Commit Graph

8 Commits

Author SHA1 Message Date
David Howells 4e8ae72a75 X.509: Make algo identifiers text instead of enum
Make the identifier public key and digest algorithm fields text instead of
enum.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-03-03 21:49:27 +00:00
David Howells d43de6c780 akcipher: Move the RSA DER encoding check to the crypto layer
Move the RSA EMSA-PKCS1-v1_5 encoding from the asymmetric-key public_key
subtype to the rsa crypto module's pkcs1pad template.  This means that the
public_key subtype no longer has any dependencies on public key type.

To make this work, the following changes have been made:

 (1) The rsa pkcs1pad template is now used for RSA keys.  This strips off the
     padding and returns just the message hash.

 (2) In a previous patch, the pkcs1pad template gained an optional second
     parameter that, if given, specifies the hash used.  We now give this,
     and pkcs1pad checks the encoded message E(M) for the EMSA-PKCS1-v1_5
     encoding and verifies that the correct digest OID is present.

 (3) The crypto driver in crypto/asymmetric_keys/rsa.c is now reduced to
     something that doesn't care about what the encryption actually does
     and and has been merged into public_key.c.

 (4) CONFIG_PUBLIC_KEY_ALGO_RSA is gone.  Module signing must set
     CONFIG_CRYPTO_RSA=y instead.

Thoughts:

 (*) Should the encoding style (eg. raw, EMSA-PKCS1-v1_5) also be passed to
     the padding template?  Should there be multiple padding templates
     registered that share most of the code?

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-03-03 21:49:27 +00:00
Tadeusz Struk eb5798f2e2 integrity: convert digsig to akcipher api
Convert asymmetric_verify to akcipher api.

Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David Howells <dhowells@redhat.com>
2016-02-18 14:52:32 +00:00
Petko Manolov 41c89b64d7 IMA: create machine owner and blacklist keyrings
This option creates IMA MOK and blacklist keyrings.  IMA MOK is an
intermediate keyring that sits between .system and .ima keyrings,
effectively forming a simple CA hierarchy.  To successfully import a key
into .ima_mok it must be signed by a key which CA is in .system keyring.
On turn any key that needs to go in .ima keyring must be signed by CA in
either .system or .ima_mok keyrings. IMA MOK is empty at kernel boot.

IMA blacklist keyring contains all revoked IMA keys.  It is consulted
before any other keyring.  If the search is successful the requested
operation is rejected and error is returned to the caller.

Signed-off-by: Petko Manolov <petkan@mip-labs.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2015-12-15 10:01:43 -05:00
Dmitry Kasatkin 594081ee71 integrity: do zero padding of the key id
Latest KEYS code return error if hexadecimal string length id odd.
Fix it.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2014-10-06 17:33:27 +01:00
Dmitry Kasatkin d9a2e5d788 integrity: prevent flooding with 'Request for unknown key'
If file has IMA signature, IMA in enforce mode, but key is missing
then file access is blocked and single error message is printed.

If IMA appraisal is enabled in fix mode, then system runs as usual
but might produce tons of 'Request for unknown key' messages.

This patch switches 'pr_warn' to 'pr_err_ratelimited'.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2014-09-09 10:28:44 -04:00
Dmitry Kasatkin d3634d0f42 ima: read and use signature hash algorithm
All files on the filesystem, currently, are hashed using the same hash
algorithm.  In preparation for files from different packages being
signed using different hash algorithms, this patch adds support for
reading the signature hash algorithm from the 'security.ima' extended
attribute and calculates the appropriate file data hash based on it.

Changelog:
- fix scripts Lindent and checkpatch msgs - Mimi
- fix md5 support for older version, which occupied 20 bytes in the
  xattr, not the expected 16 bytes.  Fix the comparison to compare
  only the first 16 bytes.

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
2013-10-25 17:16:59 -04:00
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