linux_dsm_epyc7002/security/keys/Kconfig
Linus Torvalds c236b6dd48 request_key improvements
-----BEGIN PGP SIGNATURE-----
 
 iQIVAwUAXRPObfu3V2unywtrAQJLKA//WENO5pZDHe49T+4GCY0ZmnGHKBUnU7g9
 DUjxSNS8a/nwCyEdApZk9uHp2xsOedP6pjQ4VRWMQfrIPx0Yh9o3J+BQxvyP7PDf
 jEH+5CYC8dZnJJjjteWCcPEGrUoNb1YKfDRBU745YY+rLdHWvhHc27B6SYBg5BGT
 OwW3qyHvp0WMp7TehMALdnkqGph5gR5QMr45tOrH6DkGAhN8mAIKD699d3MqZG73
 +S5KlQOlDlEVrxbD/BgzlzEJQUBQyq8hd61taBFT7LXBNlLJJOnMhd7UJY5IJE7J
 Vi9NpcLj4Emwv4wvZ2xneV0rMbsCbxRMKZLDRuqQ6Tm17xjpjro4n1ujneTAqmmy
 d+XlrVQ2ZMciMNmGleezOoBib9QbY5NWdilc2ls5ydFGiBVL73bIOYtEQNai8lWd
 LBBIIrxOmLO7bnipgqVKRnqeMdMkpWaLISoRfSeJbRt4lGxmka9bDBrSgONnxzJK
 JG+sB8ahSVZaBbhERW8DKnBz61Yf8ka7ijVvjH3zCXu0rbLTy+LLUz5kbzbBP9Fc
 LiUapLV/v420gD2ZRCgPQwtQui4TpBkSGJKS1Ippyn7LGBNCZLM4Y8vOoo4nqr7z
 RhpEKbKeOdVjORaYjO8Zttj8gN9rT6WnPcyCTHdNEnyjotU1ykyVBkzexj+VYvjM
 C3eIdjG7Jk0=
 =c2FO
 -----END PGP SIGNATURE-----

Merge tag 'keys-request-20190626' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull request_key improvements from David Howells:
 "These are all request_key()-related, including a fix and some improvements:

   - Fix the lack of a Link permission check on a key found by
     request_key(), thereby enabling request_key() to link keys that
     don't grant this permission to the target keyring (which must still
     grant Write permission).

     Note that the key must be in the caller's keyrings already to be
     found.

   - Invalidate used request_key authentication keys rather than
     revoking them, so that they get cleaned up immediately rather than
     hanging around till the expiry time is passed.

   - Move the RCU locks outwards from the keyring search functions so
     that a request_key_rcu() can be provided. This can be called in RCU
     mode, so it can't sleep and can't upcall - but it can be called
     from LOOKUP_RCU pathwalk mode.

   - Cache the latest positive result of request_key*() temporarily in
     task_struct so that filesystems that make a lot of request_key()
     calls during pathwalk can take advantage of it to avoid having to
     redo the searching. This requires CONFIG_KEYS_REQUEST_CACHE=y.

     It is assumed that the key just found is likely to be used multiple
     times in each step in an RCU pathwalk, and is likely to be reused
     for the next step too.

     Note that the cleanup of the cache is done on TIF_NOTIFY_RESUME,
     just before userspace resumes, and on exit"

* tag 'keys-request-20190626' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  keys: Kill off request_key_async{,_with_auxdata}
  keys: Cache result of request_key*() temporarily in task_struct
  keys: Provide request_key_rcu()
  keys: Move the RCU locks outwards from the keyring search functions
  keys: Invalidate used request_key authentication keys
  keys: Fix request_key() lack of Link perm check on found key
2019-07-08 19:19:37 -07:00

123 lines
4.1 KiB
Plaintext

# SPDX-License-Identifier: GPL-2.0-only
#
# Key management configuration
#
config KEYS
bool "Enable access key retention support"
select ASSOCIATIVE_ARRAY
help
This option provides support for retaining authentication tokens and
access keys in the kernel.
It also includes provision of methods by which such keys might be
associated with a process so that network filesystems, encryption
support and the like can find them.
Furthermore, a special type of key is available that acts as keyring:
a searchable sequence of keys. Each process is equipped with access
to five standard keyrings: UID-specific, GID-specific, session,
process and thread.
If you are unsure as to whether this is required, answer N.
config KEYS_COMPAT
def_bool y
depends on COMPAT && KEYS
config KEYS_REQUEST_CACHE
bool "Enable temporary caching of the last request_key() result"
depends on KEYS
help
This option causes the result of the last successful request_key()
call that didn't upcall to the kernel to be cached temporarily in the
task_struct. The cache is cleared by exit and just prior to the
resumption of userspace.
This allows the key used for multiple step processes where each step
wants to request a key that is likely the same as the one requested
by the last step to save on the searching.
An example of such a process is a pathwalk through a network
filesystem in which each method needs to request an authentication
key. Pathwalk will call multiple methods for each dentry traversed
(permission, d_revalidate, lookup, getxattr, getacl, ...).
config PERSISTENT_KEYRINGS
bool "Enable register of persistent per-UID keyrings"
depends on KEYS
help
This option provides a register of persistent per-UID keyrings,
primarily aimed at Kerberos key storage. The keyrings are persistent
in the sense that they stay around after all processes of that UID
have exited, not that they survive the machine being rebooted.
A particular keyring may be accessed by either the user whose keyring
it is or by a process with administrative privileges. The active
LSMs gets to rule on which admin-level processes get to access the
cache.
Keyrings are created and added into the register upon demand and get
removed if they expire (a default timeout is set upon creation).
config BIG_KEYS
bool "Large payload keys"
depends on KEYS
depends on TMPFS
select CRYPTO
select CRYPTO_AES
select CRYPTO_GCM
help
This option provides support for holding large keys within the kernel
(for example Kerberos ticket caches). The data may be stored out to
swapspace by tmpfs.
If you are unsure as to whether this is required, answer N.
config TRUSTED_KEYS
tristate "TRUSTED KEYS"
depends on KEYS && TCG_TPM
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
select CRYPTO_HASH_INFO
help
This option provides support for creating, sealing, and unsealing
keys in the kernel. Trusted keys are random number symmetric keys,
generated and RSA-sealed by the TPM. The TPM only unseals the keys,
if the boot PCRs and other criteria match. Userspace will only ever
see encrypted blobs.
If you are unsure as to whether this is required, answer N.
config ENCRYPTED_KEYS
tristate "ENCRYPTED KEYS"
depends on KEYS
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_AES
select CRYPTO_CBC
select CRYPTO_SHA256
select CRYPTO_RNG
help
This option provides support for create/encrypting/decrypting keys
in the kernel. Encrypted keys are kernel generated random numbers,
which are encrypted/decrypted with a 'master' symmetric key. The
'master' key can be either a trusted-key or user-key type.
Userspace only ever sees/stores encrypted blobs.
If you are unsure as to whether this is required, answer N.
config KEY_DH_OPERATIONS
bool "Diffie-Hellman operations on retained keys"
depends on KEYS
select CRYPTO
select CRYPTO_HASH
select CRYPTO_DH
help
This option provides support for calculating Diffie-Hellman
public keys and shared secrets using values stored as keys
in the kernel.
If you are unsure as to whether this is required, answer N.