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This adds userspace access to Diffie-Hellman computations through a new keyctl() syscall command to calculate shared secrets or public keys using input parameters stored in the keyring. Input key ids are provided in a struct due to the current 5-arg limit for the keyctl syscall. Only user keys are supported in order to avoid exposing the content of logon or encrypted keys. The output is written to the provided buffer, based on the assumption that the values are only needed in userspace. Future support for other types of key derivation would involve a new command, like KEYCTL_ECDH_COMPUTE. Once Diffie-Hellman support is included in the crypto API, this code can be converted to use the crypto API to take advantage of possible hardware acceleration and reduce redundant code. Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
99 lines
3.2 KiB
Plaintext
99 lines
3.2 KiB
Plaintext
#
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# Key management configuration
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#
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config KEYS
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bool "Enable access key retention support"
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select ASSOCIATIVE_ARRAY
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help
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This option provides support for retaining authentication tokens and
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access keys in the kernel.
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It also includes provision of methods by which such keys might be
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associated with a process so that network filesystems, encryption
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support and the like can find them.
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Furthermore, a special type of key is available that acts as keyring:
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a searchable sequence of keys. Each process is equipped with access
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to five standard keyrings: UID-specific, GID-specific, session,
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process and thread.
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If you are unsure as to whether this is required, answer N.
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config PERSISTENT_KEYRINGS
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bool "Enable register of persistent per-UID keyrings"
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depends on KEYS
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help
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This option provides a register of persistent per-UID keyrings,
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primarily aimed at Kerberos key storage. The keyrings are persistent
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in the sense that they stay around after all processes of that UID
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have exited, not that they survive the machine being rebooted.
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A particular keyring may be accessed by either the user whose keyring
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it is or by a process with administrative privileges. The active
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LSMs gets to rule on which admin-level processes get to access the
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cache.
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Keyrings are created and added into the register upon demand and get
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removed if they expire (a default timeout is set upon creation).
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config BIG_KEYS
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bool "Large payload keys"
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depends on KEYS
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depends on TMPFS
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select CRYPTO
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select CRYPTO_AES
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select CRYPTO_ECB
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select CRYPTO_RNG
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help
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This option provides support for holding large keys within the kernel
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(for example Kerberos ticket caches). The data may be stored out to
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swapspace by tmpfs.
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If you are unsure as to whether this is required, answer N.
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config TRUSTED_KEYS
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tristate "TRUSTED KEYS"
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depends on KEYS && TCG_TPM
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select CRYPTO
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select CRYPTO_HMAC
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select CRYPTO_SHA1
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select CRYPTO_HASH_INFO
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help
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This option provides support for creating, sealing, and unsealing
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keys in the kernel. Trusted keys are random number symmetric keys,
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generated and RSA-sealed by the TPM. The TPM only unseals the keys,
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if the boot PCRs and other criteria match. Userspace will only ever
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see encrypted blobs.
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If you are unsure as to whether this is required, answer N.
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config ENCRYPTED_KEYS
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tristate "ENCRYPTED KEYS"
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depends on KEYS
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select CRYPTO
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select CRYPTO_HMAC
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select CRYPTO_AES
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select CRYPTO_CBC
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select CRYPTO_SHA256
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select CRYPTO_RNG
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help
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This option provides support for create/encrypting/decrypting keys
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in the kernel. Encrypted keys are kernel generated random numbers,
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which are encrypted/decrypted with a 'master' symmetric key. The
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'master' key can be either a trusted-key or user-key type.
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Userspace only ever sees/stores encrypted blobs.
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If you are unsure as to whether this is required, answer N.
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config KEY_DH_OPERATIONS
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bool "Diffie-Hellman operations on retained keys"
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depends on KEYS
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select MPILIB
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help
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This option provides support for calculating Diffie-Hellman
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public keys and shared secrets using values stored as keys
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in the kernel.
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If you are unsure as to whether this is required, answer N.
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