wbrawner/openssl
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions
openssl/doc/man7/provider-mac.pod
Richard Levitte 92d9d0ae2b Rename ctx_{get,set}_params to {get,set}_ctx_params 
Recently, we added dispatched functions to get parameter descriptions,
and those for operation context parameters ended up being called
something_gettable_ctx_params and something_settable_ctx_params.

The corresponding dispatched functions to actually perform parameter
transfers were previously called something_ctx_get_params and
something_ctx_set_params, which doesn't quite match, so we rename them
to something_get_ctx_params and something_set_ctx_params.

An argument in favor of this name change is English, where you'd
rather say something like "set the context parameters".

This only change the libcrypto <-> provider interface.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9612)
2019-08-16 09:04:29 +02:00

255 lines
8.6 KiB
Text
Raw Blame History

=pod
=head1 NAME
provider-mac - The mac library E<lt>-E<gt> provider functions
=head1 SYNOPSIS
=for comment multiple includes
#include <openssl/core_numbers.h>
#include <openssl/core_names.h>
/*
* None of these are actual functions, but are displayed like this for
* the function signatures for functions that are offered as function
* pointers in OSSL_DISPATCH arrays.
*/
/* Context management */
void *OP_mac_newctx(void *provctx);
void OP_mac_freectx(void *mctx);
void *OP_mac_dupctx(void *src);
/* Encryption/decryption */
int OP_mac_init(void *mctx);
int OP_mac_update(void *mctx, const unsigned char *in, size_t inl);
int OP_mac_final(void *mctx, unsigned char *out, size_t *outl, size_t outsize);
/* MAC parameter descriptors */
const OSSL_PARAM *OP_mac_get_params(void);
const OSSL_PARAM *OP_mac_get_ctx_params(void);
const OSSL_PARAM *OP_mac_set_ctx_params(void);
/* MAC parameters */
int OP_mac_get_params(OSSL_PARAM params[]);
int OP_mac_get_ctx_params(void *mctx, OSSL_PARAM params[]);
int OP_mac_set_ctx_params(void *mctx, const OSSL_PARAM params[]);
=head1 DESCRIPTION
This documentation is primarily aimed at provider authors. See L<provider(7)>
for further information.
The MAC operation enables providers to implement mac algorithms and make
them available to applications via the API functions L<EVP_MAC_init(3)>,
L<EVP_MACM_update(3)> and L<EVP_MAC_final(3)>.
All "functions" mentioned here are passed as function pointers between
F<libcrypto> and the provider in B<OSSL_DISPATCH> arrays via
B<OSSL_ALGORITHM> arrays that are returned by the provider's
provider_query_operation() function
(see L<provider-base(7)/Provider Functions>).
All these "functions" have a corresponding function type definition
named B<OSSL_{name}_fn>, and a helper function to retrieve the
function pointer from an B<OSSL_DISPATCH> element named
B<OSSL_get_{name}>.
For example, the "function" OP_mac_newctx() has these:
typedef void *(OSSL_OP_mac_newctx_fn)(void *provctx);
static ossl_inline OSSL_OP_mac_newctx_fn
OSSL_get_OP_mac_newctx(const OSSL_DISPATCH *opf);
B<OSSL_DISPATCH> arrays are indexed by numbers that are provided as
macros in L<openssl-core_numbers.h(7)>, as follows:
OP_mac_newctx OSSL_FUNC_MAC_NEWCTX
OP_mac_freectx OSSL_FUNC_MAC_FREECTX
OP_mac_dupctx OSSL_FUNC_MAC_DUPCTX
OP_mac_init OSSL_FUNC_MAC_INIT
OP_mac_update OSSL_FUNC_MAC_UPDATE
OP_mac_final OSSL_FUNC_MAC_FINAL
OP_mac_get_params OSSL_FUNC_MAC_GET_PARAMS
OP_mac_get_ctx_params OSSL_FUNC_MAC_GET_CTX_PARAMS
OP_mac_set_ctx_params OSSL_FUNC_MAC_SET_CTX_PARAMS
OP_mac_gettable_params OSSL_FUNC_MAC_GETTABLE_PARAMS
OP_mac_gettable_ctx_params OSSL_FUNC_MAC_GETTABLE_CTX_PARAMS
OP_mac_settable_ctx_params OSSL_FUNC_MAC_SETTABLE_CTX_PARAMS
A mac algorithm implementation may not implement all of these functions.
In order to be a consistent set of functions, at least the following functions
must be implemented: OP_mac_newctx(), OP_mac_freectx(), OP_mac_init(),
OP_mac_update(), OP_mac_final().
All other functions are optional.
=head2 Context Management Functions
OP_mac_newctx() should create and return a pointer to a provider side
structure for holding context information during a mac operation.
A pointer to this context will be passed back in a number of the other mac
operation function calls.
The paramater I<provctx> is the provider context generated during provider
initialisation (see L<provider(3)>).
OP_mac_freectx() is passed a pointer to the provider side mac context in
the I<mctx> parameter.
If it receives NULL as I<mctx> value, it should not do anything other than
return.
This function should free any resources associated with that context.
OP_mac_dupctx() should duplicate the provider side mac context in the
I<mctx> parameter and return the duplicate copy.
=head2 Encryption/Decryption Functions
OP_mac_init() initialises a mac operation given a newly created provider
side mac context in the I<mctx> paramter.
OP_mac_update() is called to supply data for MAC computation of a previously
initialised mac operation.
The I<mctx> parameter contains a pointer to a previously initialised provider
side context.
OP_mac_update() may be called multiple times for a single mac operation.
OP_mac_final() completes the MAC computation started through previous
OP_mac_init() and OP_mac_update() calls.
The I<mctx> parameter contains a pointer to the provider side context.
The resulting MAC should be written to I<out> and the amount of data written
to I<*outl>, which should not exceed I<outsize> bytes.
The same expectations apply to I<outsize> as documented for
L<EVP_MAC_final(3)>.
=head2 Mac Parameters
See L<OSSL_PARAM(3)> for further details on the parameters structure used by
these functions.
OP_mac_get_params() gets details of parameter values associated with the
provider algorithm and stores them in I<params>.
OP_mac_set_ctx_params() sets mac parameters associated with the given
provider side mac context I<mctx> to I<params>.
Any parameter settings are additional to any that were previously set.
OP_mac_get_ctx_params() gets details of currently set parameter values
associated with the given provider side mac context I<mctx> and stores them
in I<params>.
OP_mac_gettable_params(), OP_mac_gettable_ctx_params(), and
OP_mac_settable_ctx_params() all return constant B<OSSL_PARAM> arrays
as descriptors of the parameters that OP_mac_get_params(),
OP_mac_get_ctx_params(), and OP_mac_set_ctx_params() can handle,
respectively.
Parameters currently recognised by built-in macs are as follows. Not all
parameters are relevant to, or are understood by all macs:
=over 4
=item B<OSSL_MAC_PARAM_KEY> (octet string)
Sets the key in the associated MAC ctx.
=item B<OSSL_MAC_PARAM_IV> (octet string)
Sets the IV of the underlying cipher, when applicable.
=item B<OSSL_MAC_PARAM_CUSTOM> (utf8 string)
Sets the custom string in the associated MAC ctx.
=item B<OSSL_MAC_PARAM_SALT> (octet string)
Sets the salt of the underlying cipher, when applicable.
=item B<OSSL_MAC_PARAM_BLOCK_XOF> (int)
Sets XOF mode in the associated MAC ctx.
0 means no XOF mode, 1 means XOF mode.
=item B<OSSL_MAC_PARAM_FLAGS> (int)
Gets flags associated with the MAC.
=for comment We need to investigate if this is the right approach
=item B<OSSL_MAC_PARAM_ALGORITHM> (utf8 string)
Sets the name of the underlying algorithm to be used.
It must name a suitable algorithm for the MAC that's being used.
=item B<OSSL_MAC_PARAM_MD> (utf8 string)
=item B<OSSL_MAC_PARAM_DIGEST> (utf8 string)
=item B<OSSL_MAC_PARAM_CIPHER> (utf8 string)
These have the same meaning as B<OSSL_MAC_PARAM_ALGORITHM>, but specify
the expected operation for the underlying algorithm.
These are regarded as antiquated, but are kept for easier transition from
legacy MAC implementations.
=item B<OSSL_MAC_PARAM_ENGINE> (utf8 string)
Sets the name of an engine that implements the underlying algorithm.
This must be given together with the algorithm naming parameter to be
considered valid.
=item B<OSSL_MAC_PARAM_PROPERTIES> (utf8 string)
Sets the properties to be queried when trying to fetch the underlying algorithm.
This must be given together with the algorithm naming parameter to be
considered valid.
Note that both this and B<OSSL_MAC_PARAM_ENGINE> can be given at the same time.
If the underlying algorithm ends up being fetched from a provider, offered by
and engine, or a built in legacy function depends on what is available.
=item B<OSSL_MAC_PARAM_SIZE> (int)
=item B<OSSL_MAC_PARAM_DIGESTSIZE> (int)
=item B<OSSL_MAC_PARAM_OUTLEN> (int)
All three names are considered the same.
B<OSSL_MAC_PARAM_SIZE> and B<OSSL_MAC_PARAM_DIGESTSIZE> are considered
antiquated, but are kept for easier transition from legacy MAC implementations.
=back
=head1 RETURN VALUES
OP_mac_newctx() and OP_mac_dupctx() should return the newly created
provider side mac context, or NULL on failure.
OP_mac_init(), OP_mac_update(), OP_mac_final(), OP_mac_get_params(),
OP_mac_get_ctx_params() and OP_mac_set_ctx_params() should return 1 for
success or 0 on error.
OP_mac_gettable_params(), OP_mac_gettable_ctx_params() and
OP_mac_settable_ctx_params() should return a constant B<OSSL_PARAM>
array, or NULL if none is offered.
=head1 SEE ALSO
L<provider(7)>
=head1 HISTORY
The provider MAC interface was introduced in OpenSSL 3.0.
=head1 COPYRIGHT
Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut
Reference in a new issue View git blame Copy permalink