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path: root/crypto/asymmetric_keys/asym_tpm.c
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2018-10-26KEYS: asym_tpm: Add support for the sign operation [ver #2]Denis Kenzior
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 <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement tpm_sign [ver #2]Denis Kenzior
Signed-off-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement signature verification [ver #2]Denis Kenzior
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 <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement the decrypt operation [ver #2]Denis Kenzior
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 <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement tpm_unbind [ver #2]Denis Kenzior
Signed-off-by: Denis Kenzior <denkenz@gmail.com> Reviewed-by: James Morris <james.morris@microsoft.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Add loadkey2 and flushspecific [ver #2]Denis Kenzior
This commit adds TPM_LoadKey2 and TPM_FlushSpecific operations. Signed-off-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <james.morris@microsoft.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement encryption operation [ver #2]Denis Kenzior
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 <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: Implement pkey_query [ver #2]Denis Kenzior
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 <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: extract key size & public key [ver #2]Denis Kenzior
The parsed BER/DER blob obtained from user space contains a TPM_Key structure. This structure has some information about the key as well as the public key portion. This patch extracts this information for future use. Signed-off-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>
2018-10-26KEYS: asym_tpm: add skeleton for asym_tpm [ver #2]Denis Kenzior
This patch adds the basic skeleton for the asym_tpm asymmetric key subtype. Signed-off-by: Denis Kenzior <denkenz@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Marcel Holtmann <marcel@holtmann.org> Reviewed-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: James Morris <james.morris@microsoft.com>