1SSL_alert_type_string(3) OpenSSL SSL_alert_type_string(3)
2
6 SSL_alert_type_string, SSL_alert_type_string_long,
7 SSL_alert_desc_string, SSL_alert_desc_string_long - get textual
8 description of alert information
9
11 #include <openssl/ssl.h>
12 const char *SSL_alert_type_string(int value);
14 const char *SSL_alert_type_string_long(int value);
15 const char *SSL_alert_desc_string(int value);
17 const char *SSL_alert_desc_string_long(int value);
18
20 SSL_alert_type_string() returns a one letter string indicating the type
21 of the alert specified by value.
22 SSL_alert_type_string_long() returns a string indicating the type of
24 the alert specified by value.
25 SSL_alert_desc_string() returns a two letter string as a short form
27 describing the reason of the alert specified by value.
28 SSL_alert_desc_string_long() returns a string describing the reason of
30 the alert specified by value.
31
33 When one side of an SSL/TLS communication wants to inform the peer
34 about a special situation, it sends an alert. The alert is sent as a
35 special message and does not influence the normal data stream (unless
36 its contents results in the communication being canceled).
37 A warning alert is sent, when a non-fatal error condition occurs. The
39 "close notify" alert is sent as a warning alert. Other examples for
40 non-fatal errors are certificate errors ("certificate expired", "unsup‐
41 ported certificate"), for which a warning alert may be sent. (The
42 sending party may however decide to send a fatal error.) The receiving
43 side may cancel the connection on reception of a warning alert on it
44 discretion.
45 Several alert messages must be sent as fatal alert messages as speci‐
47 fied by the TLS RFC. A fatal alert always leads to a connection abort.
48
50 The following strings can occur for SSL_alert_type_string() or
51 SSL_alert_type_string_long():
52 "W"/"warning"
54 "F"/"fatal"
55 "U"/"unknown"
56 This indicates that no support is available for this alert type.
57 Probably value does not contain a correct alert message.
58 The following strings can occur for SSL_alert_desc_string() or
60 SSL_alert_desc_string_long():
61 "CN"/"close notify"
63 The connection shall be closed. This is a warning alert.
64 "UM"/"unexpected message"
66 An inappropriate message was received. This alert is always fatal
67 and should never be observed in communication between proper imple‐
68 mentations.
69 "BM"/"bad record mac"
71 This alert is returned if a record is received with an incorrect
72 MAC. This message is always fatal.
73 "DF"/"decompression failure"
75 The decompression function received improper input (e.g. data that
76 would expand to excessive length). This message is always fatal.
77 "HF"/"handshake failure"
79 Reception of a handshake_failure alert message indicates that the
80 sender was unable to negotiate an acceptable set of security param‐
81 eters given the options available. This is a fatal error.
82 "NC"/"no certificate"
84 A client, that was asked to send a certificate, does not send a
85 certificate (SSLv3 only).
86 "BC"/"bad certificate"
88 A certificate was corrupt, contained signatures that did not verify
89 correctly, etc
90 "UC"/"unsupported certificate"
92 A certificate was of an unsupported type.
93 "CR"/"certificate revoked"
95 A certificate was revoked by its signer.
96 "CE"/"certificate expired"
98 A certificate has expired or is not currently valid.
99 "CU"/"certificate unknown"
101 Some other (unspecified) issue arose in processing the certificate,
102 rendering it unacceptable.
103 "IP"/"illegal parameter"
105 A field in the handshake was out of range or inconsistent with
106 other fields. This is always fatal.
107 "DC"/"decryption failed"
109 A TLSCiphertext decrypted in an invalid way: either it wasn't an
110 even multiple of the block length or its padding values, when
111 checked, weren't correct. This message is always fatal.
112 "RO"/"record overflow"
114 A TLSCiphertext record was received which had a length more than
115 2^14+2048 bytes, or a record decrypted to a TLSCompressed record
116 with more than 2^14+1024 bytes. This message is always fatal.
117 "CA"/"unknown CA"
119 A valid certificate chain or partial chain was received, but the
120 certificate was not accepted because the CA certificate could not
121 be located or couldn't be matched with a known, trusted CA. This
122 message is always fatal.
123 "AD"/"access denied"
125 A valid certificate was received, but when access control was
126 applied, the sender decided not to proceed with negotiation. This
127 message is always fatal.
128 "DE"/"decode error"
130 A message could not be decoded because some field was out of the
131 specified range or the length of the message was incorrect. This
132 message is always fatal.
133 "CY"/"decrypt error"
135 A handshake cryptographic operation failed, including being unable
136 to correctly verify a signature, decrypt a key exchange, or vali‐
137 date a finished message.
138 "ER"/"export restriction"
140 A negotiation not in compliance with export restrictions was
141 detected; for example, attempting to transfer a 1024 bit ephemeral
142 RSA key for the RSA_EXPORT handshake method. This message is always
143 fatal.
144 "PV"/"protocol version"
146 The protocol version the client has attempted to negotiate is rec‐
147 ognized, but not supported. (For example, old protocol versions
148 might be avoided for security reasons). This message is always
149 fatal.
150 "IS"/"insufficient security"
152 Returned instead of handshake_failure when a negotiation has failed
153 specifically because the server requires ciphers more secure than
154 those supported by the client. This message is always fatal.
155 "IE"/"internal error"
157 An internal error unrelated to the peer or the correctness of the
158 protocol makes it impossible to continue (such as a memory alloca‐
159 tion failure). This message is always fatal.
160 "US"/"user canceled"
162 This handshake is being canceled for some reason unrelated to a
163 protocol failure. If the user cancels an operation after the hand‐
164 shake is complete, just closing the connection by sending a
165 close_notify is more appropriate. This alert should be followed by
166 a close_notify. This message is generally a warning.
167 "NR"/"no renegotiation"
169 Sent by the client in response to a hello request or by the server
170 in response to a client hello after initial handshaking. Either of
171 these would normally lead to renegotiation; when that is not appro‐
172 priate, the recipient should respond with this alert; at that
173 point, the original requester can decide whether to proceed with
174 the connection. One case where this would be appropriate would be
175 where a server has spawned a process to satisfy a request; the
176 process might receive security parameters (key length, authentica‐
177 tion, etc.) at startup and it might be difficult to communicate
178 changes to these parameters after that point. This message is
179 always a warning.
180 "UK"/"unknown"
182 This indicates that no description is available for this alert
183 type. Probably value does not contain a correct alert message.
184
186 ssl(3), SSL_CTX_set_info_callback(3)
1870.9.8b 2001-09-07 SSL_alert_type_string(3)