MirOS Manual: SSL_alert_desc_string(3), SSL_alert_desc_string_long(3), SSL_alert_type_string(3), SSL_alert_type_string_long(3)


SSL_ALERT_TYPE_STRING(3)     OpenSSL     SSL_ALERT_TYPE_STRING(3)

NAME

     SSL_alert_type_string, SSL_alert_type_string_long,
     SSL_alert_desc_string, SSL_alert_desc_string_long - get tex-
     tual description of alert information

SYNOPSIS

      #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);

DESCRIPTION

     SSL_alert_type_string() returns a one letter string indicat-
     ing 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.

NOTES

     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.

RETURN VALUES

     The following strings can occur for SSL_alert_type_string()
     or SSL_alert_type_string_long():

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     "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 communica-
         tion 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 mes-
         sage 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

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         certificate, rendering it unacceptable.

     "IP"/"illegal parameter"
         A field in the handshake was out of range or incon-
         sistent 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 pad-
         ding 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 cer-
         tificate 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 con-
         trol 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 nego-
         tiate is recognized, but not supported. (For example,
         old protocol versions might be avoided for security rea-
         sons). This message is always fatal.

     "IS"/"insufficient security"

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         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 correct-
         ness 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 unre-
         lated 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 reci-
         pient 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.

SEE ALSO

     ssl(3), SSL_CTX_set_info_callback(3)

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