linux.git/crypto, branch v4.20-rc2

KEYS: asym_tpm: Add support for the sign operation [ver #2]

2018-10-26T08:30:47+00:00

The sign operation can operate in a non-hashed mode by running the RSA
sign operation directly on the input.  This assumes that the input is
less than key_size_in_bytes - 11.  Since the TPM performs its own PKCS1
padding, it isn't possible to support 'raw' mode, only 'pkcs1'.

Alternatively, a hashed version is also possible.  In this variant the
input is hashed (by userspace) via the selected hash function first.
Then this implementation takes care of converting the hash to ASN.1
format and the sign operation is performed on the result.  This is
similar to the implementation inside crypto/rsa-pkcs1pad.c.

ASN1 templates were copied from crypto/rsa-pkcs1pad.c.  There seems to
be no easy way to expose that functionality, but likely the templates
should be shared somehow.

The sign operation is implemented via TPM_Sign operation on the TPM.
It is assumed that the TPM wrapped key provided uses
TPM_SS_RSASSAPKCS1v15_DER signature scheme.  This allows the TPM_Sign
operation to work on data up to key_len_in_bytes - 11 bytes long.

In theory, we could also use TPM_Unbind instead of TPM_Sign, but we would
have to manually pkcs1 pad the digest first.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement tpm_sign [ver #2]

2018-10-26T08:30:47+00:00

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement signature verification [ver #2]

2018-10-26T08:30:47+00:00

This patch implements the verify_signature operation.  The public key
portion extracted from the TPM key blob is used.  The operation is
performed entirely in software using the crypto API.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement the decrypt operation [ver #2]

2018-10-26T08:30:47+00:00

This patch implements the pkey_decrypt operation using the private key
blob.  The blob is first loaded into the TPM via tpm_loadkey2.  Once the
handle is obtained, tpm_unbind operation is used to decrypt the data on
the TPM and the result is returned.  The key loaded by tpm_loadkey2 is
then evicted via tpm_flushspecific operation.

This patch assumes that the SRK authorization is a well known 20-byte of
zeros and the same holds for the key authorization of the provided key.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement tpm_unbind [ver #2]

2018-10-26T08:30:47+00:00

Signed-off-by: Denis Kenzior 
Reviewed-by: James Morris 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Add loadkey2 and flushspecific [ver #2]

2018-10-26T08:30:47+00:00

This commit adds TPM_LoadKey2 and TPM_FlushSpecific operations.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Reviewed-by: James Morris 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: trusted: Expose common functionality [ver #2]

2018-10-26T08:30:47+00:00

This patch exposes some common functionality needed to send TPM commands.
Several functions from keys/trusted.c are exposed for use by the new tpm
key subtype and a module dependency is introduced.

In the future, common functionality between the trusted key type and the
asym_tpm subtype should be factored out into a common utility library.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement encryption operation [ver #2]

2018-10-26T08:30:47+00:00

This patch impelements the pkey_encrypt operation.  The public key
portion extracted from the TPM key blob is used.  The operation is
performed entirely in software using the crypto API.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: asym_tpm: Implement pkey_query [ver #2]

2018-10-26T08:30:46+00:00

This commit implements the pkey_query operation.  This is accomplished
by utilizing the public key portion to obtain max encryption size
information for the operations that utilize the public key (encrypt,
verify).  The private key size extracted from the TPM_Key data structure
is used to fill the information where the private key is used (decrypt,
sign).

The kernel uses a DER/BER format for public keys and does not support
setting the key via the raw binary form.  To get around this a simple
DER/BER formatter is implemented which stores the DER/BER formatted key
and exponent in a temporary buffer for use by the crypto API.

The only exponent supported currently is 65537.  This holds true for
other Linux TPM tools such as 'create_tpm_key' and
trousers-openssl_tpm_engine.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris

KEYS: Add parser for TPM-based keys [ver #2]

2018-10-26T08:30:46+00:00

For TPM based keys, the only standard seems to be described here:
http://david.woodhou.se/draft-woodhouse-cert-best-practice.html#rfc.section.4.4

Quote from the relevant section:
"Rather, a common form of storage for "wrapped" keys is to encode the
binary TCPA_KEY structure in a single ASN.1 OCTET-STRING, and store the
result in PEM format with the tag "-----BEGIN TSS KEY BLOB-----". "

This patch implements the above behavior.  It is assumed that the PEM
encoding is stripped out by userspace and only the raw DER/BER format is
provided.  This is similar to how PKCS7, PKCS8 and X.509 keys are
handled.

Signed-off-by: Denis Kenzior 
Signed-off-by: David Howells 
Tested-by: Marcel Holtmann 
Reviewed-by: Marcel Holtmann 
Signed-off-by: James Morris