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2022-03-03crypto: dh - split out deserialization code from crypto_dh_decode()Nicolai Stange
A subsequent commit will introduce "dh" wrapping templates of the form "ffdhe2048(dh)", "ffdhe3072(dh)" and so on in order to provide built-in support for the well-known safe-prime ffdhe group parameters specified in RFC 7919. Those templates' ->set_secret() will wrap the inner "dh" implementation's ->set_secret() and set the ->p and ->g group parameters as appropriate on the way inwards. More specifically, - A ffdheXYZ(dh) user would call crypto_dh_encode() on a struct dh instance having ->p == ->g == NULL as well as ->p_size == ->g_size == 0 and pass the resulting buffer to the outer ->set_secret(). - This outer ->set_secret() would then decode the struct dh via crypto_dh_decode_key(), set ->p, ->g, ->p_size as well as ->g_size as appropriate for the group in question and encode the struct dh again before passing it further down to the inner "dh"'s ->set_secret(). The problem is that crypto_dh_decode_key() implements some basic checks which would reject parameter sets with ->p_size == 0 and thus, the ffdheXYZ templates' ->set_secret() cannot use it as-is for decoding the passed buffer. As the inner "dh"'s ->set_secret() will eventually conduct said checks on the final parameter set anyway, the outer ->set_secret() really only needs the decoding functionality. Split out the pure struct dh decoding part from crypto_dh_decode_key() into the new __crypto_dh_decode_key(). __crypto_dh_decode_key() gets defined in crypto/dh_helper.c, but will have to get called from crypto/dh.c and thus, its declaration must be somehow made available to the latter. Strictly speaking, __crypto_dh_decode_key() is internal to the dh_generic module, yet it would be a bit over the top to introduce a new header like e.g. include/crypto/internal/dh.h containing just a single prototype. Add the __crypto_dh_decode_key() declaration to include/crypto/dh.h instead. Provide a proper kernel-doc annotation, even though __crypto_dh_decode_key() is purposedly not on the function list specified in Documentation/crypto/api-kpp.rst. 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>
2022-03-03crypto: dh - constify struct dh's pointer membersNicolai Stange
struct dh contains several pointer members corresponding to DH parameters: ->key, ->p and ->g. A subsequent commit will introduce "dh" wrapping templates of the form "ffdhe2048(dh)", "ffdhe3072(dh)" and so on in order to provide built-in support for the well-known safe-prime ffdhe group parameters specified in RFC 7919. These templates will need to set the group parameter related members of the (serialized) struct dh instance passed to the inner "dh" kpp_alg instance, i.e. ->p and ->g, to some constant, static storage arrays. Turn the struct dh pointer members' types into "pointer to const" in preparation for this. 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>
2022-03-03crypto: dh - remove struct dh's ->q memberNicolai Stange
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>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152Thomas Gleixner
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>
2018-07-09crypto: dh - add public key verification testStephan Mueller
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>
2017-10-12crypto: dh - return unsigned value for crypto_dh_key_len()Tudor-Dan Ambarus
DH_KPP_SECRET_MIN_SIZE and dh_data_size() are both returning unsigned values. Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-06-10crypto: kpp, (ec)dh - fix typosTudor-Dan Ambarus
While here, add missing argument description (ndigits). Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-13crypto: doc - add KPP documentationStephan Mueller
Add the KPP API documentation to the kernel crypto API Sphinx documentation. This addition includes the documentation of the ECDH and DH helpers which are needed to create the approrpiate input data for the crypto_kpp_set_secret function. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-06-23crypto: dh - Add DH software implementationSalvatore Benedetto
* 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>