linux_dsm_epyc7002/security/integrity/Kconfig
Dmitry Kasatkin e0751257a6 ima: digital signature verification using asymmetric keys
Asymmetric keys were introduced in linux-3.7 to verify the signature on
signed kernel modules. The asymmetric keys infrastructure abstracts the
signature verification from the crypto details. This patch adds IMA/EVM
signature verification using asymmetric keys. Support for additional
signature verification methods can now be delegated to the asymmetric
key infrastructure.

Although the module signature header and the IMA/EVM signature header
could use the same format, to minimize the signature length and save
space in the extended attribute, this patch defines a new IMA/EVM
header format.  The main difference is that the key identifier is a
sha1[12 - 19] hash of the key modulus and exponent, similar to the
current implementation.  The only purpose of the key identifier is to
identify the corresponding key in the kernel keyring.  ima-evm-utils
was updated to support the new signature format.

While asymmetric signature verification functionality supports many
different hash algorithms, the hash used in this patch is calculated
during the IMA collection phase, based on the configured algorithm.
The default algorithm is sha1, but for backwards compatibility md5
is supported.  Due to this current limitation, signatures should be
generated using a sha1 hash algorithm.

Changes in this patch:
- Functionality has been moved to separate source file in order to get rid of
  in source #ifdefs.
- keyid is derived according to the RFC 3280. It does not require to assign
  IMA/EVM specific "description" when loading X509 certificate. Kernel
  asymmetric key subsystem automatically generate the description. Also
  loading a certificate does not require using of ima-evm-utils and can be
  done using keyctl only.
- keyid size is reduced to 32 bits to save xattr space.  Key search is done
  using partial match functionality of asymmetric_key_match().
- Kconfig option title was changed

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2013-02-06 21:22:18 -05:00

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#
config INTEGRITY
def_bool y
depends on IMA || EVM
config INTEGRITY_SIGNATURE
boolean "Digital signature verification using multiple keyrings"
depends on INTEGRITY && KEYS
default n
select SIGNATURE
help
This option enables digital signature verification support
using multiple keyrings. It defines separate keyrings for each
of the different use cases - evm, ima, and modules.
Different keyrings improves search performance, but also allow
to "lock" certain keyring to prevent adding new keys.
This is useful for evm and module keyrings, when keys are
usually only added from initramfs.
config INTEGRITY_ASYMMETRIC_KEYS
boolean "Enable asymmetric keys support"
depends on INTEGRITY_SIGNATURE
default n
select ASYMMETRIC_KEY_TYPE
select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
select PUBLIC_KEY_ALGO_RSA
select X509_CERTIFICATE_PARSER
help
This option enables digital signature verification using
asymmetric keys.
source security/integrity/ima/Kconfig
source security/integrity/evm/Kconfig