629 lines
27 KiB
Plaintext
629 lines
27 KiB
Plaintext
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.\" ========================================================================
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.\"
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.IX Title "EVP_MAC 3ossl"
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.TH EVP_MAC 3ossl "2024-01-30" "3.2.1" "OpenSSL"
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.\" For nroff, turn off justification. Always turn off hyphenation; it makes
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.\" way too many mistakes in technical documents.
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.if n .ad l
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.nh
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.SH "NAME"
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EVP_MAC, EVP_MAC_fetch, EVP_MAC_up_ref, EVP_MAC_free, EVP_MAC_is_a,
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EVP_MAC_get0_name, EVP_MAC_names_do_all, EVP_MAC_get0_description,
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EVP_MAC_get0_provider, EVP_MAC_get_params, EVP_MAC_gettable_params,
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EVP_MAC_CTX, EVP_MAC_CTX_new, EVP_MAC_CTX_free, EVP_MAC_CTX_dup,
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EVP_MAC_CTX_get0_mac, EVP_MAC_CTX_get_params, EVP_MAC_CTX_set_params,
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EVP_MAC_CTX_get_mac_size, EVP_MAC_CTX_get_block_size, EVP_Q_mac,
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EVP_MAC_init, EVP_MAC_update, EVP_MAC_final, EVP_MAC_finalXOF,
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EVP_MAC_gettable_ctx_params, EVP_MAC_settable_ctx_params,
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EVP_MAC_CTX_gettable_params, EVP_MAC_CTX_settable_params,
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EVP_MAC_do_all_provided \- EVP MAC routines
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.SH "SYNOPSIS"
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.IX Header "SYNOPSIS"
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.Vb 1
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\& #include <openssl/evp.h>
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\&
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\& typedef struct evp_mac_st EVP_MAC;
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\& typedef struct evp_mac_ctx_st EVP_MAC_CTX;
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\&
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\& EVP_MAC *EVP_MAC_fetch(OSSL_LIB_CTX *libctx, const char *algorithm,
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\& const char *properties);
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\& int EVP_MAC_up_ref(EVP_MAC *mac);
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\& void EVP_MAC_free(EVP_MAC *mac);
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\& int EVP_MAC_is_a(const EVP_MAC *mac, const char *name);
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\& const char *EVP_MAC_get0_name(const EVP_MAC *mac);
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\& int EVP_MAC_names_do_all(const EVP_MAC *mac,
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\& void (*fn)(const char *name, void *data),
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\& void *data);
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\& const char *EVP_MAC_get0_description(const EVP_MAC *mac);
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\& const OSSL_PROVIDER *EVP_MAC_get0_provider(const EVP_MAC *mac);
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\& int EVP_MAC_get_params(EVP_MAC *mac, OSSL_PARAM params[]);
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\&
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\& EVP_MAC_CTX *EVP_MAC_CTX_new(EVP_MAC *mac);
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\& void EVP_MAC_CTX_free(EVP_MAC_CTX *ctx);
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\& EVP_MAC_CTX *EVP_MAC_CTX_dup(const EVP_MAC_CTX *src);
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\& EVP_MAC *EVP_MAC_CTX_get0_mac(EVP_MAC_CTX *ctx);
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\& int EVP_MAC_CTX_get_params(EVP_MAC_CTX *ctx, OSSL_PARAM params[]);
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\& int EVP_MAC_CTX_set_params(EVP_MAC_CTX *ctx, const OSSL_PARAM params[]);
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\&
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\& size_t EVP_MAC_CTX_get_mac_size(EVP_MAC_CTX *ctx);
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\& size_t EVP_MAC_CTX_get_block_size(EVP_MAC_CTX *ctx);
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\& unsigned char *EVP_Q_mac(OSSL_LIB_CTX *libctx, const char *name, const char *propq,
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\& const char *subalg, const OSSL_PARAM *params,
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\& const void *key, size_t keylen,
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\& const unsigned char *data, size_t datalen,
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\& unsigned char *out, size_t outsize, size_t *outlen);
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\& int EVP_MAC_init(EVP_MAC_CTX *ctx, const unsigned char *key, size_t keylen,
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\& const OSSL_PARAM params[]);
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\& int EVP_MAC_update(EVP_MAC_CTX *ctx, const unsigned char *data, size_t datalen);
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\& int EVP_MAC_final(EVP_MAC_CTX *ctx,
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\& unsigned char *out, size_t *outl, size_t outsize);
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\& int EVP_MAC_finalXOF(EVP_MAC_CTX *ctx, unsigned char *out, size_t outsize);
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\&
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\& const OSSL_PARAM *EVP_MAC_gettable_params(const EVP_MAC *mac);
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\& const OSSL_PARAM *EVP_MAC_gettable_ctx_params(const EVP_MAC *mac);
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\& const OSSL_PARAM *EVP_MAC_settable_ctx_params(const EVP_MAC *mac);
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\& const OSSL_PARAM *EVP_MAC_CTX_gettable_params(EVP_MAC_CTX *ctx);
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\& const OSSL_PARAM *EVP_MAC_CTX_settable_params(EVP_MAC_CTX *ctx);
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\&
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\& void EVP_MAC_do_all_provided(OSSL_LIB_CTX *libctx,
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\& void (*fn)(EVP_MAC *mac, void *arg),
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\& void *arg);
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.Ve
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.SH "DESCRIPTION"
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.IX Header "DESCRIPTION"
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These types and functions help the application to calculate MACs of
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different types and with different underlying algorithms if there are
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any.
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.PP
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MACs are a bit complex insofar that some of them use other algorithms
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for actual computation. \s-1HMAC\s0 uses a digest, and \s-1CMAC\s0 uses a cipher.
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Therefore, there are sometimes two contexts to keep track of, one for
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the \s-1MAC\s0 algorithm itself and one for the underlying computation
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algorithm if there is one.
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.PP
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To make things less ambiguous, this manual talks about a \*(L"context\*(R" or
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\&\*(L"\s-1MAC\s0 context\*(R", which is to denote the \s-1MAC\s0 level context, and about a
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\&\*(L"underlying context\*(R", or \*(L"computation context\*(R", which is to denote the
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context for the underlying computation algorithm if there is one.
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.SS "Types"
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.IX Subsection "Types"
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\&\fB\s-1EVP_MAC\s0\fR is a type that holds the implementation of a \s-1MAC.\s0
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.PP
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\&\fB\s-1EVP_MAC_CTX\s0\fR is a context type that holds internal \s-1MAC\s0 information
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as well as a reference to a computation context, for those MACs that
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rely on an underlying computation algorithm.
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.SS "Algorithm implementation fetching"
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.IX Subsection "Algorithm implementation fetching"
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\&\fIEVP_MAC_fetch()\fR fetches an implementation of a \s-1MAC \s0\fIalgorithm\fR, given
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a library context \fIlibctx\fR and a set of \fIproperties\fR.
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See \*(L"\s-1ALGORITHM FETCHING\*(R"\s0 in \fIcrypto\fR\|(7) for further information.
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.PP
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See \*(L"Message Authentication Code (\s-1MAC\s0)\*(R" in \fIOSSL_PROVIDER\-default\fR\|(7) for the list
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of algorithms supported by the default provider.
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.PP
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The returned value must eventually be freed with
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\&\fIEVP_MAC_free\fR\|(3).
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.PP
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\&\fIEVP_MAC_up_ref()\fR increments the reference count of an already fetched
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\&\s-1MAC.\s0
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.PP
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\&\fIEVP_MAC_free()\fR frees a fetched algorithm.
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\&\s-1NULL\s0 is a valid parameter, for which this function is a no-op.
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.SS "Context manipulation functions"
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.IX Subsection "Context manipulation functions"
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\&\fIEVP_MAC_CTX_new()\fR creates a new context for the \s-1MAC\s0 type \fImac\fR.
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The created context can then be used with most other functions
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described here.
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.PP
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\&\fIEVP_MAC_CTX_free()\fR frees the contents of the context, including an
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underlying context if there is one, as well as the context itself.
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\&\s-1NULL\s0 is a valid parameter, for which this function is a no-op.
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.PP
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\&\fIEVP_MAC_CTX_dup()\fR duplicates the \fIsrc\fR context and returns a newly allocated
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context.
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.PP
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\&\fIEVP_MAC_CTX_get0_mac()\fR returns the \fB\s-1EVP_MAC\s0\fR associated with the context
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\&\fIctx\fR.
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.SS "Computing functions"
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.IX Subsection "Computing functions"
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\&\fIEVP_Q_mac()\fR computes the message authentication code
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of \fIdata\fR with length \fIdatalen\fR
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using the \s-1MAC\s0 algorithm \fIname\fR and the key \fIkey\fR with length \fIkeylen\fR.
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The \s-1MAC\s0 algorithm is fetched using any given \fIlibctx\fR and property query
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string \fIpropq\fR. It takes parameters \fIsubalg\fR and further \fIparams\fR,
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both of which may be \s-1NULL\s0 if not needed.
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If \fIout\fR is not \s-1NULL,\s0 it places the result in the memory pointed at by \fIout\fR,
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but only if \fIoutsize\fR is sufficient (otherwise no computation is made).
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If \fIout\fR is \s-1NULL,\s0 it allocates and uses a buffer of suitable length,
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which will be returned on success and must be freed by the caller.
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In either case, also on error,
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it assigns the number of bytes written to \fI*outlen\fR unless \fIoutlen\fR is \s-1NULL.\s0
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.PP
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\&\fIEVP_MAC_init()\fR sets up the underlying context \fIctx\fR with information given
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via the \fIkey\fR and \fIparams\fR arguments. The \s-1MAC \s0\fIkey\fR has a length of
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\&\fIkeylen\fR and the parameters in \fIparams\fR are processed before setting
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the key. If \fIkey\fR is \s-1NULL,\s0 the key must be set via \fIparams\fR either
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as part of this call or separately using \fIEVP_MAC_CTX_set_params()\fR.
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Providing non-NULL \fIparams\fR to this function is equivalent to calling
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\&\fIEVP_MAC_CTX_set_params()\fR with those \fIparams\fR for the same \fIctx\fR beforehand.
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Note: There are additional requirements for some \s-1MAC\s0 algorithms during
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re-initalization (i.e. calling \fIEVP_MAC_init()\fR on an \s-1EVP_MAC\s0 after \fIEVP_MAC_final()\fR
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has been called on the same object). See the \s-1NOTES\s0 section below.
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.PP
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\&\fIEVP_MAC_init()\fR should be called before \fIEVP_MAC_update()\fR and \fIEVP_MAC_final()\fR.
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.PP
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\&\fIEVP_MAC_update()\fR adds \fIdatalen\fR bytes from \fIdata\fR to the \s-1MAC\s0 input.
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.PP
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\&\fIEVP_MAC_final()\fR does the final computation and stores the result in
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the memory pointed at by \fIout\fR of size \fIoutsize\fR, and sets the number
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of bytes written in \fI*outl\fR at.
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If \fIout\fR is \s-1NULL\s0 or \fIoutsize\fR is too small, then no computation
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|
is made.
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To figure out what the output length will be and allocate space for it
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dynamically, simply call with \fIout\fR being \s-1NULL\s0 and \fIoutl\fR
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pointing at a valid location, then allocate space and make a second
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call with \fIout\fR pointing at the allocated space.
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.PP
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\&\fIEVP_MAC_finalXOF()\fR does the final computation for an \s-1XOF\s0 based \s-1MAC\s0 and stores
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the result in the memory pointed at by \fIout\fR of size \fIoutsize\fR.
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.PP
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\&\fIEVP_MAC_get_params()\fR retrieves details about the implementation
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\&\fImac\fR.
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The set of parameters given with \fIparams\fR determine exactly what
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parameters should be retrieved.
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Note that a parameter that is unknown in the underlying context is
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simply ignored.
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.PP
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\&\fIEVP_MAC_CTX_get_params()\fR retrieves chosen parameters, given the
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context \fIctx\fR and its underlying context.
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The set of parameters given with \fIparams\fR determine exactly what
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parameters should be retrieved.
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Note that a parameter that is unknown in the underlying context is
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simply ignored.
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.PP
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\&\fIEVP_MAC_CTX_set_params()\fR passes chosen parameters to the underlying
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context, given a context \fIctx\fR.
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The set of parameters given with \fIparams\fR determine exactly what
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parameters are passed down.
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If \fIparams\fR are \s-1NULL,\s0 the underlying context should do nothing and return 1.
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Note that a parameter that is unknown in the underlying context is
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simply ignored.
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Also, what happens when a needed parameter isn't passed down is
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defined by the implementation.
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.PP
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\&\fIEVP_MAC_gettable_params()\fR returns an \s-1\fIOSSL_PARAM\s0\fR\|(3) array that describes
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the retrievable and settable parameters. \fIEVP_MAC_gettable_params()\fR
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returns parameters that can be used with \fIEVP_MAC_get_params()\fR.
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.PP
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\&\fIEVP_MAC_gettable_ctx_params()\fR and \fIEVP_MAC_CTX_gettable_params()\fR
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return constant \s-1\fIOSSL_PARAM\s0\fR\|(3) arrays that describe the retrievable
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parameters that can be used with \fIEVP_MAC_CTX_get_params()\fR.
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\&\fIEVP_MAC_gettable_ctx_params()\fR returns the parameters that can be retrieved
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from the algorithm, whereas \fIEVP_MAC_CTX_gettable_params()\fR returns
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the parameters that can be retrieved in the context's current state.
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.PP
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\&\fIEVP_MAC_settable_ctx_params()\fR and \fIEVP_MAC_CTX_settable_params()\fR return
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constant \s-1\fIOSSL_PARAM\s0\fR\|(3) arrays that describe the settable parameters that
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can be used with \fIEVP_MAC_CTX_set_params()\fR. \fIEVP_MAC_settable_ctx_params()\fR
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returns the parameters that can be retrieved from the algorithm,
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whereas \fIEVP_MAC_CTX_settable_params()\fR returns the parameters that can
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be retrieved in the context's current state.
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.SS "Information functions"
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.IX Subsection "Information functions"
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\&\fIEVP_MAC_CTX_get_mac_size()\fR returns the \s-1MAC\s0 output size for the given context.
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.PP
|
|
\&\fIEVP_MAC_CTX_get_block_size()\fR returns the \s-1MAC\s0 block size for the given context.
|
|
Not all \s-1MAC\s0 algorithms support this.
|
|
.PP
|
|
\&\fIEVP_MAC_is_a()\fR checks if the given \fImac\fR is an implementation of an
|
|
algorithm that's identifiable with \fIname\fR.
|
|
.PP
|
|
\&\fIEVP_MAC_get0_provider()\fR returns the provider that holds the implementation
|
|
of the given \fImac\fR.
|
|
.PP
|
|
\&\fIEVP_MAC_do_all_provided()\fR traverses all \s-1MAC\s0 implemented by all activated
|
|
providers in the given library context \fIlibctx\fR, and for each of the
|
|
implementations, calls the given function \fIfn\fR with the implementation method
|
|
and the given \fIarg\fR as argument.
|
|
.PP
|
|
\&\fIEVP_MAC_get0_name()\fR return the name of the given \s-1MAC. \s0 For fetched MACs
|
|
with multiple names, only one of them is returned; it's
|
|
recommended to use \fIEVP_MAC_names_do_all()\fR instead.
|
|
.PP
|
|
\&\fIEVP_MAC_names_do_all()\fR traverses all names for \fImac\fR, and calls
|
|
\&\fIfn\fR with each name and \fIdata\fR.
|
|
.PP
|
|
\&\fIEVP_MAC_get0_description()\fR returns a description of the \fImac\fR, meant
|
|
for display and human consumption. The description is at the discretion
|
|
of the mac implementation.
|
|
.SH "PARAMETERS"
|
|
.IX Header "PARAMETERS"
|
|
Parameters are identified by name as strings, and have an expected
|
|
data type and maximum size.
|
|
OpenSSL has a set of macros for parameter names it expects to see in
|
|
its own \s-1MAC\s0 implementations.
|
|
Here, we show all three, the OpenSSL macro for the parameter name, the
|
|
name in string form, and a type description.
|
|
.PP
|
|
The standard parameter names are:
|
|
.ie n .IP """key"" (\fB\s-1OSSL_MAC_PARAM_KEY\s0\fR) <octet string>" 4
|
|
.el .IP "``key'' (\fB\s-1OSSL_MAC_PARAM_KEY\s0\fR) <octet string>" 4
|
|
.IX Item "key (OSSL_MAC_PARAM_KEY) <octet string>"
|
|
Its value is the \s-1MAC\s0 key as an array of bytes.
|
|
.Sp
|
|
For MACs that use an underlying computation algorithm, the algorithm
|
|
must be set first, see parameter names \*(L"algorithm\*(R" below.
|
|
.ie n .IP """iv"" (\fB\s-1OSSL_MAC_PARAM_IV\s0\fR) <octet string>" 4
|
|
.el .IP "``iv'' (\fB\s-1OSSL_MAC_PARAM_IV\s0\fR) <octet string>" 4
|
|
.IX Item "iv (OSSL_MAC_PARAM_IV) <octet string>"
|
|
Some \s-1MAC\s0 implementations (\s-1GMAC\s0) require an \s-1IV,\s0 this parameter sets the \s-1IV.\s0
|
|
.ie n .IP """custom"" (\fB\s-1OSSL_MAC_PARAM_CUSTOM\s0\fR) <octet string>" 4
|
|
.el .IP "``custom'' (\fB\s-1OSSL_MAC_PARAM_CUSTOM\s0\fR) <octet string>" 4
|
|
.IX Item "custom (OSSL_MAC_PARAM_CUSTOM) <octet string>"
|
|
Some \s-1MAC\s0 implementations (\s-1KMAC, BLAKE2\s0) accept a Customization String,
|
|
this parameter sets the Customization String. The default value is the
|
|
empty string.
|
|
.ie n .IP """salt"" (\fB\s-1OSSL_MAC_PARAM_SALT\s0\fR) <octet string>" 4
|
|
.el .IP "``salt'' (\fB\s-1OSSL_MAC_PARAM_SALT\s0\fR) <octet string>" 4
|
|
.IX Item "salt (OSSL_MAC_PARAM_SALT) <octet string>"
|
|
This option is used by \s-1BLAKE2 MAC.\s0
|
|
.ie n .IP """xof"" (\fB\s-1OSSL_MAC_PARAM_XOF\s0\fR) <integer>" 4
|
|
.el .IP "``xof'' (\fB\s-1OSSL_MAC_PARAM_XOF\s0\fR) <integer>" 4
|
|
.IX Item "xof (OSSL_MAC_PARAM_XOF) <integer>"
|
|
It's a simple flag, the value 0 or 1 are expected.
|
|
.Sp
|
|
This option is used by \s-1KMAC.\s0
|
|
.ie n .IP """digest-noinit"" (\fB\s-1OSSL_MAC_PARAM_DIGEST_NOINIT\s0\fR) <integer>" 4
|
|
.el .IP "``digest-noinit'' (\fB\s-1OSSL_MAC_PARAM_DIGEST_NOINIT\s0\fR) <integer>" 4
|
|
.IX Item "digest-noinit (OSSL_MAC_PARAM_DIGEST_NOINIT) <integer>"
|
|
A simple flag to set the \s-1MAC\s0 digest to not initialise the
|
|
implementation specific data. The value 0 or 1 is expected.
|
|
.Sp
|
|
This option is used by \s-1HMAC.\s0
|
|
.ie n .IP """digest-oneshot"" (\fB\s-1OSSL_MAC_PARAM_DIGEST_ONESHOT\s0\fR) <integer>" 4
|
|
.el .IP "``digest-oneshot'' (\fB\s-1OSSL_MAC_PARAM_DIGEST_ONESHOT\s0\fR) <integer>" 4
|
|
.IX Item "digest-oneshot (OSSL_MAC_PARAM_DIGEST_ONESHOT) <integer>"
|
|
A simple flag to set the \s-1MAC\s0 digest to be a oneshot operation.
|
|
The value 0 or 1 is expected.
|
|
.Sp
|
|
This option is used by \s-1HMAC.\s0
|
|
.ie n .IP """properties"" (\fB\s-1OSSL_MAC_PARAM_PROPERTIES\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.el .IP "``properties'' (\fB\s-1OSSL_MAC_PARAM_PROPERTIES\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.IX Item "properties (OSSL_MAC_PARAM_PROPERTIES) <UTF8 string>"
|
|
.PD 0
|
|
.ie n .IP """digest"" (\fB\s-1OSSL_MAC_PARAM_DIGEST\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.el .IP "``digest'' (\fB\s-1OSSL_MAC_PARAM_DIGEST\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.IX Item "digest (OSSL_MAC_PARAM_DIGEST) <UTF8 string>"
|
|
.ie n .IP """cipher"" (\fB\s-1OSSL_MAC_PARAM_CIPHER\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.el .IP "``cipher'' (\fB\s-1OSSL_MAC_PARAM_CIPHER\s0\fR) <\s-1UTF8\s0 string>" 4
|
|
.IX Item "cipher (OSSL_MAC_PARAM_CIPHER) <UTF8 string>"
|
|
.PD
|
|
For \s-1MAC\s0 implementations that use an underlying computation cipher or
|
|
digest, these parameters set what the algorithm should be.
|
|
.Sp
|
|
The value is always the name of the intended algorithm,
|
|
or the properties.
|
|
.Sp
|
|
Note that not all algorithms may support all digests.
|
|
\&\s-1HMAC\s0 does not support variable output length digests such as \s-1SHAKE128\s0
|
|
or \s-1SHAKE256.\s0
|
|
.ie n .IP """size"" (\fB\s-1OSSL_MAC_PARAM_SIZE\s0\fR) <unsigned integer>" 4
|
|
.el .IP "``size'' (\fB\s-1OSSL_MAC_PARAM_SIZE\s0\fR) <unsigned integer>" 4
|
|
.IX Item "size (OSSL_MAC_PARAM_SIZE) <unsigned integer>"
|
|
For \s-1MAC\s0 implementations that support it, set the output size that
|
|
\&\fIEVP_MAC_final()\fR should produce.
|
|
The allowed sizes vary between \s-1MAC\s0 implementations, but must never exceed
|
|
what can be given with a \fBsize_t\fR.
|
|
.ie n .IP """tls-data-size"" (\fB\s-1OSSL_MAC_PARAM_TLS_DATA_SIZE\s0\fR) <unsigned integer>" 4
|
|
.el .IP "``tls-data-size'' (\fB\s-1OSSL_MAC_PARAM_TLS_DATA_SIZE\s0\fR) <unsigned integer>" 4
|
|
.IX Item "tls-data-size (OSSL_MAC_PARAM_TLS_DATA_SIZE) <unsigned integer>"
|
|
This parameter is only supported by \s-1HMAC.\s0 If set then special handling is
|
|
activated for calculating the \s-1MAC\s0 of a received mac-then-encrypt \s-1TLS\s0 record
|
|
where variable length record padding has been used (as in the case of \s-1CBC\s0 mode
|
|
ciphersuites). The value represents the total length of the record that is
|
|
having the \s-1MAC\s0 calculated including the received \s-1MAC\s0 and the record padding.
|
|
.Sp
|
|
When used EVP_MAC_update must be called precisely twice. The first time with
|
|
the 13 bytes of \s-1TLS \s0\*(L"header\*(R" data, and the second time with the entire record
|
|
including the \s-1MAC\s0 itself and any padding. The entire record length must equal
|
|
the value passed in the \*(L"tls-data-size\*(R" parameter. The length passed in the
|
|
\&\fBdatalen\fR parameter to \fIEVP_MAC_update()\fR should be equal to the length of the
|
|
record after the \s-1MAC\s0 and any padding has been removed.
|
|
.PP
|
|
All these parameters should be used before the calls to any of
|
|
\&\fIEVP_MAC_init()\fR, \fIEVP_MAC_update()\fR and \fIEVP_MAC_final()\fR for a full
|
|
computation.
|
|
Anything else may give undefined results.
|
|
.SH "NOTES"
|
|
.IX Header "NOTES"
|
|
The \s-1MAC\s0 life-cycle is described in \fIlife_cycle\-mac\fR\|(7). In the future,
|
|
the transitions described there will be enforced. When this is done, it will
|
|
not be considered a breaking change to the \s-1API.\s0
|
|
.PP
|
|
The usage of the parameter names \*(L"custom\*(R", \*(L"iv\*(R" and \*(L"salt\*(R" correspond to
|
|
the names used in the standard where the algorithm was defined.
|
|
.PP
|
|
Some \s-1MAC\s0 algorithms store internal state that cannot be extracted during
|
|
re-initalization. For example \s-1GMAC\s0 cannot extract an \fB\s-1IV\s0\fR from the
|
|
underlying \s-1CIPHER\s0 context, and so calling \fIEVP_MAC_init()\fR on an \s-1EVP_MAC\s0 object
|
|
after \fIEVP_MAC_final()\fR has been called cannot reset its cipher state to what it
|
|
was when the \fB\s-1IV\s0\fR was initially generated. For such instances, an
|
|
\&\fB\s-1OSSL_MAC_PARAM_IV\s0\fR parameter must be passed with each call to \fIEVP_MAC_init()\fR.
|
|
.SH "RETURN VALUES"
|
|
.IX Header "RETURN VALUES"
|
|
\&\fIEVP_MAC_fetch()\fR returns a pointer to a newly fetched \fB\s-1EVP_MAC\s0\fR, or
|
|
\&\s-1NULL\s0 if allocation failed.
|
|
.PP
|
|
\&\fIEVP_MAC_up_ref()\fR returns 1 on success, 0 on error.
|
|
.PP
|
|
\&\fIEVP_MAC_names_do_all()\fR returns 1 if the callback was called for all names. A
|
|
return value of 0 means that the callback was not called for any names.
|
|
.PP
|
|
\&\fIEVP_MAC_free()\fR returns nothing at all.
|
|
.PP
|
|
\&\fIEVP_MAC_is_a()\fR returns 1 if the given method can be identified with
|
|
the given name, otherwise 0.
|
|
.PP
|
|
\&\fIEVP_MAC_get0_name()\fR returns a name of the \s-1MAC,\s0 or \s-1NULL\s0 on error.
|
|
.PP
|
|
\&\fIEVP_MAC_get0_provider()\fR returns a pointer to the provider for the \s-1MAC,\s0 or
|
|
\&\s-1NULL\s0 on error.
|
|
.PP
|
|
\&\fIEVP_MAC_CTX_new()\fR and \fIEVP_MAC_CTX_dup()\fR return a pointer to a newly
|
|
created \s-1EVP_MAC_CTX,\s0 or \s-1NULL\s0 if allocation failed.
|
|
.PP
|
|
\&\fIEVP_MAC_CTX_free()\fR returns nothing at all.
|
|
.PP
|
|
\&\fIEVP_MAC_CTX_get_params()\fR and \fIEVP_MAC_CTX_set_params()\fR return 1 on
|
|
success, 0 on error.
|
|
.PP
|
|
\&\fIEVP_Q_mac()\fR returns a pointer to the computed \s-1MAC\s0 value, or \s-1NULL\s0 on error.
|
|
.PP
|
|
\&\fIEVP_MAC_init()\fR, \fIEVP_MAC_update()\fR, \fIEVP_MAC_final()\fR, and \fIEVP_MAC_finalXOF()\fR
|
|
return 1 on success, 0 on error.
|
|
.PP
|
|
\&\fIEVP_MAC_CTX_get_mac_size()\fR returns the expected output size, or 0 if it isn't
|
|
set. If it isn't set, a call to \fIEVP_MAC_init()\fR will set it.
|
|
.PP
|
|
\&\fIEVP_MAC_CTX_get_block_size()\fR returns the block size, or 0 if it isn't set.
|
|
If it isn't set, a call to \fIEVP_MAC_init()\fR will set it.
|
|
.PP
|
|
\&\fIEVP_MAC_do_all_provided()\fR returns nothing at all.
|
|
.SH "EXAMPLES"
|
|
.IX Header "EXAMPLES"
|
|
.Vb 5
|
|
\& #include <stdlib.h>
|
|
\& #include <stdio.h>
|
|
\& #include <string.h>
|
|
\& #include <stdarg.h>
|
|
\& #include <unistd.h>
|
|
\&
|
|
\& #include <openssl/evp.h>
|
|
\& #include <openssl/err.h>
|
|
\& #include <openssl/params.h>
|
|
\&
|
|
\& int main() {
|
|
\& EVP_MAC *mac = EVP_MAC_fetch(NULL, getenv("MY_MAC"), NULL);
|
|
\& const char *cipher = getenv("MY_MAC_CIPHER");
|
|
\& const char *digest = getenv("MY_MAC_DIGEST");
|
|
\& const char *key = getenv("MY_KEY");
|
|
\& EVP_MAC_CTX *ctx = NULL;
|
|
\&
|
|
\& unsigned char buf[4096];
|
|
\& size_t read_l;
|
|
\& size_t final_l;
|
|
\&
|
|
\& size_t i;
|
|
\&
|
|
\& OSSL_PARAM params[3];
|
|
\& size_t params_n = 0;
|
|
\&
|
|
\& if (cipher != NULL)
|
|
\& params[params_n++] =
|
|
\& OSSL_PARAM_construct_utf8_string("cipher", (char*)cipher, 0);
|
|
\& if (digest != NULL)
|
|
\& params[params_n++] =
|
|
\& OSSL_PARAM_construct_utf8_string("digest", (char*)digest, 0);
|
|
\& params[params_n] = OSSL_PARAM_construct_end();
|
|
\&
|
|
\& if (mac == NULL
|
|
\& || key == NULL
|
|
\& || (ctx = EVP_MAC_CTX_new(mac)) == NULL
|
|
\& || !EVP_MAC_init(ctx, (const unsigned char *)key, strlen(key),
|
|
\& params))
|
|
\& goto err;
|
|
\&
|
|
\& while ( (read_l = read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
|
|
\& if (!EVP_MAC_update(ctx, buf, read_l))
|
|
\& goto err;
|
|
\& }
|
|
\&
|
|
\& if (!EVP_MAC_final(ctx, buf, &final_l, sizeof(buf)))
|
|
\& goto err;
|
|
\&
|
|
\& printf("Result: ");
|
|
\& for (i = 0; i < final_l; i++)
|
|
\& printf("%02X", buf[i]);
|
|
\& printf("\en");
|
|
\&
|
|
\& EVP_MAC_CTX_free(ctx);
|
|
\& EVP_MAC_free(mac);
|
|
\& exit(0);
|
|
\&
|
|
\& err:
|
|
\& EVP_MAC_CTX_free(ctx);
|
|
\& EVP_MAC_free(mac);
|
|
\& fprintf(stderr, "Something went wrong\en");
|
|
\& ERR_print_errors_fp(stderr);
|
|
\& exit (1);
|
|
\& }
|
|
.Ve
|
|
.PP
|
|
A run of this program, called with correct environment variables, can
|
|
look like this:
|
|
.PP
|
|
.Vb 3
|
|
\& $ MY_MAC=cmac MY_KEY=secret0123456789 MY_MAC_CIPHER=aes\-128\-cbc \e
|
|
\& LD_LIBRARY_PATH=. ./foo < foo.c
|
|
\& Result: C5C06683CD9DDEF904D754505C560A4E
|
|
.Ve
|
|
.PP
|
|
(in this example, that program was stored in \fIfoo.c\fR and compiled to
|
|
\&\fI./foo\fR)
|
|
.SH "SEE ALSO"
|
|
.IX Header "SEE ALSO"
|
|
\&\fIproperty\fR\|(7)
|
|
\&\s-1\fIOSSL_PARAM\s0\fR\|(3),
|
|
\&\s-1\fIEVP_MAC\-BLAKE2\s0\fR\|(7),
|
|
\&\s-1\fIEVP_MAC\-CMAC\s0\fR\|(7),
|
|
\&\s-1\fIEVP_MAC\-GMAC\s0\fR\|(7),
|
|
\&\s-1\fIEVP_MAC\-HMAC\s0\fR\|(7),
|
|
\&\s-1\fIEVP_MAC\-KMAC\s0\fR\|(7),
|
|
\&\fIEVP_MAC\-Siphash\fR\|(7),
|
|
\&\fIEVP_MAC\-Poly1305\fR\|(7),
|
|
\&\fIprovider\-mac\fR\|(7),
|
|
\&\fIlife_cycle\-mac\fR\|(7)
|
|
.SH "HISTORY"
|
|
.IX Header "HISTORY"
|
|
These functions were added in OpenSSL 3.0.
|
|
.SH "COPYRIGHT"
|
|
.IX Header "COPYRIGHT"
|
|
Copyright 2018\-2024 The OpenSSL Project Authors. All Rights Reserved.
|
|
.PP
|
|
Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use
|
|
this file except in compliance with the License. You can obtain a copy
|
|
in the file \s-1LICENSE\s0 in the source distribution or at
|
|
<https://www.openssl.org/source/license.html>.
|