The tpm2-tss-engine project implements a cryptographic engine for OpenSSL for Trusted Platform Module (TPM 2.0) using the tpm2-tss software stack that follows the Trusted Computing Groups (TCG) TPM Software Stack (TSS 2.0). It uses the Enhanced System API (ESAPI) interface of the TSS 2.0 for downwards communication. It supports RSA decryption and signatures as well as ECDSA signatures.
The keys used by this engine are all located underneath an ECC restricted primary storage decryption key. This key is created on each invocation (since ECC key creation is faster than RSA's). Thus, no persistent SRK key need to be predeployed.
The authorization value for the storage hierarchie (the owner password) is assumed to be clear (of zero length).
The RSA keys are created with the ability to sign as well as to decrypt. This allows all RSA keys to be used for either operation. Note: The TPM's RSA sign operation will enforce tagging payloads with an ASN.1 encoded identifier of the used hash algorithm. This is incompatible with OpelSSL's RSA interface structures. Thus, the TPM2_RSA_Decrypt method is also used for signing operations which also requires decrypt capabilities to be activated for this key.
The ECDSA keys are created as ECDSA keys with the ability to perform signature operations.
Instructions to build and install tpm2-tss are available in the INSTALL file.
In order to use this engine without make install for testing call:
export LD_LIBRAY_PATH=${TPM2TSS}/src/tss2-{tcti,mu,sys,esys}/.libs:${PWD}/.libs
export OPENSSL_ENGINES=${PWD}/.libs
export PATH=${PWD}:${PATH}
export PKG_CONFIG_PATH=$PWD/../tpm2-tss/lib
./bootstrap
./configure \
CFLAGS="-I$PWD/../tpm2-tss/include" \
LDFLAGS="-L$PWD/../tpm2-tss/src/tss2-{esys,sys,mu,tcti}/.libs"
make
tpm_server
make check
make check will use any available TPM (including /dev/tpm0, /dev/tpmrm0) at this moment, until ESAPI allows runtime configuration of TCTI.
PRECONDITION: The owner password of the TPM must be set to zero.
Engine informations can be retrieved using
openssl engine -t -c tpm2tss
A set of 10 random bytes can be retrieved using
openssl rand -engine tpm2tss -hex 10
engine "tpm2tss" set.
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-default.so
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-tabrmd.so
40ac9191079e490d17b7
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-default.so
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-tabrmd.so
The following sequence of commands creates an RSA key using the TPM, exports the public key, encrypts a data file and decrypts it using the TPM:
tpm2tss-genkey -a rsa -s 2048 mykey
openssl rsa -engine tpm2tss -inform engine -in mykey -pubout -outform pem -out mykey.pub
openssl pkeyutl -pubin -inkey mykey.pub -in mydata -encrypt -out mycipher
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -decrypt -in mycipher -out mydata
Alternatively, the data can be encrypted directly with the TPM key using:
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -encrypt -in mydata -out mycipher
The following sequence of commands creates an RSA key using the TPM, exports the public key, signs a data file using the TPM and validates the signature:
openssl rsa -engine tpm2tss -inform engine -in mykey -pubout -outform pem -out mykey.pub
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -sign -in mydata -out mysig
openssl pkeyutl -pubin -inkey mykey.pub -verify -in mydata -sigfile mysig
Alternatively, the data can be validated directly using:
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -verify -in mydata -sigfile mysig
Note: mydata must not exceed the size of the RSA key, since these operation
do not perform any hashing of the input data.
The following sequence of commands creates an ECDSA key using the TPM, exports the public key, signs a data file using the TPM and validates the signature:
tpm2tss-genkey -a ecdsa mykey
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -sign -in mydata -out mysig
openssl pkeyutl -engine tpm2tss -keyform engine -inkey mykey -verify -in mydata -sigfile mysig
The following sequence of commands creates self signed certificate using TPM key. Openssl command mentions tpm2tss as engine and generate self signed certificate based on provided CSR configuration information.
tpm2tss-genkey -a rsa rsa.tss
Initializing
Setting owner auth to empty auth.
Generating RSA key for 2048 bits keysize.
Establishing connection with TPM.
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-default.so
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-tabrmd.so
Creating primary key under owner.
Generating the RSA key inside the TPM.
Generated the RSA key inside the TPM.
openssl req -new -x509 -engine tpm2tss -key rsa.tss -keyform engine -out rsa.crt
Initializing
engine "tpm2tss" set.
Loading private key rsa.tss
get_auth called for object user key with ui_method 0xffe690
Enter password for user key:
password is
Loaded key uses alg-id 1
Creating RSA key object.
Created RSA key object.
TPM2 Key loaded
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:IN
State or Province Name (full name) [Some-State]:MAHARASHTRA
Locality Name (eg, city) []:PUNE
Organization Name (eg, company) [Internet Widgits Pty Ltd]:SecureThings
Organizational Unit Name (eg, section) []:Eng
Common Name (e.g. server FQDN or YOUR name) []:webapp.securitydemos.net
Email Address []:[email protected]
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-default.so
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-tabrmd.so
rsa_priv_enc called for scheme 1 and input data(size=51):
3031300d06096086480165030402010500042087b64a295bcf928a2d188133740fbea18b7754b5b4696e80b1a26f991130920a
Padded digest data (size=256):
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
Establishing connection with TPM.
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-default.so
WARNING:esys:src/tss2-esys/esys_tcti_default.c:137:tcti_from_file() Could not load TCTI file: libtss2-tcti-tabrmd.so
Creating primary key under owner.
Loading key blob.
Signing (via decrypt operation).
Signature done (size=256):
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
├── doc : documentation and man pages
├── include : include files for system-wide installation
├── src : the source files
└── test : integration tests