diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 13:16:50 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-24 13:16:50 -0700 |
commit | 7cf6a8a17f5b134b7e783c2d45c53298faef82a7 (patch) | |
tree | e5a6346abf5d9efbe49b91e6291349afcacfb7d3 /Documentation/security | |
parent | a9d1046a846571422a92d2b8fbf8a8b24221b9a3 (diff) | |
parent | 7f3113e3b9f7207f0bd57b5fdae1a1b9c8215e08 (diff) |
Merge tag 'tpmdd-next-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd
Pull tpm updates from Jarkko Sakkinen:
- Tightened validation of key hashes for SYSTEM_BLACKLIST_HASH_LIST. An
invalid hash format causes a compilation error. Previously, they got
included to the kernel binary but were silently ignored at run-time.
- Allow root user to append new hashes to the blacklist keyring.
- Trusted keys backed with Cryptographic Acceleration and Assurance
Module (CAAM), which part of some of the new NXP's SoC's. Now there
is total three hardware backends for trusted keys: TPM, ARM TEE and
CAAM.
- A scattered set of fixes and small improvements for the TPM driver.
* tag 'tpmdd-next-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
MAINTAINERS: add KEYS-TRUSTED-CAAM
doc: trusted-encrypted: describe new CAAM trust source
KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
crypto: caam - add in-kernel interface for blob generator
crypto: caam - determine whether CAAM supports blob encap/decap
KEYS: trusted: allow use of kernel RNG for key material
KEYS: trusted: allow use of TEE as backend without TCG_TPM support
tpm: Add field upgrade mode support for Infineon TPM2 modules
tpm: Fix buffer access in tpm2_get_tpm_pt()
char: tpm: cr50_i2c: Suppress duplicated error message in .remove()
tpm: cr50: Add new device/vendor ID 0x504a6666
tpm: Remove read16/read32/write32 calls from tpm_tis_phy_ops
tpm: ibmvtpm: Correct the return value in tpm_ibmvtpm_probe()
tpm/tpm_ftpm_tee: Return true/false (not 1/0) from bool functions
certs: Explain the rationale to call panic()
certs: Allow root user to append signed hashes to the blacklist keyring
certs: Check that builtin blacklist hashes are valid
certs: Make blacklist_vet_description() more strict
certs: Factor out the blacklist hash creation
tools/certs: Add print-cert-tbs-hash.sh
Diffstat (limited to 'Documentation/security')
-rw-r--r-- | Documentation/security/keys/trusted-encrypted.rst | 60 |
1 files changed, 51 insertions, 9 deletions
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index f614dad7de12..0bfb4c339748 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -35,6 +35,13 @@ safe. Rooted to Hardware Unique Key (HUK) which is generally burnt in on-chip fuses and is accessible to TEE only. + (3) CAAM (Cryptographic Acceleration and Assurance Module: IP on NXP SoCs) + + When High Assurance Boot (HAB) is enabled and the CAAM is in secure + mode, trust is rooted to the OTPMK, a never-disclosed 256-bit key + randomly generated and fused into each SoC at manufacturing time. + Otherwise, a common fixed test key is used instead. + * Execution isolation (1) TPM @@ -46,6 +53,10 @@ safe. Customizable set of operations running in isolated execution environment verified via Secure/Trusted boot process. + (3) CAAM + + Fixed set of operations running in isolated execution environment. + * Optional binding to platform integrity state (1) TPM @@ -63,6 +74,11 @@ safe. Relies on Secure/Trusted boot process for platform integrity. It can be extended with TEE based measured boot process. + (3) CAAM + + Relies on the High Assurance Boot (HAB) mechanism of NXP SoCs + for platform integrity. + * Interfaces and APIs (1) TPM @@ -74,10 +90,13 @@ safe. TEEs have well-documented, standardized client interface and APIs. For more details refer to ``Documentation/staging/tee.rst``. + (3) CAAM + + Interface is specific to silicon vendor. * Threat model - The strength and appropriateness of a particular TPM or TEE for a given + The strength and appropriateness of a particular trust source for a given purpose must be assessed when using them to protect security-relevant data. @@ -87,22 +106,32 @@ Key Generation Trusted Keys ------------ -New keys are created from random numbers generated in the trust source. They -are encrypted/decrypted using a child key in the storage key hierarchy. -Encryption and decryption of the child key must be protected by a strong -access control policy within the trust source. +New keys are created from random numbers. They are encrypted/decrypted using +a child key in the storage key hierarchy. Encryption and decryption of the +child key must be protected by a strong access control policy within the +trust source. The random number generator in use differs according to the +selected trust source: - * TPM (hardware device) based RNG + * TPM: hardware device based RNG - Strength of random numbers may vary from one device manufacturer to - another. + Keys are generated within the TPM. Strength of random numbers may vary + from one device manufacturer to another. - * TEE (OP-TEE based on Arm TrustZone) based RNG + * TEE: OP-TEE based on Arm TrustZone based RNG RNG is customizable as per platform needs. It can either be direct output from platform specific hardware RNG or a software based Fortuna CSPRNG which can be seeded via multiple entropy sources. + * CAAM: Kernel RNG + + The normal kernel random number generator is used. To seed it from the + CAAM HWRNG, enable CRYPTO_DEV_FSL_CAAM_RNG_API and ensure the device + is probed. + +Users may override this by specifying ``trusted.rng=kernel`` on the kernel +command-line to override the used RNG with the kernel's random number pool. + Encrypted Keys -------------- @@ -189,6 +218,19 @@ Usage:: specific to TEE device implementation. The key length for new keys is always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). +Trusted Keys usage: CAAM +------------------------ + +Usage:: + + keyctl add trusted name "new keylen" ring + keyctl add trusted name "load hex_blob" ring + keyctl print keyid + +"keyctl print" returns an ASCII hex copy of the sealed key, which is in a +CAAM-specific format. The key length for new keys is always in bytes. +Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). + Encrypted Keys usage -------------------- |