Attestation Client

The Attestation Client implements the Platform Trust Services (PTS) based on a Trusted Platform Module (TPM) and fetches the Boot Event Log and the corresponding final state of the Platform Configuration Registers (PCRs) where all the individual event hashes have been extended to during the pre-boot and boot phases.

On a Linux platform an attacker with root privileges might be able to change the Boot Event Log usually stored in the binary file

/sys/kernel/security/tpm0/binary_bios_measurements

but the PCR registers stored in the protected RAM of the TPM device cannot be tampered with. The TPM 2.0 certifies the correctness of the final PCR values by signing a hash over them using its Attestation Key (AK) securely stored in the TPM 2.0.

Attestation IMC

The Attestation IMC implements the over-engineered, feature-laden TCG Attestation PTS Protocol: Binding to TNC IF-M v1.0, an extension to the PA-TNC (TCG TNC IF-M) measurement protocol. It allows to collect BIOS events and certify the measurements based on the local TPM 2.0.

Attestation Server >

Plugin Configuration

For Remote Attestation, the OS IMC and the Attestation IMC have to be enabled in the /etc/tnc_config configuration file

#IMC-Configuration

IMC "OS"           /usr/lib/ipsec/imcvs/imc-os.so
IMC "Attestation"  /usr/lib/ipsec/imcvs/imc-attestation.so

These two Integrity Measurement Collectors have to be built beforehand with the ./configure options

--enable-imc-os --enable-imc-attestation

In the imc-os and imc-attestation subsections of strongswan.conf some parameters have to be configured. As a minimum the following entries are needed

libimcv {
  plugins {
    imc-os {
      device_handle = 0x81010003
    }
    imc-attestation {
      aik_handle = 0x81010003
    }
  }
}

Both the device_handle and aik_handle point to an RSA or ECC Attestation Key (AK) stored in the TPM 2.0. This means that the keyid of the AK public key is used as a strong hardware ID of the endpoint and the final state of the PCRs after the boot measurements will be signed by the AK private key. As an alternative to aik_handle, the aik_cert option can be chosen to specify the path to an X.509 certificate containing the AK public key.

When the charon daemon starts up, it establishes a connection to the TPM 2.0 device

00[DMN] Starting IKE charon daemon (strongSwan 5.9.7, Linux 5.13.0-44-generic, x86_64)
00[PTS] TPM 2.0 - "/dev/tpmrm0" in-kernel resource manager is present
00[PTS] TPM 2.0 - "libtss2-tcti-device.so.0" successfully loaded

The OS IMC and Attestaton IMC are dynamically loaded and subscribe to the PA-TNC subtypes IETF/Operating System and TCG/PTS, respectively

00[TNC] loading IMCs from '/etc/tnc_config'
00[TNC] added IETF attributes
00[TNC] added ITA-HSR attributes
00[TNC] added PWG attributes
00[TNC] added TCG attributes
00[PTS] added TCG functional component namespace
00[PTS] added ITA-HSR functional component namespace
00[PTS] added ITA-HSR functional component 'Trusted GRUB Boot Loader'
00[PTS] added ITA-HSR functional component 'Trusted Boot'
00[PTS] added ITA-HSR functional component 'Linux IMA'
00[LIB] libimcv initialized
00[IMC] IMC 1 "OS" initialized
00[IMC] processing "/etc/os-release" file
00[IMC] operating system type is 'Ubuntu'
00[IMC] operating system name is 'Ubuntu'
00[IMC] operating system version is '20.04 x86_64'
00[TNC] IMC 1 supports 1 message type: 'IETF/Operating System' 0x000000/0x00000001
00[TNC] IMC 1 "OS" loaded from '/usr/lib/ipsec/imcvs/imc-os.so'
00[IMC] IMC 2 "Attestation" initialized
00[PTS]   mandatory PTS measurement algorithm HASH_SHA1[openssl] available
00[PTS]   mandatory PTS measurement algorithm HASH_SHA2_256[openssl] available
00[PTS]   optional  PTS measurement algorithm HASH_SHA2_384[openssl] available
00[PTS]   optional  PTS measurement algorithm HASH_SHA2_512[openssl] available
00[PTS]   optional  PTS DH group MODP_2048[openssl] available
00[PTS]   optional  PTS DH group MODP_1536[openssl] available
00[PTS]   optional  PTS DH group MODP_1024[openssl] available
00[PTS]   mandatory PTS DH group ECP_256[openssl] available
00[PTS]   optional  PTS DH group ECP_384[openssl] available
00[TNC] IMC 2 supports 1 message type: 'TCG/PTS' 0x005597/0x00000001
00[TNC] IMC 2 "ATTESTATION" loaded from '/usr/lib/ipsec/imcvs/imc-attestation.so'

Attestation Server >

VPN Configuration

The VPN configuration choses for this example is the same as for the general TNC client but just uses different client and server identities. For reasons of brevity we will omit the PT-EAP and IKEv2 EAP transport layers. Authentication is based on a TLS client certificate.

Attestation Server >

PB-TNC Connection

The PB-TNC (TCG TNC IF-TNCCS 2.0) Connection ID 1 is assigned to the connection by the TNC client and a new state is created for both the OS IMC and the Attestation IMC

09[TNC] assigned TNCCS Connection ID 1
09[IMC] IMC 1 "OS" created a state for IF-TNCCS 2.0 Connection ID 1: +long +excl -soh
09[IMC]   over IF-T for Tunneled EAP 2.0 with maximum PA-TNC message size of 32722 bytes
09[IMC] IMC 2 "Attestation" created a state for IF-TNCCS 2.0 Connection ID 1: +long +excl -soh
09[IMC]   over IF-T for Tunneled EAP 2.0 with maximum PA-TNC message size of 32722 bytes
09[IMC] IMC 1 "OS" changed state of Connection ID 1 to 'Handshake'
09[IMC] IMC 2 "Attestation" changed state of Connection ID 1 to 'Handshake'

Attestation Server >

OS Information

The OS IMC gathers information on the operating system and creates seven PA-TNC attributes and puts them in a PA-TNC message of the standard subtype Operating System

09[IMC] operating system numeric version is 20.4
09[IMC] last boot: May 31 08:26:18 UTC 2022, 12009 s ago
09[IMC] IPv4 forwarding is enabled
09[IMC] factory default password is disabled
09[IMC] device ID is 732c769e8d1b2efef8b64d5ae83f84d129733fdd
09[TNC] creating PA-TNC message with ID 0xa8ddde49
09[TNC] creating PA-TNC attribute type 'IETF/Product Information' 0x000000/0x00000002
09[TNC] creating PA-TNC attribute type 'IETF/String Version' 0x000000/0x00000004
09[TNC] creating PA-TNC attribute type 'IETF/Numeric Version' 0x000000/0x00000003
09[TNC] creating PA-TNC attribute type 'IETF/Operational Status' 0x000000/0x00000005
09[TNC] creating PA-TNC attribute type 'IETF/Forwarding Enabled' 0x000000/0x0000000b
09[TNC] creating PA-TNC attribute type 'IETF/Factory Default Password Enabled' 0x000000/0x0000000c
09[TNC] creating PA-TNC attribute type 'ITA-HSR/Device ID' 0x00902a/0x00000008
09[TNC] creating PB-PA message type 'IETF/Operating System' 0x000000/0x00000001

The PA-TNC message is sent in a TNC Client Data batch to the TNC server

09[TNC] PB-TNC state transition from 'Init' to 'Server Working'
09[TNC] creating PB-TNC CDATA batch
09[TNC] adding IETF/PB-Language-Preference message
09[TNC] adding IETF/PB-PA message
09[TNC] sending PB-TNC CDATA batch (269 bytes) for Connection ID 1

Attestation Client >

PDP-Referral

The TNC client receives a PB-TNC PDP-Referral payload defined in the TGC namespace and two PA-TNC messages in a PB-TNC Server Data batch

10[TNC] received TNCCS batch (274 bytes)
10[TNC] TNC client is handling inbound connection
10[TNC] processing PB-TNC SDATA batch for Connection ID 1
10[TNC] PB-TNC state transition from 'Server Working' to 'Client Working'
10[TNC] processing TCG/PB-PDP-Referral message (41 bytes)
10[TNC] processing IETF/PB-PA message (141 bytes)
10[TNC] processing IETF/PB-PA message (84 bytes)

In the PB-TNC PDP-Referral payload, the TNC server forwards the hostname of the Policy Decision Point (PDP) and the TCP port through which the PDP will be reachable via PT-TLS transport after the IPsec connection has been successfully established.

10[TNC] PDP server 'edu.strongsec.com' is listening on port 271

Thus after the endpoint has connected to the internal network via VPN, continuous health measurements would be possible. This dynamic switch-over from PT-EAP to PT-TLS transport of the PB-TNC connection hasn’t been implemented yet, though.

OS Assessment Result

The first PA-TNC message of standard subtype Operating System is handled by the OS IMC and contains the standard Assessment Result and Remediation Instructions attributes

10[TNC] handling PB-PA message type 'IETF/Operating System' 0x000000/0x00000001
10[IMC] IMC 1 "OS" received message for Connection ID 1 from IMV 1
10[TNC] processing PA-TNC message with ID 0xc82bacd2
10[TNC] processing PA-TNC attribute type 'IETF/Assessment Result' 0x000000/0x00000009
10[TNC] processing PA-TNC attribute type 'IETF/Remediation Instructions' 0x000000/0x0000000a
10[IMC] ***** assessment of IMC 1 "OS" from IMV 1 *****
10[IMC] assessment result is 'don't know'
10[IMC] remediation string: [en]
10[IMC] IP Packet Forwarding
10[IMC]   Please disable the forwarding of IP packets
10[IMC] ***** end of assessment *****

Attestation Server >

PTS Configuration

The second PA-TNC message of subtype PTS defined in the TCG namespace is handled by the Attestation IMC and contains the following three attributes defined in the TCG namespace

- Segmentation Contract Request
- Request PTS Protocol Capabilities
- PTS Measurement Algorithm Request

Since the local TPM 2.0 only supports SHA1 and SHA256 PCR banks, the PTS measurement algorithm is set to SHA2_256

10[TNC] handling PB-PA message type 'TCG/PTS' 0x005597/0x00000001
10[IMC] IMC 2 "Attestation" received message for Connection ID 1 from IMV 2
10[TNC] processing PA-TNC message with ID 0x0c1897a0
10[TNC] processing PA-TNC attribute type 'TCG/Segmentation Contract Request' 0x005597/0x00000021
10[TNC] processing PA-TNC attribute type 'TCG/Request PTS Protocol Capabilities' 0x005597/0x01000000
10[TNC] processing PA-TNC attribute type 'TCG/PTS Measurement Algorithm Request' 0x005597/0x06000000
10[IMC] IMC 2 received a segmentation contract request from IMV 2 for PA message type 'TCG/PTS' 0x005597/0x00000001
10[IMC]   no message size limit, maximum segment size of 65466 bytes
10[IMC]   lowered maximum segment size to 32698 bytes
10[PTS] supported PTS protocol capabilities: .VDT.
10[PTS] selected PTS measurement algorithm is HASH_SHA2_256

As a response the following three attributes defined in the TCG namespace

- Segmentation Contract Response
- PTS Protocol Capabilities
- PTS Measurement Algorithm

are put into a PA-TNC message of subtype PTS defined in the TCG namespace

10[TNC] creating PA-TNC message with ID 0x056d62cb
10[TNC] creating PA-TNC attribute type 'TCG/Segmentation Contract Response' 0x005597/0x00000022
10[TNC] creating PA-TNC attribute type 'TCG/PTS Protocol Capabilities' 0x005597/0x02000000
10[TNC] creating PA-TNC attribute type 'TCG/PTS Measurement Algorithm' 0x005597/0x07000000
10[TNC] creating PB-PA message type 'TCG/PTS' 0x005597/0x00000001

The PA-TNC message is sent in a TNC Client Data batch to the TNC server

10[TNC] TNC client is handling outbound connection
10[TNC] PB-TNC state transition from 'Client Working' to 'Server Working'
10[TNC] creating PB-TNC CDATA batch
10[TNC] adding IETF/PB-PA message
10[TNC] sending PB-TNC CDATA batch (92 bytes) for Connection ID 1

The TNC client receives a PB-TNC Server Data batch containing a PA-TNC message

05[TNC] received TNCCS batch (56 bytes)
05[TNC] TNC client is handling inbound connection
05[TNC] processing PB-TNC SDATA batch for Connection ID 1
05[TNC] PB-TNC state transition from 'Server Working' to 'Client Working'
05[TNC] processing IETF/PB-PA message (48 bytes)

The PA-TNC message of subtype PTS defined in the TCG namespace contains a DH Nonce Parameters Request. The ECP_256 Diffie-Hellman group and a nonce length of 20 bytes is chosen

05[TNC] handling PB-PA message type 'TCG/PTS' 0x005597/0x00000001
05[IMC] IMC 2 "Attestation" received message for Connection ID 1 from IMV 2
05[TNC] processing PA-TNC message with ID 0x87e01f73
05[TNC] processing PA-TNC attribute type 'TCG/DH Nonce Parameters Request' 0x005597/0x03000000
05[PTS] selected PTS DH group is ECP_256
05[PTS] nonce length is 20

The DH Nonce Parameters Response is put into a PA-TNC message of subtype PTS defined in the TCG namespace

05[TNC] creating PA-TNC message with ID 0x9b6ae702
05[TNC] creating PA-TNC attribute type 'TCG/DH Nonce Parameters Response' 0x005597/0x04000000
05[TNC] creating PB-PA message type 'TCG/PTS' 0x005597/0x00000001

The PA-TNC message is sent in a TNC Client Data batch to the TNC server

05[TNC] TNC client is handling outbound connection
05[TNC] PB-TNC state transition from 'Client Working' to 'Server Working'
05[TNC] creating PB-TNC CDATA batch
05[TNC] adding IETF/PB-PA message
05[TNC] sending PB-TNC CDATA batch (144 bytes) for Connection ID 1

The TNC client receives a PB-TNC Server Data batch containing a PA-TNC message

10[TNC] received TNCCS batch (172 bytes)
10[TNC] TNC client is handling inbound connection
10[TNC] processing PB-TNC SDATA batch for Connection ID 1
10[TNC] PB-TNC state transition from 'Server Working' to 'Client Working'
10[TNC] processing IETF/PB-PA message (164 bytes)

The PA-TNC message of subtype PTS defined in the TCG namespace contains the following three attributes defined in the TCG namespace

- DH Nonce Finish
- Get TPM Version Information
- Get Attestation Identity Key

10[TNC] handling PB-PA message type 'TCG/PTS' 0x005597/0x00000001
10[IMC] IMC 2 "Attestation" received message for Connection ID 1 from IMV 2
10[TNC] processing PA-TNC message with ID 0xfbdd9494
10[TNC] processing PA-TNC attribute type 'TCG/DH Nonce Finish' 0x005597/0x05000000
10[TNC] processing PA-TNC attribute type 'TCG/Get TPM Version Information' 0x005597/0x08000000
10[TNC] processing PA-TNC attribute type 'TCG/Get Attestation Identity Key' 0x005597/0x0d000000
10[PTS] selected DH hash algorithm is HASH_SHA2_256

The TPM Version Information and the Attestation Identity Key attributes, both defined in the TCG namespace are inserted into a PA-TNC message of subtype PTS defined in the TCG namespace

10[TNC] creating PA-TNC message with ID 0x436bed34
10[TNC] creating PA-TNC attribute type 'TCG/TPM Version Information' 0x005597/0x09000000
10[TNC] creating PA-TNC attribute type 'TCG/Attestation Identity Key' 0x005597/0x0e000000
10[TNC] creating PB-PA message type 'TCG/PTS' 0x005597/0x00000001

The PA-TNC message is sent in a TNC Client Data batch to the TNC server

10[TNC] TNC client is handling outbound connection
10[TNC] PB-TNC state transition from 'Client Working' to 'Server Working'
10[TNC] creating PB-TNC CDATA batch
10[TNC] adding IETF/PB-PA message
10[TNC] sending PB-TNC CDATA batch (172 bytes) for Connection ID 1

Attestation Server >

Boot Event Measurements

The TNC client receives a PB-TNC Server Data batch containing a PA-TNC message

05[TNC] received TNCCS batch (93 bytes)
05[TNC] TNC client is handling inbound connection
05[TNC] processing PB-TNC SDATA batch for Connection ID 1
05[TNC] PB-TNC state transition from 'Server Working' to 'Client Working'
05[TNC] processing IETF/PB-PA message (85 bytes)

The PA-TNC message of subtype PTS defined in the TCG namespace contains three attributes:

Get Symlinks defined in the ITA-HSR namespace:
Request a list of symbolic links created by the operating system due to UsrMerge (eg. /bin → /usr/bin).
Request Functional Component Evidence defined in the TCG namespace:
BIOS pre-boot evidence is requested.
Generate Attestation Evidence definedd in the TDG namespace:
Generate a TPM Quote Signature over the final state of the PCR registers involved in the evidence measurement.

05[TNC] handling PB-PA message type 'TCG/PTS' 0x005597/0x00000001
05[IMC] IMC 2 "Attestation" received message for Connection ID 1 from IMV 2
05[TNC] processing PA-TNC message with ID 0xcf126135
05[TNC] processing PA-TNC attribute type 'ITA-HSR/Get Symlinks' 0x00902a/0x00000009
05[TNC] processing PA-TNC attribute type 'TCG/Request Functional Component Evidence' 0x005597/0x00100000
05[TNC] processing PA-TNC attribute type 'TCG/Generate Attestation Evidence' 0x005597/0x00200000
05[IMC] evidence requested for 1 functional components
05[PTS] TPM 2.0 - locality indicator set to 3

The Boot Events log containing 136 entries and the corresponding PCR event hashes are extracted

05[PTS] loaded bios measurements '/sys/kernel/security/tpm0/binary_bios_measurements' (136 entries)

The final state of the PCRs 0..9 and 14 are concatenaded into a PCR Composite value, hashed into a digest and then signed together with additional system information into a TPM Quote Signature

05[PTS] PCR values hashed into PCR Composite:
05[PTS] PCR  0 06:15:6c:e6:46:85:9e:e3:81:09:57:54:9a:18:4b:7a:2e:a6:c6:c0:4f:3d:db:8a:2c:d3:a3:67:f4:93:16:71  ok
05[PTS] PCR  1 6c:b0:42:07:6e:c2:b8:67:a9:2b:cb:8e:12:f9:14:d6:4a:06:e2:9b:a1:08:0c:e4:e0:27:55:c0:21:23:6c:81  ok
05[PTS] PCR  2 30:3b:09:87:95:4c:d0:9c:a1:78:b8:6b:dd:60:55:40:f4:00:40:e8:e6:42:bd:11:73:ac:45:bc:9b:36:a3:49  ok
05[PTS] PCR  3 3d:45:8c:fe:55:cc:03:ea:1f:44:3f:15:62:be:ec:8d:f5:1c:75:e1:4a:9f:cf:9a:72:34:a1:3f:19:8e:79:69  ok
05[PTS] PCR  4 a3:1d:bf:9d:3b:ce:32:03:f2:54:59:8d:69:35:1d:8e:4b:7e:1b:54:cd:43:3d:1c:71:07:92:52:24:6a:ec:ef  ok
05[PTS] PCR  5 bb:49:6d:97:1f:ab:ac:31:bc:4d:1c:a2:f2:ea:f7:c0:82:f3:e9:3c:25:6f:07:93:e0:cf:67:14:fd:36:40:4d  ok
05[PTS] PCR  6 3d:45:8c:fe:55:cc:03:ea:1f:44:3f:15:62:be:ec:8d:f5:1c:75:e1:4a:9f:cf:9a:72:34:a1:3f:19:8e:79:69  ok
05[PTS] PCR  7 44:6f:7a:67:d5:78:b2:f9:47:c4:e1:12:f7:69:96:e7:e3:67:d2:74:af:af:be:77:89:94:c4:1a:4b:67:bc:fe  ok
05[PTS] PCR  8 36:77:2c:b7:7b:34:c1:bc:dc:41:6e:3c:c0:50:e7:26:7b:64:c2:91:28:12:9b:6a:3a:13:8a:74:c6:58:73:ad  ok
05[PTS] PCR  9 e2:09:7c:e2:17:04:a8:46:b3:55:3f:24:df:4e:57:26:f1:b9:86:dc:31:c3:11:b8:30:28:8d:86:00:21:ee:57  ok
05[PTS] PCR 14 e3:99:1b:7d:dd:47:be:7e:92:72:6a:83:2d:68:74:c5:34:9b:52:b7:89:fa:0d:b8:b5:58:c6:9f:ea:29:57:4e  ok
05[PTS] PCR Composite digest: => 32 bytes @ 0x7f1858b57bf3
05[PTS]    0: 29 6C 1D BC 8B F0 3D A1 AD 87 AC 08 45 34 78 64  )l....=.....E4xd
05[PTS]   16: 78 EE 63 92 1B D0 E5 E2 C8 54 AB 4E A7 7D 53 E6  x.c......T.N.}S.
05[PTS] TPM Quote Info: => 145 bytes @ 0x7f1858b57b82
05[PTS]    0: FF 54 43 47 80 18 00 22 00 0B BD E2 F1 F3 E7 B6  .TCG..."........
05[PTS]   16: 0C A6 6D 93 1C EC AC 7D 25 B4 69 F0 E3 9E 96 9D  ..m....}%.i.....
05[PTS]   32: 3D B8 A8 79 89 FB E2 C1 9B C5 00 20 7E 42 B5 09  =..y....... ~B..
05[PTS]   48: 42 91 35 72 87 1A 47 61 8F FF F5 C0 FE CD 4D A7  B.5r..Ga......M.
05[PTS]   64: AE 2C 98 F0 A9 81 F9 B7 F7 C4 27 19 00 00 00 00  .,........'.....
05[PTS]   80: 5F A7 4E 12 00 00 01 13 00 00 00 00 01 00 01 01  _.N.............
05[PTS]   96: 02 00 00 00 00 00 00 00 01 00 0B 03 FF 43 00 00  .............C..
05[PTS]  112: 20 29 6C 1D BC 8B F0 3D A1 AD 87 AC 08 45 34 78   )l....=.....E4x
05[PTS]  128: 64 78 EE 63 92 1B D0 E5 E2 C8 54 AB 4E A7 7D 53  dx.c......T.N.}S
05[PTS]  144: E6                                               .
05[PTS] qualifiedSigner: => 34 bytes @ 0x7f1858b57b8a
05[PTS]    0: 00 0B BD E2 F1 F3 E7 B6 0C A6 6D 93 1C EC AC 7D  ..........m....}
05[PTS]   16: 25 B4 69 F0 E3 9E 96 9D 3D B8 A8 79 89 FB E2 C1  %.i.....=..y....
05[PTS]   32: 9B C5                                            ..
05[PTS] extraData: => 32 bytes @ 0x7f1858b57bae
05[PTS]    0: 7E 42 B5 09 42 91 35 72 87 1A 47 61 8F FF F5 C0  ~B..B.5r..Ga....
05[PTS]   16: FE CD 4D A7 AE 2C 98 F0 A9 81 F9 B7 F7 C4 27 19  ..M..,........'.
05[PTS] clockInfo: => 17 bytes @ 0x7f1858b57bce
05[PTS]    0: 00 00 00 00 5F A7 4E 12 00 00 01 13 00 00 00 00  ...._.N.........
05[PTS]   16: 01                                               .
05[PTS] firmwareVersion: => 8 bytes @ 0x7f1858b57bdf
05[PTS]    0: 00 01 01 02 00 00 00 00                          ........
05[PTS] pcrSelect: => 10 bytes @ 0x7f1858b57be7
05[PTS]    0: 00 00 00 01 00 0B 03 FF 43 00                    ........C.
05[PTS] PCR digest algorithm is SHA256
05[PTS] TPM Quote Signature: => 64 bytes @ 0x7f18400063c0
05[PTS]    0: E6 6D 59 65 48 EB 08 E7 94 E3 62 CB 18 43 D8 4A  .mYeH.....b..C.J
05[PTS]   16: 93 CA 19 27 D7 43 D9 6B 34 BE 4A 13 93 96 15 68  ...'.C.k4.J....h
05[PTS]   32: 29 93 67 C2 77 60 57 80 89 AA 69 04 E5 0A DA 75  ).g.w`W...i....u
05[PTS]   48: EC BF 84 83 1B 5F FD 9F F6 7E 4D 65 D9 82 21 31  ....._...~Me..!1

The Symlinks attribute defined in the ITA-HSR namespace, 136 Simple Component Evidence attributes plus the Simple Evidence Final attribute defined in the TCG namespace are inserted into a PA-TNC message of subtype PTS defined in the TCG namespace

05[TNC] creating PA-TNC message with ID 0x23ebec16
05[TNC] creating PA-TNC attribute type 'ITA-HSR/Symlinks' 0x00902a/0x0000000a
05[TNC] creating PA-TNC attribute type 'TCG/Simple Component Evidence' 0x005597/0x00300000
05[TNC] creating PA-TNC attribute type 'TCG/Simple Component Evidence' 0x005597/0x00300000
        ...
05[TNC] creating PA-TNC attribute type 'TCG/Simple Component Evidence' 0x005597/0x00300000
05[TNC] creating PA-TNC attribute type 'TCG/Simple Component Evidence' 0x005597/0x00300000
05[TNC] creating PA-TNC attribute type 'TCG/Simple Evidence Final' 0x005597/0x00400000
05[TNC] creating PB-PA message type 'TCG/PTS' 0x005597/0x00000001

The PA-TNC message is sent in a TNC Client Data batch to the TNC server

05[TNC] TNC client is handling outbound connection
05[TNC] PB-TNC state transition from 'Client Working' to 'Server Working'
05[TNC] creating PB-TNC CDATA batch
05[TNC] adding IETF/PB-PA message
05[TNC] sending PB-TNC CDATA batch (11789 bytes) for Connection ID 1

Attestation Server >

TNC Assessment Result

The TNC client receives a PB-TNC Result batch containing a PA-TNC message as well as both a PB-TNC Assessment-Result and a PB-TNC Access-Recommendation payload

05[TNC] received TNCCS batch (88 bytes)
05[TNC] TNC client is handling inbound connection
05[TNC] processing PB-TNC RESULT batch for Connection ID 1
05[TNC] PB-TNC state transition from 'Server Working' to 'Decided'
05[TNC] processing IETF/PB-PA message (48 bytes)
05[TNC] processing IETF/PB-Assessment-Result message (16 bytes)
05[TNC] processing IETF/PB-Access-Recommendation message (16 bytes)

The Assessment Result attribute received in the PA-TNC message of subtype PTS defined in the TCG namespace as well as the overall PB-TNC assessment says compliant and the recommendation is Access Allowed

05[TNC] handling PB-PA message type 'TCG/PTS' 0x005597/0x00000001
05[IMC] IMC 2 "Attestation" received message for Connection ID 1 from IMV 2
05[TNC] processing PA-TNC message with ID 0x6d4576ee
05[TNC] processing PA-TNC attribute type 'IETF/Assessment Result' 0x000000/0x00000009
05[IMC] ***** assessment of IMC 2 "Attestation" from IMV 2 *****
05[IMC] assessment result is 'compliant'
05[IMC] ***** end of assessment *****
05[TNC] PB-TNC assessment result is 'compliant'
05[TNC] PB-TNC access recommendation is 'Access Allowed'
05[IMC] IMC 1 "OS" changed state of Connection ID 1 to 'Allowed'
05[IMC] IMC 2 "Attestation" changed state of Connection ID 1 to 'Allowed'

A PB-TNC Close batch is sent to the TNC server

05[TNC] TNC client is handling outbound connection
05[TNC] PB-TNC state transition from 'Decided' to 'End'
05[TNC] creating PB-TNC CLOSE batch
05[TNC] sending PB-TNC CLOSE batch (8 bytes) for Connection ID 1

Attestation Server >

IKEv2 Authentication Success

An EAP-SUCCESS message is received from the EAP server. The EAP client authenticates itself via an IKEv2 AUTH payload based on the MSK (Master Session Key) derived from the EAP-TTLS session

10[NET] received packet: from 10.10.0.150[4500] to 10.10.1.52[4500] (80 bytes)
10[ENC] parsed IKE_AUTH response 25 [ EAP/SUCC ]
10[IKE] EAP method EAP_TTLS succeeded, MSK established
10[IKE] authentication of 'mijas.strongsec.com' (myself) with EAP
10[ENC] generating IKE_AUTH request 26 [ AUTH ]
10[NET] sending packet: from 10.10.1.52[4500] to 10.10.0.150[4500] (112 bytes)

The IKEv2 server in turn authenticates itself again via an AUTH payload depending on the EAP-TTLS MSK as well. The OS IMC and Attestation IMC states as well as the PB-TNC connection are deleted

01[NET] received packet: from 10.10.0.150[4500] to 10.10.1.52[4500] (272 bytes)
01[ENC] parsed IKE_AUTH response 26 [ AUTH CPRP(ADDR DNS) SA TSi TSr N(AUTH_LFT) N(MOBIKE_SUP) N(ADD_6_ADDR) ]
01[IKE] authentication of 'vpn.strongswan.org' with EAP successful
01[TNC] TODO: setup PT-TLS connection to edu.strongsec.com:271
01[IMC] IMC 1 "OS" deleted the state of Connection ID 1
01[IMC] IMC 2 "Attestation" deleted the state of Connection ID 1
01[TNC] removed TNCCS Connection ID 1

The IKEv2 connection has been successfully established.

01[IKE] IKE_SA tnc[1] established between 10.10.1.52[mijas.strongsec.com]...10.10.0.150[vpn.strongswan.org]
01[IKE] scheduling reauthentication in 10136s
01[IKE] maximum IKE_SA lifetime 11216s
01[IKE] installing DNS server 10.10.0.1 to /etc/resolv.conf
01[IKE] installing new virtual IP 10.10.1.65
01[IKE] CHILD_SA tnc{1} established with SPIs cbc81685_i ce4c682b_o and TS 10.10.1.65/32 == 10.10.0.150/32

Attestation Server >