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@ -1,17 +1,105 @@
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# `Passing a secret to a TPM using only the EK`
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# Passing a secret to a TPM using only the public key of Endorsement Key (EK)
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This is example code to pass a secret to a system by just knowing the endorsenment key.
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This is example code to pass a secret to a system by just knowing its endorsenment key's public key.
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We will be using the current (commit 07a92e9fa75548ea102ce90b3b6182093b3f7a73 or later) master branch of https://github.com/tpm2-software/tpm2-pytss
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We will be using the current (commit 07a92e9fa75548ea102ce90b3b6182093b3f7a73 or later) master branch of https://github.com/tpm2-software/tpm2-pytss
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The terms for the systems are `client`, the system we want to pass the secret to and `server`, the system which has the secret but doesn't need a TPM.
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The terms for the systems are `client`, the system we want to pass the secret to and `server`, the system which has the secret but doesn't need a TPM.
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One assumtion that will be made is that you already have the EKpub for the remote system on the local system, and trust it.
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One assumtion that will be made is that you already have the EKpub for the remote system on the local system, and trust it.
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While we will use the EK in this guide any key accepted by ActivateCredential should work.
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While we will use the EK in this guide any key accepted by ActivateCredential should work.
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## Background
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What we want is something akin to asymmetric encryption, with the local
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system encrypting to the public key of the remote system. The local
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system would send the ciphertext to the remote system, and the remote
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system would decrypt it using its private key.
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The TPM does support plain asymmetric decryption using
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`TPM2_RSA_Decrypt()`. However, the `EK` is a [restricted
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key](/Intro/README.md#Restricted-Cryptographic-Keys), specifically a
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[restricted decryption key](/Intro/README.md#Restricted-Decryption-Keys)
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which means that `TPM2_RSA_Decrypt()` will not work.
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The TPM supports two constrained asymmetric decryption operations with
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[restricted decryption
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keys](/Intro/README.md#Restricted-Decryption-Keys):
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- [`TPM2_Import()`](/TPM-Commands/TPM2_Import.md)
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- [`TPM2_ActivateCredential()`](/TPM-Commands/TPM2_ActivateCredential.md)
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The sender sides of those two functions are, respectively:
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- [`TPM2_Duplicate()`](/TPM-Commands/TPM2_Duplicate.md)
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- [`TPM2_MakeCredential()`](/TPM-Commands/TPM2_MakeCredential.md)
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`TPM2_Duplicate()`/`TPM2_Import()` are specifically about sharing
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private key objects from one TPM to another. We won't use those here.
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[`TPM2_MakeCredential()`](/TPM-Commands/TPM2_MakeCredential.md) allows
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us to encrypt a small secret (e.g., an AES key) to a remote system's
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`EKpub`, and then the remote system can decrypt that with its `EK` using
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[`TPM2_ActivateCredential()`](/TPM-Commands/TPM2_ActivateCredential.md).
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The key background concepts here are:
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- [restricted decryption keys](/Intro/README.md#Restricted-Decryption-Keys),
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- and access controlled decryption with restricted decryption keys.
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Most importantly,
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[`TPM2_MakeCredential()`](/TPM-Commands/TPM2_MakeCredential.md) allows
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the sender to specify an authorization policy that the caller of
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[`TPM2_ActivateCredential()`](/TPM-Commands/TPM2_ActivateCredential.md)
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must meet in order for it to be willing to decrypt the ciphertext.
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> Note that `TPM2_MakeCredential()` can be implemented entirely in
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> software.
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> Note that duplicating a key that is fixed to TPMs requires using
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> `TPM2_Duplicate()` on that TPM, otherwise if the key is not fixed to
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> the TPM then `TPM2_Duplicate()` can be implemented in software.
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## Concept
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## Concept
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The concept is that the key being activated by a call to ActivateCredential on the remote system doesn't have to be generated on the TPM, as long as the public and private parts are loaded it will succeed.
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By generating a temporary key pair on the local system we can run MakeCredential with the remote system EK, name of the locally generated key and the secret.
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`TPM2_MakeCredential()` requires three inputs. Besides the target's
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`EKpub` and the small secret to send to it, `TPM2_MakeCredential()` also
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requires the [cryptographic name](/Intro/README.md#Cryptographic-Object-Naming)
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of a key object that must reside on the target system's TPM -- this is
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known as the _activation object_.
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The key insight is that the actual public key of the object named by the
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activation object name input of `TPM2_MakeCredential()` is not used at
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all. Neither does `TPM2_ActivateCredential()` use the private key of
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that object. The only things that matter about the activation object
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are that:
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a) it must exist on the target system,
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b) its cryptographic name must be the same as was used on the sender side,
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c) and that the caller of `TPM2_ActivateCredential()` must satisfy the activation object's [_authorization policy_](/Intro/README.md#Policies) (_if_ `adminWithPolicy` is set as an attribute of the activation object).
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> NOTE: The cryptographic name of an object binds the authorization
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> policy set on that object. Therefore the caller of
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> `TPM2_MakeCredential()` specifies an authorization policy that the
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> caller of `TPM2_ActivateCredential()` must meet if the
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> `adminWithPolicy` attribute is set on the activation object.
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> NOTE: Learn more about [restricted keys](/Intro/README.md#Restricted-Cryptographic-Keys),
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> [authorization policies](/Intro/README.md#Policies), and
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> user roles in our [introductory tutorial](/Intro/README.md).
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Since the private and public key parts of the activation object are not
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used and are irrelevant, they can even be fixed and published for all to
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see, even the private key.
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By using a well-known activation key we can avoid having to know the
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cryptographic name of some unique object on the remote system's TPM!
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Or we can generate a unique key but send its private part in the clear
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to the remote system.
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Thus we need only know the target system's TPM's `EKpub`.
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## server script
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## server script
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```python
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```python
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#!/usr/bin/python3
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#!/usr/bin/python3
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@ -79,6 +167,7 @@ credlob: where to save the encrypted credential generated by MakeCredential
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secret: where to save the encrypted secret generated by MakeCredential
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secret: where to save the encrypted secret generated by MakeCredential
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## client script
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## client script
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```python
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```python
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#!/usr/bin/python3
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#!/usr/bin/python3
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@ -171,5 +260,136 @@ temp-sensitive: the temp-sensitive output from the local system script
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credblob: the credblob output from the local system script
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credblob: the credblob output from the local system script
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secret: the secret output from the local system script
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secret: the secret output from the local system script
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## Example (bash)
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This example uses two bash scripts:
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- [`send-to-tpm.sh`](send-to-tpm.sh)
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- [`tpm-receive.sh`](tpm-receive.sh)
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Usage messages for those two scripts:
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```
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Usage: send-to-tpm.sh EK-PUB-FILE SECRET-FILE OUT-FILE [POLICY-CMD [ARGS [\; ...]]]
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send-to-tpm.sh -P well-known-key-name EK-PUB-FILE SECRET-FILE OUT-FILE
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Options:
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-h This help message.
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-P WKname Use the given cryptographic name binding a policy for
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recipient to meet.
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-f Overwrite OUT-FILE.
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-x Trace this script.
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```
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```
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Usage: receive.sh CIPHERTEXT-FILE OUT-FILE [POLICY-CMD [ARGS] [;] ...]
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"Activates" (decrypts) CIPHERTEXT-FILE made with TPM2_MakeCredential and
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writes the plaintext to OUT-FILE.
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The POLICY-CMD and arguments are one or more commands that must
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leave a policy digest in a file named 'policy' in the current
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directory (which will be a temporary directory).
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Options:
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-h This help message.
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-f Overwrite OUT-FILE.
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-x Trace this script.
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```
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Example (without policy, both scripts running on the same system):
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```
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: ; # NOTE: The shell prompt ($PS1) is set to ': ; ' to make it easy to
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: ; # cut-and-paste.
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: ;
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: ; # Get the EKpub:
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: ; tpm2 createek --ek-context ek.ctx --public ek.pub
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: ;
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: ; # Make a small secret:
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: ; echo hello world > secret.txt
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: ;
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: ; # Make ciphertext:
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: ; /tmp/send-to-tpm.sh -f ek.pub /tmp/secret /tmp/cipher
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: ;
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: ; # Decrypt ciphertext:
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: ; /tmp/receive.sh -f /tmp/cipher /tmp/plain
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name:
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000b9f40e7a7a85bcc39bba777b7eda5764d91a28512d91d395ca114b14621ae321e
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837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa
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certinfodata:68656c6c6f20776f726c640a
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: ;
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: ; # Show plaintext:
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: ; cat /tmp/plain
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hello world
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```
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Example (with policy, both scripts running on the same system):
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```
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: ; # NOTE: The shell prompt ($PS1) is set to ': ; ' to make it easy to
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: ; # cut-and-paste.
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: ;
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: ; # Get the EKpub:
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: ; tpm2 createek --ek-context ek.ctx --public ek.pub
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: ;
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: ; # Make a small secret:
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: ; echo hello world > secret.txt
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: ;
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: ; /tmp/send-to-tpm.sh -f ek.pub /tmp/secret /tmp/cipher \
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> tpm2 policysecret --session session.ctx \
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> --object-context endorsement -L policy \; \
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> tpm2 policycommandcode -S session.ctx -L policy \
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> TPM2_CC_ActivateCredential
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|
837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa
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|
cd9917cf18c3848c3a2e606986a066c68142f9bc2710a278287a650ca3bbf245
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: ;
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: ; /tmp/tpm-receive.sh -f /tmp/cipher /tmp/plain \
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> tpm2 policysecret --session session.ctx \
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--object-context endorsement \
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-L policy \; \
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tpm2 policycommandcode -S session.ctx -L policy \
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TPM2_CC_ActivateCredential
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|
837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa
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|
cd9917cf18c3848c3a2e606986a066c68142f9bc2710a278287a650ca3bbf245
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|
name: 000bec987554f57b9918285794542c05549aa778832be169351494066907d6d95abf
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|
837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa
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|
837197674484b3f81a90cc8d46a5d724fd52d76e06520b64f2a1da1b331469aa
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|
cd9917cf18c3848c3a2e606986a066c68142f9bc2710a278287a650ca3bbf245
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|
certinfodata:68656c6c6f20776f726c640a
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: ; cat /tmp/plain
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hello world
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: ;
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```
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You can pass policy commands to the `send-to-tpm.sh` and `tpm-receive.sh`
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commands as arguments, with multiple policy commands separated by a
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single semi-colon (quoted, to avoid evaluation by the shell):
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```bash
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|
send-to-tpm.sh ek.pub /tmp/secret /tmp/cipher \
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tpm2 policypcr -S session.ctx -l "sha256:0,1,2,3" -f $PWD/pcr.dat \
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-L policy \; \
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tpm2 policycommandcode -S session.ctx -L policy TPM2_CC_ActivateCredential
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```
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## Issues
|
## Issues
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there is no TPM based protection against replay attacks in this example
|
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- The secret sent this way has to be small: no larger than the digest
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size for the digest algorithm being used.
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If the application needs to send larger secrets, then it should
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generate an AES key and send that as the small secret, then encrypt
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the larger secret in the AES key and send that ciphertext. (But
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don't forget to also include an HMAC or MAC of the ciphertext to make
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detection of errors / tampering possible.)
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|
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- There is no protection against replay attacks in this example.
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Replay protection can be added by adding a timestamp to the secret
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data, and by using a replay cache on the remote system.
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- There is no authentication of the sender. To authenticate the sender
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simply add a digital signature of the ciphertext.
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131
Attestation/send-to-tpm.sh
Executable file
131
Attestation/send-to-tpm.sh
Executable file
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@ -0,0 +1,131 @@
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#!/bin/bash
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PROG=${0##*/}
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set -euo pipefail
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|
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|
function usage {
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((${1:-1} > 0)) && exec 1>&2
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|
cat <<EOF
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|
Usage: $PROG EK-PUB-FILE SECRET-FILE OUT-FILE
|
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|
$PROG EK-PUB-FILE SECRET-FILE OUT-FILE [POLICY-CMD [ARGS [\\; ...]]]
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$PROG -P well-known-key-name EK-PUB-FILE SECRET-FILE OUT-FILE
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|
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|
Options:
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|
|
||||||
|
-h This help message.
|
||||||
|
-P WKname Use the given cryptographic name binding a policy for
|
||||||
|
recipient to meet.
|
||||||
|
-f Overwrite OUT-FILE.
|
||||||
|
-x Trace this script.
|
||||||
|
EOF
|
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|
exit ${1:-1}
|
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|
}
|
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|
|
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|
force=false
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|
wkname=
|
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|
while getopts +:hfxP: opt; do
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|
case "$opt" in
|
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|
P) wkname=$OPTARG;;
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|
h) usage 0;;
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|
f) force=true;;
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|
x) set -vx;;
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|
*) usage;;
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|
esac
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|
done
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|
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|
shift $((OPTIND - 1))
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|
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(($# >= 3)) || usage
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|
ekpub_file=$1
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|
secret_file=$2
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|
out_file=$3
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|
shift 3
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|
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|
function err {
|
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|
echo "ERROR: $*" 1>&2
|
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|
exit 1
|
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|
}
|
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|
|
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|
[[ -f ${ekpub_file:-} ]] || usage
|
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|
[[ -f ${secret_file:-} ]] || usage
|
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|
[[ -f ${out_file:-} ]] && $force && rm -f "${out_file:-}"
|
||||||
|
[[ -f ${out_file:-} ]] && err "output file ($out_file) exists"
|
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|
|
||||||
|
# Make a temp dir and remove it when we exit:
|
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|
d=
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|
trap 'rm -rf "$d"' EXIT
|
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|
d=$(mktemp -d)
|
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|
|
||||||
|
function exec_policy {
|
||||||
|
while (($# > 0)); do
|
||||||
|
cmd=()
|
||||||
|
while (($# > 0)) && [[ $1 != ';' ]]; do
|
||||||
|
cmd+=("$1")
|
||||||
|
shift
|
||||||
|
done
|
||||||
|
(($# > 0)) && shift
|
||||||
|
# Run the policy command in the temp dir. It -or the last command- must
|
||||||
|
# leave a file there named 'policy'.
|
||||||
|
(cd "$d" && "${cmd[@]}")
|
||||||
|
done
|
||||||
|
}
|
||||||
|
|
||||||
|
function make_policyDigest {
|
||||||
|
# Start a trial session, execute the given policy commands, save the
|
||||||
|
# policyDigest.
|
||||||
|
tpm2 flushcontext --transient-object
|
||||||
|
tpm2 flushcontext --loaded-session
|
||||||
|
tpm2 startauthsession --session "${d}/session.ctx"
|
||||||
|
exec_policy "$@"
|
||||||
|
}
|
||||||
|
|
||||||
|
function wkname {
|
||||||
|
# This is the WK. It was generated with:
|
||||||
|
# openssl genpkey -genparam \
|
||||||
|
# -algorithm EC \
|
||||||
|
# -out "${d}/ecp.pem" \
|
||||||
|
# -pkeyopt ec_paramgen_curve:secp384r1 \
|
||||||
|
# -pkeyopt ec_param_enc:named_curve
|
||||||
|
# openssl genpkey -paramfile "${d}/ecp.pem"
|
||||||
|
cat > "${d}/wkpriv.pem" <<EOF
|
||||||
|
-----BEGIN PRIVATE KEY-----
|
||||||
|
MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDAlMnCWue7CfXjNLibH
|
||||||
|
PTJrsOLUcoxqU3FLWYEWMI+HuPnzcwwl7SkKN6cpf4H3oQihZANiAAQ1pw6D5QVw
|
||||||
|
vymljYVDyrUriOet8zPB/9tq9XJ7A54qsVkaVufAuEJ6GIvD4xUZ27manMosJADS
|
||||||
|
aW2TLJkwxecRh2eTwPtSx2U32M2/yHeuWRV/0juiIozefPsTAlHAi3E=
|
||||||
|
-----END PRIVATE KEY-----
|
||||||
|
EOF
|
||||||
|
|
||||||
|
tpm2 flushcontext --saved-session
|
||||||
|
|
||||||
|
# Load
|
||||||
|
attrs='decrypt|sign'
|
||||||
|
loadexternal_args=()
|
||||||
|
if (($# > 0)); then
|
||||||
|
make_policyDigest "$@" 1>&2
|
||||||
|
loadexternal_args+=(-L "${d}/policy")
|
||||||
|
attrs='adminwithpolicy|decrypt|sign'
|
||||||
|
fi
|
||||||
|
|
||||||
|
# Load the WK
|
||||||
|
tpm2 flushcontext --transient-object 1>&2
|
||||||
|
tpm2 flushcontext --loaded-session 1>&2
|
||||||
|
tpm2 loadexternal -C n \
|
||||||
|
-Gecc \
|
||||||
|
-r "${d}/wkpriv.pem" \
|
||||||
|
"${loadexternal_args[@]}" \
|
||||||
|
-a "$attrs" \
|
||||||
|
-c "${d}/wk.ctx" |
|
||||||
|
grep ^name: |
|
||||||
|
cut -d' ' -f2
|
||||||
|
}
|
||||||
|
|
||||||
|
[[ -z $wkname ]] && wkname=$(wkname "$@")
|
||||||
|
|
||||||
|
tpm2 makecredential \
|
||||||
|
--tcti "none" \
|
||||||
|
--encryption-key "${ekpub_file}" \
|
||||||
|
--name "$wkname" \
|
||||||
|
--secret "${secret_file}" \
|
||||||
|
--credential-blob "$out_file"
|
175
Attestation/tpm-receive.sh
Executable file
175
Attestation/tpm-receive.sh
Executable file
|
@ -0,0 +1,175 @@
|
||||||
|
#!/bin/bash
|
||||||
|
|
||||||
|
PROG=${0##*/}
|
||||||
|
|
||||||
|
set -euo pipefail
|
||||||
|
|
||||||
|
function usage {
|
||||||
|
echo "Usage: $PROG [OPTIONS] CIPHERTEXT-FILE OUT-FILE [POLICY-CMD [ARGS] [\; ...]]"
|
||||||
|
cat <<EOF
|
||||||
|
Usage: $PROG CIPHERTEXT-FILE OUT-FILE [POLICY-CMD [ARGS] [;] ...]
|
||||||
|
|
||||||
|
"Activates" (decrypts) CIPHERTEXT-FILE made with TPM2_MakeCredential and
|
||||||
|
writes the plaintext to OUT-FILE.
|
||||||
|
|
||||||
|
The POLICY-CMD and arguments are one or more commands that must
|
||||||
|
leave a policy digest in a file named 'policy' in the current
|
||||||
|
directory (which will be a temporary directory).
|
||||||
|
|
||||||
|
Options:
|
||||||
|
|
||||||
|
-h This help message.
|
||||||
|
-f Overwrite OUT-FILE.
|
||||||
|
-x Trace this script.
|
||||||
|
EOF
|
||||||
|
exit 1
|
||||||
|
}
|
||||||
|
|
||||||
|
force=false
|
||||||
|
verbose=false
|
||||||
|
while getopts +:hfvx opt; do
|
||||||
|
case "$opt" in
|
||||||
|
h) usage 0;;
|
||||||
|
f) force=true;;
|
||||||
|
v) verbose=true;;
|
||||||
|
x) set -vx;;
|
||||||
|
*) usage;;
|
||||||
|
esac
|
||||||
|
done
|
||||||
|
|
||||||
|
shift $((OPTIND - 1))
|
||||||
|
|
||||||
|
(($# >= 2)) || usage
|
||||||
|
ciphertext_file=$1
|
||||||
|
out_file=$2
|
||||||
|
shift 2
|
||||||
|
|
||||||
|
[[ -f ${ciphertext_file:-} ]] || usage
|
||||||
|
[[ -f ${out_file:-} ]] && $force && rm -f "$out_file"
|
||||||
|
[[ -f ${out_file:-} ]] && usage
|
||||||
|
|
||||||
|
d=
|
||||||
|
trap 'rm -rf "$d"' EXIT
|
||||||
|
d=$(mktemp -d)
|
||||||
|
|
||||||
|
function v {
|
||||||
|
if $verbose; then
|
||||||
|
printf 'Running:'
|
||||||
|
printf ' %q' "$@"
|
||||||
|
printf '\n'
|
||||||
|
fi >/dev/tty || true
|
||||||
|
if "$@"; then
|
||||||
|
$verbose && printf '(SUCCESS)\n' >/dev/tty || true
|
||||||
|
else
|
||||||
|
stat=$?
|
||||||
|
printf 'ERROR: Command exited with %d\n' $stat >/dev/tty || true
|
||||||
|
return $stat
|
||||||
|
fi
|
||||||
|
}
|
||||||
|
|
||||||
|
function exec_policy {
|
||||||
|
while (($# > 0)); do
|
||||||
|
cmd=()
|
||||||
|
while (($# > 0)) && [[ $1 != ';' ]]; do
|
||||||
|
cmd+=("$1")
|
||||||
|
shift
|
||||||
|
done
|
||||||
|
(($# > 0)) && shift
|
||||||
|
# Run the policy command in the temp dir. It -or the last command- must
|
||||||
|
# leave a file there named 'policy'.
|
||||||
|
if (v cd "$d" && v "${cmd[@]}" 1> "${d}/out" 2> "${d}/err"); then
|
||||||
|
cat "${d}/out" >/dev/tty || true
|
||||||
|
else
|
||||||
|
stat=$?
|
||||||
|
echo "ERROR: Failed to run \"${cmd[0]} ...\":"
|
||||||
|
cat "${d}/out"
|
||||||
|
cat "${d}/err" 1>&2
|
||||||
|
exit $stat
|
||||||
|
fi
|
||||||
|
done
|
||||||
|
}
|
||||||
|
|
||||||
|
function make_policyDigest {
|
||||||
|
tpm2 flushcontext --transient-object
|
||||||
|
tpm2 flushcontext --loaded-session
|
||||||
|
v tpm2 startauthsession --session "${d}/session.ctx"
|
||||||
|
exec_policy "$@"
|
||||||
|
}
|
||||||
|
|
||||||
|
# Get the EK handle:
|
||||||
|
tpm2 flushcontext --transient-object
|
||||||
|
tpm2 flushcontext --loaded-session
|
||||||
|
tpm2 createek --key-algorithm rsa \
|
||||||
|
--ek-context "${d}/ek.ctx" \
|
||||||
|
--public "${d}/ek.pub"
|
||||||
|
|
||||||
|
# Make policyDigest and load WK
|
||||||
|
attrs='decrypt|sign'
|
||||||
|
loadexternal_args=()
|
||||||
|
if (($# > 0)); then
|
||||||
|
make_policyDigest "$@"
|
||||||
|
loadexternal_args+=(-L "${d}/policy")
|
||||||
|
attrs='adminwithpolicy|decrypt|sign'
|
||||||
|
fi
|
||||||
|
|
||||||
|
rm -f "${d}/session.ctx"
|
||||||
|
|
||||||
|
# This is the WK. It was generated with:
|
||||||
|
# openssl genpkey -genparam \
|
||||||
|
# -algorithm EC \
|
||||||
|
# -out "${d}/ecp.pem" \
|
||||||
|
# -pkeyopt ec_paramgen_curve:secp384r1 \
|
||||||
|
# -pkeyopt ec_param_enc:named_curve
|
||||||
|
# openssl genpkey -paramfile "${d}/ecp.pem"
|
||||||
|
cat > "${d}/wkpriv.pem" <<EOF
|
||||||
|
-----BEGIN PRIVATE KEY-----
|
||||||
|
MIG2AgEAMBAGByqGSM49AgEGBSuBBAAiBIGeMIGbAgEBBDAlMnCWue7CfXjNLibH
|
||||||
|
PTJrsOLUcoxqU3FLWYEWMI+HuPnzcwwl7SkKN6cpf4H3oQihZANiAAQ1pw6D5QVw
|
||||||
|
vymljYVDyrUriOet8zPB/9tq9XJ7A54qsVkaVufAuEJ6GIvD4xUZ27manMosJADS
|
||||||
|
aW2TLJkwxecRh2eTwPtSx2U32M2/yHeuWRV/0juiIozefPsTAlHAi3E=
|
||||||
|
-----END PRIVATE KEY-----
|
||||||
|
EOF
|
||||||
|
|
||||||
|
# Load the WK
|
||||||
|
tpm2 flushcontext --transient-object 1>&2
|
||||||
|
tpm2 flushcontext --loaded-session 1>&2
|
||||||
|
if v tpm2 loadexternal -C n \
|
||||||
|
-Gecc \
|
||||||
|
-r "${d}/wkpriv.pem" \
|
||||||
|
"${loadexternal_args[@]}" \
|
||||||
|
-a "$attrs" \
|
||||||
|
-c "${d}/wk.ctx" > "${d}/out" 2> "${d}/err"; then
|
||||||
|
cat "${d}/out" 1>&2
|
||||||
|
else
|
||||||
|
stat=$?
|
||||||
|
echo "ERROR: Failed to load WK:" 1>&2
|
||||||
|
cat "${d}/out"
|
||||||
|
cat "${d}/err" 1>&2
|
||||||
|
exit $stat
|
||||||
|
fi
|
||||||
|
|
||||||
|
# Create empty auth session for EK
|
||||||
|
v tpm2 flushcontext --transient-object
|
||||||
|
v tpm2 flushcontext --loaded-session
|
||||||
|
v tpm2 startauthsession --session "${d}/sessionek.ctx" --policy-session
|
||||||
|
v tpm2 policysecret --session "${d}/sessionek.ctx" --object-context endorsement
|
||||||
|
|
||||||
|
activatecredential_args=()
|
||||||
|
if (($# > 0)); then
|
||||||
|
activatecredential_args+=(--credentialedkey-auth session:"${d}/session.ctx")
|
||||||
|
# Create auth session for the WK, since it has adminWithPolicy
|
||||||
|
v tpm2 flushcontext --transient-object
|
||||||
|
v tpm2 flushcontext --loaded-session
|
||||||
|
v tpm2 startauthsession --session "${d}/session.ctx" --policy-session
|
||||||
|
exec_policy "$@"
|
||||||
|
v tpm2 flushcontext --transient-object
|
||||||
|
v tpm2 flushcontext --loaded-session
|
||||||
|
fi
|
||||||
|
# Finally, ActivateCredential
|
||||||
|
$verbose && tpm2 readpublic -c "${d}/wk.ctx" | grep name:
|
||||||
|
v tpm2 activatecredential --credentialedkey-context "${d}/wk.ctx" \
|
||||||
|
"${activatecredential_args[@]}" \
|
||||||
|
--credentialkey-context "${d}/ek.ctx" \
|
||||||
|
--credentialkey-auth session:"${d}/sessionek.ctx" \
|
||||||
|
--credential-blob "$ciphertext_file" \
|
||||||
|
-o "$out_file"
|
Loading…
Reference in a new issue