NAME¶

fido_cbor_info_new, fido_cbor_info_free, fido_dev_get_cbor_info, fido_cbor_info_aaguid_ptr, fido_cbor_info_extensions_ptr, fido_cbor_info_protocols_ptr, fido_cbor_info_transports_ptr, fido_cbor_info_versions_ptr, fido_cbor_info_options_name_ptr, fido_cbor_info_options_value_ptr, fido_cbor_info_algorithm_type, fido_cbor_info_algorithm_cose, fido_cbor_info_algorithm_count, fido_cbor_info_certs_name_ptr, fido_cbor_info_certs_value_ptr, fido_cbor_info_certs_len, fido_cbor_info_aaguid_len, fido_cbor_info_extensions_len, fido_cbor_info_protocols_len, fido_cbor_info_transports_len, fido_cbor_info_versions_len, fido_cbor_info_options_len, fido_cbor_info_maxmsgsiz, fido_cbor_info_maxcredbloblen, fido_cbor_info_maxcredcntlst, fido_cbor_info_maxcredidlen, fido_cbor_info_maxlargeblob, fido_cbor_info_maxrpid_minpinlen, fido_cbor_info_minpinlen, fido_cbor_info_fwversion, fido_cbor_info_uv_attempts, fido_cbor_info_uv_modality, fido_cbor_info_rk_remaining, fido_cbor_info_new_pin_required — FIDO2 CBOR Info API

SYNOPSIS¶

#include <fido.h>

fido_cbor_info_t *
fido_cbor_info_new(void);

void
fido_cbor_info_free(fido_cbor_info_t **ci_p);

int
fido_dev_get_cbor_info(fido_dev_t *dev, fido_cbor_info_t *ci);

const unsigned char *
fido_cbor_info_aaguid_ptr(const fido_cbor_info_t *ci);

char **
fido_cbor_info_extensions_ptr(const fido_cbor_info_t *ci);

const uint8_t *
fido_cbor_info_protocols_ptr(const fido_cbor_info_t *ci);

char **
fido_cbor_info_transports_ptr(const fido_cbor_info_t *ci);

char **
fido_cbor_info_versions_ptr(const fido_cbor_info_t *ci);

char **
fido_cbor_info_options_name_ptr(const fido_cbor_info_t *ci);

const bool *
fido_cbor_info_options_value_ptr(const fido_cbor_info_t *ci);

const char *
fido_cbor_info_algorithm_type(const fido_cbor_info_t *ci, size_t idx);

int
fido_cbor_info_algorithm_cose(const fido_cbor_info_t *ci, size_t idx);

size_t
fido_cbor_info_algorithm_count(const fido_cbor_info_t *ci);

char **
fido_cbor_info_certs_name_ptr(const fido_cbor_info_t *ci);

const uint64_t *
fido_cbor_info_certs_value_ptr(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_certs_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_aaguid_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_extensions_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_protocols_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_transports_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_versions_len(const fido_cbor_info_t *ci);

size_t
fido_cbor_info_options_len(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxmsgsiz(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxcredbloblen(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxcredcntlst(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxcredidlen(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxlargeblob(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_maxrpid_minpinlen(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_minpinlen(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_fwversion(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_uv_attempts(const fido_cbor_info_t *ci);

uint64_t
fido_cbor_info_uv_modality(const fido_cbor_info_t *ci);

int64_t
fido_cbor_info_rk_remaining(const fido_cbor_info_t *ci);

bool
fido_cbor_info_new_pin_required(const fido_cbor_info_t *ci);

DESCRIPTION¶

The fido_cbor_info_new() function returns a pointer to a newly allocated, empty fido_cbor_info_t type. If memory cannot be allocated, NULL is returned.

The fido_cbor_info_free() function releases the memory backing *ci_p, where *ci_p must have been previously allocated by fido_cbor_info_new(). On return, *ci_p is set to NULL. Either ci_p or *ci_p may be NULL, in which case fido_cbor_info_free() is a NOP.

The fido_dev_get_cbor_info() function transmits a CTAP_CBOR_GETINFO command to dev and fills ci with attributes retrieved from the command's response. The fido_dev_get_cbor_info() function may block.

The fido_cbor_info_aaguid_ptr(), fido_cbor_info_extensions_ptr(), fido_cbor_info_protocols_ptr(), fido_cbor_info_transports_ptr(), and fido_cbor_info_versions_ptr() functions return pointers to the authenticator attestation GUID, supported extensions, PIN protocol, transports, and CTAP version strings of ci. The corresponding length of a given attribute can be obtained by fido_cbor_info_aaguid_len(), fido_cbor_info_extensions_len(), fido_cbor_info_protocols_len(), fido_cbor_info_transports_len(), or fido_cbor_info_versions_len().

The fido_cbor_info_options_name_ptr() and fido_cbor_info_options_value_ptr() functions return pointers to the array of option names and their respective values in ci. The length of the options array is returned by fido_cbor_info_options_len().

The fido_cbor_info_algorithm_count() function returns the number of supported algorithms in ci. The fido_cbor_info_algorithm_cose() function returns the COSE identifier of algorithm idx in ci, or 0 if the COSE identifier is unknown or unset. The fido_cbor_info_algorithm_type() function returns the type of algorithm idx in ci, or NULL if the type is unset. Please note that the first algorithm in ci has an idx (index) value of 0.

The fido_cbor_info_certs_name_ptr() and fido_cbor_info_certs_value_ptr() functions return pointers to the array of certification names and their respective values in ci. The length of the certifications array is returned by fido_cbor_info_certs_len().

The fido_cbor_info_maxmsgsiz() function returns the maximum message size attribute of ci.

The fido_cbor_info_maxcredbloblen() function returns the maximum “credBlob” length in bytes supported by the authenticator as reported in ci.

The fido_cbor_info_maxcredcntlst() function returns the maximum supported number of credentials in a single credential ID list as reported in ci.

The fido_cbor_info_maxcredidlen() function returns the maximum supported length of a credential ID as reported in ci.

The fido_cbor_info_maxrpid_minpinlen() function returns the maximum number of RP IDs that may be passed to fido_dev_set_pin_minlen_rpid(3), as reported in ci. The minimum PIN length attribute is a CTAP 2.1 addition. If the attribute is not advertised by the authenticator, the fido_cbor_info_maxrpid_minpinlen() function returns zero.

The fido_cbor_info_maxlargeblob() function returns the maximum length in bytes of an authenticator's serialized largeBlob array as reported in ci.

The fido_cbor_info_minpinlen() function returns the minimum PIN length enforced by the authenticator as reported in ci. The minimum PIN length attribute is a CTAP 2.1 addition. If the attribute is not advertised by the authenticator, the fido_cbor_info_minpinlen() function returns zero.

The fido_cbor_info_fwversion() function returns the firmware version attribute of ci.

The fido_cbor_info_uv_attempts() function returns the number of UV attempts that the platform may attempt before falling back to PIN authentication. If 1, then all fido_dev_get_uv_retry_count(3) retries are handled internally by the authenticator and the platform may only attempt non-PIN UV once. The UV attempts attribute is a CTAP 2.1 addition. If the attribute is not advertised by the authenticator, the fido_cbor_info_uv_attempts() function returns zero.

The fido_cbor_info_uv_modality() function returns a bitmask representing different UV modes supported by the authenticator, as defined in the FIDO Registry of Predefined Values and reported in ci. See the FIDO_UV_MODE_* definitions in <fido/param.h> for the set of values defined by libfido2 and a brief description of each. The UV modality attribute is a CTAP 2.1 addition. If the attribute is not advertised by the authenticator, the fido_cbor_info_uv_modality() function returns zero.

The fido_cbor_info_rk_remaining() function returns the estimated number of additional resident/discoverable credentials that can be stored on the authenticator as reported in ci. The estimated number of remaining resident credentials is a CTAP 2.1 addition. If the attribute is not advertised by the authenticator, the fido_cbor_info_rk_remaining() function returns -1.

The fido_cbor_info_new_pin_required() function returns whether a new PIN is required by the authenticator as reported in ci. If fido_cbor_info_new_pin_required() returns true, operations requiring PIN authentication will fail until a new PIN is set on the authenticator. The fido_dev_set_pin(3) function can be used to set a new PIN.

A complete example of how to use these functions can be found in the example/info.c file shipped with libfido2.

RETURN VALUES¶

The fido_cbor_info_aaguid_ptr(), fido_cbor_info_extensions_ptr(), fido_cbor_info_protocols_ptr(), fido_cbor_info_transports_ptr(), fido_cbor_info_versions_ptr(), fido_cbor_info_options_name_ptr(), and fido_cbor_info_options_value_ptr() functions return NULL if the respective field in ci is absent. If not NULL, returned pointers are guaranteed to exist until any API function that takes ci without the const qualifier is invoked.

SEE ALSO¶

fido_dev_get_uv_retry_count(3), fido_dev_open(3), fido_dev_set_pin(3), fido_dev_set_pin_minlen_rpid(3)

FIDO Registry of Predefined Values, https://fidoalliance.org/specs/common-specs/fido-registry-v2.2-rd-20210525.html, FIDO Alliance, 2021-05-25, Review Draft, Version 2.2.