omg dds security submission presentation (september 2013 - 6th revised submission)

Your systems. Working as one.

DDS SECURITY 6th Revised Submission (Joint) Presented at OMG Mars Task Force on September 24, 2013

Doc num: mars/2013-‐09-‐09 SpecificaTon lead: Gerardo Pardo-‐Castellote, Ph.D. CTO, Real-‐Time InnovaTons, Inc.

SubmiVers: Real-‐Time InnovaTons, Inc. PrismTech Corp. eProsima (supporter)

© 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved

Outline for DDS Security Spec

•  Status recap •  Scope •  Threats •  Summary of RFP requirements •  SpecificaTon details

–  Overview –  Security Model –  DDS & RTPS support for security –  Security Plugin Architecture

•  Security Plugins –  AuthenTcaTon plugin –  AccessControl plugin –  Cryptographic plugin –  DataTagging plugin –  DataLogging plugin

10/9/13 © 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved 2

Status recap •  Started with two separate submissions by RTI and PrismTech

•  As of the December 2012 all joined the RTI submission

•  Several reviews, last one in Berlin idenTfied a couple of vulnerabiliTes – Sequence Number AVack on reliable channels – Cuckoo aVack on ParTcipant GUID

• Most current version cleaned spec and addresses idenTfied vulnerabiliTes

•  Some under-‐specified issues remain 10/9/13 © 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved 3

Scope


Security as a system problem

•  UlTmately security is a system property –  Involves hardware, soaware, humans, procedures…

•  Most directly related:

1.  Securing the data-‐centric bus

2.  IntegraTng across security domains

3.  Securing the operaTng system

4.  Securing the hardware & soaware configuraTon


Scope of the RFP

Out of Scope

Scope of the DDS Security RFP

Three security boundaries

•  Boundary security

•  Transport-‐Level – Network (layer 3) security – Session (layer 4/5) security

•  Fine-‐grained Data-‐Centric Security

10/9/13 © 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved

Ul5mately you need to implement the 3 of them

6

Fine-‐Grained Data-‐Centric Security

•  Access control per Topic •  Read versus-‐write permissions

•  Field-‐specific permissions (not addressed)

Topics

10/9/13 7 © 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved

Threats


Threats 1.  Unauthorized subscripTon 2.  Unauthorized publicaTon 3.  Tampering and replay 4.  Unauthorized access to data

by infrastructure services


Alice: Allowed to publish topic T Bob: Allowed to subscribe to topic T Eve: Non-‐authorized eavesdropper Trudy: Intruder Trent: Trusted infrastructure service Mallory: Malicious insider

Data-‐centric/mulTcast Insider Threats

•  Two insider threats affecTng (mulTcast) data-‐centric systems are of unique significance 1.   Reader mis-‐behaves as unauthorized writer

An applicaTon uses knowledge gained as authorized reader to spoof the system as a writer

2.   Compromise of Infrastructure Service A service that is trusted to read and write data on behalf

of others (e.g. a persistence service ) becomes compromised


Reader mis-‐behaves as unauthorized writer

•  SituaTon: –  Alice -‐ creates a Crypto Key per Topic/DataWriter –  Alice -‐ shares its Key with all intended readers as needed to mulTcast –  Mallory – is an authorized reader so it has Alice’s key –  Mallory – behaves maliciously and uses Alice’s key to create fake UDP messages pukng

Alice’s informaTon (IP, Port, GUIDs, etc.) but with bad data.

•  ImplicaTons: –  Bob sees message from Mallory and processes it believing it is from Alice –  Mallory can provide a system-‐wide failure for all subscribers to topic T, making them

process wrong data, delete instances, –  Depending on the Topic this can be catastrophic for the system

•  Notes: –  The problem is that all secrets shared by Alice and Bob are also known to Mallory

•  So the aVack cannot be solved with a MAC or HMAC if Alice’s key is also shared with all readers…

–  The problem can be solved with a digital signature but that is 1000X slower than a MAC


Session Sequence Number AVack •  Background:

–  Reliable protocols rely on a session_id and a sequence number to avoid duplicates and detect message loss

–  RTPS protocol can use GAP messages and HeartBeat messages to advance the session (DataWriter) sequence number

•  Vulnerability: –  An aVacker can spoof a packet with the session ID and Hearbeat/GAP causing the DataReader to advance the session sequence-‐numbers blocking future messages recepTon

–  AVacker only needs GUID of the DataWriter to aVack, which can be obtained from snooping traffic.

–  AaVack can be used to prevent the AuthenTcaTon of legiTmate ParTcipants


Cuckoo AVack on GUID •  Background:

–  DDS DomainParTcipants are idenTfied by unique GUID, Readers/Writers derive their GUID from it.

–  GUID used to uniquely idenTfies the RTPS sessions and the locaTon of each parTcipant

•  Vulnerability: –  An aVacker with legit IdenTty can authenTcate using the GUID of another ParTcipant

–  AVacker with be accepted with “cuckooed” GUID blocking legiTmate ParTcipant from using its GUID

–  AVacker only needs GUID of the ParTcipant to aVack, which can be obtained from snooping traffic.


Summary of RFP requirements


RFP Mandatory Requirements

Proposals shall define … 6.5.1 … a Plasorm Independent Security Model for DDS

independent of the programming language used… 6.5.2 … a collecTon of Plasorm Independent IntercepTon

Points and SPIs … 6.5.3 … built-‐in Plasorm Independent Security Plugins that

implement the Plasorm Independent Interfaces 6.5.4 … plasorm specific mappings for the built-‐in plugins to

all the language PSMs supported by DDS 6.5.5 … how the DDS Interoperability Wire Protocol is used

to allow DDS applicaTons to interoperate securely


Mandatory Requirements 6.5.1: Security Model

The Security Model for DDS shall … 6.5.1.1 … support mechanisms that establish the ability for a DDS ParTcipant to run in a

plasorm

6.5.1.2 … support mechanisms to configure and access the credenTals of the underlying DDS ParTcipants …

6.5.1.3 … allow specificaTon of authorizaTon policies, controlling

[1] Joining a DDS Domain

[2] Access to DDS Discovery Data [3] Publishing a DDS Topic, [4] Subscribing to a DDS Topic

[5] Publishing on a DDS ParTTon, [6] Subscribing on a DDS ParTTon

6.5.1.4 … include the concept of data tagging

6.5.1.5 … support mechanism for ensuring data integrity, including

[1] traceability, pedigree, and tamper [2] digital signatures

[3] data encrypTon

[4] use of different keys for data from different DataWriters


Mandatory Requirements 6.5.2: Set of IntercepTon Points and SPIs

The Plugin SPIs shall … 6.5.2.1 … allow applicaTons to exchange credenTals with a DDS ParTcipant

[1] exchanging credenTals for authenTcaTon

[2] delegaTon of authority for authenTcaTon

6.5.2.2 … allow an external plugin to perform all the authorizaTon funcTons

[1] full support of the authorizaTon policies [3] support delegaTon of authority

[4] support delegaTon of authority separately for each DDS Topic

6.5.2.3 … allow an external plugin to perform all the tagging and tag-‐accessing funcTons

6.5.2.4 … allow an external plugin to perform all the encrypTon and decrypTon funcTons

6.5.2.5 … external plugin to perform all the digital signing and verificaTon funcTons


RFP OpTonal Requirements

Proposals may define authorizaTon policies that control … 6.6.1 … the content a DDS ParTcipant is allowed to publish on a Topic. 6.6.2 … the content a DDS ParTcipant is allowed to subscribe on a Topic.. 6.6.3 … the QoS Policies a DDS ParTcipants can use when publishing a Topic 6.6.4 … the QoS Policies a DDS ParTcipant can use when subscribing to a

Topic.

Proposals may define … 6.6.5 … data-‐tagging plugins that apply different tags for each data-‐sample

published by a DDS DataWriter. 6.6.6 … built-‐in plugins that interoperate with standard authenTcaTon and

authorizaTon protocols and services, such as, LDAP and SAML. 6.6.7 … a PSM mapping of the DDS-‐RTPS Interoperability Wire Protocol to a

secure transport, such as, DTLS. 6.6.8 … a PSM of the DDS-‐RTPS Interoperability Wire Protocol allowing

interoperability over UnidirecTonal Transports.


Overview of DDS Security spec.


Submission Guiding Principles •  Performance & Scalability

–  Do not impact parts of the system that do not have security needs

–  Allow opTng out of specific features such as MAC, EncrypTon. Digital Signature with sufficient granularity

–  Limit use of asymmetric keys to discovery & session establishment

–  Support MulTcast

•  Robustness & Availability –  Be robust to the failure or compromise of any single component.

–  Limit privileges of infrastructure services and relays

–  Avoid centralized policy decisions/services

–  Avoid mulT-‐party key agreement protocols

•  Fitness to data-‐centric model –  Express policies and permissions in terms of familiar DDS terminology and objects –  Support all of DDS: consumpTon of samples out of order, best efforts, Tme filters, history cache,

etc.

•  Leverage exis5ng technologies –  Support plugging in exiTng technologies for ciphers, MAC, PKI

•  Ease of use & Flexibility –  Do not preclude integraTng with their exisTng security and crypto infrastructure.


Audience and Purpose for this SpecificaTon

•  Audience: – DDS vendors/implementers, not the users of DDS

•  Purpose: – Define a Security Model for DDS systems – Define concrete IntercepTon points in the middleware where SPI interfaces must be called

– Define concrete SPI Interfaces vendors must invoke at the IntercepTon Points and the behavior upon various returns

– Define specific SPI implementaTons to the extent required for interoperability

– NOT guidance to users implemenTng secure DDS systems

– NOT defini5on of security technologies beyond what is required to implement the specificaTon


DDS Security covers 4 related concerns


Security Plugin APIs & Behavior

DDS & RTPS support for Security

Buil5n Plugins

Security Model

Security Model


Security Model

•  A security model is defined in terms of: – The subjects (principals) – The objects being protected

•  The operaTons that are protected on the objects – Access Control Model

•  A way to map each subject to the objects they can perform operaTons on and which are the allowed operaTons


MR# 6.5.1

Security Model Example: UNIX FileSystem (simplified)

•  Subjects: Users, specifically processes execuTng on behalf of a specific userid •  Protected Objects: Files and Directories

•  Protected OperaTons on Objects:

–  Directory.list, Directory.createFile, Directory.createDir, Directory.removeFile, Directory.removeDir, Directory.renameFile

–  File.view, File.modify, File.execute

•  Access Control Model: –  A subject is given a userId and a set of groupId –  Each object is assigned a OWNER and a GROUP

–  Each Object is given a combinaTon of READ, WRITE, EXECUTE permissions for the assigned OWNER and GROUP

–  Each protected operaTon is mapped to a check, for example •  File.view is allowed if and only if

–  File.owner == Subject.userId AND File.permissions(OWNER) includes READ

–  OR File.group IS-‐IN Subject.groupId[] AND File.permissions(GROUP) includes READ


DDS Security Model •  Subjects: DDS DomainParTcipant (ParTcipant GUID) •  Protected Objects: DDS Domain and DDS Topic

•  Protected Opera5ons on Objects (logical view):

–  DomainParTcipant.join –  DomainParTcipant.set_read_parTTons .set_write_parTTons

–  Topic.create –  Topic.set_qos –  Topic.set_reader_qos –  Topic.read –  Topic.set_writer_qos –  Topic.write –  Topic.create_instance –  Topic.update_instance –  Topic.dispose_instance


MR# 6.5.1

Mapping of DDS API to protected operaTons


DDS API Call Protected Opera5on DomainParTcipantFactory.create_parTcipant Discovery.match_remote_parTcipant DomainParTcipant.join DomainParTcipant.create_publisher Publisher.set_qos DomainParTcipant.set_write_parTTons DomainParTcipant.create_subscriber Subscriber.set_qos DomainParTcipant.set_read_parTTons

DomainParTcipant.create_topic Discovery.dicover_topic Topic.create, Topic.seq_qos Topic.set_qos Topic.set_qos Subscriber.create_datareader Discovery.dicover_datareader Topic.read, Topic.set_reader_qos DataReader.set_qos Discovery.change_datareader_qos Topic.set_reader_qos Publisher.create_datawriter Discovery.dicover_datawriter Topic.write, Topic.set_writer_qos DataWriter.set_qos Discovery.change_datawriter_qos Topic.set_writer_qos DataWriter.register_instance DataWriter.write Protocol.receive_instance_new

Topic.create_instance

DataWriter.dispose Protocol.receive_dispose Topic.dispose_instance

MR# 6.5.1

DDS & RTPS Support for Security


Support for Security in DDS & RTPS

•  DDS ParTcipants need to exchange security informaTon –  CerTficates for AuthenTcaTon & Permissions –  Handshake messages for mutual authenTcaTon and shared-‐

secret establishment –  KeyTokens for key-‐exchange

•  Some reuse of exisTng DDS mechanisms –  Discovery topics –  BuilTn data readers / writers

•  AddiTon of a InterparTcipantStatelessWriter/Reader •  EncrypTon and signatures introduce new RTPS Submessage and Submessage elements

–  SecureSubMessage –  SecuredData


Extensions to BuilTnTopics

•  DCPSParTcipants: – AddiTonal members:

idenTty_token : IdenTtyToken (PID 0x1001) permissions_token : PermissionsToken (PID 0x1002)

•  DCPSPublicaTons and DCPSSubscripTons: – AddiTonal member:

data_tags : DataTag (PID 0x1003)

struct Tag { string name; string value;

}; struct DataTags {

sequence<Tag>; };

struct DataHolder { string classid; StringMap properties; OctetsMap properties; StringSeq strings_value; OctetSeq binary_value1; OctetSeq binary_value2; LongLongSeq longlongs_value; }; //@Extensibility MUTABLE_EXTENSIBILITY

struct Token DataHolder ; typedef <XXX>Token Token;

Changed

InterParTcipantStateless channel •  Inherent “sequence number” vulnerability with any stateful channel.

–  Send a Heartbeat for a future sequence number effecTvely shuts down channel

•  Well-‐known in TCP. But miTgated via: –  Random start sequence number per session –  RejecTon of sequence numbers outside window

These “works” for TCP because it is point-‐to-‐point and is not communicaTng state (so no GAPs). It would not work for discovery, using mulTcast, etc.

To be robust to this aVack you need a protocol that does not reject things based on sequence numbers

This is already supported in the RTPS specificaTon


InterParTcipant Stateless channel •  InterparTcipantStatelessWriter and InterparTcipantStatelessReader

•  InterparTcipantStatelessGenericMessage


struct MessageIdenTty { octet source_guid[16]; long long sequence_number;

};

typedef string<> GenericMessageClassId; struct InterParTcipantStatelessGenericMessage { // target for the request. Can be GUID_UNKNOWN

BuilTnTopicKey_t des5na5on_par5cipant_key; MessageIdenTty messageIdenTty; MessageIdenTty relatedMessageIdenTty; GenericMessageClassId msgClassid; DataHolder msgData; //@shared

}; //@Extensibility MUTABLE_EXTENSIBILITY

Uses the RTPS stateless writers and readers RTPS v. 2.1 SecTon 8.4.7.2 and 8.4.10.2

Security informaTon exchanged via InterParTcipantStatelessWriter/Reader

Behavior:

RTPS v 2.1 stateless writer/rdr (secTon 8.4.7.2 & 8.4.10.2)

•  Does not reject messages based on sequence number

•  Robust against sequence number aVack


struct MessageIdenTty { octet source_guid[16]; long long sequence_number;

};

typedef string<> GenericMessageClassId; struct InterParTcipantStatelessGenericMessage { // target. Can be GUID_UNKNOWN

BuilTnTopicKey_t des5na5on_par5cipant_key; MessageIdenTty message_idenTty; MessageIdenTty related_message_idenTty; GenericMessageClassId message_classid; DataHolder message_data; //@shared

}; //@Extensibility MUTABLE_EXTENSIBILITY

Changed

4 message kinds:

GMCLASSID_SECURITY_AUTH_HANDSHAKE

GMCLASSID_SECURITY_PARTICIPANT_CRYPTO_TOKENS

GMCLASSID_SECURITY_DATAWRITER_CRYPTO_TOKENS GMCLASSID_SECURITY_DATAREADER_CRYPTO_TOKENS

Security informaTon exchanged via InterParTcipantStateless Writer/Reader


struct CryptoTokensMsg { octet sending_guid[16]; octet receiving_guid[16]; sequence<CryptoToken> crypto_tokens; };

typedef Token HandshakeTokenMsg; typedef CryptoTokensMsg Par5cipantCryptoTokensMsg; typedef CryptoTokensMsg DatawriterCryptoTokensMsg; typedef CryptoTokensMsg DatareaderCryptoTokensMsg;

4 message kinds:

GMCLASSID_SECURITY_AUTH_HANDSHAKE

GMCLASSID_SECURITY_PARTICIPANT_CRYPTO_TOKENS GMCLASSID_SECURITY_DATAWRITER_CRYPTO_TOKENS

GMCLASSID_SECURITY_DATAREADER_CRYPTO_TOKENS

Protocol-‐level support Background: RTPS


RTPS SubMessage

RTPS Header

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

SubMsg Header

SubMsg Element

SubMsg Element

SerializedData

RTPS SubMessage

RTPS Message

Cryptographic SPI at the wire-‐protocol level

© 2012 RTI • UNCLASSIFIED • PROPRIETARY

RTPS SubMessage

SerializedData

RTPS SubMessage

SerializedData

RTPS Header RTPS Header

RTPS SubMessage (*)

RTPS SubMessage

SecuredData

SerializedData

RTPS SubMessage

SecuredData

SerializedData

RTPS SubMessage (*)

RTPS SubMessage (*)

Secure encoding

Secure decoding

Message TransformaTon

Security Plugin Architecture


Plasorm Independent IntercepTon Pts + SPIs


Service Plugin Purpose Interactions

Authentication Authenticate the principal that is joining a DDS Domain.

Handshake and establish shared secret between participants

The principal may be an application/process or the user associated with that application or process. Participants may messages to do mutual authentication and establish shared secret

Access Control Decide whether a principal is allowed to perform a protected operation.

Protected operations include joining a specific DDS domain, creating a Topic, reading a Topic, writing a Topic, etc.

Cryptography Perform the encryption and decryption operations. Create & Exchange Keys. Compute digests, compute and verify Message Authentication Codes. Sign and verify signatures of messages.

Invoked by DDS middleware to encrypt data compute and verify MAC, compute & verify Digital Signatures

Logging Log all security relevant events Invoked by middleware to log

Data Tagging Add a data tag for each data sample

MR# 6.5.2

Plasorm Independent SPIs


MR# 6.5.2

BuilTn Plugins


SPI Buil5n Plungin Notes

AuthenTcaTon DDS:Auth:PKI-‐RSA/DSA-‐DH Uses PKI with a pre-‐configured shared CerTficate Authority. DSA and Diffie-‐Hellman for authenTcaTon and key exchange Establishes shared secret

AccessControl DDS:Access:PKI-‐Signed-‐XML-‐Permissions

Permissions document signed by shared CerTficate Authority

Cryptography DDS:Crypto:AES-‐CTR-‐HMAC-‐RSA/DSA-‐DH

Protected key distribuTon AES128 and AES256 for encrypTon (in counter mode) SHA1 and SHA256 for digest HMAC-‐SHA1 and HMAC-‐256 for MAC

DataTagging Discovered_EndpointTags Send Tags via Endpoint Discovery

Logging DedicatedDDS_LogTopic

MR# 6.5.3

Mapping to DDS Language PSMs

•  Plugin SPIs to be defined using IDL •  IDL-‐to-‐Language mappings used for each Language PSM

•  No need to define mappings to new Javs5 PSM and STD-‐C++ PSM –  IDL-‐derived Language PSMs suffice as these are low-‐level interfaces that will only be exercised by SPI plugin implementers.

NOTE: IDL file is missing from submission


MR# 6.5.4

AuthenTcaTon


AuthenTcaTon SPI


MR# 6.5.2

Full AuthenTcaTon SPI

•  validate_local_idenTty •  get_idenTty_token •  set_permissions_credenTal_and_token •  validate_remote_idenTty •  begin_handshake_request •  begin_handshake_reply •  process_handshake •  get_shared_secret •  get_peer_permissions_credenTal_token •  set_listener •  return_idenTty_token •  return_peer_permissions_credenTal_token •  return_handshake_handle •  return_idenTty_handle •  return_sharedsecret_handle


AuthenTcaTon Behavior 10/9/13 © 2012 Real-‐Time InnovaTons, Inc. -‐ All rights reserved 45

MR# 6.5.2

Meta-‐Protocol to handshake and establish shared secret

BuilTn DDS:Auth:PKI-‐DSA-‐DH

•  Uses shared CerTficate Authority (CA) – All ParTcipants pre-‐configured with shared-‐CA

•  Performs mutual authenTcaTon between discovered parTcipants using the Digital Signature Algorithm (DSA)

•  Establishes a shared secret using Diffie-‐Hellman.


ConfiguraTon of Auth:PKI-‐DS-‐DH

•  Three things: –  X.509 cerTficate that defines the shared CA. This cerTficate contains the Public Key of the CA.

–  RSA private key of the DomainParTcipant. – A (PEM-‐encoded) X.509 cerTficate that chains up to the CA, that binds the DomainParTcipant public key to the disTnguished name (subject name) for the parTcipant and any intermediate CA cerTficates required to build the chain.

•  ConfiguraTon API outside scope of specificaTon – Vendors can use file, QoS property, etc.


Behavior of Auth:PKI-‐DS-‐DH

•  validate_local_parTcipant –  IdenTtyCredenTalToken has X.509 cerTficate –  Validates cerTficate against CA

•  begin_handshake_request –  Sends X.509 CerTficate to peer parTcipant –  Sends Signed Permissions to to peer parTcipant –  Sends Challenge

•  begin_handshake_reply –  Sends X.509 CerTficate to peer parTcipant –  Sends Signed Permissions to to peer parTcipant –  Replies to Challenge & sends counter Challenge

•  process_handshake –  Verifies challenge response –  Responds to final challenge –  Exchanges SharedSecret



Remote ParTcipant AuthenTcaTon

ParTcipants receive Hash(X.509 IdenTtyCert) & Hash (Permissions Doc) of remote parTcipant via discovery


Each ParTcipant calls validate_remote_idenTty(). ParTcipant with highest GUID returns PENDING_HANDSHAKE_REQUEST, the other PENDING_HANDSAHKE_MESSAGE



ParTcipant1 creates CHALLENGE1 = “CHALLENGE:<nonce> and sends message via ParTcipantMessageWriter with HanshakeMessageToken := {CHALLENGE1, IdenTty, Permissions}



ParTcipant2 validates IdenTty of ParTcipant1 against CA ParTcipant2 creates CHALLENGE2 := CHALLENGE:<nonce> ParTcipant2 sends to ParTcipant1 message with MessageToken := {SIGN(CHALLENGE1), CHALLENGE2, IdenTty, Permissions}



Part1 validates IdenTty of ParTcipant2 against CA Part1 verifies SIGN(CHALLENGE1) using ParTcipant2’s PK Part1 computes a SharedSecret Part1 sends message with contents: MessageToken := { ENCRYPT(SharedSecret), SIGN( HASH(CHALLENGE2 # ENCRYPT(SharedSecret))) } Encrypt uses Part2’s PK.



Part2 verifies SIGN( HASH(CHALLENGE2 # ENCRYPT(SharedSecret)))using Part1’s PK Part2 decrypts ENCRYPT(SharedSecret) using its own PK

We have Mutual Authen5ca5on and a SharedSecret


Access Control


Access Control SPI


MR# 6.5.2

Full AccessControl SPI •  check_create_parTcipant •  check_create_datawriter

•  check_create_datareader

•  check_create_topic

•  check_local_datawriter_register_instance

•  check_local_datawriter_dispose_instance

•  check_remote_parTcipant

•  check_remote_datawriter

•  check_remote_datareader

•  check_remote_topic

•  check_local_datawriter_match

•  check_local_datareader_match

•  check_remote_datawriter_register_instance

•  check_remote_datawriter_dispose_instance

•  get_permissions_token

•  get_permissions_credenTal_token

•  set_listener

•  return_permissions_token

•  return_permissions_credenTal_token

•  validate_local_permissions

•  validate_remote_permissions


Support for AccessControl on data-‐tags and parTTons

•  check_local_datawriter_match

•  check_local_datareader_match – OperaTons receive the reader & writer Permissions Handles and DataTags •  The PermissionsHandles can cache any QoS that is relevant to access control decisions

Supports AccessControl rules based on DataTags or matching of other writer/reader aVributes (e.g. based on parTTon names)


BuilTn DDS:AC:PKI SPI

•  Configured with: –  X.509 CerTficate of shared Permissions CA –  PermissionsCredenTalToken

•  PermissionsCredenTalToken contains –  XML file with permissions –  Includes SubjectName matching the one on IdenTtyCredenTalToken

– All signed by Permissions CA –  FormaXed as PKCS#7 document of type signed data

This binds the permissions to the idenTty established by the AuthenTcaTonPlugin


Example Permissions


Cryptographic


Full Cryptographic SPI (CryptoKeyFactory)

•  register_local_parTcipant •  register_matched_remote_parTcipant

•  register_local_datawriter •  register_matched_remote_datareader

•  register_local_datareader •  register_matched_remote_datawriter

•  unregister_parTcipant •  unregister_datawriter •  unregister_datareader


Full Cryptographic SPI (CryptoKeyExchnage)

•  encode_serialized_data •  encode_datawriter_submessage

•  encode_datareader_submessage

•  encode_rtps_message

•  decode_rtps_message

•  preprocess_secure_submsg

•  decode_datawriter_submessage

•  decode_datareader_submessage

•  decode_serialized_data


Full Cryptographic SPI (CryptoTransform)

•  register_local_parTcipant •  register_matched_remote_parTcipant

•  register_local_datawriter •  register_matched_remote_datareader

•  register_local_datareader •  register_matched_remote_datawriter

•  unregister_parTcipant •  unregister_datawriter •  unregister_datareader


RTPS SubMessage

SerializedData


RTPS SubMessage

SecuredData

SerializedData

encode_serialized_data

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS Header

encode_datawriter_submessage

RTPS Header

RTPS SecureSubMsg

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS Header

encode_datareader_submessage

RTPS Header

RTPS SecureSubMsg

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage


RTPS SecureSubMsg

encode_rtps_message

RTPS SubMessage RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

RTPS SubMessage

SerializedData

RTPS SubMessage

SerializedData


RTPS SecSubMsg

RTPS SubMessage

SecuredData

SerializedData

RTPS SubMessage

SecuredData

SerializedData

RTPS SecSubMsg

RTPS SecSubMsg

encode_rtps_message

encode_datawriter_submessage

encode_serialized_data

Crypto-‐AES-‐CTR-‐HMAC-‐DSA-‐DH

•  EncrypTon uses AES in counter mode –  Similar to SRTP, but enhanced to support mulTple topics within a single RTPS message and infrastructure services like a relay or persistence

•  Use of counter mode turns the AES block cipher into a stream cipher –  Each DDS sample is separately encrypted and can be decrypted without process the previous message

•  This is criTcal to support DDS QoS like history, content filters, best-‐efforts etc.

•  DSA and Diffie-‐Hellman used for mutual authenTcaTon and secure key exchange


MR# 6.5.3

BuilTn DDS:Crypto-‐AES-‐CTR-‐HMAC-‐DSA-‐DH SPI

•  Shared secret used to create a KeyExchangeKey •  KeyExchangeKey used to send following Master Key Material using the

BuilTnPublicaTonWriter: –  MasterKey –  MasterSalt –  MasterHMACSalt

•  Based on this the following Key Material is computed: –  SessionSalt := HMAC(MasterKey,"SessionSalt" + MasterSalt + SessionId + 0x00) [ Truncated to 128 bits] –  SessionKey := HMAC(MasterKey,"SessionKey" + MasterSalt + SessionId + 0x01) –  SessionHMACKey := HMAC(MasterKey,"SessionHMACKey" + MasterHMACSalt + SessionId) Note: SessionId goes on the EncryptedMessage Envelope

•  EncrypTon uses AES in Counter (CTR) mode –  The session counter is sent on EncryptedMessage Envelope.


Data Tagging


DataTagging: DDS:Tagging:DDS_Discovery

•  DataWriter and DataReader enTTes have associated tags

•  DataWriter Tags are propagated via DDS discovery •  AccessControl plugin has visibility into tags and can make decisions based on that

•  BuilTn plugins – AccessControl plugin ignores tags –  Permissions document format does not allow rules based on data-‐tags

–  Rules can be added when use-‐case is beVer understood


Data Logging


DataLogging: DDS:Logging:DDS_LogTopic

[SecTon sTll missing]

•  Intent is to use a dedicated DDS Topic to Log the security-‐relevant messages

•  DDS Secure Log Topic will be encrypted


Status & Conclusions

•  We feel specificaTon will be ready to adopt in December

•  Tasks/Missing items –  Update UML with added operaTons

–  Complete secTons 7.2.3 and 7.2.4 (extra details on how RTPS is affected)

–  Add descripTon on how discovery traffic is secured (Kx for builTn topics)

–  Add descripTon of the built-‐in Logging plugin –  Review document for grammar


Find out more… www.rT.com

community.rT.com

demo.rT.com

www.youtube.com/realTmeinnovaTons

blogs.rT.com

www.twiVer.com/RealTimeInnov

www.facebook.com/RTIsoaware

www.slideshare.net/GerardoPardo

dds.omg.org

www.omg.org

© 2012 RTI • ALL RIGHTS RESERVED 77

omg dds security submission presentation (september 2013 - 6th revised submission)

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