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SSL_ALERT_TYPE_STRING(3)
Contents
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SSL_alert_type_string, SSL_alert_type_string_long,
SSL_alert_desc_string, SSL_alert_desc_string_long - get
textual description of alert information
#include <openssl/ssl.h>
const char *SSL_alert_type_string(int value);
const char *SSL_alert_type_string_long(int value);
const char *SSL_alert_desc_string(int value);
const char *SSL_alert_desc_string_long(int value);
SSL_alert_type_string() returns a one letter string indicating
the type of the alert specified by value.
SSL_alert_type_string_long() returns a string indicating
the type of the alert specified by value.
SSL_alert_desc_string() returns a two letter string as a
short form describing the reason of the alert specified by
value.
SSL_alert_desc_string_long() returns a string describing
the reason of the alert specified by value.
When one side of an SSL/TLS communication wants to inform
the peer about a special situation, it sends an alert. The
alert is sent as a special message and does not influence
the normal data stream (unless its contents results in the
communication being canceled).
A warning alert is sent, when a non-fatal error condition
occurs. The "close notify" alert is sent as a warning
alert. Other examples for non-fatal errors are certificate
errors ("certificate expired", "unsupported certificate"),
for which a warning alert may be sent. (The sending party
may however decide to send a fatal error.) The receiving
side may cancel the connection on reception of a warning
alert on it discretion.
Several alert messages must be sent as fatal alert messages
as specified by the TLS RFC. A fatal alert always
leads to a connection abort.
The following strings can occur for
SSL_alert_type_string() or SSL_alert_type_string_long():
"W"/"warning"
"F"/"fatal"
"U"/"unknown"
This indicates that no support is available for this
alert type. Probably value does not contain a correct
alert message.
The following strings can occur for
SSL_alert_desc_string() or SSL_alert_desc_string_long():
"CN"/"close notify"
The connection shall be closed. This is a warning
alert.
"UM"/"unexpected message"
An inappropriate message was received. This alert is
always fatal and should never be observed in communication
between proper implementations.
"BM"/"bad record mac"
This alert is returned if a record is received with an
incorrect MAC. This message is always fatal.
"DF"/"decompression failure"
The decompression function received improper input
(e.g. data that would expand to excessive length).
This message is always fatal.
"HF"/"handshake failure"
Reception of a handshake_failure alert message indicates
that the sender was unable to negotiate an
acceptable set of security parameters given the
options available. This is a fatal error.
"NC"/"no certificate"
A client, that was asked to send a certificate, does
not send a certificate (SSLv3 only).
"BC"/"bad certificate"
A certificate was corrupt, contained signatures that
did not verify correctly, etc
"UC"/"unsupported certificate"
A certificate was of an unsupported type.
"CR"/"certificate revoked"
A certificate was revoked by its signer.
"CE"/"certificate expired"
A certificate has expired or is not currently valid.
"CU"/"certificate unknown"
Some other (unspecified) issue arose in processing the
certificate, rendering it unacceptable.
"IP"/"illegal parameter"
A field in the handshake was out of range or inconsistent
with other fields. This is always fatal.
"DC"/"decryption failed"
A TLSCiphertext decrypted in an invalid way: either it
wasn't an even multiple of the block length or its
padding values, when checked, weren't correct. This
message is always fatal.
"RO"/"record overflow"
A TLSCiphertext record was received which had a length
more than 2^14+2048 bytes, or a record decrypted to a
TLSCompressed record with more than 2^14+1024 bytes.
This message is always fatal.
"CA"/"unknown CA"
A valid certificate chain or partial chain was
received, but the certificate was not accepted because
the CA certificate could not be located or couldn't be
matched with a known, trusted CA. This message is
always fatal.
"AD"/"access denied"
A valid certificate was received, but when access control
was applied, the sender decided not to proceed
with negotiation. This message is always fatal.
"DE"/"decode error"
A message could not be decoded because some field was
out of the specified range or the length of the message
was incorrect. This message is always fatal.
"CY"/"decrypt error"
A handshake cryptographic operation failed, including
being unable to correctly verify a signature, decrypt
a key exchange, or validate a finished message.
"ER"/"export restriction"
A negotiation not in compliance with export restrictions
was detected; for example, attempting to transfer
a 1024 bit ephemeral RSA key for the RSA_EXPORT
handshake method. This message is always fatal.
"PV"/"protocol version"
The protocol version the client has attempted to negotiate
is recognized, but not supported. (For example,
old protocol versions might be avoided for security
reasons). This message is always fatal.
"IS"/"insufficient security"
Returned instead of handshake_failure when a negotiation
has failed specifically because the server
requires ciphers more secure than those supported by
the client. This message is always fatal.
"IE"/"internal error"
An internal error unrelated to the peer or the correctness
of the protocol makes it impossible to continue
(such as a memory allocation failure). This message
is always fatal.
"US"/"user canceled"
This handshake is being canceled for some reason unrelated
to a protocol failure. If the user cancels an
operation after the handshake is complete, just closing
the connection by sending a close_notify is more
appropriate. This alert should be followed by a
close_notify. This message is generally a warning.
"NR"/"no renegotiation"
Sent by the client in response to a hello request or
by the server in response to a client hello after initial
handshaking. Either of these would normally lead
to renegotiation; when that is not appropriate, the
recipient should respond with this alert; at that
point, the original requester can decide whether to
proceed with the connection. One case where this would
be appropriate would be where a server has spawned a
process to satisfy a request; the process might
receive security parameters (key length, authentication,
etc.) at startup and it might be difficult to
communicate changes to these parameters after that
point. This message is always a warning.
"UK"/"unknown"
This indicates that no description is available for
this alert type. Probably value does not contain a
correct alert message.
ssl(3), SSL_CTX_set_info_callback(3)
OpenBSD 3.6 2002-05-14 4 [ Back ] |
