[PATCH v2 2/3] KEYS: trusted: Introduce support for NXP DCP-based trusted keys
DCP (Data Co-Processor) is the little brother of NXP's CAAM IP.
Beside of accelerated crypto operations, it also offers support for
hardware-bound keys. Using this feature it is possible to implement a blob
mechanism just like CAAM offers. Unlike on CAAM, constructing and
parsing the blob has to happen in software.
We chose the following format for the blob:
/*
* struct dcp_blob_fmt - DCP BLOB format.
*
* @fmt_version: Format version, currently being %1
* @blob_key: Random AES 128 key which is used to encrypt @payload,
*@blob_key itself is encrypted with OTP or UNIQUE device key in
*AES-128-ECB mode by DCP.
* @nonce: Random nonce used for @payload encryption.
* @payload_len: Length of the plain text @payload.
* @payload: The payload itself, encrypted using AES-128-GCM and @blob_key,
* GCM auth tag of size AES_BLOCK_SIZE is attached at the end of it.
*
* The total size of a DCP BLOB is sizeof(struct dcp_blob_fmt) + @payload_len +
* AES_BLOCK_SIZE.
*/
struct dcp_blob_fmt {
__u8 fmt_version;
__u8 blob_key[AES_KEYSIZE_128];
__u8 nonce[AES_KEYSIZE_128];
__le32 payload_len;
__u8 payload[];
} __packed;
@payload is the key provided by trusted_key_ops->seal().
By default the UNIQUE device key is used, it is also possible to use
the OTP key. While the UNIQUE device key should be unique it is not
entirely clear whether this is the case due to unclear documentation.
If someone wants to be sure they can burn their own unique key
into the OTP fuse and set the use_otp_key module parameter.
Co-developed-by: Richard Weinberger
Signed-off-by: Richard Weinberger
Co-developed-by: David Oberhollenzer
Signed-off-by: David Oberhollenzer
Signed-off-by: David Gstir
---
.../admin-guide/kernel-parameters.txt | 13 +
MAINTAINERS | 9 +
include/keys/trusted_dcp.h| 13 +
security/keys/trusted-keys/Kconfig| 9 +-
security/keys/trusted-keys/Makefile | 2 +
security/keys/trusted-keys/trusted_core.c | 6 +-
security/keys/trusted-keys/trusted_dcp.c | 313 ++
7 files changed, 363 insertions(+), 2 deletions(-)
create mode 100644 include/keys/trusted_dcp.h
create mode 100644 security/keys/trusted-keys/trusted_dcp.c
diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt
index 0a1731a0f0ef..c11eda8b38e0 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6566,6 +6566,7 @@
- "tpm"
- "tee"
- "caam"
+ - "dcp"
If not specified then it defaults to iterating through
the trust source list starting with TPM and assigns the
first trust source as a backend which is initialized
@@ -6581,6 +6582,18 @@
If not specified, "default" is used. In this case,
the RNG's choice is left to each individual trust
source.
+ trusted.dcp_use_otp_key
+ This is intended to be used in combination with
+ trusted.source=dcp and will select the DCP OTP key
+ instead of the DCP UNIQUE key blob encryption.
+
+ trusted.dcp_skip_zk_test
+ This is intended to be used in combination with
+ trusted.source=dcp and will disable the check if all
+ the blob key is zero'ed. This is helpful for situations
where
+ having this key zero'ed is acceptable. E.g. in testing
+ scenarios.
+
tsc=Disable clocksource stability checks for TSC.
Format:
[x86] reliable: mark tsc clocksource as reliable, this
diff --git a/MAINTAINERS b/MAINTAINERS
index 90f13281d297..988d01226131 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11647,6 +11647,15 @@ S: Maintained
F: include/keys/trusted_caam.h
F: security/keys/trusted-keys/trusted_caam.c
+KEYS-TRUSTED-DCP
+M: David Gstir
+R: sigma star Kernel Team
+L: linux-integr...@vger.kernel.org
+L: keyri...@vger.kernel.org
+S: Supported
+F: include/keys/trusted_dcp.h
+F: security/keys/trusted-keys/trusted_dcp.c
+
KEYS-TRUSTED-TEE
M: Sumit Garg
L: linux-integr...@vger.kernel.org
diff --git a/include/keys/trusted_dcp.h b/include/keys/trusted_dcp.h
new file mode 100644
index ..7b2a1275c527
--- /dev/null
+++ b/include/keys/trusted_dcp.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2021 sigma star gmbh
+ * Authors: David Gstir
+ * Richard Weinberger
+ */
+
+#ifndef TRUSTED_DCP_H
+#define TRUSTED_DCP_H
+
+extern struct trusted_key_ops dcp_trusted_key_ops;
+
Re: [PATCH v2 2/3] KEYS: trusted: Introduce support for NXP DCP-based trusted keys
On Tue Sep 12, 2023 at 2:11 PM EEST, David Gstir wrote:
> DCP (Data Co-Processor) is the little brother of NXP's CAAM IP.
>
> Beside of accelerated crypto operations, it also offers support for
> hardware-bound keys. Using this feature it is possible to implement a blob
> mechanism just like CAAM offers. Unlike on CAAM, constructing and
> parsing the blob has to happen in software.
>
> We chose the following format for the blob:
> /*
> * struct dcp_blob_fmt - DCP BLOB format.
> *
> * @fmt_version: Format version, currently being %1
> * @blob_key: Random AES 128 key which is used to encrypt @payload,
> *@blob_key itself is encrypted with OTP or UNIQUE device key in
> *AES-128-ECB mode by DCP.
> * @nonce: Random nonce used for @payload encryption.
> * @payload_len: Length of the plain text @payload.
> * @payload: The payload itself, encrypted using AES-128-GCM and @blob_key,
> * GCM auth tag of size AES_BLOCK_SIZE is attached at the end of it.
> *
> * The total size of a DCP BLOB is sizeof(struct dcp_blob_fmt) + @payload_len
> +
> * AES_BLOCK_SIZE.
> */
> struct dcp_blob_fmt {
> __u8 fmt_version;
> __u8 blob_key[AES_KEYSIZE_128];
> __u8 nonce[AES_KEYSIZE_128];
> __le32 payload_len;
> __u8 payload[];
> } __packed;
>
> @payload is the key provided by trusted_key_ops->seal().
>
> By default the UNIQUE device key is used, it is also possible to use
> the OTP key. While the UNIQUE device key should be unique it is not
> entirely clear whether this is the case due to unclear documentation.
> If someone wants to be sure they can burn their own unique key
> into the OTP fuse and set the use_otp_key module parameter.
>
> Co-developed-by: Richard Weinberger
> Signed-off-by: Richard Weinberger
> Co-developed-by: David Oberhollenzer
> Signed-off-by: David Oberhollenzer
> Signed-off-by: David Gstir
> ---
> .../admin-guide/kernel-parameters.txt | 13 +
> MAINTAINERS | 9 +
> include/keys/trusted_dcp.h| 13 +
> security/keys/trusted-keys/Kconfig| 9 +-
> security/keys/trusted-keys/Makefile | 2 +
> security/keys/trusted-keys/trusted_core.c | 6 +-
> security/keys/trusted-keys/trusted_dcp.c | 313 ++
> 7 files changed, 363 insertions(+), 2 deletions(-)
> create mode 100644 include/keys/trusted_dcp.h
> create mode 100644 security/keys/trusted-keys/trusted_dcp.c
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> index 0a1731a0f0ef..c11eda8b38e0 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -6566,6 +6566,7 @@
> - "tpm"
> - "tee"
> - "caam"
> + - "dcp"
> If not specified then it defaults to iterating through
> the trust source list starting with TPM and assigns the
> first trust source as a backend which is initialized
> @@ -6581,6 +6582,18 @@
> If not specified, "default" is used. In this case,
> the RNG's choice is left to each individual trust
> source.
>
> + trusted.dcp_use_otp_key
> + This is intended to be used in combination with
> + trusted.source=dcp and will select the DCP OTP key
> + instead of the DCP UNIQUE key blob encryption.
> +
> + trusted.dcp_skip_zk_test
> + This is intended to be used in combination with
> + trusted.source=dcp and will disable the check if all
> + the blob key is zero'ed. This is helpful for situations
> where
> + having this key zero'ed is acceptable. E.g. in testing
> + scenarios.
> +
> tsc=Disable clocksource stability checks for TSC.
> Format:
> [x86] reliable: mark tsc clocksource as reliable, this
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 90f13281d297..988d01226131 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11647,6 +11647,15 @@ S: Maintained
> F: include/keys/trusted_caam.h
> F: security/keys/trusted-keys/trusted_caam.c
>
> +KEYS-TRUSTED-DCP
> +M: David Gstir
> +R: sigma star Kernel Team
> +L: linux-integr...@vger.kernel.org
> +L: keyri...@vger.kernel.org
> +S: Supported
> +F: include/keys/trusted_dcp.h
> +F: security/keys/trusted-keys/trusted_dcp.c
> +
> KEYS-TRUSTED-TEE
> M: Sumit Garg
> L: linux-integr...@vger.kernel.org
> diff --git a/include/keys/trusted_dcp.h b/include/keys/trusted_dcp.h
> new file mode 100644
> index ..7b2a1275c527
> --- /dev/null
> +++ b/include/keys/trusted_dcp.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
>
