This is a revival of the previous patch set submitted by Richard Weinberger:
https://lore.kernel.org/linux-integrity/[email protected]/
v5 is here:
https://lore.kernel.org/keyrings/[email protected]/
v5 -> v6:
- Cleaned up coding style and commit messages to make the whole series more
coherent as suggested by Jarkko Sakkinen
- Added Acked-By from Jarkko Sakkinen to patch #4 - thanks!
- Rebased against next-20240307
v4 -> v5:
- Make Kconfig for trust source check scalable as suggested by Jarkko Sakkinen
- Add Acked-By from Herbert Xu to patch #1 - thanks!
v3 -> v4:
- Split changes on MAINTAINERS and documentation into dedicated patches
- Use more concise wording in commit messages as suggested by Jarkko Sakkinen
v2 -> v3:
- Addressed review comments from Jarkko Sakkinen
v1 -> v2:
- Revive and rebase to latest version
- Include review comments from Ahmad Fatoum
The Data Co-Processor (DCP) is an IP core built into many NXP SoCs such
as i.mx6ull.
Similar to the CAAM engine used in more powerful SoCs, DCP can AES-
encrypt/decrypt user data using a unique, never-disclosed,
device-specific key. Unlike CAAM though, it cannot directly wrap and
unwrap blobs in hardware. As DCP offers only the bare minimum feature
set and a blob mechanism needs aid from software. A blob in this case
is a piece of sensitive data (e.g. a key) that is encrypted and
authenticated using the device-specific key so that unwrapping can only
be done on the hardware where the blob was wrapped.
This patch series adds a DCP based, trusted-key backend and is similar
in spirit to the one by Ahmad Fatoum [0] that does the same for CAAM.
It is of interest for similar use cases as the CAAM patch set, but for
lower end devices, where CAAM is not available.
Because constructing and parsing the blob has to happen in software,
we needed to decide on a blob format and chose the following:
struct dcp_blob_fmt {
__u8 fmt_version;
__u8 blob_key[AES_KEYSIZE_128];
__u8 nonce[AES_KEYSIZE_128];
__le32 payload_len;
__u8 payload[];
} __packed;
The `fmt_version` is currently 1.
The encrypted key is stored in the payload area. It is AES-128-GCM
encrypted using `blob_key` and `nonce`, GCM auth tag is attached at
the end of the payload (`payload_len` does not include the size of
the auth tag).
The `blob_key` itself is encrypted in AES-128-ECB mode by DCP using
the OTP or UNIQUE device key. A new `blob_key` and `nonce` are generated
randomly, when sealing/exporting the DCP blob.
This patchset was tested with dm-crypt on an i.MX6ULL board.
[0] https://lore.kernel.org/keyrings/[email protected]/
David Gstir (6):
crypto: mxs-dcp: Add support for hardware-bound keys
KEYS: trusted: improve scalability of trust source config
KEYS: trusted: Introduce NXP DCP-backed trusted keys
MAINTAINERS: add entry for DCP-based trusted keys
docs: document DCP-backed trusted keys kernel params
docs: trusted-encrypted: add DCP as new trust source
.../admin-guide/kernel-parameters.txt | 13 +
.../security/keys/trusted-encrypted.rst | 85 +++++
MAINTAINERS | 9 +
drivers/crypto/mxs-dcp.c | 104 +++++-
include/keys/trusted_dcp.h | 11 +
include/soc/fsl/dcp.h | 20 ++
security/keys/trusted-keys/Kconfig | 18 +-
security/keys/trusted-keys/Makefile | 2 +
security/keys/trusted-keys/trusted_core.c | 6 +-
security/keys/trusted-keys/trusted_dcp.c | 309 ++++++++++++++++++
10 files changed, 563 insertions(+), 14 deletions(-)
create mode 100644 include/keys/trusted_dcp.h
create mode 100644 include/soc/fsl/dcp.h
create mode 100644 security/keys/trusted-keys/trusted_dcp.c
--
2.35.3
This covers trusted keys backed by NXP's DCP (Data Co-Processor) chip
found in smaller i.MX SoCs.
Signed-off-by: David Gstir <[email protected]>
Acked-by: Jarkko Sakkinen <[email protected]>
---
MAINTAINERS | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 976a5cea1577..ca7f42ca9338 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12019,6 +12019,15 @@ S: Maintained
F: include/keys/trusted_caam.h
F: security/keys/trusted-keys/trusted_caam.c
+KEYS-TRUSTED-DCP
+M: David Gstir <[email protected]>
+R: sigma star Kernel Team <[email protected]>
+L: [email protected]
+L: [email protected]
+S: Supported
+F: include/keys/trusted_dcp.h
+F: security/keys/trusted-keys/trusted_dcp.c
+
KEYS-TRUSTED-TEE
M: Sumit Garg <[email protected]>
L: [email protected]
--
2.35.3