Gsasl_callback_function ()

int
(*Gsasl_callback_function) (Gsasl *ctx,
                            Gsasl_session *sctx,
                            Gsasl_property prop);

Prototype of function that the application should implement. Use gsasl_callback_set() to inform the library about your callback function.

It is called by the SASL library when it need some information from the application. Depending on the value of prop , it should either set some property (e.g., username or password) using gsasl_property_set(), or it should extract some properties (e.g., authentication and authorization identities) using gsasl_property_fast() and use them to make a policy decision, perhaps returning GSASL_AUTHENTICATION_ERROR or GSASL_OK depending on whether the policy permitted the operation.

Since: 0.2.0

gsasl_init ()

int
gsasl_init (Gsasl **ctx);

This functions initializes libgsasl. The handle pointed to by ctx is valid for use with other libgsasl functions iff this function is successful. It also register all builtin SASL mechanisms, using gsasl_register().

gsasl_done ()

void
gsasl_done (Gsasl *ctx);

This function destroys a libgsasl handle. The handle must not be used with other libgsasl functions after this call.

gsasl_check_version ()

const char *
gsasl_check_version (const char *req_version);

Check GNU SASL Library version.

See GSASL_VERSION for a suitable req_version string.

This function is one of few in the library that can be used without a successful call to gsasl_init().

gsasl_callback_set ()

void
gsasl_callback_set (Gsasl *ctx,
                    Gsasl_callback_function cb);

Store the pointer to the application provided callback in the library handle. The callback will be used, via gsasl_callback(), by mechanisms to discover various parameters (such as username and passwords). The callback function will be called with a Gsasl_property value indicating the requested behaviour. For example, for GSASL_ANONYMOUS_TOKEN, the function is expected to invoke gsasl_property_set(CTX , GSASL_ANONYMOUS_TOKEN, "token") where "token" is the anonymous token the application wishes the SASL mechanism to use. See the manual for the meaning of all parameters.

Since: 0.2.0

gsasl_callback ()

int
gsasl_callback (Gsasl *ctx,
                Gsasl_session *sctx,
                Gsasl_property prop);

Invoke the application callback. The prop value indicate what the callback is expected to do. For example, for GSASL_ANONYMOUS_TOKEN, the function is expected to invoke gsasl_property_set(SCTX , GSASL_ANONYMOUS_TOKEN, "token") where "token" is the anonymous token the application wishes the SASL mechanism to use. See the manual for the meaning of all parameters.

Since: 0.2.0

gsasl_callback_hook_set ()

void
gsasl_callback_hook_set (Gsasl *ctx,
                         void *hook);

Store application specific data in the libgsasl handle.

The application data can be later (for instance, inside a callback) be retrieved by calling gsasl_callback_hook_get(). This is normally used by the application to maintain a global state between the main program and callbacks.

Since: 0.2.0

gsasl_callback_hook_get ()

void *
gsasl_callback_hook_get (Gsasl *ctx);

Retrieve application specific data from libgsasl handle.

The application data is set using gsasl_callback_hook_set(). This is normally used by the application to maintain a global state between the main program and callbacks.

Since: 0.2.0

gsasl_session_hook_set ()

void
gsasl_session_hook_set (Gsasl_session *sctx,
                        void *hook);

Store application specific data in the libgsasl session handle.

The application data can be later (for instance, inside a callback) be retrieved by calling gsasl_session_hook_get(). This is normally used by the application to maintain a per-session state between the main program and callbacks.

Since: 0.2.14

gsasl_session_hook_get ()

void *
gsasl_session_hook_get (Gsasl_session *sctx);

Retrieve application specific data from libgsasl session handle.

The application data is set using gsasl_callback_hook_set(). This is normally used by the application to maintain a per-session state between the main program and callbacks.

Since: 0.2.14

gsasl_property_set ()

int
gsasl_property_set (Gsasl_session *sctx,
                    Gsasl_property prop,
                    const char *data);

Make a copy of data and store it in the session handle for the indicated property prop .

You can immediately deallocate data after calling this function, without affecting the data stored in the session handle.

Since: 0.2.0

gsasl_property_set_raw ()

int
gsasl_property_set_raw (Gsasl_session *sctx,
                        Gsasl_property prop,
                        const char *data,
                        size_t len);

Make a copy of len sized data and store a zero terminated version of it in the session handle for the indicated property prop .

You can immediately deallocate data after calling this function, without affecting the data stored in the session handle.

Except for the length indicator, this function is identical to gsasl_property_set.

Since: 0.2.0

gsasl_property_free ()

void
gsasl_property_free (Gsasl_session *sctx,
                     Gsasl_property prop);

Deallocate associated data with property prop in session handle. After this call, gsasl_property_fast(sctx , prop ) will always return NULL.

Since: 2.0.0

gsasl_property_get ()

const char *
gsasl_property_get (Gsasl_session *sctx,
                    Gsasl_property prop);

Retrieve the data stored in the session handle for given property prop , possibly invoking the application callback to get the value.

The pointer is to live data, and must not be deallocated or modified in any way.

This function will invoke the application callback, using gsasl_callback(), when a property value is not known.

Since: 0.2.0

gsasl_property_fast ()

const char *
gsasl_property_fast (Gsasl_session *sctx,
                     Gsasl_property prop);

Retrieve the data stored in the session handle for given property prop .

The pointer is to live data, and must not be deallocated or modified in any way.

This function will not invoke the application callback.

Since: 0.2.0

gsasl_client_mechlist ()

int
gsasl_client_mechlist (Gsasl *ctx,
                       char **out);

Return a newly allocated string containing SASL names, separated by space, of mechanisms supported by the libgsasl client. out is allocated by this function, and it is the responsibility of caller to deallocate it.

gsasl_client_support_p ()

int
gsasl_client_support_p (Gsasl *ctx,
                        const char *name);

Decide whether there is client-side support for a specified mechanism.

gsasl_client_suggest_mechanism ()

const char *
gsasl_client_suggest_mechanism (Gsasl *ctx,
                                const char *mechlist);

Given a list of mechanisms, suggest which to use.

gsasl_server_mechlist ()

int
gsasl_server_mechlist (Gsasl *ctx,
                       char **out);

Return a newly allocated string containing SASL names, separated by space, of mechanisms supported by the libgsasl server. out is allocated by this function, and it is the responsibility of caller to deallocate it.

gsasl_server_support_p ()

int
gsasl_server_support_p (Gsasl *ctx,
                        const char *name);

Decide whether there is server-side support for a specified mechanism.

gsasl_mechanism_name_p ()

int
gsasl_mechanism_name_p (const char *mech);

Check if the mechanism name string mech follows syntactical rules. It does not check that the name is registered with IANA. It does not check that the mechanism name is actually implemented and supported.

SASL mechanisms are named by strings, from 1 to 20 characters in length, consisting of upper-case letters, digits, hyphens, and/or underscores.

Since: 2.0.0

gsasl_client_start ()

int
gsasl_client_start (Gsasl *ctx,
                    const char *mech,
                    Gsasl_session **sctx);

This functions initiates a client SASL authentication. This function must be called before any other gsasl_client_*() function is called.

gsasl_server_start ()

int
gsasl_server_start (Gsasl *ctx,
                    const char *mech,
                    Gsasl_session **sctx);

This functions initiates a server SASL authentication. This function must be called before any other gsasl_server_*() function is called.

gsasl_step ()

int
gsasl_step (Gsasl_session *sctx,
            const char *input,
            size_t input_len,
            char **output,
            size_t *output_len);

Perform one step of SASL authentication. This reads data from the other end (from input and input_len ), processes it (potentially invoking callbacks to the application), and writes data to server (into newly allocated variable output and output_len that indicate the length of output ).

The contents of the output buffer is unspecified if this functions returns anything other than GSASL_OK or GSASL_NEEDS_MORE. If this function return GSASL_OK or GSASL_NEEDS_MORE, however, the output buffer is allocated by this function, and it is the responsibility of caller to deallocate it by calling gsasl_free(output ).

gsasl_step64 ()

int
gsasl_step64 (Gsasl_session *sctx,
              const char *b64input,
              char **b64output);

This is a simple wrapper around gsasl_step() that base64 decodes the input and base64 encodes the output.

The contents of the b64output buffer is unspecified if this functions returns anything other than GSASL_OK or GSASL_NEEDS_MORE. If this function return GSASL_OK or GSASL_NEEDS_MORE, however, the b64output buffer is allocated by this function, and it is the responsibility of caller to deallocate it by calling gsasl_free(b64output ).

gsasl_finish ()

void
gsasl_finish (Gsasl_session *sctx);

Destroy a libgsasl client or server handle. The handle must not be used with other libgsasl functions after this call.

gsasl_encode ()

int
gsasl_encode (Gsasl_session *sctx,
              const char *input,
              size_t input_len,
              char **output,
              size_t *output_len);

Encode data according to negotiated SASL mechanism. This might mean that data is integrity or privacy protected.

The output buffer is allocated by this function, and it is the responsibility of caller to deallocate it by calling gsasl_free(output ).

gsasl_decode ()

int
gsasl_decode (Gsasl_session *sctx,
              const char *input,
              size_t input_len,
              char **output,
              size_t *output_len);

Decode data according to negotiated SASL mechanism. This might mean that data is integrity or privacy protected.

The output buffer is allocated by this function, and it is the responsibility of caller to deallocate it by calling gsasl_free(output ).

gsasl_mechanism_name ()

const char *
gsasl_mechanism_name (Gsasl_session *sctx);

This function returns the name of the SASL mechanism used in the session. The pointer must not be deallocated by the caller.

Since: 0.2.28

gsasl_strerror ()

const char *
gsasl_strerror (int err);

Convert return code to human readable string explanation of the reason for the particular error code.

This string can be used to output a diagnostic message to the user.

This function is one of few in the library that can be used without a successful call to gsasl_init().

gsasl_strerror_name ()

const char *
gsasl_strerror_name (int err);

Convert return code to human readable string representing the error code symbol itself. For example, gsasl_strerror_name(GSASL_OK) returns the string "GSASL_OK".

This string can be used to output a diagnostic message to the user.

This function is one of few in the library that can be used without a successful call to gsasl_init().

Since: 0.2.29

gsasl_saslprep ()

int
gsasl_saslprep (const char *in,
                Gsasl_saslprep_flags flags,
                char **out,
                int *stringpreprc);

Prepare string using SASLprep. On success, the out variable must be deallocated by the caller.

Since: 0.2.3

gsasl_nonce ()

int
gsasl_nonce (char *data,
             size_t datalen);

Store unpredictable data of given size in the provided buffer.

gsasl_random ()

int
gsasl_random (char *data,
              size_t datalen);

Store cryptographically strong random data of given size in the provided buffer.

gsasl_hash_length ()

size_t
gsasl_hash_length (Gsasl_hash hash);

Return the digest output size for hash function hash . For example, gsasl_hash_length(GSASL_HASH_SHA256) returns GSASL_HASH_SHA256_SIZE which is 32.

Since: 1.10

gsasl_scram_secrets_from_salted_password ()

int
gsasl_scram_secrets_from_salted_password
                               (Gsasl_hash hash,
                                const char *salted_password,
                                char *client_key,
                                char *server_key,
                                char *stored_key);

Helper function to derive SCRAM ClientKey/ServerKey/StoredKey. The client_key , server_key , and stored_key buffers must have room to hold digest for given hash , use GSASL_HASH_MAX_SIZE which is sufficient for all hashes.

Since: 1.10

gsasl_scram_secrets_from_password ()

int
gsasl_scram_secrets_from_password (Gsasl_hash hash,
                                   const char *password,
                                   unsigned int iteration_count,
                                   const char *salt,
                                   size_t saltlen,
                                   char *salted_password,
                                   char *client_key,
                                   char *server_key,
                                   char *stored_key);

Helper function to generate SCRAM secrets from a password. The salted_password , client_key , server_key , and stored_key buffers must have room to hold digest for given hash , use GSASL_HASH_MAX_SIZE which is sufficient for all hashes.

Since: 1.10

gsasl_simple_getpass ()

int
gsasl_simple_getpass (const char *filename,
                      const char *username,
                      char **key);

Retrieve password for user from specified file. The buffer key contain the password if this function is successful. The caller is responsible for deallocating it.

The file should be on the UoW "MD5 Based Authentication" format, which means it is in text format with comments denoted by # first on the line, with user entries looking as "usernameTABpassword". This function removes CR and LF at the end of lines before processing. TAB, CR, and LF denote ASCII values 9, 13, and 10, respectively.

gsasl_base64_to ()

int
gsasl_base64_to (const char *in,
                 size_t inlen,
                 char **out,
                 size_t *outlen);

Encode data as base64. The out string is zero terminated, and outlen holds the length excluding the terminating zero. The out buffer must be deallocated by the caller.

Since: 0.2.2

gsasl_base64_from ()

int
gsasl_base64_from (const char *in,
                   size_t inlen,
                   char **out,
                   size_t *outlen);

Decode Base64 data. The out buffer must be deallocated by the caller.

Since: 0.2.2

gsasl_hex_to ()

int
gsasl_hex_to (const char *in,
              size_t inlen,
              char **out,
              size_t *outlen);

Hex encode data. The out string is zero terminated, and outlen holds the length excluding the terminating zero. The out buffer must be deallocated by the caller.

Since: 1.10

gsasl_hex_from ()

int
gsasl_hex_from (const char *in,
                char **out,
                size_t *outlen);

Decode hex data. The out buffer must be deallocated by the caller.

Since: 1.10

gsasl_free ()

void
gsasl_free (void *ptr);

Invoke free(ptr ) to de-allocate memory pointer. Typically used on strings allocated by other libgsasl functions.

This is useful on Windows where libgsasl is linked to one CRT and the application is linked to another CRT. Then malloc/free will not use the same heap. This happens if you build libgsasl using mingw32 and the application with Visual Studio.

Since: 0.2.19

Gsasl

  typedef struct Gsasl Gsasl;

Handle to global library context.

Gsasl_session

  typedef struct Gsasl_session Gsasl_session;

Handle to SASL session context.

enum Gsasl_rc

Error codes for library functions.

enum Gsasl_property

Callback/property types.

enum Gsasl_mechname_limits

SASL mechanisms are named by strings, from 1 to 20 characters in length, consisting of upper-case letters, digits, hyphens, and/or underscores. See also gsasl_mechanism_name_p().

enum Gsasl_qop

Quality of Protection types (DIGEST-MD5 and GSSAPI). The integrity and confidentiality values is about application data wrapping. We recommend that you use GSASL_QOP_AUTH with TLS as that combination is generally more secure and have better chance of working than the integrity/confidentiality layers of SASL.

enum Gsasl_saslprep_flags

Flags for the SASLprep function, see gsasl_saslprep(). For background, see the GNU Libidn documentation.

enum Gsasl_hash

Hash functions. You may use gsasl_hash_length() to get the output size of a hash function.

Currently only used as parameter to gsasl_scram_secrets_from_salted_password() and gsasl_scram_secrets_from_password() to specify for which SCRAM mechanism to prepare secrets for.

Since: 1.10

enum Gsasl_hash_length

Identifiers specifying the output size of hash functions.

These can be used when statically allocating the buffers needed for, e.g., gsasl_scram_secrets_from_password().

Since: 1.10