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SSL_alert_type_string(3)
Contents
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SSL_alert_type_string, SSL_alert_type_string_long - Get
textual description of alert information
#include <openssl/ssl.h>
char *SSL_alert_type_string(
int value ); char *SSL_alert_type_string_long(
int value ); char *SSL_alert_desc_string(
int value ); char *SSL_alert_desc_string_long(
int value );
The SSL_alert_type_string() function returns a one letter
string indicating the type of the alert specified by
value.
The SSL_alert_type_string_long() function returns a string
indicating the type of the alert specified by value.
The SSL_alert_desc_string() function returns a two letter
string as a short form describing the reason of the alert
specified by value.
The SSL_alert_desc_string_long() function 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 result 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 of non-fatal errors are certificate
errors, such as "certificate expired'' and "unsupported
certificate," for which a warning alert might be sent.
(The sending party might decide to send a fatal error.)
The receiving side, at its discretion, can cancel the connection
after receiving a warning alert.
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 SSL_alert_type_string() or
SSL_alert_type_string_long()functions return a one letter
string indicating the type of the alert specified by
value: Warning Fatal 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 the
SSL_alert_desc_string() or SSL_alert_desc_string_long()
functions: close notify
The connection will be closed. This is a warning
alert. unexpected message
An inappropriate message was received. This alert
is always fatal and should never be observed in
communication between proper implementations. bad
record mac
This alert is returned if a record is received with
an incorrect MAC. This message is always fatal.
decompression failure
The decompression function received improper input
(e.g. data that would expand to excessive length).
This message is always fatal. 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. no certificate
A client, that was asked to send a certificate,
does not send a certificate (SSLv3 only). bad certificate
A certificate was corrupt, contained signatures
that did not verify correctly, etc. unsupported
certificate
A certificate was of an unsupported type. certificate
revoked
A certificate was revoked by its signer. certificate
expired
A certificate has expired or is not currently
valid. certificate unknown
Some other (unspecified) issue arose in processing
the certificate, rendering it unacceptable. illegal
parameter
A field in the handshake was out of range or inconsistent
with other fields. This is always fatal.
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. 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. 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. 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. 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. decrypt error
A handshake cryptographic operation failed, including
being unable to correctly verify a signature,
decrypt a key exchange, or validate a finished message.
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. 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.
insufficient security
Returned instead of handshake_failure when a negotiation
fails, specifically because the server
requires ciphers more secure than those supported
by the client. This message is always fatal.
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. user cancelled
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. 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. unknown
This indicates that no description is available for
this alert type. The value probably does not contain
a correct alert message.
Functions: ssl(3), SSL_CTX_set_info_callback(3),
SSL_alert_desc_string(3)
SSL_alert_type_string(3)
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