fluent-plugin-secure-forward
Fluentd input/output plugin to forward fluentd messages over SSL with authentication.
Plugin status
NOTE: This plugin will not be updated anymore.
Fluentd v0.14.12 supports event forwarding via encrypted network communication. Use that feature instead of using this plugin.
Overview
This plugin makes you to be able to:
- protect your data from others in transferring with SSL
- with certificate signed and registered correctly/publicly
- with private CA certificates generated by users
- with automatically generated and self-signed certificates in vulnerable way
- authenticate by shared_key check from both of client(out_secure_forward) and server(in_secure_forward)
- authenticate with username / password pairs
Installation
install with gem or fluent-gem command as:
### native gem
$ gem install fluent-plugin-secure-forward
### fluentd gem
$ fluent-gem install fluent-plugin-secure-forward
Using SSL certificates issued from trusted CA
To communicate over SSL with valid certificate issued from public CA, configure params below for input plugin:
-
secure
: setyes
ortrue
-
cert_path
: set path of certificate file issued from CA -
private_key_path
: set path of private key file -
private_key_passphrase
: set passphrase of private key
<source>
@type secure_forward
# bind 0.0.0.0 # default
# port 24284 # default
self_hostname server.fqdn.example.com
shared_key secret_string
secure yes
cert_path /path/for/certificate/cert.pem
private_key_path /path/for/certificate/key.pem
private_key_passphrase secret_foo_bar_baz
</source>
For output plugin, specify just 2 options below:
-
secure
: setyes
ortrue
-
enable_strict_verification
: specifyyes
ortrue
to verify FQDN of servers (input plugin)
<match secret.data.**>
@type secure_forward
self_hostname client.fqdn.local
shared_key secret_string
secure yes
enable_strict_verification yes
<server>
host server.fqdn.example.com # or IP
# port 24284
</server>
<server>
host 203.0.113.8 # ip address to connect
hostlabel server.fqdn.example.com # specify hostlabel for FQDN verification if ipaddress is used for host
</server>
</match>
Using private CA file and key
This plugin has a simple utility command to generate private CA cert/key files just for secure-forward.
$ secure-forward-ca-generate /path/for/dir/of/certs "passphrase for private CA secret key"
This command generates ca_cert.pem
and ca_key.pem
on /path/for/dir/of/certs
. For SSL communication with private CA, users must deploy both files for input plugins, and also must deploy ca_cert.pem
for output plugins.
And then, configure Fluentd with these files and the passphrase. With this configuration, server certificates are automatically generated and issued by private CA.
<source>
@type secure_forward
# bind 0.0.0.0 # default
# port 24284 # default
self_hostname myserver.local
shared_key secret_string
secure yes
ca_cert_path /path/for/certificate/ca_cert.pem
ca_private_key_path /path/for/certificate/ca_key.pem
ca_private_key_passphrase passphrase for private CA secret key
</source>
For output plugin, specify just 2 options below:
-
secure
: setyes
ortrue
-
enable_strict_verification
: specifyyes
ortrue
<match secret.data.**>
@type secure_forward
self_hostname myclient.local
shared_key secret_string
secure yes
ca_cert_path /path/for/certificate/ca_cert.pem
# enable_strict_verification yes
<server>
host server.fqdn.example.com # or IP
# port 24284
</server>
<server>
host 203.0.113.8 # ip address to connect
hostlabel server.fqdn.example.com # specify hostlabel for FQDN verification if ipaddress is used for host
</server>
</match>
Using insecure self-signed certificates
This is very dangerous and vulnerable to man-in-the-middle attacks
For just testing or data center internal communications, this plugin has a feature to communicate without any verification of certificates. Turn secure
option to false
to use this feature.
<source>
@type secure_forward
self_hostname myserver.local
shared_key secret_string
secure no
</source>
Configure output plugin just same way:
<match data.**>
@type secure_forward
self_hostname myclient.local
shared_key secret_string
secure no
<server>
host server.fqdn.example.com # or IP
</server>
</match>
In this mode, output plugin cannot verify peer node of connections. Man-in-the-middle attackers can spoof messages from output plugins under many various situations.
Configuration
SecureForwardInput
Default settings:
- listen 0.0.0.0:24284
bind 192.168.0.101
port 24284
- allow to accept from any sources
- allow to connect without authentications
- use certificate automatically generated
generate_private_key_length 2048
generate_cert_country US
generate_cert_state CA
generate_cert_locality Mountain View
generate_cert_common_name SAME_WITH_SELF_HOSTNAME_PARAMETER
- use TLSv1.2
Minimal configurations like below:
<source>
@type secure_forward
shared_key secret_string
self_hostname server.fqdn.local # This fqdn is used as CN (Common Name) of certificates
secure yes
# and configurations for certs
</source>
To check username/password from clients, like this:
<source>
@type secure_forward
shared_key secret_string
self_hostname server.fqdn.local
secure yes
# and configurations for certs
authentication yes # Deny clients without valid username/password
<user>
username tagomoris
password foobar012
</user>
<user>
username frsyuki
password yakiniku
</user>
</source>
To deny unknown source IP/hosts:
<source>
@type secure_forward
shared_key secret_string
self_hostname server.fqdn.local
secure yes
# and configurations for certs
allow_anonymous_source no # Allow to accept from nodes of <client>
<client>
host 192.168.10.30
</client>
<client>
host your.host.fqdn.local
# wildcard (ex: *.host.fqdn.local) NOT Supported now
</client>
<client>
network 192.168.16.0/24 # network address specification
</client>
</source>
You can use both of username/password check and client check:
<source>
@type secure_forward
shared_key secret_string
self_hostname server.fqdn.local
secure yes
# and configurations for certs
allow_anonymous_source no # Allow to accept from nodes of <client>
authentication yes # Deny clients without valid username/password
<user>
username tagomoris
password foobar012
</user>
<user>
username frsyuki
password sukiyaki
</user>
<user>
username repeatedly
password sushi
</user>
<client>
host 192.168.10.30 # allow all users to connect from 192.168.10.30
</client>
<client>
host 192.168.10.31
users tagomoris,frsyuki # deny repeatedly from 192.168.10.31
</client>
<client>
host 192.168.10.32
shared_key less_secret_string # limited shared_key for 192.168.10.32
users repeatedly # and repatedly only
</client>
</source>
SecureForwardOutput
Minimal configurations like this:
<match secret.data.**>
@type secure_forward
shared_key secret_string
self_hostname client.fqdn.local
secure yes
# and configurations for certs/verification
<server>
host server.fqdn.local # or IP
# port 24284
</server>
</match>
Without hostname ACL (and it's not implemented yet), self_hostname
is not checked in any state. ${hostname}
placeholder is available for such cases.
<match secret.data.**>
@type secure_forward
shared_key secret_string
self_hostname ${hostname}
secure yes
# and configurations for certs/verification
<server>
host server.fqdn.local # or IP
# port 24284
</server>
</match>
When specified 2 or more <server>
, this plugin uses these nodes in simple round-robin order. And servers with standby yes
will be selected until all of non-standby servers goes down.
If server requires username/password, set username
and password
in <server>
section:
<match secret.data.**>
@type secure_forward
shared_key secret_string
self_hostname client.fqdn.local
secure yes
# and configurations for certs/verification
<server>
host first.fqdn.local
hostlabel server.fqdn.local
username repeatedly
password sushi
</server>
<server>
host second.fqdn.local
hostlabel server.fqdn.local
username sasatatsu
password karaage
</server>
<server>
host standby.fqdn.local
hostlabel server.fqdn.local
username kzk
password hawaii
standby yes
</server>
</match>
Specify hostlabel
if server (in_forward
) have different hostname (self_host
configuration of in_forward
) from DNS name (first.fqdn.local
, second.fqdn.local
or standby.fqdn.local
). This configuration variable will be used to check common name (CN) of certifications.
To specify keepalive timeouts, use keepalive
configuration with seconds. SSL connection will be disconnected and re-connected for each 1 hour with configuration below. In Default (and with keepalive 0
), connections will not be disconnected without any communication troubles. (This feature is for dns name updates, and SSL common key refreshing.)
<match secret.data.**>
@type secure_forward
shared_key secret_string
self_hostname client.fqdn.local
secure yes
# and configurations for certs/verification
keepalive 3600
<server>
host server.fqdn.local # or IP
# port 24284
</server>
</match>
If you connect via Proxy,
set for proxy_uri
in <server>
section:
<match secret.data.**>
@type secure_forward
shared_key secret_string
self_hostname client.fqdn.local
secure yes
# and configurations for certs/verification
<server>
host server.fqdn.local # or IP
# port 24284
proxy_uri http://foo.bar.local:3128
</server>
</match>
Scenario (developer document)
- server
- in_secure_forward
- client
- out_secure_forward
Handshake
- (client) connect to server
- on SSL socket handshake, checks certificate and its significate (in client)
- (server)
- check network/domain acl (if enabled)
- check client dns reverse lookup result (if enabled)
- disconnect when failed
- (server) send HELO
- ['HELO', options(hash)]
- options:
- nonce: string as nonce: used for shared key digest (required, v0.3.2 or later)
- auth: string or blank_string (string: authentication required, and its salt is this value)
- keepalive: bool (allowed or not)
- (client) send PING
- ['PING', selfhostname, sharedkey_salt, sha512_hex(sharedkey_salt + selfhostname + nonce + sharedkey), username || '', sha512_hex(auth_salt + username + password) || '']
- (server) check PING
- check sharedkey
- check username / password (if required)
- send PONG FAILURE if failed
- ['PONG', false, 'reason of authentication failure', '', '']
- (server) send PONG
- ['PONG', bool(authentication result), 'reason if authentication failed', selfhostname, sha512_hex(salt + selfhostname + nonce + sharedkey)]
- (client) check PONG
- check sharedkey
- disconnect when failed
- connection established
- send data from client (until keepalive expiration)
Data transferring
CONSIDER RETURN ACK OR NOT
- Current version has no ACKs
- only supports burst transferring (same as ForwardInput/Output)
- ack for each message ?
- pipeline mode and one-by-one mode ?
- data sequence number in keepalive session ?
TODO
- ACK mode (protocol)
- support disabling keepalive (input/output)
- access control (input plugin)
- network acl / domain acl
- check connecting source ip and its dns reverse lookup result (for domaian acl)
- access deny on accept (against DoS)
- pluggable authentication database (input plugin)
- RDBMS, LDAP, or ...
- Authentication by clients certificate
- TESTS!
Copyright
- Copyright (c) 2013- TAGOMORI Satoshi (tagomoris)
- License
- Apache License, Version 2.0