1TLS_CONN_VERSION(3) BSD Library Functions Manual TLS_CONN_VERSION(3)
2
4 tls_conn_version, tls_conn_cipher, tls_conn_cipher_strength,
5 tls_conn_alpn_selected, tls_conn_servername, tls_conn_session_resumed,
6 tls_peer_cert_provided, tls_peer_cert_contains_name,
7 tls_peer_cert_chain_pem, tls_peer_cert_issuer, tls_peer_cert_subject,
8 tls_peer_cert_hash, tls_peer_cert_notbefore, tls_peer_cert_notafter —
9 inspect an established TLS connection
10
12 #include <tls.h>
13
14 const char *
15 tls_conn_version(struct tls *ctx);
16
17 const char *
18 tls_conn_cipher(struct tls *ctx);
19
20 int
21 tls_conn_cipher_strength(struct tls *ctx);
22
23 const char *
24 tls_conn_alpn_selected(struct tls *ctx);
25
26 const char *
27 tls_conn_servername(struct tls *ctx);
28
29 int
30 tls_conn_session_resumed(struct tls *ctx);
31
32 int
33 tls_peer_cert_provided(struct tls *ctx);
34
35 int
36 tls_peer_cert_contains_name(struct tls *ctx, const char *name);
37
38 const uint8_t *
39 tls_peer_cert_chain_pem(struct tls *ctx, size_t *size);
40
41 const char *
42 tls_peer_cert_issuer(struct tls *ctx);
43
44 const char *
45 tls_peer_cert_subject(struct tls *ctx);
46
47 const char *
48 tls_peer_cert_hash(struct tls *ctx);
49
50 time_t
51 tls_peer_cert_notbefore(struct tls *ctx);
52
53 time_t
54 tls_peer_cert_notafter(struct tls *ctx);
55
57 These functions return information about a TLS connection and will only
58 succeed after the handshake is complete (the connection information
59 applies to both clients and servers, unless noted otherwise):
60
61 tls_conn_version() returns a string corresponding to a TLS version nego‐
62 tiated with the peer connected to ctx.
63
64 tls_conn_cipher() returns a string corresponding to the cipher suite
65 negotiated with the peer connected to ctx.
66
67 tls_conn_cipher_strength() returns the strength in bits for the symmetric
68 cipher that is being used with the peer connected to ctx.
69
70 tls_conn_alpn_selected() returns a string that specifies the ALPN proto‐
71 col selected for use with the peer connected to ctx. If no protocol was
72 selected then NULL is returned.
73
74 tls_conn_servername() returns a string corresponding to the servername
75 that the client connected to ctx requested by sending a TLS Server Name
76 Indication extension (server only).
77
78 tls_conn_session_resumed() indicates whether a TLS session has been
79 resumed during the handshake with the server connected to ctx (client
80 only).
81
82 tls_peer_cert_provided() checks if the peer of ctx has provided a cer‐
83 tificate.
84
85 tls_peer_cert_contains_name() checks if the peer of a TLS ctx has pro‐
86 vided a certificate that contains a SAN or CN that matches name.
87
88 tls_peer_cert_chain_pem() returns a pointer to memory containing a PEM-
89 encoded certificate chain for the peer certificate from ctx.
90
91 tls_peer_cert_subject() returns a string corresponding to the subject of
92 the peer certificate from ctx.
93
94 tls_peer_cert_issuer() returns a string corresponding to the issuer of
95 the peer certificate from ctx.
96
97 tls_peer_cert_hash() returns a string corresponding to a hash of the raw
98 peer certificate from ctx prefixed by a hash name followed by a colon.
99 The hash currently used is SHA256, though this could change in the
100 future. The hash string for a certificate in file mycert.crt can be gen‐
101 erated using the commands:
102
103 h=$(openssl x509 -outform der -in mycert.crt | sha256)
104 printf "SHA256:${h}\n"
105
106 tls_peer_cert_notbefore() returns the time corresponding to the start of
107 the validity period of the peer certificate from ctx.
108
109 tls_peer_cert_notafter() returns the time corresponding to the end of the
110 validity period of the peer certificate from ctx.
111
113 The tls_conn_session_resumed() function returns 1 if a TLS session was
114 resumed or 0 if it was not.
115
116 The tls_peer_cert_provided() and tls_peer_cert_contains_name() functions
117 return 1 if the check succeeds or 0 if it does not.
118
119 tls_peer_cert_notbefore() and tls_peer_cert_notafter() return a time in
120 epoch-seconds on success or -1 on error.
121
122 The functions that return a pointer return NULL on error or an out of
123 memory condition.
124
126 tls_configure(3), tls_handshake(3), tls_init(3),
127 tls_ocsp_process_response(3)
128
130 tls_conn_version(), tls_conn_cipher(), tls_peer_cert_provided(),
131 tls_peer_cert_contains_name(), tls_peer_cert_issuer(),
132 tls_peer_cert_subject(), tls_peer_cert_hash(), tls_peer_cert_notbefore(),
133 and tls_peer_cert_notafter() appeared in OpenBSD 5.9.
134
135 tls_conn_servername() and tls_conn_alpn_selected() appeared in
136 OpenBSD 6.1.
137
138 tls_conn_session_resumed() appeared in OpenBSD 6.3.
139
140 tls_conn_cipher_strength() appeared in OpenBSD 6.7.
141
143 Bob Beck <beck@openbsd.org>
144 Joel Sing <jsing@openbsd.org>
145
146BSD November 2, 2019 BSD