October 2021 - tpm2 - Ml01.01.Org

Help implementing "OR" PCR policy using C lib

by michael.g.millsap＠intel.com

I'm implementing the sealing of a LUKS key against secure boot PCRs and am trying to enable firmware updates using Esys_PolicyOR(). I can't find any example code. I am currently doing an Esys_PolicyPCR(), followed by Esys_PolicyGetDigest() and then I seal against that digest. How would I add the PolicyOR step? Would I do an Esys_PolicyPCR() & Esys_PolicyGetDigest() for each set of PCR values, followed by a Esys_PolicyOR() and then another Esys_PolicyGetDigest() to get the final digest to seal against? What would the unseal process look like? Thanks, Mike

3 weeks, 6 days

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SAPI

by Chat Overlay Streaming

Hi there, We're now using TPM2 CLI commands like tpm2_createprimary, tpm2_load, tpm2_nvundefine and etc. to manipulate a tpm. My question is if we want to switch to the SAPI library, can we do the same things? For example, write a function using SAPI calls to implement the CLI tpm2_createprimary command. Is there any sample code or resource I can look at? Thanks, Ben

1 month

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Write My Persuasive Case Brief

by sadieblair80＠gmail.com

A case brief is an academic assignment that aims to summarize the particular case, provide background information about it, identify the legal arguments that have been made, as well as analyze the decision taken by the court. Sounds too difficult? Write an appeal by saying write my persuasive case brief https://super-essays-service.com/write-my-case-brief

1 month, 1 week

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quality essay

by jstane961＠gmail.com

Hello! I love mathematics very much, it is easy and simple for me to understand and solve problems. But now I'm writing a quality essay I'm stuck in math. I'm so ashamed! In general, I need to draw a grid of inverted cubes in orthoprojection to make my work more diverse and interesting. I can't calculate the rotation of a cube so that it is perfectly isometric. Can anyone help? I will send a photo to the post office. Is it better to just order an essay at http://quality-essay.com and not come up with a problem?

1 month, 1 week

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Maximum number of transient objects?

by Petr Gotthard

Hello, I still wonder how many transient objects (virtual handles) can I create with the tpm2-abrmd? There is TPM_PT_HR_TRANSIENT_MIN, which is said to be a minimum. An explanation from Tadeusz: This tells you what is the minimum number of persistent objects a TPM needs to support to be able to support all TPM command implemented by the given TPM chip. But then there are statements in the RM specification that: For the TPM this is a minimum, but for the RM it’s both a minimum and a maximum for the maximum number of loaded objects. (Section 3.15.3) The RM SHALL NOT allow the creation of more concurrent objects than TPM_PT_HR_TRANSIENT_MIN. (Section 3.15.12) Does this mean that for one connection the tpm2-abrmd will allow only (max) TPM_PT_HR_TRANSIENT_MIN transient objects? Because the section 3.4 then says A TAB/RM MAY enforce a maximum number of session and/or object and sequence handles per connection and MAY guarantee a minimum number of such handles per connection. Petr

1 month, 2 weeks

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Re: CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts

by Petr Gotthard

Hi Bill, >> Example 1: OpenSSL often duplicates hash sequences: To hash sequences A,B,C1 and then A,B,C2 they first hash A,B, then duplicate/fork the hash sequence and then complete the hash first for C1 and then for C2. This is a great performance optimization, but when too many dup (forks) are made, the TPM runs out of objects. > Why are we doing hashing with the TPM? If we're in an OpenSSL provider cant we just use software provided hashing routines? I see hashing is configurable, but I would imagine off be default is what you want. Do we use validation tickets or anything like that or just the resulting digest? If all we use are the digests, I would make TPM not hash and make that option a nop. Signing by a restricted signing key requires validation tickets, so the hash must be done by the TPM. The OpenSSL has a combined operation "EVP_DigestSign", which enables the tpm2 provider to hash, obtain the validation ticket and then immediately sign the hash using this ticket. This is beautiful, but it needs the TPM hashing. >> Example 2: The CMP key update needs 4 objects to operate (old client key, new client key, server key and hash sequence), but the kernel RM (tpm_space.context_tbl) allows only 3 objects. (If I am right.) > It does seem that way, but TPM commands only ever need 3 objects alive at once, so that's likely why that was chosen. Yeah, I thought this is so. > Does CMP key really need all 4 of those things in the TPM at once, because currently today that's not actually happening as abrmd is just swapping them in and out. Currently, the tpm2 provider does not do any internal resource management. If someone loads a public / private key, the provider creates a TPM object for this. This key may be used for some later TPM operation or even not used at all, for example when a pubkey is being validated against a privkey. Unfortunately, the provider cannot know in advance if and how the key being loaded will be used. (The user is free not to use the TPM provider for loading a pubkey, but if it does a TPM object is created.) Typical OpenSSL based implementations are not optimized to reduce the number of concurrently loaded keys. The code often pre-loads all keys and then uses the keys in various operations. Even though a single operation never needs more than 3 objects, the code may prepare more than 3 objects because it is going to invoke more than one operation later. > Also, doesn't CMP use public objects (x509 certs) for some of it? Yes, it does. X.509 certs also include pubkeys and CMP sometimes wants to extract a pubkey from a certificate to match it against a privkey it has. This also consumes two objects (one for the pubkey and one for the privkey) although no TPM operation can be invoked. (But it might be and we don't know, as said above.) > Are public key operations implemented in software? In tpm2-pkcs11 we implement them in software and hash in software and I have yet to have someone hit a limit but perhaps they are all using abrmd but I thought some were using in-kernel RM. Yes. Some public key operations are implemented. Applications can use only one RSA/ECC key management-- if a TPM based RSA (or ECC) key management is loaded in OpenSSL, it will be used for both sign and validate operations-- a typical OpenSSL application cannot say "do privkey in the TPM and pubkey in the default provider"; it can choose only one for both (or create two contexts, but nobody does that). This is OK because TPM can do public key operations too, but it needs more resources if the app pre-loads everything as said above. I can see 3 possible solutions how to solve the resource problem: 1) Optimize the code for resource consumption. But then the OpenSSL applications must be TPM aware, which is what I wanted to avoid. 2) Implement some more intelligent resource (less greedy) usage in the tpm2 provider itself. But this feels like re-implementing the RM elsewhere. 3) Rely on the RM (abrmd?) to swap the objects as needed and create the illusion of a much larger object space. Can the abrmd swap resources from a single user? I thought the purpose is to swap resources from multiple connections (users), but in this case there is just one greedy user. The https://github.com/tpm2-software/tpm2-abrmd README.md says: The current implementations are mostly equivalent with a few differences. But if abrmd can swap resources much better than the in-kernel RM, then I wouldn't call them "mostly equivalent". Petr

1 month, 2 weeks

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Re: CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts

by Petr Gotthard

Bill, we solved this particular issue, but I expect more resource-related troubles are yet to come. Example 1: OpenSSL often duplicates hash sequences: To hash sequences A,B,C1 and then A,B,C2 they first hash A,B, then duplicate/fork the hash sequence and then complete the hash first for C1 and then for C2. This is a great performance optimization, but when too many dup (forks) are made, the TPM runs out of objects. Example 2: The CMP key update needs 4 objects to operate (old client key, new client key, server key and hash sequence), but the kernel RM (tpm_space.context_tbl) allows only 3 objects. (If I am right.) In general, the OpenSSL code often pre-loads or caches objects, which will be used later, which causes troubles with the space-constrained TPM. I was not sure whether the tpm2-openssl provider should act as another level of a resource manager and swap the objects to simulate more space than available on the TPM hardware, or whether this is something the resource manager could/should do. It's definitely a nice problem to think about and most likely something which will need to be addressed in the tpm2-openssl 2.0 Petr ______________________________________________________________ > Od: "Roberts, William C" <william.c.roberts(a)intel.com> > Komu: "Chris Newman" <chris(a)mode51.software>, "tpm2(a)lists.01.org" <tpm2(a)lists.01.org>, "Petr Gotthard" <petr.gotthard(a)centrum.cz> > Datum: 08.10.2021 17:46 > Předmět: [tpm2] Re: CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts > Thats:tpm2_rc_decode 0x00000902 tpm:warn(2.0): out of memory for object contextsAre you running against a resource manager? You should probably either use /dev/tpmrm0 or tpm2-abrmd.You can set the TCTI via the TPM2OPENSSL_TCTI which AFAICT takes strings like tpm2-tools, so something like:"device:/dev/tpmrm0" or "abrmd". This also might be a bug, the provider is pretty new. Petr any other ideas I am missing? Bill From: Chris Newman <chris(a)mode51.software> Sent: Sunday, October 3, 2021 6:40 PM To: tpm2(a)lists.01.org <tpm2(a)lists.01.org> Subject: [tpm2] CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts Hi, I create an EK and AK using tpm2_createek, tpm2_createak and tpm2_evictcontrol to persist the AK in 0x81010002. The I use the following command with DigiCert's CMPv2 server: openssl cmp -config /opt/sdk/openssl/current/ssl/openssl.cnf -provider tpm2 -provider default -propquery ?provider=tpm2,tpm2.digest!=yes -cmd ir -server https://demo.one.digicert.com/iot/api/v1/cmp/IOT_1234 <https://demo.one.digicert.com/iot/api/v1/cmp/IOT_1234> -ref 1234 -secret pass:1234 -recipient "/CN=mode51.software" -key handle:0x81010002 -subject "/CN=TestTest" -cacertsout ./capubs.pem -certout ./cl_cert.pem -tls_used -verbosity 8 I get the following error: DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST DUP DIGEST FINAL DIGEST FREE DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST DUP WARNING:esys:src/tss2-esys/api/Esys_ContextLoad.c:279:Esys_ContextLoad_Finish() Received TPM Error ERROR:esys:src/tss2-esys/api/Esys_ContextLoad.c:93:Esys_ContextLoad() Esys Finish ErrorCode (0x00000902) DIGEST FREE DIGEST FREE DIGEST FREE CMP DEBUG: disconnected from CMP server CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts CMP error: not able to copy ctx CMP error: internal error CMP error: error sending CMP error: shutdown while in init CMP error: transfer error:request sent: IR, expected response: IP RSA FREE RAND FREE RAND FREE RAND FREE PROVIDER TEARDOWN I've tried tpm2_flushcontext -t. I recompiled tpm2-openssl with the following option and that appears to have worked around the issue: --disable-op-digest Is this what "?provider=tpm2,tpm2.digest!=yes" should effectively do? -- Chris Newman https://mode51.software <https://mode51.software> @mode51software <https://twitter.com/mode51software>

1 month, 2 weeks

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CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts

by Chris Newman

Hi, I create an EK and AK using tpm2_createek, tpm2_createak and tpm2_evictcontrol to persist the AK in 0x81010002. The I use the following command with DigiCert's CMPv2 server: openssl cmp -config /opt/sdk/openssl/current/ssl/openssl.cnf -provider tpm2 -provider default -propquery ?provider=tpm2,tpm2.digest!=yes -cmd ir -server https://demo.one.digicert.com/iot/api/v1/cmp/IOT_1234 -ref 1234 -secret pass:1234 -recipient "/CN=mode51.software" -key handle:0x81010002 -subject "/CN=TestTest" -cacertsout ./capubs.pem -certout ./cl_cert.pem -tls_used -verbosity 8 I get the following error: DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST DUP DIGEST FINAL DIGEST FREE DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST NEW DIGEST INIT DIGEST UPDATE DIGEST DUP WARNING:esys:src/tss2-esys/api/Esys_ContextLoad.c:279:Esys_ContextLoad_Finish() Received TPM Error ERROR:esys:src/tss2-esys/api/Esys_ContextLoad.c:93:Esys_ContextLoad() Esys Finish ErrorCode (0x00000902) DIGEST FREE DIGEST FREE DIGEST FREE CMP DEBUG: disconnected from CMP server *CMP error: cannot duplicate context:2306 tpm:warn(2.0): out of memory for object contexts* CMP error: not able to copy ctx CMP error: internal error CMP error: error sending CMP error: shutdown while in init CMP error: transfer error:request sent: IR, expected response: IP RSA FREE RAND FREE RAND FREE RAND FREE PROVIDER TEARDOWN I've tried tpm2_flushcontext -t. I recompiled tpm2-openssl with the following option and that appears to have worked around the issue: --disable-op-digest Is this what "?provider=tpm2,tpm2.digest!=yes" should effectively do? -- Chris Newman https://mode51.software <https://mode51.software> @mode51software <https://twitter.com/mode51software> mode51 Software Ltd is registered in England and Wales Company Number 13007792 Registered Office 3 Orchard Way, CB24 1AG, UK GPG Encryption key <https://mode51.software/downloads/chrisnewman-mode51-pub-20201111.asc>

1 month, 3 weeks

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How to decrypt a symmetric key in the TPM that was wrapped by an asymmetric key generated by that TPM

by snambakam＠gmail.com

My client host that has the TPM generates a key pair and sends the public key to the server. The server generates a symmetric key that is encrypted by the public key it received and sends the result to the client. I can do decrypt operation to retrieve the symmetric key. How to decrypt the key but keep it in the TPM for a subsequent encrypt/decrypt operation? Thanks!

1 month, 3 weeks

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TCG CodeGen Developer Challenge

by Fuchs, Andreas

HI all, I'm forwarding this email by Chloe who tried to reach the mailinglist: On behalf of the TCG Marketing Work Group, we would like to spread the word about the TCG CodeGen Developers Challenge. May we send the following information to the mailing list, please? Many thanks! “Registration for Trusted Computing Group (TCG)’s Virtual CodeGen Developer Challenge is open now! The week-long event, taking place October 18-22, 2021, will ask developers to create a functional prototype built off a TCG standard. The challenge will provide an opportunity for brilliant talents to create their works with the help of TCG mentors, who will be virtually available throughout the event, while also experiencing the unforgettable thrill of coming together with peers who share the same passion for digital technology and innovation. Competing developers have the chance to win up to US$5,000. The theme of the challenge will be “Pervasive Security and Application of TCG standards in software and hardware development”. Participants will have the opportunity to create solutions that can make an impact for the security community, as well as SW and HW developers seeking to integrate security into their platforms. The challenge is open to both teams and individuals, and whoever impresses the judges most will be awarded. The event is free and open to non-TCG members only, as well as individuals from TCG member companies who have not had an active member login to the technical Work Groups. Registration deadline for the challenge is Monday, October 11, 2021. Register at: https://bit.ly/3FnRT9u For more information on how to get involved, please visit the TCG website. An overview video about participation and the prizes that are up for grabs is also available on YouTube.” Kind regards, Chloe Groom PR Consultant PROACTIVE INTERNATIONAL PR OFFICE: +44 (0)1636 704888 MOBILE: +44 (0)7384254585 TWITTER: @Proactive_PR<http://twitter.com/#!/Proactive_PR> www.proactive-pr.com<http://www.proactive-pr.com/>

1 month, 3 weeks

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tpm2 October 2021