There is an inherent DoS network amplification attack that exploits peer-to-peer discovery. See https://issues.omg.org/browse/DDSIRTP26-6

This issue should be addressed by DDS-Security. Likely using some pre-shared key mechanics to protect all messages not otherwise protected. For example, the authentication handshakes.

Provide a layer of PSK protection

Peovide the means to use a pre-shared secret to protect any RTPS message (e.g. bootstrap messges) that is not otherwise protected by the keys that the DomainParticipants exchange.

Also define the "pre-shared" key mechanism as a separate "builtin" plugin

When "performing authentication only," the encode_serialized_payload operation wraps the SerializedPayload inside CryptoHeader and CryptoFooter. This resulting byte stream takes the place of the original SerializedPayload submessage element in a Data(Frag) submessage.

On the receiving side, this modified submessage element is passed to decode_serialized_payload. The problem comes in parsing this CryptoHeader-SeralizedPayload-CryptoFooter group.

The CryptoHeader is of fixed size and only contains octet-width data (therefore has no padding), so parsing it and determining where SerializedPaylod starts is trivial.

Then the implementation needs to determine where SerializedPayload ends in order to determine which bytes to authenticate. There is no in-stream indication of where the SerializePayload ends.

One possibility would be to look at the end of the byte sequence that decode_serialized_payload received and "step backwards" by the length of the CryptoFooter, however the CryptoFooter is variable length (with receiver_specific_macs). Even if the implementation has external knowledge that receiver_specific_macs are not in use, the alignment requirement of the plugin_sec_tag.receiver_specific_macs.length effectively makes this a variable-length element (also see issue #58).

To resolve this, an additional element for "length" could be added before the SerializedPayload, just like the CryptoContent submessage element does. This would make parsing the encoded payload similar for the encrypt and auth-only cases.

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The description of is_write_protected starts with "Indicates if read access". This should be "Indicates if write access."

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domainId is not listed in section 8.4.2.9.12

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In 9.5.3.3.4.2 remove this part:
"Note that the cipher operations have 16-byte block-size and add padding when needed. Therefore the secure data.length (“N”) will always be a multiple of 16."

AES-GCM doesn't add padding. The implication of this is that the CryptoContent Submessage Element may end at an arbitrary point in the stream (from the point of view of alignment). Bringing the stream "back into alignment" will depend on the usage context:

• When encoding payload, the CryptoFooter follows directly after CryptoContent. This means that CryptoFooter's first element (common_mac) may start unaligned. Then receiver_specific_macs.length appears in the stream as a 32-bit value so it will be preceded by 0-3 padding bytes depending on the length of CryptoContent.
• When encoding a submessage or full message, CryptoContent is followed by the start of another submessage which must be aligned to 4 per the RTPS spec.

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9.5.3.3.6 "The message digest is computed on the crypto_header and the ciphertext."

This statement appears to contradict the descriptions of common_mac and receiver_specific_macs in 9.5.3.3.4.4 (payload), 9.5.3.3.4.5 (submessage), and 9.5.3.3.4.6 (message).

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XML Schema doesn't use all-caps TRUE and FALSE.
https://www.w3.org/TR/xmlschema-2/#boolean

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In the Table 70 row for register_local_datareader, the ReaderKeyMaterial is created based on Data Protection Kind. This should be Metadata Protection Kind because the ReaderKeyMaterial signs/encrypts submessages and not data payloads.

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The term CryptoKeyTransform is used 3 times (section name of 9.5.3.3, text of 9.5.3.3.1, caption of Table 72). These should be CryptoTransform.

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participant_security_attributes is currently spelled participant_security_atributes on page 25 of the specification.

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Section 9.3.1.3 (Identity Certificate) indicates it is possible to use certificate chains.

However the language of this section is confusing because an X.509 v3 Certificate does not contain a chain. It is a single certificate. What can contain a chain of certificates is a file. E.g. the standard "PEM" file format referenced in Table 44 can contain a certificate chain.

To clarify this the following modifications are suggested:
(1) In table 44, row for "identity_certificate" change from:
"URI to a X509 certificate signed by the IdentityCA in PEM format"...
To
"URI to a X509 certificate (or certificate chain) signed by the IdentityCA, either as the root CA or as an intermediate CA, in PEM format"

(2) In section 9.3.1.3 change from:
"An X.509 v3 Certificate [39] that chains up to the Identity CA (see 9.3.1.1)."
To:
"A X.509 v3 Certificate chain [39] that is signed by the Identity CA (see 9.3.1.1) either as the root or as an intermediate CA in the chain"

(3) In section 9.3
In bullet 3. Clarify it may not be a single X.509 rather it can be a chain.

(4) In table 49, field "c.id" indicate this is not a single certificate but a certificate chain. As that is what was configured in the PropertyQosPolicy.

(5) In table 50, field "c.id" indicate this is not a single certificate but a certificate chain. As that is what was configured in the PropertyQosPolicy.

(5) In table 52, field "validate_local_identity" indicate this is not a single certificate but a certificate chain.

(6) In Table 53 IdentityCertificate is undefined. Maybe it should be "identity_certificate" and refer to the property defined in Table 44.

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The behavior of the built-in CryptoKeyFactory operations is described in Table 70. Many entries of this table include direct references to details of the built-in Access Control plugin's configuration file (an example, "see 9.4.1.2.5.6").

It would be easier to follow and more modular if this was changed to instead reference the data structure that the CryptoKeyFactory can actually see, which in this case is ParticipantSecurityAttributes.

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All the other flag names defined here take the form of "PLUGIN_PARTICIPANT_SECURITY_ATTRIBUTES_FLAG_IS_XXX_YYY". Should the BUILTIN part of this flag really be there? I believe this should instead read: PLUGIN_PARTICIPANT_SECURITY_ATTRIBUTES_FLAG_IS_DISCOVERY_ENCRYPTED.

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Table 70 introduces the term "Participant2ParticipantKxKeyMaterial" which isn't used anywhere else in the spec.

It would be helpful to have a table that lists each "key material" object along with which operation creates it and how it's used.

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The last paragraph of 9.5.3.3.4.3 refers to the "CryptoHeader", this should be "CryptoFooter"

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Section 7.2.5 changes QoS in ways that break RTPS compatibility, however minor modifications can fix this.

Because the mapping for PropertyQosPolicy in Table 10 (is this an implied entry in Table 12 as well?) conflicts with RTPS's definition of PID 0x59, the Binary Property values may not be sent on the wire. Note that RTPS has no concept of appendable extensibility, and requires backwards compatibility for all 2.x versions.

We can represent this restriction on PropertyQosPolicy in IDL4:

@extensibility(FINAL)
struct PropertyQosPolicy {
  PropertySeq value;

  @non-serialized
  BinaryPropertySeq binary_value;
};

The practical effect of this change is that any BinaryProperty entry with propagate == TRUE is not actually propagated inside PropertyQosPolicy. However a search through the specification indicates that there is no requirement for this, at least for built-in plugins. Any other plugins are necessarily vendor specific so those are not necessarily restricted from using an appendable policy, as long as they are aware of the compatibility issues (for allow_unauthenticated_participants == TRUE).

Also, for consistency the Tag and DataTags structs could be made @extensibility(FINAL). This is not as important since only Security-aware implementations will know about DataTagQosPolicy.

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There are a few cross-references that don't resolve, resulting in the text "see 0" or "in subclause 0" in the spec:

• Table 30 plugin_endpoint_attributes column 3 contains "found in 0"
• Table 52 get_authenticated_peer_credential_token contains "See section 0"
• 9.4.1.2.6.7 right before the bullet list
• Table 63 validate_remote_permissions
• 9.5.3.3.4.1 final paragraph has "subclause 0"

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In the normative IDL, the struct ParticipantSecurityAttributes's field plugin_participant_attributes has type ParticipantSecurityAttributesMask but it should have type PluginParticipantSecurityAttributesMask

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Section 7.4.4.2 "TopicSecurityAtributes" should be "Attributes"

Section 8.8.9.1, 8.8.9.2, and 8.8.9.3 "cripto" should be "crypto"

Section 8.8.3 "best-efforts" should be "best-effort"

Section 8.8.4 "simultanepusly" should be "simultaneously"

Table 63 caption: "bulitin" should be "built-in"

Section 9.5 "BEST_EFFORTS" should be "BEST_EFFORT"

Section 9.5.2.3 "indentifier" should be "identifier"

Section 9.5.3.1 "ciphetext' should be "ciphertext"

Normative IDL parameter 1 of create_local_data_crypto_tokens "cryto" should be "crypto"

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Section 7.4.1.3 'Reserved RTPS parameter IDs' reserves the whole 0x1000 to 0x1FFF (plus 0x5000 to 0x5FFF for must-understand) . That is 2 x 4096 PIDs. In reality DDS security only uses 6 PIDs... So this is a bit too much of a land grab.

It would be better to be more conservative and reserve a smaller range which can then be expanded as needed.

RTPS version 2.4 states that the reserved range for DDS security is 0x1000 to 0x10FF and 0x5000 to 0x50FF.

Section 7.4.1.3 should be updated to reflect this reduced range.

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In CryptoKeyFactory, all operations other than the unregister_* ones return handles. But the descriptions of register_matched_remote_participant and register_local_datawriter (8.5.1.7.2-3) end with "operation returns false". That should be "operation returns HandleNIL".

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In Table 48 (9.3.2.4), "properties" should be "binary_properties" so that the property future_challenge is treated as binary, matching Table 49's challenge1.

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DDS security does not provide any additional means to secure the DDS-RPC service calls. Absent this the protection would be based on the underlying DDS Topics.

DDS-RPC maps all operations of an interface to two unkeyed Topics. One for the request and one for the reply. The request Topic is used for all operations and likewise the reply Topic.

Thus relying on the underlying Topics would provide access control granularity at the level of the service and not allow to give narrower permissions. E.g. invoke certain operations and not others. This is not acceptable in some deployment situations.

One solution may be to make the Topics keyed by the operation. This is possible now that IDL42 allows the discriminator of a union to act as the key.

Alternatively DDS-Security could specify some other mechanism, for example designate a data-tag to indicate the operations that the request DataWriter may invoke. The receiver side would check that the operation invoked matches the DataWriter tag before processing the request.

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In section 8.8.2.2, it's established that the BuiltinParticipantStatelessMessage built-in endpoints are used for exchanging the "authentication handshake" messages. This makes sense based on how those built-in endpoints are defined in 7.4.3 and how they're used in some parts of 8.3.2.9 and .11.

However there are parts of 8.3.2.11 and 8.8.2 that describe this handshake using the names BuiltinParticipantMessageWriter / Reader (note the absence of "Stateless"). The name BuiltinParticipantMessageWriter is defined by the RTPS spec as the endpoint used to implement the participant scoped liveliness (see RTPS 2.2 section 8.4.13.2).

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If the crypto plugin transforms the payload but the layers containing the payload (submessage or message) are not transformed, the resulting Data/Frag submessage contains no indication that its payload has a nonstandard format.
Since this spec is essentially defining a new minor version of RTPS (along with RTPS RTF process concurrent to this), one of the reserved flags in the submessage header of Data/Frag can be defined as FLAG_S meaning that the format of the SerializedPayload submessage element is defined by the security spec.

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9.4.1.2.6.4 describes Enable Read Access Control, however the bullet list within this section uses the xml tag <enable_write_access_control> (twice), it should be <enable_read_access_control>.

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The rows in Table 61 is_submessage_encrypted and is_payload_encrypted each have paragraphs starting "If is_*_encrypted is FALSE..." and including "GCM authenticated encryption", which should be "GMAC authentication transformation" like the corresponding rows of Table 59.

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In Table 30, the entry for is_payload_protected says "If is_payload_protected is FALSE, then the CryptoKeyFactory, KeyExchange and CryptoTransform operations are called only if is_payload_protected is TRUE", but the last phrase should be "only if is_submessage_protected is TRUE".

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2nd parameter to get_topic_sec_attributes has type "String", should be "string".

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The last paragraph of 7.4.2 indicates that TopicSecurityAttributes::is_liveliness_protected is used to determine if a liveliness message should be sent using the new DCPSParticipantMessageSecure builtin endpoint or the old DCPSParticipantMessage builtin endpoint.

However it is not clear which topic's TopicSecurityAttributes are to be used. The liveliness message essentially belongs to the participant and not any given topic (see RTPS v2.2 8.4.13.5). Should the security spec use ParticipantSecurityAttributes here instead?

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Section 7.4.3.2:

The data type associated with these endpoints is ParticipantStatelessMessage defined
below (see also 7.2.5):
typedef ParticipantStatelessMessage ParticipantGenericMessage;

Two issues:
a. I don't see how this relates to 7.2.5, should that be 7.2.6?
b. The typedef is backwards. Typedef declares a new name (second) from an existing type (first).

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SubscriptionBuiltinTopicDataSecure should inherit from SubscriptionBuiltinTopicData in the local module, not the one in the DDS:: module.

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Operation: get_datarwriter_sec_attributes
should be
Operation: get_datawriter_sec_attributes

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The permissions document allow and deny rules contain a section for matching the data tags of the DataReader/DataWriter. The match is based on an exact match of the tag-name and tag-value.

For consistency with the way we match the permissions for Topic and Partitions we should also allow an expression for the tag-value portion. This is only for the permission rule itself. Not for the DataTag QosPolicy.

So to match the rule the DataTag name in the Qos must exactly match the name in the permissions document (no expressions here) and the DataTag value in the Qos should match (using fnmatch) the expression in the permissions document.

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Normative IDL has no parameter handshake_message_in (from Table 23). It would be possible to use handshake_message_out to serve the purposes of "in" since it's an inout parameter in IDL, but is that the intention here?

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In the normative IDL interface CryptoTransform, the decode_datawriter_submessage operation uses the "in" parameter passing mode for SecurityException – should be "out" or "inout".

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The normative IDL doesn't have SecureSubmessageCategory_t, but it does have SecureSumessageCategory_t which appears to be a typo.

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Table 32 (8.4.2.9) has a topic_name parameter for both get_datawriter_sec_attributes and get_datareader_sec_attributes, however this parameter is not present in the normative IDL.

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In the normative IDL, the type of the 2nd parameter for set_permissions_credential_and_token is listed as PermissionsCredential but should PermissionsCredentialToken.

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DDS::Security::LongLongSeq is not used so it should be removed from the normative IDL.

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The specification contains full copies of the machine readable XSD files:

• DDS Security Access Control Permissions XSD
• DDS Security Access Control Governance XSD

This causes problems as updates may not always be done consistently.

Therefore it would be better if the specification removed this duplication and just referenced the external machine-readable files.

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The specification depends on many other standards that appear referenced thought the specification and in Annex A (References) but do not appear in Section 3.

Section 3 should be expanded to include the subset of those references that are used for normative behavior. [46], [47], and [52] are clear examples of references that should be moved to Section 3.

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The UML diagrams in the specification use UML stereotypes, such as <<discovery>>. However these are not documented anywhere in the specification nor do they appear in the XMI.

Also the diagrams are non-standard UML in that they show superclasses in the top right corner. See for example Figure 10.

These issues should be corrected.

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The authentication handshake requires participants to exchange their permission files. This is done as clear text.

Visibility into the permissions file leaks information as to what the system Topic names are as well as what the application publishes and subscribes. This can be sensitive for some systems.

Aside form this sending this document is potentially expensive as the knowledge could be available on a separate channel.

The RTF should look share this information only with authenticated participants and possibly also avoid sending it if it is already known to the peer participant.

Related this is the fact that permissions are "monolithic" of you need to add a permission to a Participant you need to create and sign a new document. Would be nice to have some way to grant/propagate incremental permissions. E.g. something that could be bundled into the propagation of the Endpoint discovery data itself.

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The Security plugin model supports being able to control access to each DDS Topic instance (instead of just controlling access to the DDS Topic). However the builtin plugin permission files do not provide a way to configure these permissions.

This is important for many DDS-Security use-cases where each instance represents a different object and needs to separately indicate who has access to it. For example imaging a "CarPosition" topic that is used to publish the position of cars. Someone may be given permission to suscribe or publish its own car position, but not other cars. Likewise a manufactured or insurance company may be given permissions to the cars that they manage but not others.

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At end of 2nd to last para document has (matching the errata):

"sending the ParticipantSecurityInfo (the default value of zero has is_valid=0) or sending it with is_valid."

It should probably be

"sending the ParticipantSecurityInfo (the default value of zero has is_valid=0) or sending it with is_valid set to zero.”

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In 7.2.3.1, DataHolder is a struct annotated with @extensibility(APPENDABLE) and no optional fields.
However in ptc/17-09-26 (normative IDL), DataHolder has no @extensibility annotation and two optional fields.

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An implementation of the built-in Cryptography plugin is not compatible with the local implementation of the built-in Authentication, unless it uses/understands the same type of SharedSecretHandle. (SharedSecretHandle is the interface defined at the architecture level.) Therefore, the two built-in plugins are tied together and you cannot replace one or another with any other implementation of the same built-in plugin.
It is possible to make them independent in two possible ways (at least):

1. Define a BuiltinSharedSecretHandle that extends SharedSecretHandle interface, and has 3 methods like this:
   • octet[] getChallenge1(): returns challenge1 from the authentication handshake
   • octet[] getChallenge2(): returns challenge2 from the authentication handshake
   • octet[] getSharedSecret(): returns the shared secret from the authentication handshake
2. OR define a new type of Token (IDL structure) - e.g. HandshakeResultToken - for the final output of the Authentication handshake like this:
   • class_id DDS:Auth:PKI-DH:1.0+Result
   • binary_properties: challenge1, challenge2, SharedSecret

In both cases, it would change the specs of the methods get_shared_secret() and return_shared_handle() of the Authentication plugin, section 9.3.3.

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It is not clear whether the Permissions XSD allows to express all kinds of wildcard permissions. Just to make sure we cover all cases, we should give examples of permissions XML that grant only...

1. all permissions to any domain? ("all permissions" = join, pub/sub/relay to any topic/partition/data_tag, etc.)
2. all permissions to a specific domain, e.g. domain 0?
3. all permissions to all topics of domain 0? ("all permissions" = pub/sub/relay, etc.)
4. all permissions to all partitions of domain 0?
5. all permissions to a specific topic, e.g. "Circle1", of domain 0?
6. all permissions to a specific partition, e.g. "P1", of domain 0?
7. the permission to publish to any topic of domain 0? (but not subscribe/relay)
8. the permission to publish to any partition of domain 0? (but not subscribe/relay)

Such examples would be very useful in the spec as well.

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There are some issues with the UML model that should be improved. This came from the AB review of the RTF 1 report:

● SubmessageKind should be an Enumeration not a Class. And it’s missing its Literals. Tables 4,5 indicate Literals would include SEC_BODY, SEC_PREFIX, SEC_POSTFIX, SRTPS_PREFIX, SRTPS_POSTFIX
● SubmessageFlag is totally underspecified but probably should not be a PrimitiveType
● Likewise CryptoState. In fact there are far too many PrimitiveTypes, none of them documented, which should probably be Strings.

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The machine-readable files have comments that trace their changes to the Jira issues that caused them. This hurts the use of the specification so they should be removed.

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The following two sections in DDS-Security 1.1 affect future versions of DDSI-RTPS.

The DDSI-RTPS should include language that makes sure future versions do not conflict with what DDS-Security and future revisions thereof may do.

Specifically the following two sections of DDS-Security 1.1 should be taken into consideration

7.3.6.1 Change to the RTPS minor version number
Implementations of this specification shall set the RTPS protocol version number present in the RTPS Header. The RTPS Major version number shall be set to 2 and the RTPS Minor version number shall be set to 3. Future revisions of the DDS-RTPS specification shall take into consideration this fact.

7.4.1.3 Reserved RTPS parameter IDs
This specification reserves the RTPS Simple Discovery Protocol ParameterIDs in the range:
0x1000 to 0x1FFF and 0x5000 to 0x5FFF. The second interval covers the same range of parametersID, except they have the must-understand bit set. This reserved range applies to RTPS version 2.3 (see 7.3.6.1) and higher minor revisions of RTPS. Future revisions of the DDS-RTPS specification shall take into consideration this fact.

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The Authentication Plugin Model specifies a state machine to be implemented by the DDS middleware to manage the authentication of the remote Participants. The implementation of this state machine is complex because:

• It is not specified when to call validate_remote_identity (for each received SPDP or only for the first received SPDP from a newly discovered Participant? What if a malicious Participant send a SPDP at first, usurping the GUID of a legit Participant?)
• The handshake could be initiated from both sides at nearly the same time (nothing forbid this in §8.3)
• There is no indication in the specification to tell how parallel handshakes between 2 Participants should interact
• It is difficult to determine at which sense a received message belongs
• In §8.3.2.8.1 it's specified that "The DDS security implementation shall pass to the AuthenticationPlugin any message received by the BuiltinParticipantStatelessMessageReader...". But there are states in the state machine where it's not specified how to pass those messages (e.g. when validate_remote_identity has not been called yet, and the state machine is not initialized)

This results in quite complex code, and this is a weakness in a mechanism which needs to be very strong.

Anyway, the state machine in the middleware is redundant with the one needed in the plugin. In addition, it has to deal with events where it doesn't know what is really going on. Only the plugin has the real information. Therefore, we think this middleware state machine is useless, add extra complexity which makes the authentication less robust, and consumes a lot of resources.

Instead, we suggest to remove it and to change the mechanism to the following:

• remove all the "_handshake" methods on the Authentication Plugin
• add a treat_message method to the authentication plugin to handle any incoming authentication ParticipantStatelessMessage
• add a send_message method to the authentication listener interface to tell the middleware to send an authentication ParticipantStatelessMessage
• add a validated_remote_participant method to the authentication listener interface to tell the middleware that the indicated participant is authenticated
• add a invalidated_remote_participant method to the authentication listener interface to tell the middleware that the indicated participant is not authenticated
• once the authentication is initialised with validate_remote_identity, all the state machine is managed directly by the plugin which sends the appropriate messages and is given the received ones, until its decision is given to the DDS middleware through the authentication listener.

This will provide the necessary functionality in a much simple, efficient and robust manner.

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The goal of this issues is to identify incorporate any additions that would allow systems built using DDS-Security to meet the CNSSP-15 security requirements.
https://imlive.s3.amazonaws.com/Federal%20Government/ID151830346965529215587195222610265670631/CNSSP15.pdf)

This is an important requirements for many systems and we are running into many users that are asking whether DDS-Security can be used to meet CNSSP-15 security requirements.

It seems like currently the "builtin plugins" are not enough because they do not include support for stronger asymmetric key algorithms. For example when using ECDSA digital signatures the minimal requirement is using 384-bit keys (e,g, NITS's Curve P-384). However the builtin plugins only include support for 256 bit EC keys.

Add support for additional crypto algorithms

Reorganize specification separating the definition of the crypto algorithms from its use by the plugins, such that, it becomes possible to extend the algorithms used, specifically adding support for algorithms that meet CNSSP-15 top-secret requoirements.

The builtin plugins create session keys for multiple DDS entities (DomainParticipant, DataWriter, DataReader) and share those with the matched Entities that successfully authenticate and have the proper authorization. The session key(s) are used to protect the messages sent by the entity using encryption and/or message-authentication codes.

Importantly the same key (e.g. a DataWriter key) may be shared with multiple matched DataReaders.

There are situations where an Entity may need to change is Session Key. E.g. if it has been used to encode too many messages, or if there is a need to "revoke" access for one or more existing matched Endpoints.

The specification should provide and describe the mechanism that implementations may use to change session Keys such that they are able to interoperate across vendors.

Add a mechanism to change session keys

Provide a mechanism to change session keys and send the modified keys to the authenticated authorized Participants

DomainTag was added to DDSI-RTPS as a mechanism to further identify/isolate DDS Domains beyond the separation provided by the DomainId. For two participants to be on the same domain both the DomainId and the DomainTag (a string) must match. The domain-tag string matching is literal (strcmp() character by character) there is no expressions.

Resulting from this it makes sense to add support for them to DDS security, without this support there would be no way to have different governance or permissions for domains that differ only on the DomainTag.

Adding support will impact the SPIs (e.g. extra parameters on validate_local_identity, validate_local_permissions, and most of thje check_operations. Operations that currently take the DomainId_t as a parameter should be expanded to also take a DomainTag.

Adding support will impact Governance and Permissions files.
E.g. the DomainIdSet should which is used on both files be expanded to incorporate domain tags.

Add specification of domainTag to governance and permissions

Extend governance and permissions documents to allow specifying the domain tags that identify the domain(s) to which the rules apply.

Starting with DDS-XTYPES version 1.2 a data type can be serialized using XCDR version 1 or version 2. This impacts the serialization of APPENDABLE and MUTABLE types. It does not impact the serialization of FINAL types unless they contain 8-byte primitives (long long or double) or optional members.

DDS-Security was written before DDS-XTYPES 1.2 came out. So all the products are using XCDR version 1.

Going forward DDS-Security should specify that it always uses XCDR version 1 for serialization of the types defined in the specification.

Be precise about the XCDR version used for serialization

Specify XCDR version f1 or serializing the data exchanged by DDS Security plugins.

Topic uses the DDS::Time_t which rolls over at 2038.
We should update to the newer definition to be adopted in DDS 1.6

We may need to use a different type name to allow both to co-exist
Curent definition is this:

extensibility(APPENDABLE) // After DDSSEC12-29
struct BuiltinLoggingType {
    octet  facility;  // Set to 0x0A (10). Indicates sec/auth msgs
    LoggingLevel severity;
    Time_t timestamp; // Since epoch 1970-01-01 00:00:00 +0000 (UTC)
    string hostname;  // IP host name of originator
    string hostip;    // IP address of originator
    string appname;   // Identify the device or application 
    string procid;    // Process name/ID for syslog system
    string msgid;     // Identify the type of message
    string message;   // Free-form message

    // Note that certain string keys (SD-IDs) are reserved by IANA
    map<string, NameValuePairSeq>  structured_data; 
};

Modify BuiltinLoggingType to use 64 bits to hold the timestamp seconds

Introduce a new Log topic that uses a 64-bit integer for the seconds.
Since this is defined as an "application-level" topic discovery and type matching will take care of interoperability with earlier versions of the specification.

Old topic name is deprecated but an implementation can support it for backwards compatibility.

The string literal "SessionKey" (and "SessionReceiverKey") is used without additional context as part of the binary input to HMAC. Add to this section that the ASCII encoding of "SessionKey" without a nul terminator is required.

Section 9.3.3.3.2 talks about a "bit array" type, clarify what that is.

Change "bit array" to "octet array" and clarify string concatenation in 9.5.3.3.3

Add clarification regarding how the strings are concatenated to create teh input to the HMAC256 functions

IdentityStatusToken, AuthenticatedPeerCredentialToken, AuthRequestMessageToken are specified in Table 46, Table 47, Table 48 of the DDS Security 1.1 spec. as containing "properties".

This is inconsistent with the description of HandshakeRequestMessageToken, HandshakeReplyMessageToken, and HandshakeFinalMessageToken. These specify binary_property.

They should be consistent. In fact AuthRequestMessageToken specifies that the content of the property with key "future_challenge" should match what is sent in HandshakeRequestMessageToken "challenge1"

It appears vendors are all using binary_properties as they are all interoperating. Therefore Table 46, Table 47, Table 48 should be modified to say "binary_property' for the attribute name.

Modify attribute name in the tables for dentityStatusToken, AuthenticatedPeerCredentialToken, AuthRequestMessageToken

Per the issue description, Attribute name "properties" in tables 46, 47, 48, defining IdentityStatusToken, AuthenticatedPeerCredentialToken, AuthRequestMessageToken should be modified to "binary_properties"

XTypes defines 4 new built-in endpoints for its TypeLookup Service. DDS-Security should define secure versions of these, just like the secure versions of discovery built-in endpoints.

Secure TypeLookup Built-In Endpoints

Secure DDS deployments that make use of XTypes features including its TypeLookup Service must have a secure way of communicating TypeLookup information.

The HandshakeRequestMessageToken's dh1 property (Table 49) contains a Diffie-Hellman Public Key. The text of Table 49 says that this is encoded as a CDR Big Endian Serialization. However, the data type of the Public Key is neither a CDR Built-In type nor specified in IDL. Thus the encoding is underspecified.

Explain the encoding of diffie-hellman keys in the handshake tokens

Explain the encoding of public keys into octet sequences

The DDS Security version 1.1 specification mentions:

If the Participant Private Key is a RSA key, then:

The value of the c.dsign_algo property shall be “RSASSA-PSS-SHA256”.
The digital signature shall be computed using the RSASSA-PSS algorithm specified in PKCS #1 (IETF 3447) RSA Cryptography Specifications Version 2.1 [44], using SHA256 as hash function, and MGF1 with SHA256 (mgf1sha256) as mask generation function.
This RFC is the one aforementioned. It states:

This encoding method is parameterized by the choice of hash function, mask generation function, and salt length. These options should be fixed for a given RSA key, except that the salt length can be variable (see [31] for discussion). Suggested hash and mask generation functions are given in Appendix B.

In the appendix, we can see an example where the salt length is the same as the hash length:

RSASSA-PSS-params ::= SEQUENCE
Unknown macro:
Unknown macro:

However, the salt length doesn't have to be the hash length. The WolfSSL and OpenSSL crypto libraries support several options (Openssl doc here and WolfSSL doc here). Our current approach is to use OpenSSL's default option: "maximum permissible value" (pkcsBlockLen - hLen - 2) when signing and auto (detect salt length from the signature) when verifying.

proposed solution
The specification should mention the salt length used when generating the signature. Otherwise, it should say that auto must be used when verifying the signature. This would allow interoperability (WolfSSL for example doesn't use auto by default).

Specify how to configure the salt length for RSA digital signatures

Merging with DDSSEC12-90 because the section referenced in the issue description ( 9.3.2.5.2) no longer describes algorithm-specific details, rather the crypto algorithms description are in a new dedicated section under section 8 "Common Cryptographic Algorithms" . So it is simpler to handle adding this detail to Issue 90.

Section 8.2.1 Message Module says:

To provide a deterministic behavior and a deterministic message size, DataWriters associated with an TsnTalker in the Deployment configuration (see subclause 7.2.3.1) may need to limit their RTPS Message exchange to RTPS Messages that include the following RTPS Submessages:
• InfoTimestamp
• Data
• DataFrag

This should be expanded to include the RTPS HeaderExtension as well as GAP.

Later in the section there is an explanation of why GAP may not be needed:

RTPS Submessages responsible for achieving reliability or in-order delivery, such as Gap, AckNack, NackFrag; as well as the rest of Interpreter Submessages, may be sent as part of “Best Effort” Streams. However, given the guarantees of the underlying TSN system, this sort of traffic may be unnecessary for TSN-enabled DataReaders and DataWriters. Also, retransmissions and other types of aperiodic traffic may fail to meet the schedule and configuration of the TSN Streams associated with the delivery of time-critical data.

However GAP is not just for reliability or in-order delivery. It is also used in best-efforts in situation where a sample is not relevant to a reader (e.g. because of writer-side content filtering), even if the sample is sent best-efforts.
Gaps are needed to distinguish lost samples from samples that are intentionally-skipped. If the gap is not present, the reader side will interpret non sequential sequence numbers as sample loss, impacting status variables in in the DataReader.

This issue was entered in the wrong RTF

This issue was entered in the wrong RTF. Should have been entered in DDSTSN. Refiling there....

The specification does not address whether DDS-Security can be deployed on top of TSN.
The logical assumption would be yes, but then the use of the RTPS sub-messages introduced by DDS security (e.g. SRTPS_PREFIX) should be mentioned.

This issue was entered in the wrong RTF

This issue was entered in the wrong RTF. Should have been entered in DDSTSN. Refiling there....

In 9.4.1.3.2 Grant Section, the spec states:

"A permissions [sic, should be grant] Section with a subject name that does not match the subject name given in the corresponding Authorization certificate shall be ignored."

It is not clear what algorithm should be applied to determine if two subject_names "match"; and this has interoperability implications.

A 'simple' approach would be a simple string comparison.

A 'complex' approach would be to do the following:

1) parse each subject_name as a series of name=value pairs,
2) check that all name's exist in each subject_name
3) check that for each name, the corresponding 'value' matches, using regex (for example fnmatch(), or similar) processing.

The more complex approach might be beneficial, because it could support using a 'wildcard' Common Name. For example, in the permissions file, use a Subject Name like this:

      <subject_name>/C=US/ST=CO/O=Twin Oaks Computing/CN=*.twinoakscomputing.com/[email protected]</subject_name>

Then, the Identity Cert's could be constructed with a more specific Subject Name, like "CN=participant1.twinoakscomputing.com", and it would match.

Specify format of subject name and rules for comparison

The string format of the subject name should be specified. The proposal is to follow IETF RFC 4514 (https://datatracker.ietf.org/doc/html/rfc4514#section-3), that is a ","-separated sequence of <name>=<value> pairs. For example:

"C=US, ST=CO, O=Twin Oaks, Computing, CN=*.twinoakscomputing.com/[email protected]"

The matching of subject names should check the list of names is the same and the corresponding values match using the fnmatch() function (POSIX 1003.2-1992, Section B.6)

The order of the names does not impact the matching.

Note that "," may be present in the value part. Likely we do not want to constrain this as it is generated from tools like openssl which may put those commas based on user input.
However this can be unabiguously parsed making the following assumptions.

• The character '=' is reserved. it can only appear to separate the name v. value pair.
• Whitespace surrounding the "=" is ignored/removed for the purposes of comparison
• The name can;t have whitespace. and can;' have ","
• The value starts after the '=' skipping any whistapce that immediately follows the '=' abd ectends to the last "," before the next "="

The operations
check_create_participant
check_create_datawriter
check_create_datareader
check_remote_participant
check_remote_datawriter
check_remote_datareader
check_local_datawriter_match
check_local_datareader_match

Should be called when the Qos (or the discovery XXXBuiltinTopicData) change for the one of the involved entities.

This should be added to the proper 8.4.2.9.x sections.

Indicate that AccessControl operations called on a change of Qos

When the Qos of a local DDS Entity changes the corresponding operation on the Access Control that checks thet the Participant has the necessary permissions should be called.

When the Qos of a remote DDS Entity changes the corresponding operation on the Access Control that checks that the remote Participant has the necessary permissions should be called.

The check_create_participant entry of "Table 63 - Actions undertaken..." in the case where is_access_protected is true and all topic entries in Governance have enable_read_access_control and enable_write_access_control both true specifies that check_create_participant returns false. Thus the participant can't be created and this configuration won't be usable.

If the intent of enable_read/write_access_control is to defer to the Permissions document to determine both readability and write-ability of this participant (for the given topic) it would seem like this case should be supported and allowed by check_create_participant.

As part of resolving this issue we should also address DDSSEC12-85, meaning state whether a <default> clause should always be present.

Clarify interpretation of enable_read/write_access_control

Clarify behavior as suggested in issue description

In 7.3.5 (Immutability of Publisher Partition Qos in combination with non-volatile...)

The criteria (1) is not consistent with the goal stated at the end of the section about "prevents data that was published while the DataWriter had associated a set of Partitions from being sent to DataReaders that were not matching before the Partition change and match after the Partition is changed."

To accomplish this criteria (1) should be re-stated to say this impacts if the Topic associated with the DataWriter has TopicSecurityAttributes with is_read_protected set to TRUE.

*Change wording in 7.3.5 item (1) *

Modify wording in 7.3.5 "Immutability of Publisher Partition Qos in combination with non-volatile Durability kind" item (1)
to state that this applies if the the Topic has "is_read_protected" set to true.

In the definition of the various Handshake Tokens, certain property values are specified with literal strings in the spec (such as "RSASSA-PSA-SHA256"). Since these are inserted into binary_properties, the spec should describe the encoding: is there a length prefix (like CDR string?), is there a trailing nul (like CDR string?), assume the encoding is ASCII but it would be good to specify this.

Merge with DDSSEC12-90

DDSSEC12-90 is already making similar clarifications and adds the following explanation to 7.3.3.1:

When setting the BinaryProperty_t value octet sequence from an ASCII string, the length of the sequence shall be set to the number of characters in the string, counting the NUL terminating character, and each octet in the sequene shall be set to the ASCII value of the corresponding character in the string, including the NUL terminating character.
For example, if an object the string “ECDSA-SHA256” shall result in an octet sequence value with length 13 where the first octet is 0x45 (ASCII code for ‘E’) and the last octet is 0x00.

So we can mark this issue as duplicate of DDSSEC12-90

Section 7.5.1.2.3 Mapping of Operations to the ReplyTopic Types cotntains the following IDL:

@Choice @Autoid
struct RobotControl_command_Result { 
    RobotControl_command_Out result;
};@Choice @Autoid
struct RobotControl_stop_Result { 
    RobotControl_getSpeed_Out result;
};
};@Choice @Autoid
struct RobotControl_setSpeed_Result {
      RobotControl_setSpeed_Out result;
      TooFast toofast_ex;
};
};@Choice @Autoid
struct RobotControl_getSpeed_Result {
      RobotControl_getStatus_Out result;
};

This IDL is not correct. It contains extra "};" preceding the @Choice annotations in several places. The correct IDL would be:

@Choice @Autoid
struct RobotControl_command_Result { 
    RobotControl_command_Out result;
};

@Choice @Autoid
struct RobotControl_stop_Result { 
    RobotControl_getSpeed_Out result;
};

@Choice @Autoid
struct RobotControl_setSpeed_Result {
      RobotControl_setSpeed_Out result;
      TooFast toofast_ex;
};

@Choice @Autoid
struct RobotControl_getSpeed_Result {
      RobotControl_getStatus_Out result;
};

This was entered in the wrong RTF

This issue was filed in the wrong RTF. It should have been filed on RPC over DDS 1.1 RTF. It has already been entered there. See https://issues.omg.org/browse/DDSRPC11-2.

The check_remote_participant row of Table 63 contains the text:

If the Permissions document contains a Grant for the remote
DomainParticipant and the Grant contains an allow rule on the
DomainParticipant domain_id, then the operation shall succeed and
return TRUE.

It seems like the intent is to ensure that there is some possible Action that this participant can do in the domain. That should take into account a <default>ALLOW</default> permission.

In general the <default> XML element seems to be not fully/consistently described in the section for Built-In Access Control. The xsd says it must be present, but section 9.4.1.3.2.3 says it may not be.

Merge with DDSSEC12-79

This issue impacts the same table/rules as https://issues.omg.org/browse/DDSSEC12-79

we propose to handle them toguether.

The syntax in DDS-XML containes places where an object references another object. This is done normally using an attribute with type elementNameReference defined in http://www.omg.org/spec/DDS-XML/20170301/dds-xml_domain_definitions_nonamespace.xsd

However the specification does not deny any rules/constraints on the references themselves. In fact those references must follow a precise syntax to uniquely select an element which require a full path down the containment hierarchy down to the selected element.

The specification should define this and provide some examples.

This issue was entered here in error. It was an issue for a different FTF

This issue should have been filed for http://issues.omg.org/browse/DDSXML

Therefore it should be closed here (and filed in the other FTF).

Section 7.3.7.3 defines CryptoHeader as inheriting from CryptoTransformIdentifier. However CryptoHeader is APPENDABLE and CryptoTransformIdentifier is FINAL.

This does not seem possible according to XTYPES.

Other places of the spec (section 9.5.2.3 "DDS:Crypto:AES-GCM-GMAC CryptoHeader") define it as final.

Change CryptoHeader definition in 7.3.7.3. to final

In section 7.3.7.3 "Mapping of the CryptoHeader SubmessageElement"
modify the extensibility of CryptoHeader from "APPENDABLE" to "FINAL" resulting in the following IDL:

@extensibility(FINAL)
struct CryptoHeader : CryptoTransformIdentifier  {
    // Extra plugin-specific information added below
    // PluginHeader   plugin_crypto_header_extra;
};

The specification does not state what to do when Permissions and Governance files contain "extra elements" that are not valid according to the XSD.

This is expected to occur both as a result of vendor extensions as well as due to additions in future versions of DDS Security.

Allowing these extensions/additions without breaking compatibility is important. So the spec should be clear in that they are allowed and also provide rules/guidelines on them.

Some possibilities:

• Simply state that elements that are not expected/understood should be ignored
• Same as above but provide some structure for those elements. E.g. specify that they must have a "vendorId" attribute (used to avoid collisions) and a "mustUnderstand" attribute used to force failure in some cases.
• Define an "extensions" element that has known structure (e.g. name/value pairs) which is the one used for the extensions.
• Others to be proposed.

Common approaches are described here: http://www.ibm.com/developerworks/library/x-xtendschema/
This document also discusses various approaches: https://www.xml.com/pub/a/2004/10/27/extend.html

Add mechanism to extend Governance and Permissions document

Define how the Governance and Permission documents could be extended and the rules to apply when processing the document and encountering an extension.