Interval
# Get the ZSK lifetime for this type of key from the config
zsks = @config.keys.zsks.select{|zsk|
(zsk.algorithm == key.algorithm) &&
(zsk.alg_length == key.key_length)}
next if (zsks.length == 0)
# Take the "safest" value - i.e. the longest one in this case
zsk_lifetime = 0
zsks.each {|z|
zsk_lifetime = z.lifetime if (z.lifetime > zsk_lifetime)
}
lifetime = zsk_lifetime + @enforcer_interval + @validity
if timestamp < (Time.now.to_i - lifetime)
msg = "ZSK #{key.key_tag} in use too long - should be max #{lifetime} seconds but has been #{Time.now.to_i-timestamp} seconds"
@parent.log(LOG_WARNING, msg)
end
else
# c) Warn if KSK inuse longer than KSK:Lifetime + Enforcer:Interval
# Get the KSK lifetime for this type of key from the config
ksks = @config.keys.ksks.select{|ksk| (ksk.algorithm == key.algorithm) &&
(ksk.alg_length == key.key_length)}
next if (ksks.length == 0)
# Take the "safest" value - i.e. the longest one in this case
ksk_lifetime = 0
ksks.each {|k|
ksk_lifetime = k.lifetime if (k.lifetime > ksk_lifetime)
}
lifetime = ksk_lifetime + @enforcer_interval + @validity
if timestamp < (Time.now.to_i - lifetime)
# msg = "KSK #{key.key_tag} in use too long - should be max #{lifetime} seconds but has been #{Time.now.to_i-timestamp} seconds"
msg = "KSK #{key.key_tag} reaching end of lifetime - should be max #{lifetime} seconds but has been #{Time.now.to_i-timestamp} seconds, not including time taken for DS to be seen"
@parent.log(LOG_WARNING, msg)
end
end
}
if (@config.audit_tag_present)
check_inuse_keys_history(key_ttl)
end
end
def check_inuse_keys_history(key_ttl)
# Error if a key is seen in use without having first been seen in prepublished for at least the zone key TTL
# Remember not to warn if we haven't been running as long as the zone key TTL...
if (Time.now.to_i >= (@initial_timestamp + key_ttl))
# Has a key jumped to in-use without having gone through prepublished for at least key_ttl?
# Just load the cache from disk again - then we could compare the two
old_cache = load_tracker_cache(false)
@cache.inuse.keys.each {|new_inuse_key|
next if old_cache.include_inuse_key?new_inuse_key
next if (new_inuse_key.sep_key?) # KSKs aren't prepublished any more
old_key_timestamp, old_key_first_timestamp = old_cache.include_prepublished_key?new_inuse_key
if (!old_key_timestamp)
@parent.log(LOG_ERR, "Key (#{new_inuse_key.key_tag}) has gone straight to active use without a prepublished phase")
next
end
if ((Time.now.to_i - old_key_timestamp) < key_ttl)
@parent.log(LOG_ERR, "Key (#{new_inuse_key.key_tag}) has gone to active use, but has only been prepublished for" +
" #{(Time.now.to_i - old_key_timestamp)} seconds. Zone DNSKEY ttl is #{key_ttl}")
end
}
end
end
def update_cache(keys, keys_used)
# We need to update the cache with this new information.
# We can obviously add any revoked keys to retired.
# Any keys in the cache that aren't in the zone are moved to dead
# Any new keys are added to the appropriate state
# All continuing keys are updated
# This means :
# a) All keys in keys_used should be in inuse
# b) inuse should contain no other keys (than those in keys_usd)
# c) only keys in keys should be in prepublished or retired
# d) All keys with REVOKED should be retired
# e) If not previously seen, keys in keys but not keys_used should be in prepublished
# f) Keys which are not inuse, but still in zone, and which were previously known, should be retired
keys.each {|key|
# print "Checking published key #{key.key_tag_pre_revoked}\n"
if !@cache.include_inuse_key?(key)
# print "Unseen key #{key.key_tag_pre_revoked}\n"
if !keys_used.include?(key.key_tag_pre_revoked)
# print "Unseen key #{key.key_tag_pre_revoked} not in use - adding to prepublished\n"
@cache.add_prepublished_key(key)
end
else
if key.revoked?
# print "Handling revoked key #{key.key_tag_pre_revoked}\n"
@cache.add_retired_key(key)
@cache.delete_prepublished_key(key)
elsif !keys_used.include?(key.key_tag_pre_revoked)
# print "Previously seen non-revoked key #{key.key_tag} still published but not in use - adding to retired\n"
@cache.add_retired_key(key)
@cache.delete_prepublished_key(key)
end
end
}
keys_used.each {|key|
# Now find the key with that tag
keys.each {|k|
if (key == k.key_tag)
# print "Taking inuse key #{key} and removing from prepublished\n"
@cache.add_inuse_key(k)
@cache.delete_prepublished_key(k)
end
}
}
@cache.inuse.keys.each {|key|
if !keys_used.include?key.key_tag_pre_revoked
# print "Deleting key #{key.key_tag_pre_revoked} from inuse\n"
@cache.delete_inuse_key(key)
end
}
@cache.prepublished.keys.each {|key|
found = false
keys.each {|k|
if ((key == k) || (k.key_tag_pre_revoked == key.key_tag_pre_revoked))
found = true
end
}
# print "Deleting missing #{key.key_tag_pre_revoked} key from prepublished\n" if !found
@cache.delete_prepublished_key(key) if !found
}
@cache.retired.keys.each {|key|
found = false
keys.each {|k|
if ((key == k) || (k.key_tag_pre_revoked == key.key_tag_pre_revoked))
found = true
end
}
# print "Deleting missing #{key.key_tag_pre_revoked} key from retired\n" if !found
@cache.delete_retired_key(key) if !found
}
end
end
end
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