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Diffstat (limited to 'Documentation/security/keys/trusted-encrypted.rst')
| -rw-r--r-- | Documentation/security/keys/trusted-encrypted.rst | 138 |
1 files changed, 137 insertions, 1 deletions
diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index f4d7e162d5e4..ddff7c7c2582 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -10,6 +10,37 @@ of a Trust Source for greater security, while Encrypted Keys can be used on any system. All user level blobs, are displayed and loaded in hex ASCII for convenience, and are integrity verified. +Trusted Keys as Protected key +============================= +It is the secure way of keeping the keys in the kernel key-ring as Trusted-Key, +such that: + +- Key-blob, an encrypted key-data, created to be stored, loaded and seen by + userspace. +- Key-data, the plain-key text in the system memory, to be used by + kernel space only. + +Though key-data is not accessible to the user-space in plain-text, but it is in +plain-text in system memory, when used in kernel space. Even though kernel-space +attracts small surface attack, but with compromised kernel or side-channel +attack accessing the system memory can lead to a chance of the key getting +compromised/leaked. + +In order to protect the key in kernel space, the concept of "protected-keys" is +introduced which will act as an added layer of protection. The key-data of the +protected keys is encrypted with Key-Encryption-Key(KEK), and decrypted inside +the trust source boundary. The plain-key text never available out-side in the +system memory. Thus, any crypto operation that is to be executed using the +protected key, can only be done by the trust source, which generated the +key blob. + +Hence, if the protected-key is leaked or compromised, it is of no use to the +hacker. + +Trusted keys as protected keys, with trust source having the capability of +generating: + +- Key-Blob, to be loaded, stored and seen by user-space. Trust Source ============ @@ -50,6 +81,14 @@ safe. and the UNIQUE key. Default is to use the UNIQUE key, but selecting the OTP key can be done via a module parameter (dcp_use_otp_key). + (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore) + + Rooted to a unique, per-LPAR key, which is derived from a system-wide, + randomly generated LPAR root key. Both the per-LPAR keys and the LPAR + root key are stored in hypervisor-owned secure memory at runtime, + and the LPAR root key is additionally persisted in secure locations + such as the processor SEEPROMs and encrypted NVRAM. + * Execution isolation (1) TPM @@ -71,6 +110,14 @@ safe. environment. Only basic blob key encryption is executed there. The actual key sealing/unsealing is done on main processor/kernel space. + (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore) + + Fixed set of cryptographic operations done on on-chip hardware + cryptographic acceleration unit NX. Keys for wrapping and unwrapping + are managed by PowerVM Platform KeyStore, which stores keys in an + isolated in-memory copy in secure hypervisor memory, as well as in a + persistent copy in hypervisor-encrypted NVRAM. + * Optional binding to platform integrity state (1) TPM @@ -98,6 +145,11 @@ safe. Relies on Secure/Trusted boot process (called HAB by vendor) for platform integrity. + (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore) + + Relies on secure and trusted boot process of IBM Power systems for + platform integrity. + * Interfaces and APIs (1) TPM @@ -118,6 +170,11 @@ safe. Vendor-specific API that is implemented as part of the DCP crypto driver in ``drivers/crypto/mxs-dcp.c``. + (5) PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore) + + Platform Keystore has well documented interfaces in PAPR document. + Refer to ``Documentation/arch/powerpc/papr_hcalls.rst`` + * Threat model The strength and appropriateness of a particular trust source for a given @@ -160,6 +217,10 @@ selected trust source: a dedicated hardware RNG that is independent from DCP which can be enabled to back the kernel RNG. + * PKWM (PowerVM Key Wrapping Module: IBM PowerVM + Platform KeyStore) + + The normal kernel random number generator is used to generate keys. + 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. @@ -252,7 +313,7 @@ in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). Trusted Keys usage: CAAM ------------------------ -Usage:: +Trusted Keys Usage:: keyctl add trusted name "new keylen" ring keyctl add trusted name "load hex_blob" ring @@ -262,6 +323,21 @@ Usage:: CAAM-specific format. The key length for new keys is always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). +Trusted Keys as Protected Keys Usage:: + + keyctl add trusted name "new keylen pk [options]" ring + keyctl add trusted name "load hex_blob [options]" ring + keyctl print keyid + + where, 'pk' is used to direct trust source to generate protected key. + + options: + key_enc_algo = For CAAM, supported enc algo are ECB(2), CCM(1). + +"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). + Trusted Keys usage: DCP ----------------------- @@ -275,6 +351,26 @@ Usage:: specific to this DCP key-blob implementation. The key length for new keys is always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). +Trusted Keys usage: PKWM +------------------------ + +Usage:: + + keyctl add trusted name "new keylen [options]" ring + keyctl add trusted name "load hex_blob" ring + keyctl print keyid + + options: + wrap_flags= ascii hex value of security policy requirement + 0x00: no secure boot requirement (default) + 0x01: require secure boot to be in either audit or + enforced mode + 0x02: require secure boot to be in enforced mode + +"keyctl print" returns an ASCII hex copy of the sealed key, which is in format +specific to PKWM key-blob implementation. The key length for new keys is +always in bytes. Trusted Keys can be 32 - 128 bytes (256 - 1024 bits). + Encrypted Keys usage -------------------- @@ -343,6 +439,46 @@ Load a trusted key from the saved blob:: f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b e4a8aea2b607ec96931e6f4d4fe563ba +Create and save a trusted key as protected key named "kmk" of length 32 bytes. + +:: + + $ keyctl add trusted kmk "new 32 pk key_enc_algo=1" @u + 440502848 + + $ keyctl show + Session Keyring + -3 --alswrv 500 500 keyring: _ses + 97833714 --alswrv 500 -1 \_ keyring: _uid.500 + 440502848 --alswrv 500 500 \_ trusted: kmk + + $ keyctl print 440502848 + 0101000000000000000001005d01b7e3f4a6be5709930f3b70a743cbb42e0cc95e18e915 + 3f60da455bbf1144ad12e4f92b452f966929f6105fd29ca28e4d4d5a031d068478bacb0b + 27351119f822911b0a11ba3d3498ba6a32e50dac7f32894dd890eb9ad578e4e292c83722 + a52e56a097e6a68b3f56f7a52ece0cdccba1eb62cad7d817f6dc58898b3ac15f36026fec + d568bd4a706cb60bb37be6d8f1240661199d640b66fb0fe3b079f97f450b9ef9c22c6d5d + dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471dc6d13ecf8298b946f65345faa5ef0 + f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b + e4a8aea2b607ec96931e6f4d4fe563ba + + $ keyctl pipe 440502848 > kmk.blob + +Load a trusted key from the saved blob:: + + $ keyctl add trusted kmk "load `cat kmk.blob` key_enc_algo=1" @u + 268728824 + + $ keyctl print 268728824 + 0101000000000000000001005d01b7e3f4a6be5709930f3b70a743cbb42e0cc95e18e915 + 3f60da455bbf1144ad12e4f92b452f966929f6105fd29ca28e4d4d5a031d068478bacb0b + 27351119f822911b0a11ba3d3498ba6a32e50dac7f32894dd890eb9ad578e4e292c83722 + a52e56a097e6a68b3f56f7a52ece0cdccba1eb62cad7d817f6dc58898b3ac15f36026fec + d568bd4a706cb60bb37be6d8f1240661199d640b66fb0fe3b079f97f450b9ef9c22c6d5d + dd379f0facd1cd020281dfa3c70ba21a3fa6fc2471dc6d13ecf8298b946f65345faa5ef0 + f1f8fff03ad0acb083725535636addb08d73dedb9832da198081e5deae84bfaf0409c22b + e4a8aea2b607ec96931e6f4d4fe563ba + Reseal (TPM specific) a trusted key under new PCR values:: $ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`" |