diff options
Diffstat (limited to 'Documentation/security/keys-trusted-encrypted.txt')
| -rw-r--r-- | Documentation/security/keys-trusted-encrypted.txt | 52 |
1 files changed, 33 insertions, 19 deletions
diff --git a/Documentation/security/keys-trusted-encrypted.txt b/Documentation/security/keys-trusted-encrypted.txt index 8fb79bc1ac4b..5f50ccabfc8a 100644 --- a/Documentation/security/keys-trusted-encrypted.txt +++ b/Documentation/security/keys-trusted-encrypted.txt @@ -53,12 +53,19 @@ they are only as secure as the user key encrypting them. The master user key should therefore be loaded in as secure a way as possible, preferably early in boot. +The decrypted portion of encrypted keys can contain either a simple symmetric +key or a more complex structure. The format of the more complex structure is +application specific, which is identified by 'format'. + Usage: - keyctl add encrypted name "new key-type:master-key-name keylen" ring - keyctl add encrypted name "load hex_blob" ring - keyctl update keyid "update key-type:master-key-name" + keyctl add encrypted name "new [format] key-type:master-key-name keylen" + ring + keyctl add encrypted name "load hex_blob" ring + keyctl update keyid "update key-type:master-key-name" + +format:= 'default | ecryptfs' +key-type:= 'trusted' | 'user' -where 'key-type' is either 'trusted' or 'user'. Examples of trusted and encrypted key usage: @@ -114,15 +121,25 @@ Reseal a trusted key under new pcr values: 7ef6a24defe4846104209bf0c3eced7fa1a672ed5b125fc9d8cd88b476a658a4434644ef df8ae9a178e9f83ba9f08d10fa47e4226b98b0702f06b3b8 -Create and save an encrypted key "evm" using the above trusted key "kmk": +The initial consumer of trusted keys is EVM, which at boot time needs a high +quality symmetric key for HMAC protection of file metadata. The use of a +trusted key provides strong guarantees that the EVM key has not been +compromised by a user level problem, and when sealed to specific boot PCR +values, protects against boot and offline attacks. Create and save an +encrypted key "evm" using the above trusted key "kmk": +option 1: omitting 'format' $ keyctl add encrypted evm "new trusted:kmk 32" @u 159771175 +option 2: explicitly defining 'format' as 'default' + $ keyctl add encrypted evm "new default trusted:kmk 32" @u + 159771175 + $ keyctl print 159771175 - trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b382dbbc55 - be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e024717c64 - 5972dcb82ab2dde83376d82b2e3c09ffc + default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3 + 82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0 + 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc $ keyctl pipe 159771175 > evm.blob @@ -132,14 +149,11 @@ Load an encrypted key "evm" from saved blob: 831684262 $ keyctl print 831684262 - trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b382dbbc55 - be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e024717c64 - 5972dcb82ab2dde83376d82b2e3c09ffc - - -The initial consumer of trusted keys is EVM, which at boot time needs a high -quality symmetric key for HMAC protection of file metadata. The use of a -trusted key provides strong guarantees that the EVM key has not been -compromised by a user level problem, and when sealed to specific boot PCR -values, protects against boot and offline attacks. Other uses for trusted and -encrypted keys, such as for disk and file encryption are anticipated. + default trusted:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b3 + 82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e0 + 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc + +Other uses for trusted and encrypted keys, such as for disk and file encryption +are anticipated. In particular the new format 'ecryptfs' has been defined in +in order to use encrypted keys to mount an eCryptfs filesystem. More details +about the usage can be found in the file 'Documentation/keys-ecryptfs.txt'. |