freebsd-skq/sys/opencrypto/cryptodev_if.m
jhb ddcef18974 Refactor driver and consumer interfaces for OCF (in-kernel crypto).
- The linked list of cryptoini structures used in session
  initialization is replaced with a new flat structure: struct
  crypto_session_params.  This session includes a new mode to define
  how the other fields should be interpreted.  Available modes
  include:

  - COMPRESS (for compression/decompression)
  - CIPHER (for simply encryption/decryption)
  - DIGEST (computing and verifying digests)
  - AEAD (combined auth and encryption such as AES-GCM and AES-CCM)
  - ETA (combined auth and encryption using encrypt-then-authenticate)

  Additional modes could be added in the future (e.g. if we wanted to
  support TLS MtE for AES-CBC in the kernel we could add a new mode
  for that.  TLS modes might also affect how AAD is interpreted, etc.)

  The flat structure also includes the key lengths and algorithms as
  before.  However, code doesn't have to walk the linked list and
  switch on the algorithm to determine which key is the auth key vs
  encryption key.  The 'csp_auth_*' fields are always used for auth
  keys and settings and 'csp_cipher_*' for cipher.  (Compression
  algorithms are stored in csp_cipher_alg.)

- Drivers no longer register a list of supported algorithms.  This
  doesn't quite work when you factor in modes (e.g. a driver might
  support both AES-CBC and SHA2-256-HMAC separately but not combined
  for ETA).  Instead, a new 'crypto_probesession' method has been
  added to the kobj interface for symmteric crypto drivers.  This
  method returns a negative value on success (similar to how
  device_probe works) and the crypto framework uses this value to pick
  the "best" driver.  There are three constants for hardware
  (e.g. ccr), accelerated software (e.g. aesni), and plain software
  (cryptosoft) that give preference in that order.  One effect of this
  is that if you request only hardware when creating a new session,
  you will no longer get a session using accelerated software.
  Another effect is that the default setting to disallow software
  crypto via /dev/crypto now disables accelerated software.

  Once a driver is chosen, 'crypto_newsession' is invoked as before.

- Crypto operations are now solely described by the flat 'cryptop'
  structure.  The linked list of descriptors has been removed.

  A separate enum has been added to describe the type of data buffer
  in use instead of using CRYPTO_F_* flags to make it easier to add
  more types in the future if needed (e.g. wired userspace buffers for
  zero-copy).  It will also make it easier to re-introduce separate
  input and output buffers (in-kernel TLS would benefit from this).

  Try to make the flags related to IV handling less insane:

  - CRYPTO_F_IV_SEPARATE means that the IV is stored in the 'crp_iv'
    member of the operation structure.  If this flag is not set, the
    IV is stored in the data buffer at the 'crp_iv_start' offset.

  - CRYPTO_F_IV_GENERATE means that a random IV should be generated
    and stored into the data buffer.  This cannot be used with
    CRYPTO_F_IV_SEPARATE.

  If a consumer wants to deal with explicit vs implicit IVs, etc. it
  can always generate the IV however it needs and store partial IVs in
  the buffer and the full IV/nonce in crp_iv and set
  CRYPTO_F_IV_SEPARATE.

  The layout of the buffer is now described via fields in cryptop.
  crp_aad_start and crp_aad_length define the boundaries of any AAD.
  Previously with GCM and CCM you defined an auth crd with this range,
  but for ETA your auth crd had to span both the AAD and plaintext
  (and they had to be adjacent).

  crp_payload_start and crp_payload_length define the boundaries of
  the plaintext/ciphertext.  Modes that only do a single operation
  (COMPRESS, CIPHER, DIGEST) should only use this region and leave the
  AAD region empty.

  If a digest is present (or should be generated), it's starting
  location is marked by crp_digest_start.

  Instead of using the CRD_F_ENCRYPT flag to determine the direction
  of the operation, cryptop now includes an 'op' field defining the
  operation to perform.  For digests I've added a new VERIFY digest
  mode which assumes a digest is present in the input and fails the
  request with EBADMSG if it doesn't match the internally-computed
  digest.  GCM and CCM already assumed this, and the new AEAD mode
  requires this for decryption.  The new ETA mode now also requires
  this for decryption, so IPsec and GELI no longer do their own
  authentication verification.  Simple DIGEST operations can also do
  this, though there are no in-tree consumers.

  To eventually support some refcounting to close races, the session
  cookie is now passed to crypto_getop() and clients should no longer
  set crp_sesssion directly.

- Assymteric crypto operation structures should be allocated via
  crypto_getkreq() and freed via crypto_freekreq().  This permits the
  crypto layer to track open asym requests and close races with a
  driver trying to unregister while asym requests are in flight.

- crypto_copyback, crypto_copydata, crypto_apply, and
  crypto_contiguous_subsegment now accept the 'crp' object as the
  first parameter instead of individual members.  This makes it easier
  to deal with different buffer types in the future as well as
  separate input and output buffers.  It's also simpler for driver
  writers to use.

- bus_dmamap_load_crp() loads a DMA mapping for a crypto buffer.
  This understands the various types of buffers so that drivers that
  use DMA do not have to be aware of different buffer types.

- Helper routines now exist to build an auth context for HMAC IPAD
  and OPAD.  This reduces some duplicated work among drivers.

- Key buffers are now treated as const throughout the framework and in
  device drivers.  However, session key buffers provided when a session
  is created are expected to remain alive for the duration of the
  session.

- GCM and CCM sessions now only specify a cipher algorithm and a cipher
  key.  The redundant auth information is not needed or used.

- For cryptosoft, split up the code a bit such that the 'process'
  callback now invokes a function pointer in the session.  This
  function pointer is set based on the mode (in effect) though it
  simplifies a few edge cases that would otherwise be in the switch in
  'process'.

  It does split up GCM vs CCM which I think is more readable even if there
  is some duplication.

- I changed /dev/crypto to support GMAC requests using CRYPTO_AES_NIST_GMAC
  as an auth algorithm and updated cryptocheck to work with it.

- Combined cipher and auth sessions via /dev/crypto now always use ETA
  mode.  The COP_F_CIPHER_FIRST flag is now a no-op that is ignored.
  This was actually documented as being true in crypto(4) before, but
  the code had not implemented this before I added the CIPHER_FIRST
  flag.

- I have not yet updated /dev/crypto to be aware of explicit modes for
  sessions.  I will probably do that at some point in the future as well
  as teach it about IV/nonce and tag lengths for AEAD so we can support
  all of the NIST KAT tests for GCM and CCM.

- I've split up the exising crypto.9 manpage into several pages
  of which many are written from scratch.

- I have converted all drivers and consumers in the tree and verified
  that they compile, but I have not tested all of them.  I have tested
  the following drivers:

  - cryptosoft
  - aesni (AES only)
  - blake2
  - ccr

  and the following consumers:

  - cryptodev
  - IPsec
  - ktls_ocf
  - GELI (lightly)

  I have not tested the following:

  - ccp
  - aesni with sha
  - hifn
  - kgssapi_krb5
  - ubsec
  - padlock
  - safe
  - armv8_crypto (aarch64)
  - glxsb (i386)
  - sec (ppc)
  - cesa (armv7)
  - cryptocteon (mips64)
  - nlmsec (mips64)

Discussed with:	cem
Relnotes:	yes
Sponsored by:	Chelsio Communications
Differential Revision:	https://reviews.freebsd.org/D23677
2020-03-27 18:25:23 +00:00

180 lines
6.1 KiB
Objective-C

#-
# Copyright (c) 2006, Sam Leffler
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
#include <sys/malloc.h>
#include <opencrypto/cryptodev.h>
INTERFACE cryptodev;
CODE {
static int null_freesession(device_t dev,
crypto_session_t crypto_session)
{
return 0;
}
};
/**
* @brief Probe to see if a crypto driver supports a session.
*
* The crypto framework invokes this method on each crypto driver when
* creating a session for symmetric crypto operations to determine if
* the driver supports the algorithms and mode requested by the
* session.
*
* If the driver does not support a session with the requested
* parameters, this function should fail with an error.
*
* If the driver does support a session with the requested parameters,
* this function should return a negative value indicating the
* priority of this driver. These negative values should be derived
* from one of the CRYPTODEV_PROBE_* constants in
* <opencrypto/cryptodev.h>.
*
* This function's return value is similar to that used by
* DEVICE_PROBE(9). However, a return value of zero is not supported
* and should not be used.
*
* @param dev the crypto driver device
* @param csp crypto session parameters
*
* @retval negative if the driver supports this session - the
* least negative value is used to select the
* driver for the session
* @retval EINVAL if the driver does not support the session
* @retval positive if some other error occurs
*/
METHOD int probesession {
device_t dev;
const struct crypto_session_params *csp;
};
/**
* @brief Initialize a new crypto session object
*
* Invoked by the crypto framework to initialize driver-specific data
* for a crypto session. The framework allocates and zeroes the
* driver's per-session memory object prior to invoking this method.
* The driver is able to access it's per-session memory object via
* crypto_get_driver_session().
*
* @param dev the crypto driver device
* @param crypto_session session being initialized
* @param csp crypto session parameters
*
* @retval 0 success
* @retval non-zero if some kind of error occurred
*/
METHOD int newsession {
device_t dev;
crypto_session_t crypto_session;
const struct crypto_session_params *csp;
};
/**
* @brief Destroy a crypto session object
*
* The crypto framework invokes this method when tearing down a crypto
* session. After this callback returns, the frame will explicitly
* zero and free the drvier's per-session memory object. If the
* driver requires additional actions to destroy a session, it should
* perform those in this method. If the driver does not require
* additional actions it does not need to provide an implementation of
* this method.
*
* @param dev the crypto driver device
* @param crypto_session session being destroyed
*/
METHOD void freesession {
device_t dev;
crypto_session_t crypto_session;
} DEFAULT null_freesession;
/**
* @brief Perform a symmetric crypto operation
*
* The crypto framework invokes this method for each symmetric crypto
* operation performed on a session. A reference to the containing
* session is stored as a member of 'struct cryptop'. This routine
* should not block, but queue the operation if necessary.
*
* This method may return ERESTART to indicate that any internal
* queues are full so the operation should be queued in the crypto
* framework and retried in the future.
*
* To report errors with a crypto operation, 'crp_etype' should be set
* and the operation completed by calling 'crypto_done'. This method
* should then return zero.
*
* @param dev the crypto driver device
* @param op crypto operation to perform
* @param flags set to CRYPTO_HINT_MORE if additional symmetric
* crypto operations are queued for this driver;
* otherwise set to zero.
*
* @retval 0 success
* @retval ERESTART internal queue is full
*/
METHOD int process {
device_t dev;
struct cryptop *op;
int flags;
};
/**
* @brief Perform an asymmetric crypto operation
*
* The crypto framework invokes this method for each asymmetric crypto
* operation. Each asymmetric crypto operation should be
* self-contained and is not assicated with any persistent session.
* This routine should not block, but queue the operation if
* necessary.
*
* This method may return ERESTART to indicate that any internal
* queues are full so the operation should be queued in the crypto
* framework and retried in the future.
*
* To report errors with a crypto operation, 'krp_status' should be set
* and the operation completed by calling 'crypto_kdone'. This method
* should then return zero.
*
* @param dev the crypto driver device
* @param op crypto operation to perform
* @param flags set to CRYPTO_HINT_MORE if additional asymmetric
* crypto operations are queued for this driver;
* otherwise set to zero.
*
* @retval 0 success
* @retval ERESTART internal queue is full
*/
METHOD int kprocess {
device_t dev;
struct cryptkop *op;
int flags;
};