fido_assert_set_authdata(3)

1FIDO_ASSERT_SET_AUTHD... BSD Library Functions Manual FIDO_ASSERT_SET_AUTHD...
2

NAME

4     fido_assert_set_authdata, fido_assert_set_authdata_raw,
5     fido_assert_set_clientdata, fido_assert_set_clientdata_hash,
6     fido_assert_set_count, fido_assert_set_extensions,
7     fido_assert_set_hmac_salt, fido_assert_set_hmac_secret,
8     fido_assert_set_up, fido_assert_set_uv, fido_assert_set_rp,
9     fido_assert_set_sig — set parameters of a FIDO2 assertion
10

SYNOPSIS

12     #include <fido.h>
13
14     typedef enum {
15             FIDO_OPT_OMIT = 0, /* use authenticator's default */
16             FIDO_OPT_FALSE,    /* explicitly set option to false */
17             FIDO_OPT_TRUE,     /* explicitly set option to true */
18     } fido_opt_t;
19
20     int
21     fido_assert_set_authdata(fido_assert_t *assert, size_t idx,
22         const unsigned char *ptr, size_t len);
23
24     int
25     fido_assert_set_authdata_raw(fido_assert_t *assert, size_t idx,
26         const unsigned char *ptr, size_t len);
27
28     int
29     fido_assert_set_clientdata(fido_assert_t *assert,
30         const unsigned char *ptr, size_t len);
31
32     int
33     fido_assert_set_clientdata_hash(fido_assert_t *assert,
34         const unsigned char *ptr, size_t len);
35
36     int
37     fido_assert_set_count(fido_assert_t *assert, size_t n);
38
39     int
40     fido_assert_set_extensions(fido_assert_t *assert, int flags);
41
42     int
43     fido_assert_set_hmac_salt(fido_assert_t *assert,
44         const unsigned char *ptr, size_t len);
45
46     int
47     fido_assert_set_hmac_secret(fido_assert_t *assert, size_t idx,
48         const unsigned char *ptr, size_t len);
49
50     int
51     fido_assert_set_up(fido_assert_t *assert, fido_opt_t up);
52
53     int
54     fido_assert_set_uv(fido_assert_t *assert, fido_opt_t uv);
55
56     int
57     fido_assert_set_rp(fido_assert_t *assert, const char *id);
58
59     int
60     fido_assert_set_sig(fido_assert_t *assert, size_t idx,
61         const unsigned char *ptr, size_t len);
62

DESCRIPTION

64     The fido_assert_set_authdata set of functions define the various parame‐
65     ters of a FIDO2 assertion, allowing a fido_assert_t type to be prepared
66     for a subsequent call to fido_dev_get_assert(3) or fido_assert_verify(3).
67     For the complete specification of a FIDO2 assertion and the format of its
68     constituent parts, please refer to the Web Authentication (webauthn)
69     standard.
70
71     The fido_assert_set_count() function sets the number of assertion state‐
72     ments in assert to n.
73
74     The fido_assert_set_authdata() and fido_assert_set_sig() functions set
75     the authenticator data and signature parts of the statement with index
76     idx of assert to ptr, where ptr points to len bytes.  A copy of ptr is
77     made, and no references to the passed pointer are kept.  Please note that
78     the first assertion statement of assert has an idx of 0.  The authentica‐
79     tor data passed to fido_assert_set_authdata() must be a CBOR-encoded byte
80     string, as obtained from fido_assert_authdata_ptr().  Alternatively, a
81     raw binary blob may be passed to fido_assert_set_authdata_raw().
82
83     The fido_assert_set_clientdata_hash() function sets the client data hash
84     of assert to ptr, where ptr points to len bytes.  A copy of ptr is made,
85     and no references to the passed pointer are kept.
86
87     The fido_assert_set_clientdata() function allows an application to set
88     the client data hash of assert by specifying the assertion's unhashed
89     client data.  This is required by Windows Hello, which calculates the
90     client data hash internally.  For compatibility with Windows Hello, ap‐
91     plications should use fido_assert_set_clientdata() instead of
92     fido_assert_set_clientdata_hash().
93
94     The fido_assert_set_rp() function sets the relying party id of assert,
95     where id is a NUL-terminated UTF-8 string.  The content of id is copied,
96     and no references to the passed pointer are kept.
97
98     The fido_assert_set_extensions() function sets the extensions of assert
99     to the bitmask flags.  At the moment, only the FIDO_EXT_CRED_BLOB,
100     FIDO_EXT_HMAC_SECRET, and FIDO_EXT_LARGEBLOB_KEY extensions are sup‐
101     ported.  If flags is zero, the extensions of assert are cleared.
102
103     The fido_assert_set_hmac_salt() and fido_assert_set_hmac_secret() func‐
104     tions set the hmac-salt and hmac-secret parts of assert to ptr, where ptr
105     points to len bytes.  A copy of ptr is made, and no references to the
106     passed pointer are kept.  The HMAC Secret (hmac-secret) Extension is a
107     CTAP 2.0 extension.  The fido_assert_set_hmac_secret() function is nor‐
108     mally only useful when writing tests.
109
110     The fido_assert_set_up() and fido_assert_set_uv() functions set the up
111     (user presence) and uv (user verification) attributes of assert.  Both
112     are FIDO_OPT_OMIT by default, allowing the authenticator to use its de‐
113     fault settings.
114
115     Use of the fido_assert_set_authdata set of functions may happen in two
116     distinct situations: when asking a FIDO2 device to produce a series of
117     assertion statements, prior to fido_dev_get_assert(3) (i.e, in the con‐
118     text of a FIDO2 client), or when verifying assertion statements using
119     fido_assert_verify(3) (i.e, in the context of a FIDO2 server).
120
121     For a complete description of the generation of a FIDO2 assertion and its
122     verification, please refer to the FIDO2 specification.  An example of how
123     to use the fido_assert_set_authdata set of functions can be found in the
124     examples/assert.c file shipped with libfido2.
125

RETURN VALUES

127     The fido_assert_set_authdata functions return FIDO_OK on success.  The
128     error codes returned by the fido_assert_set_authdata set of functions are
129     defined in <fido/err.h>.
130

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUES

SEE ALSO