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FIDO_ASSERT_NEW(3) FreeBSD Library Functions Manual FIDO_ASSERT_NEW(3)
NAME
fido_assert_new, fido_assert_free, fido_assert_count, fido_assert_rp_id,
fido_assert_user_display_name, fido_assert_user_icon,
fido_assert_user_name, fido_assert_authdata_ptr, fido_assert_blob_ptr,
fido_assert_clientdata_hash_ptr, fido_assert_hmac_secret_ptr,
fido_assert_largeblob_key_ptr, fido_assert_user_id_ptr,
fido_assert_sig_ptr, fido_assert_id_ptr, fido_assert_authdata_len,
fido_assert_blob_len, fido_assert_clientdata_hash_len,
fido_assert_hmac_secret_len, fido_assert_largeblob_key_len,
fido_assert_user_id_len, fido_assert_sig_len, fido_assert_id_len,
fido_assert_sigcount, fido_assert_flags - FIDO2 assertion API
SYNOPSIS
#include <fido.h>
fido_assert_t *
fido_assert_new(void);
void
fido_assert_free(fido_assert_t **assert_p);
size_t
fido_assert_count(const fido_assert_t *assert);
const char *
fido_assert_rp_id(const fido_assert_t *assert);
const char *
fido_assert_user_display_name(const fido_assert_t *assert, size_t idx);
const char *
fido_assert_user_icon(const fido_assert_t *assert, size_t idx);
const char *
fido_assert_user_name(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_authdata_ptr(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_clientdata_hash_ptr(const fido_assert_t *assert);
const unsigned char *
fido_assert_blob_ptr(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_hmac_secret_ptr(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_largeblob_key_ptr(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_user_id_ptr(const fido_assert_t *assert, size_t idx);
const unsigned char *
fido_assert_sig_ptr(const fido_assert_t *assert, size_t idx);
fido_assert_clientdata_hash_len(const fido_assert_t *assert);
size_t
fido_assert_blob_len(const fido_assert_t *assert, size_t idx);
size_t
fido_assert_hmac_secret_len(const fido_assert_t *assert, size_t idx);
size_t
fido_assert_largeblob_key_len(const fido_assert_t *assert, size_t idx);
size_t
fido_assert_user_id_len(const fido_assert_t *assert, size_t idx);
size_t
fido_assert_sig_len(const fido_assert_t *assert, size_t idx);
size_t
fido_assert_id_len(const fido_assert_t *assert, size_t idx);
uint32_t
fido_assert_sigcount(const fido_assert_t *assert, size_t idx);
uint8_t
fido_assert_flags(const fido_assert_t *assert, size_t idx);
DESCRIPTION
A FIDO2 assertion is a collection of statements, each statement a map
between a challenge, a credential, a signature, and ancillary attributes.
In libfido2, a FIDO2 assertion is abstracted by the fido_assert_t type.
The functions described in this page allow a fido_assert_t type to be
allocated, deallocated, and inspected. For other operations on
fido_assert_t, please refer to fido_assert_set_authdata(3),
fido_assert_allow_cred(3), fido_assert_verify(3), and
fido_dev_get_assert(3).
The fido_assert_new() function returns a pointer to a newly allocated,
empty fido_assert_t type. If memory cannot be allocated, NULL is
returned.
The fido_assert_free() function releases the memory backing *assert_p,
where *assert_p must have been previously allocated by fido_assert_new().
On return, *assert_p is set to NULL. Either assert_p or *assert_p may be
NULL, in which case fido_assert_free() is a NOP.
The fido_assert_count() function returns the number of statements in
assert.
The fido_assert_rp_id() function returns a pointer to a NUL-terminated
string holding the relying party ID of assert.
The fido_assert_user_display_name(), fido_assert_user_icon(), and
fido_assert_user_name(), functions return pointers to the user display
name, icon, and name attributes of statement idx in assert. If not NULL,
the values returned by these functions point to NUL-terminated UTF-8
strings. The user display name, icon, and name attributes will typically
only be returned by the authenticator if user verification was performed
by the authenticator and multiple resident/discoverable credentials were
involved in the assertion.
The fido_assert_hmac_secret_ptr() function returns a pointer to the hmac-
secret attribute of statement idx in assert. The HMAC Secret Extension
(hmac-secret) is a CTAP 2.0 extension. Note that the resulting hmac-
secret varies according to whether user verification was performed by the
authenticator.
The fido_assert_blob_ptr() and fido_assert_largeblob_key_ptr() functions
return pointers to the "credBlob" and "largeBlobKey" attributes of
statement idx in assert. Credential Blob (credBlob) and Large Blob Key
(largeBlobKey) are CTAP 2.1 extensions.
The fido_assert_authdata_len(), fido_assert_clientdata_hash_len(),
fido_assert_id_len(), fido_assert_user_id_len(), fido_assert_sig_len(),
fido_assert_hmac_secret_len(), fido_assert_blob_len(), and
fido_assert_largeblob_key_len() functions return the length of a given
attribute.
Please note that the first statement in assert has an idx (index) value
of 0.
The authenticator data and signature parts of an assertion statement are
typically passed to a FIDO2 server for verification.
RETURN VALUES
The authenticator data returned by fido_assert_authdata_ptr() is a CBOR-
encoded byte string, as obtained from the authenticator.
The fido_assert_rp_id(), fido_assert_user_display_name(),
fido_assert_user_icon(), fido_assert_user_name(),
fido_assert_authdata_ptr(), fido_assert_clientdata_hash_ptr(),
fido_assert_id_ptr(), fido_assert_user_id_ptr(), fido_assert_sig_ptr(),
fido_assert_hmac_secret_ptr(), fido_assert_blob_ptr(), and
fido_assert_largeblob_key_ptr() functions may return NULL if the
respective field in assert is not set. If not NULL, returned pointers
are guaranteed to exist until any API function that takes assert without
the const qualifier is invoked.
SEE ALSO
fido_assert_allow_cred(3), fido_assert_set_authdata(3),
fido_assert_verify(3), fido_dev_get_assert(3), fido_dev_largeblob_get(3)
FreeBSD 14.0-RELEASE-p11 April 27, 2022 FreeBSD 14.0-RELEASE-p11