As the ->q in struct dh_ctx gets never set anywhere, the code in
dh_is_pubkey_valid() for doing the full public key validation in accordance
to SP800-56Arev3 is effectively dead.
However, for safe-prime groups Q = (P - 1)/2 by definition and
as the safe-prime groups are the only possible groups in FIPS mode (via
those ffdheXYZ() templates), this enables dh_is_pubkey_valid() to calculate
Q on the fly for these.
Implement this.
With this change, the last code accessing struct dh_ctx's ->q is now gone.
Remove this member from struct dh_ctx.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Ephemeral key generation can be requested from any of the ffdheXYZ(dh)
variants' common ->set_secret() by passing it an (encoded) struct dh
with the key parameter being unset, i.e. with ->key_size == 0. As the
whole purpose of the ffdheXYZ(dh) templates is to fill in the group
parameters as appropriate, they expect ->p and ->g to be unset in any
input struct dh as well. This means that a user would have to encode an
all-zeroes struct dh instance via crypto_dh_encode_key() when requesting
ephemeral key generation from a ffdheXYZ(dh) instance, which is kind of
pointless.
Make dh_safe_prime_set_secret() to decode a struct dh from the supplied
buffer only if the latter is non-NULL and initialize it with all zeroes
otherwise.
That is, it is now possible to call
crypto_kpp_set_secret(tfm, NULL, 0);
on any ffdheXYZ(dh) tfm for requesting ephemeral key generation.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The support for NVME in-band authentication currently in the works ([1])
needs to generate ephemeral DH keys for use with the RFC 7919 safe-prime
FFDHE groups.
In analogy to ECDH and its ecc_gen_privkey(), implement a
dh_safe_prime_gen_privkey() and invoke it from the ffdheXYZ(dh) templates'
common ->set_secret(), i.e. dh_safe_prime_set_secret(), in case the input
->key_size is zero.
As the RFC 7919 FFDHE groups are classified as approved safe-prime groups
by SP800-56Arev3, it's worthwhile to make the new
dh_safe_prime_gen_privkey() to follow the approach specified in
SP800-56Arev3, sec. 5.6.1.1.3 ("Key-Pair Generation Using Extra Random
Bits") in order to achieve conformance.
SP800-56Arev3 specifies a lower as well as an upper bound on the generated
key's length:
- it must be >= two times the maximum supported security strength of
the group in question and
- it must be <= the length of the domain parameter Q.
For any safe-prime group Q = (P - 1)/2 by definition and the individual
maximum supported security strengths as specified by SP800-56Arev3 have
been made available as part of the FFDHE dh_safe_prime definitions
introduced with a previous patch. Make dh_safe_prime_gen_privkey() pick
twice the maximum supported strength rounded up to the next power of two
for the output key size. This choice respects both, the lower and upper
bounds given by SP800-90Arev3 for any of the approved safe-prime groups and
is also in line with the NVME base spec 2.0, which requires the key size to
be >= 256bits.
[1] https://lore.kernel.org/r/20211202152358.60116-1-hare@suse.de
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Current work on NVME in-band authentication support ([1]) needs to invoke
DH with the FFDHE safe-prime group parameters specified in RFC 7919.
Introduce a new CRYPTO_DH_RFC7919_GROUPS Kconfig option. If enabled, make
dh_generic register a couple of ffdheXYZ(dh) templates, one for each group:
ffdhe2048(dh), ffdhe3072(dh), ffdhe4096(dh), ffdhe6144(dh) and
ffdhe8192(dh). Their respective ->set_secret() expects a (serialized)
struct dh, just like the underlying "dh" implementation does, but with the
P and G values unset so that the safe-prime constants for the given group
can be filled in by the wrapping template.
Internally, a struct dh_safe_prime instance is being defined for each of
the ffdheXYZ(dh) templates as appropriate. In order to prepare for future
key generation, fill in the maximum security strength values as specified
by SP800-56Arev3 on the go, even though they're not needed at this point
yet.
Implement the respective ffdheXYZ(dh) crypto_template's ->create() by
simply forwarding any calls to the __dh_safe_prime_create() helper
introduced with the previous commit, passing the associated dh_safe_prime
in addition to the received ->create() arguments.
[1] https://lore.kernel.org/r/20211202152358.60116-1-hare@suse.de
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Recent work on NVME in-band authentication support ([1]) needs to invoke
the "dh" KPP with the FFDHE safe-prime group parameters as specified in
RFC 7919 and generate ephemeral keys suitable for the respective group. By
coincidence, the requirements from NIST SP800-56Arev3,
sec. 5.5.2 ("Assurance of Domain-Parameter Validity") basically boil down
to disallowing any group parameters not among the approved safe-prime
groups specified in either RFC 7919 or RFC 3526 in FIPS mode. Furthermore,
SP800-56Arev3 specifies the respective security strength for each of the
approved safe-prime groups, which has a direct impact on the minimum key
lengths.
In this light, it's desirable to introduce built-in support for the
RFC 7919 safe-prime groups to the kernel's DH implementation, provide a
SP800-56Arev3 conforming key generation primitive for those and render
non-approved group parameters unusable in FIPS mode on the way.
As suggested ([2]) in the course of discussion to previous iterations of
this patchset, the built-in support for ffdhe groups would be best made
available in the form of templates wrapping the existing "dh"
implementation, one for each group specified by RFC 7919: ffdhe2048(dh),
ffdhe3072(dh), ffdhe4096(dh), ffdhe6144(dh) and ffdhe8192(dh). As these
templates differ only in the safe-prime constants they'd configure the
inner "dh" transforms with, they can share almost all of their
"dh"-wrapping template implementation code.
Introduce this common code to dh_generic. The actual dump of the RFC 7919
safe-prime constants will be deferred to the next patch in order to
facilitate review. The ephemeral key generation primitive mentioned above
likewise deserves a patch on its own, as does the mechanism by which
unapproved groups are rendered unusable in FIPS mode.
Define a struct dh_safe_prime container for specifying the individual
templates' associated safe-prime group constants. All ffdheXYZ(dh) template
instances will store a pointer to such a dh_safe_prime in their context
areas each. Implement the common __dh_safe_prime_create() template
instantiation helper. The intention is that the individual ffdheXYZ(dh)
crypto_templates' ->create() implementations will simply forward any calls
to __dh_safe_prime_create(), passing a suitable dh_safe_prime in addition
to the received ->create() arguments. __dh_safe_prime_create() would then
create and register a kpp_instance as appropriate, storing the given
dh_safe_prime pointer alongside a crypto_kpp_spawn for the inner "dh"
kpp_alg in the context area.
As the ffdheXYZ(dh) kpp_instances are supposed to act as proxies to the
inner "dh" kpp_alg, make each of their associated crypto_kpp transforms to
in turn own an inner "dh" transform, a pointer to which gets stored in the
context area. Setup and teardown are getting handled from the outer
->init_tfm() and ->exit_tfm() respectively.
In order to achieve the overall goal and let the ffdheXYZ(dh) kpp_instances
configure the inner "dh" transforms with the respective group parameters,
make their common ->set_secret(), the new dh_safe_prime_set_secret(), fill
in the P and G values before forwarding the call to the inner "dh"'s
->set_secret(). Note that the outer ->set_secret() can obtain the P value
associated with the given ffdheXYZ(dh) kpp_instance by means of the
dh_safe_prime referenced from the latter's context. The value of G OTOH
always equals constant 2 for the safe-prime groups.
Finally, make the remaining two kpp_alg primitives both operating on
kpp_requests, i.e. ->generate_public_key() and ->compute_shared_secret(),
to merely forward any request to the inner "dh" implementation. However, a
kpp_request instance received from the outside cannot get simply passed
on as-is, because its associated transform (crypto_kpp_reqtfm()) will have
been set to the outer ffdheXYZ(dh) one. In order to handle this, reserve
some space in the outer ffdheXYZ(dh) kpp_requests' context areas for in
turn storing an inner kpp_request suitable for "dh" each. Make the outer
->generate_public_key() and ->compute_shared_secret() respectively to setup
this inner kpp_request by means of the new dh_safe_prime_prepare_dh_req()
helper before handing it over to the "dh" implementation for further
processing. dh_safe_prime_prepare_dh_req() basically copies the outer
kpp_request received from the outside over to the inner one, but installs
the inner transform and its own ->complete() proxy callback therein. This
completion callback, the new dh_safe_prime_complete_req(), doesn't do
anything beyond completing the outer request. Note that there exist some
examples in crypto/, which would simply install the completion handler
from the outer request at the inner one in similar setups, e.g. seqiv.
However, this would mean that the user-provided completion handler won't
get called with the address of the outer kpp_request initially submitted
and the handler might not be prepared for this. Users could certainly work
around this by setting the callback ->data properly, but IMO it's cleaner
this way. Furthermore, it might make sense to extend
dh_safe_prime_complete_req() in the future and move e.g. those
post-computation FIPS checks from the generic "dh" implementation to the
ffdheXYZ(dh) templates.
[1] https://lore.kernel.org/r/20211202152358.60116-1-hare@suse.de
[2] https://lore.kernel.org/r/20211217055227.GA20698@gondor.apana.org.au
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The only current user of the DH KPP algorithm, the
keyctl(KEYCTL_DH_COMPUTE) syscall, doesn't set the domain parameter ->q
in struct dh. Remove it and any associated (de)serialization code in
crypto_dh_encode_key() and crypto_dh_decode_key. Adjust the encoded
->secret values in testmgr's DH test vectors accordingly.
Note that the dh-generic implementation would have initialized its
struct dh_ctx's ->q from the decoded struct dh's ->q, if present. If this
struct dh_ctx's ->q would ever have been non-NULL, it would have enabled a
full key validation as specified in NIST SP800-56A in dh_is_pubkey_valid().
However, as outlined above, ->q is always NULL in practice and the full key
validation code is effectively dead. A later patch will make
dh_is_pubkey_valid() to calculate Q from P on the fly, if possible, so
don't remove struct dh_ctx's ->q now, but leave it there until that has
happened.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
FIPS disallows DH with keys < 2048 bits. Thus, the kernel should
consider the enforcement of this limit.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
After the generation of a local public key, SP800-56A rev 3 section
5.6.2.1.3 mandates a validation of that key with a full validation
compliant to section 5.6.2.3.1.
Only if the full validation passes, the key is allowed to be used.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
SP800-56A rev3 section 5.7.1.1 step 2 mandates that the validity of the
calculated shared secret is verified before the data is returned to the
caller. This patch adds the validation check.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Acked-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use subsys_initcall for registration of all templates and generic
algorithm implementations, rather than module_init. Then change
cryptomgr to use arch_initcall, to place it before the subsys_initcalls.
This is needed so that when both a generic and optimized implementation
of an algorithm are built into the kernel (not loadable modules), the
generic implementation is registered before the optimized one.
Otherwise, the self-tests for the optimized implementation are unable to
allocate the generic implementation for the new comparison fuzz tests.
Note that on arm, a side effect of this change is that self-tests for
generic implementations may run before the unaligned access handler has
been installed. So, unaligned accesses will crash the kernel. This is
arguably a good thing as it makes it easier to detect that type of bug.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case memory resources for *base* were allocated, release them
before return.
Addresses-Coverity-ID: 1471702 ("Resource leak")
Fixes: e3fe0ae129 ("crypto: dh - add public key verification test")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
According to SP800-56A section 5.6.2.1, the public key to be processed
for the DH operation shall be checked for appropriateness. The check
shall covers the full verification test in case the domain parameter Q
is provided as defined in SP800-56A section 5.6.2.3.1. If Q is not
provided, the partial check according to SP800-56A section 5.6.2.3.2 is
performed.
The full verification test requires the presence of the domain parameter
Q. Thus, the patch adds the support to handle Q. It is permissible to
not provide the Q value as part of the domain parameters. This implies
that the interface is still backwards-compatible where so far only P and
G are to be provided. However, if Q is provided, it is imported.
Without the test, the NIST ACVP testing fails. After adding this check,
the NIST ACVP testing passes. Testing without providing the Q domain
parameter has been performed to verify the interface has not changed.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Neither 'p' nor 'g' can be NULL, as they were unpacked using
crypto_dh_decode_key(). And it makes no sense for them to be optional.
So remove the NULL checks that were copy-and-pasted into both modules.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_kpp_maxsize() asks for the output buffer size without
caring for errors. It allways assume that will be called after
a valid setkey. Comply with it and return what he wants.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
setkey can be called multiple times during the existence
of the transformation object. In case of multiple setkey calls,
the old key was not freed and we leaked memory.
Free the old MPI key if any.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Constify the buffer passed to crypto_kpp_set_secret() and
kpp_alg.set_secret, since it is never modified.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix the single instance where a positive EINVAL was returned.
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Every implementation of RSA that we have naturally generates
output with leading zeroes. The one and only user of RSA,
pkcs1pad wants to have those leading zeroes in place, in fact
because they are currently absent it has to write those zeroes
itself.
So we shouldn't be stripping leading zeroes in the first place.
In fact this patch makes rsa-generic produce output with fixed
length so that pkcs1pad does not need to do any extra work.
This patch also changes DH to use the new interface.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* Implement MPI based Diffie-Hellman under kpp API
* Test provided uses data generad by OpenSSL
Signed-off-by: Salvatore Benedetto <salvatore.benedetto@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
