gsasl

## gsasl gsasl |

## Synopsis

    #define             GSASL_API
    #define             GSASL_VERSION
    #define             GSASL_VERSION_MAJOR
    #define             GSASL_VERSION_MINOR
    #define             GSASL_VERSION_NUMBER
    #define             GSASL_VERSION_PATCH
    typedef             Gsasl;
    int                 (*Gsasl_callback_function)          (Gsasl *ctx,
                                                             Gsasl_session *sctx,
                                                             Gsasl_property prop);
    enum                Gsasl_cipher;
    enum                Gsasl_property;
    enum                Gsasl_qop;
    enum                Gsasl_rc;
    enum                Gsasl_saslprep_flags;
    typedef             Gsasl_session;
    int                 gsasl_base64_from                   (const char *in,
                                                             size_t inlen,
                                                             char **out,
                                                             size_t *outlen);
    int                 gsasl_base64_to                     (const char *in,
                                                             size_t inlen,
                                                             char **out,
                                                             size_t *outlen);
    int                 gsasl_callback                      (Gsasl *ctx,
                                                             Gsasl_session *sctx,
                                                             Gsasl_property prop);
    void *              gsasl_callback_hook_get             (Gsasl *ctx);
    void                gsasl_callback_hook_set             (Gsasl *ctx,
                                                             void *hook);
    void                gsasl_callback_set                  (Gsasl *ctx,
                                                             Gsasl_callback_function cb);
    const char *        gsasl_check_version                 (const char *req_version);
    int                 gsasl_client_mechlist               (Gsasl *ctx,
                                                             char **out);
    int                 gsasl_client_start                  (Gsasl *ctx,
                                                             const char *mech,
                                                             Gsasl_session **sctx);
    const char *        gsasl_client_suggest_mechanism      (Gsasl *ctx,
                                                             const char *mechlist);
    int                 gsasl_client_support_p              (Gsasl *ctx,
                                                             const char *name);
    int                 gsasl_decode                        (Gsasl_session *sctx,
                                                             const char *input,
                                                             size_t input_len,
                                                             char **output,
                                                             size_t *output_len);
    void                gsasl_done                          (Gsasl *ctx);
    int                 gsasl_encode                        (Gsasl_session *sctx,
                                                             const char *input,
                                                             size_t input_len,
                                                             char **output,
                                                             size_t *output_len);
    void                gsasl_finish                        (Gsasl_session *sctx);
    void                gsasl_free                          (void *ptr);
    int                 gsasl_hmac_md5                      (const char *key,
                                                             size_t keylen,
                                                             const char *in,
                                                             size_t inlen,
                                                             char *outhash[16]);
    int                 gsasl_hmac_sha1                     (const char *key,
                                                             size_t keylen,
                                                             const char *in,
                                                             size_t inlen,
                                                             char *outhash[20]);
    int                 gsasl_init                          (Gsasl **ctx);
    int                 gsasl_md5                           (const char *in,
                                                             size_t inlen,
                                                             char *out[16]);
    const char *        gsasl_mechanism_name                (Gsasl_session *sctx);
    int                 gsasl_nonce                         (char *data,
                                                             size_t datalen);
    const char *        gsasl_property_fast                 (Gsasl_session *sctx,
                                                             Gsasl_property prop);
    const char *        gsasl_property_get                  (Gsasl_session *sctx,
                                                             Gsasl_property prop);
    void                gsasl_property_set                  (Gsasl_session *sctx,
                                                             Gsasl_property prop,
                                                             const char *data);
    void                gsasl_property_set_raw              (Gsasl_session *sctx,
                                                             Gsasl_property prop,
                                                             const char *data,
                                                             size_t len);
    int                 gsasl_random                        (char *data,
                                                             size_t datalen);
    int                 gsasl_saslprep                      (const char *in,
                                                             Gsasl_saslprep_flags flags,
                                                             char **out,
                                                             int *stringpreprc);
    int                 gsasl_server_mechlist               (Gsasl *ctx,
                                                             char **out);
    int                 gsasl_server_start                  (Gsasl *ctx,
                                                             const char *mech,
                                                             Gsasl_session **sctx);
    int                 gsasl_server_support_p              (Gsasl *ctx,
                                                             const char *name);
    void *              gsasl_session_hook_get              (Gsasl_session *sctx);
    void                gsasl_session_hook_set              (Gsasl_session *sctx,
                                                             void *hook);
    int                 gsasl_sha1                          (const char *in,
                                                             size_t inlen,
                                                             char *out[20]);
    int                 gsasl_simple_getpass                (const char *filename,
                                                             const char *username,
                                                             char **key);
    int                 gsasl_step                          (Gsasl_session *sctx,
                                                             const char *input,
                                                             size_t input_len,
                                                             char **output,
                                                             size_t *output_len);
    int                 gsasl_step64                        (Gsasl_session *sctx,
                                                             const char *b64input,
                                                             char **b64output);
    const char *        gsasl_strerror                      (int err);
    const char *        gsasl_strerror_name                 (int err);

## Description

## Details

### GSASL_API

    #define GSASL_API __attribute__((__visibility__("default")))

### GSASL_VERSION

    #define GSASL_VERSION "1.8.0"

Pre-processor symbol with a string that describe the header file version number. Used together with `gsasl_check_version()` to verify header file and run-time library consistency.

### GSASL_VERSION_MAJOR

    #define GSASL_VERSION_MAJOR 1

Pre-processor symbol with a decimal value that describe the major level of the header file version number. For example, when the header version is 1.2.3 this symbol will be 1.

Since 1.1

### GSASL_VERSION_MINOR

    #define GSASL_VERSION_MINOR 8

Pre-processor symbol with a decimal value that describe the minor level of the header file version number. For example, when the header version is 1.2.3 this symbol will be 2.

Since 1.1

### GSASL_VERSION_NUMBER

    #define GSASL_VERSION_NUMBER 0x010800

Pre-processor symbol with a hexadecimal value describing the header file version number. For example, when the header version is 1.2.3 this symbol will have the value 0x010203.

Since 1.1

### GSASL_VERSION_PATCH

    #define GSASL_VERSION_PATCH 0

Pre-processor symbol with a decimal value that describe the patch level of the header file version number. For example, when the header version is 1.2.3 this symbol will be 3.

Since 1.1

### Gsasl

      typedef struct Gsasl Gsasl;

Handle to global library context.

### 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.

`ctx` : | libgsasl handle.
`sctx` : | session handle, may be NULL.
`prop` : | enumerated value of Gsasl_property type.
Returns : | Any valid return code, the interpretation of which depend on the `prop` value.

Since 0.2.0

### enum Gsasl_cipher

    typedef enum {
        GSASL_CIPHER_DES = 1,
        GSASL_CIPHER_3DES = 2,
        GSASL_CIPHER_RC4 = 4,
        GSASL_CIPHER_RC4_40 = 8,
        GSASL_CIPHER_RC4_56 = 16,
        GSASL_CIPHER_AES = 32
    } Gsasl_cipher;

Encryption types (DIGEST-MD5) for confidentiality services of application data. We recommend that you use TLS instead as it is generally more secure and have better chance of working.

`GSASL_CIPHER_DES` | Cipher DES.
`GSASL_CIPHER_3DES` | Cipher 3DES.
`GSASL_CIPHER_RC4` | Cipher RC4.
`GSASL_CIPHER_RC4_40` | Cipher RC4 with 40-bit keys.
`GSASL_CIPHER_RC4_56` | Cipher RC4 with 56-bit keys.
`GSASL_CIPHER_AES` | Cipher AES.

### enum Gsasl_property

    typedef enum {
        /* Information properties, e.g., username. */
        GSASL_AUTHID = 1,
        GSASL_AUTHZID = 2,
        GSASL_PASSWORD = 3,
        GSASL_ANONYMOUS_TOKEN = 4,
        GSASL_SERVICE = 5,
        GSASL_HOSTNAME = 6,
        GSASL_GSSAPI_DISPLAY_NAME = 7,
        GSASL_PASSCODE = 8,
        GSASL_SUGGESTED_PIN = 9,
        GSASL_PIN = 10,
        GSASL_REALM = 11,
        GSASL_DIGEST_MD5_HASHED_PASSWORD = 12,
        GSASL_QOPS = 13,
        GSASL_QOP = 14,
        GSASL_SCRAM_ITER = 15,
        GSASL_SCRAM_SALT = 16,
        GSASL_SCRAM_SALTED_PASSWORD = 17,
        GSASL_CB_TLS_UNIQUE = 18,
        GSASL_SAML20_IDP_IDENTIFIER = 19,
        GSASL_SAML20_REDIRECT_URL = 20,
        GSASL_OPENID20_REDIRECT_URL = 21,
        GSASL_OPENID20_OUTCOME_DATA = 22,
        /* Client callbacks. */
        GSASL_SAML20_AUTHENTICATE_IN_BROWSER = 250,
        GSASL_OPENID20_AUTHENTICATE_IN_BROWSER = 251,
        /* Server validation callback properties. */
        GSASL_VALIDATE_SIMPLE = 500,
        GSASL_VALIDATE_EXTERNAL = 501,
        GSASL_VALIDATE_ANONYMOUS = 502,
        GSASL_VALIDATE_GSSAPI = 503,
        GSASL_VALIDATE_SECURID = 504,
        GSASL_VALIDATE_SAML20 = 505,
        GSASL_VALIDATE_OPENID20 = 506
    } Gsasl_property;

Callback/property types.

`GSASL_AUTHID` | Authentication identity (username).
`GSASL_AUTHZID` | Authorization identity.
`GSASL_PASSWORD` | Password.
`GSASL_ANONYMOUS_TOKEN` | Anonymous identifier.
`GSASL_SERVICE` | Service name
`GSASL_HOSTNAME` | Host name.
`GSASL_GSSAPI_DISPLAY_NAME` | GSS-API credential principal name.
`GSASL_PASSCODE` | SecurID passcode.
`GSASL_SUGGESTED_PIN` | SecurID suggested PIN.
`GSASL_PIN` | SecurID PIN.
`GSASL_REALM` | User realm.
`GSASL_DIGEST_MD5_HASHED_PASSWORD` | Pre-computed hashed DIGEST-MD5 password, to avoid storing passwords in the clear.
`GSASL_QOPS` | Set of quality-of-protection values.
`GSASL_QOP` | Quality-of-protection value.
`GSASL_SCRAM_ITER` | Number of iterations in password-to-key hashing.
`GSASL_SCRAM_SALT` | Salt for password-to-key hashing.
`GSASL_SCRAM_SALTED_PASSWORD` | Pre-computed salted SCRAM key, to avoid re-computation and storing passwords in the clear.
`GSASL_CB_TLS_UNIQUE` | Base64 encoded tls-unique channel binding.
`GSASL_SAML20_IDP_IDENTIFIER` | SAML20 user IdP URL.
`GSASL_SAML20_REDIRECT_URL` | SAML 2.0 URL to access in browser.
`GSASL_OPENID20_REDIRECT_URL` | OpenID 2.0 URL to access in browser.
`GSASL_OPENID20_OUTCOME_DATA` | OpenID 2.0 authentication outcome data.
`GSASL_SAML20_AUTHENTICATE_IN_BROWSER` | Request to perform SAML 2.0 authentication in browser.
`GSASL_OPENID20_AUTHENTICATE_IN_BROWSER` | Request to perform OpenID 2.0 authentication in browser.
`GSASL_VALIDATE_SIMPLE` | Request for simple validation.
`GSASL_VALIDATE_EXTERNAL` | Request for validation of EXTERNAL.
`GSASL_VALIDATE_ANONYMOUS` | Request for validation of ANONYMOUS.
`GSASL_VALIDATE_GSSAPI` | Request for validation of GSSAPI/GS2.
`GSASL_VALIDATE_SECURID` | Reqest for validation of SecurID.
`GSASL_VALIDATE_SAML20` | Reqest for validation of SAML20.
`GSASL_VALIDATE_OPENID20` | Reqest for validation of OpenID 2.0 login.

### enum Gsasl_qop

    typedef enum {
        GSASL_QOP_AUTH = 1,
        GSASL_QOP_AUTH_INT = 2,
        GSASL_QOP_AUTH_CONF = 4
    } 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.

`GSASL_QOP_AUTH` | Authentication only.
`GSASL_QOP_AUTH_INT` | Authentication and integrity.
`GSASL_QOP_AUTH_CONF` | Authentication, integrity and confidentiality.

### enum Gsasl_rc

    typedef enum {
        GSASL_OK = 0,
        GSASL_NEEDS_MORE = 1,
        GSASL_UNKNOWN_MECHANISM = 2,
        GSASL_MECHANISM_CALLED_TOO_MANY_TIMES = 3,
        GSASL_MALLOC_ERROR = 7,
        GSASL_BASE64_ERROR = 8,
        GSASL_CRYPTO_ERROR = 9,
        GSASL_SASLPREP_ERROR = 29,
        GSASL_MECHANISM_PARSE_ERROR = 30,
        GSASL_AUTHENTICATION_ERROR = 31,
        GSASL_INTEGRITY_ERROR = 33,
        GSASL_NO_CLIENT_CODE = 35,
        GSASL_NO_SERVER_CODE = 36,
        GSASL_NO_CALLBACK = 51,
        GSASL_NO_ANONYMOUS_TOKEN = 52,
        GSASL_NO_AUTHID = 53,
        GSASL_NO_AUTHZID = 54,
        GSASL_NO_PASSWORD = 55,
        GSASL_NO_PASSCODE = 56,
        GSASL_NO_PIN = 57,
        GSASL_NO_SERVICE = 58,
        GSASL_NO_HOSTNAME = 59,
        GSASL_NO_CB_TLS_UNIQUE = 65,
        GSASL_NO_SAML20_IDP_IDENTIFIER = 66,
        GSASL_NO_SAML20_REDIRECT_URL = 67,
        GSASL_NO_OPENID20_REDIRECT_URL = 68,
        /* Mechanism specific errors. */
        GSASL_GSSAPI_RELEASE_BUFFER_ERROR = 37,
        GSASL_GSSAPI_IMPORT_NAME_ERROR = 38,
        GSASL_GSSAPI_INIT_SEC_CONTEXT_ERROR = 39,
        GSASL_GSSAPI_ACCEPT_SEC_CONTEXT_ERROR = 40,
        GSASL_GSSAPI_UNWRAP_ERROR = 41,
        GSASL_GSSAPI_WRAP_ERROR = 42,
        GSASL_GSSAPI_ACQUIRE_CRED_ERROR = 43,
        GSASL_GSSAPI_DISPLAY_NAME_ERROR = 44,
        GSASL_GSSAPI_UNSUPPORTED_PROTECTION_ERROR = 45,
        GSASL_KERBEROS_V5_INIT_ERROR = 46,
        GSASL_KERBEROS_V5_INTERNAL_ERROR = 47,
        GSASL_SHISHI_ERROR = GSASL_KERBEROS_V5_INTERNAL_ERROR,
        GSASL_SECURID_SERVER_NEED_ADDITIONAL_PASSCODE = 48,
        GSASL_SECURID_SERVER_NEED_NEW_PIN = 49,
        GSASL_GSSAPI_ENCAPSULATE_TOKEN_ERROR = 60,
        GSASL_GSSAPI_DECAPSULATE_TOKEN_ERROR = 61,
        GSASL_GSSAPI_INQUIRE_MECH_FOR_SASLNAME_ERROR = 62,
        GSASL_GSSAPI_TEST_OID_SET_MEMBER_ERROR = 63,
        GSASL_GSSAPI_RELEASE_OID_SET_ERROR = 64
          /* When adding new values, note that integers are not necessarily
             assigned monotonously increasingly. */
    } Gsasl_rc;

Error codes for library functions.

`GSASL_OK` | Successful return code, guaranteed to be always 0.
`GSASL_NEEDS_MORE` | Mechanism expects another round-trip.
`GSASL_UNKNOWN_MECHANISM` | Application requested an unknown mechanism.
`GSASL_MECHANISM_CALLED_TOO_MANY_TIMES` | Application requested too many round trips from mechanism.
`GSASL_MALLOC_ERROR` | Memory allocation failed.
`GSASL_BASE64_ERROR` | Base64 encoding/decoding failed.
`GSASL_CRYPTO_ERROR` | Cryptographic error.
`GSASL_SASLPREP_ERROR` | Failed to prepare internationalized string.
`GSASL_MECHANISM_PARSE_ERROR` | Mechanism could not parse input.
`GSASL_AUTHENTICATION_ERROR` | Authentication has failed.
`GSASL_INTEGRITY_ERROR` | Application data integrity check failed.
`GSASL_NO_CLIENT_CODE` | Library was built with client functionality.
`GSASL_NO_SERVER_CODE` | Library was built with server functionality.
`GSASL_NO_CALLBACK` | Application did not provide a callback.
`GSASL_NO_ANONYMOUS_TOKEN` | Could not get required anonymous token.
`GSASL_NO_AUTHID` | Could not get required authentication identity (username).
`GSASL_NO_AUTHZID` | Could not get required authorization identity.
`GSASL_NO_PASSWORD` | Could not get required password.
`GSASL_NO_PASSCODE` | Could not get required SecurID PIN.
`GSASL_NO_PIN` | Could not get required SecurID PIN.
`GSASL_NO_SERVICE` | Could not get required service name.
`GSASL_NO_HOSTNAME` | Could not get required hostname.
`GSASL_NO_CB_TLS_UNIQUE` | Could not get required tls-unique CB.
`GSASL_NO_SAML20_IDP_IDENTIFIER` | Could not get required SAML IdP.
`GSASL_NO_SAML20_REDIRECT_URL` | Could not get required SAML redirect URL.
`GSASL_NO_OPENID20_REDIRECT_URL` | Could not get required OpenID redirect URL.
`GSASL_GSSAPI_RELEASE_BUFFER_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_IMPORT_NAME_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_INIT_SEC_CONTEXT_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_ACCEPT_SEC_CONTEXT_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_UNWRAP_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_WRAP_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_ACQUIRE_CRED_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_DISPLAY_NAME_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_UNSUPPORTED_PROTECTION_ERROR` | An unsupported quality-of-protection layer was requeted.
`GSASL_KERBEROS_V5_INIT_ERROR` | Init error in KERBEROS_V5.
`GSASL_KERBEROS_V5_INTERNAL_ERROR` | General error in KERBEROS_V5.
`GSASL_SHISHI_ERROR` | Same as `GSASL_KERBEROS_V5_INTERNAL_ERROR`.
`GSASL_SECURID_SERVER_NEED_ADDITIONAL_PASSCODE` | SecurID mechanism needs an additional passcode.
`GSASL_SECURID_SERVER_NEED_NEW_PIN` | SecurID mechanism needs an new PIN.
`GSASL_GSSAPI_ENCAPSULATE_TOKEN_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_DECAPSULATE_TOKEN_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_INQUIRE_MECH_FOR_SASLNAME_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_TEST_OID_SET_MEMBER_ERROR` | GSS-API library call error.
`GSASL_GSSAPI_RELEASE_OID_SET_ERROR` | GSS-API library call error.

### enum Gsasl_saslprep_flags

    typedef enum {
        GSASL_ALLOW_UNASSIGNED = 1
    } Gsasl_saslprep_flags;

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

`GSASL_ALLOW_UNASSIGNED` | Allow unassigned code points.

### Gsasl_session

      typedef struct Gsasl_session Gsasl_session;

Handle to SASL session context.

### 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.

`in` : | input byte array
`inlen` : | size of input byte array
`out` : | pointer to newly allocated output byte array
`outlen` : | pointer to size of newly allocated output byte array
Returns : | Returns `GSASL_OK` on success, `GSASL_BASE64_ERROR` if input was invalid, and `GSASL_MALLOC_ERROR` on memory allocation errors.

Since 0.2.2

### gsasl_base64_to ()

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

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

`in` : | input byte array
`inlen` : | size of input byte array
`out` : | pointer to newly allocated output byte array
`outlen` : | pointer to size of newly allocated output byte array
Returns : | Returns `GSASL_OK` on success, or `GSASL_MALLOC_ERROR` if input was too large or memory allocation fail.

Since 0.2.2

### 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.

Note that if no callback has been set by the application, but the obsolete callback interface has been used, this function will translate the old callback interface into the new. This interface should be sufficient to invoke all callbacks, both new and old.

`ctx` : | handle received from `gsasl_init()`, may be NULL to derive it from `sctx`.
`sctx` : | session handle.
`prop` : | enumerated value of Gsasl_property type.
Returns : | Returns whatever the application callback returns, or `GSASL_NO_CALLBACK` if no application was known.

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.

`ctx` : | libgsasl handle.
Returns : | Returns the application specific data, or NULL.

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.

`ctx` : | libgsasl handle.
`hook` : | opaque pointer to application specific data.

Since 0.2.0

### 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.

`ctx` : | handle received from `gsasl_init()`.
`cb` : | pointer to function implemented by application.

Since 0.2.0

### 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()`.

`req_version` : | version string to compare with, or NULL.
Returns : | Check that the version of the library is at minimum the one given as a string in `req_version` and return the actual version string of the library; return NULL if the condition is not met. If NULL is passed to this function no check is done and only the version string is returned.

### 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.

`ctx` : | libgsasl handle.
`out` : | newly allocated output character array.
Returns : | Returns `GSASL_OK` if successful, or error code.

### 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.

`ctx` : | libgsasl handle.
`mech` : | name of SASL mechanism.
`sctx` : | pointer to client handle.
Returns : | Returns `GSASL_OK` if successful, or error code.

### gsasl_client_suggest_mechanism ()

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

Given a list of mechanisms, suggest which to use.

`ctx` : | libgsasl handle.
`mechlist` : | input character array with SASL mechanism names, separated by invalid characters (e.g. SPC).
Returns : | Returns name of "best" SASL mechanism supported by the libgsasl client which is present in the input string, or NULL if no supported mechanism is found.

### 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.

`ctx` : | libgsasl handle.
`name` : | name of SASL mechanism.
Returns : | Returns 1 if the libgsasl client supports the named mechanism, otherwise 0.

### 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 free(`output`).

`sctx` : | libgsasl session handle.
`input` : | input byte array.
`input_len` : | size of input byte array.
`output` : | newly allocated output byte array.
`output_len` : | size of output byte array.
Returns : | Returns `GSASL_OK` if encoding was successful, otherwise an error code.

### 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.

`ctx` : | libgsasl handle.

### 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 free(`output`).

`sctx` : | libgsasl session handle.
`input` : | input byte array.
`input_len` : | size of input byte array.
`output` : | newly allocated output byte array.
`output_len` : | size of output byte array.
Returns : | Returns `GSASL_OK` if encoding was successful, otherwise an error code.

### 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.

`sctx` : | libgsasl session handle.

### 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.

`ptr` : | memory pointer

Since 0.2.19

### gsasl_hmac_md5 ()

    int                 gsasl_hmac_md5                      (const char *key,
                                                             size_t keylen,
                                                             const char *in,
                                                             size_t inlen,
                                                             char *outhash[16]);

Compute keyed checksum of data using HMAC-MD5. The `outhash` buffer must be deallocated by the caller.

`key` : | input character array with key to use.
`keylen` : | length of input character array with key to use.
`in` : | input character array of data to hash.
`inlen` : | length of input character array of data to hash.
`outhash` : | newly allocated character array with keyed hash of data.
Returns : | Returns `GSASL_OK` iff successful.

### gsasl_hmac_sha1 ()

    int                 gsasl_hmac_sha1                     (const char *key,
                                                             size_t keylen,
                                                             const char *in,
                                                             size_t inlen,
                                                             char *outhash[20]);

Compute keyed checksum of data using HMAC-SHA1. The `outhash` buffer must be deallocated by the caller.

`key` : | input character array with key to use.
`keylen` : | length of input character array with key to use.
`in` : | input character array of data to hash.
`inlen` : | length of input character array of data to hash.
`outhash` : | newly allocated character array with keyed hash of data.
Returns : | Returns `GSASL_OK` iff successful.

Since 1.3

### 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()`.

`ctx` : | pointer to libgsasl handle.
Returns : | GSASL_OK iff successful, otherwise `GSASL_MALLOC_ERROR`.

### gsasl_md5 ()

    int                 gsasl_md5                           (const char *in,
                                                             size_t inlen,
                                                             char *out[16]);

Compute hash of data using MD5. The `out` buffer must be deallocated by the caller.

`in` : | input character array of data to hash.
`inlen` : | length of input character array of data to hash.
`out` : | newly allocated character array with hash of data.
Returns : | Returns `GSASL_OK` iff successful.

### gsasl_mechanism_name ()

    const char *        gsasl_mechanism_name                (Gsasl_session *sctx);

This function returns the name of the SASL mechanism used in the session.

`sctx` : | libgsasl session handle.
Returns : | Returns a zero terminated character array with the name of the SASL mechanism, or NULL if not known.

Since 0.2.28

### gsasl_nonce ()

    int                 gsasl_nonce                         (char *data,
                                                             size_t datalen);

Store unpredictable data of given size in the provided buffer.

`data` : | output array to be filled with unpredictable random data.
`datalen` : | size of output array.
Returns : | Returns `GSASL_OK` iff successful.

### 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.

`sctx` : | session handle.
`prop` : | enumerated value of Gsasl_property type, indicating the type of data in `data`.
Returns : | Return property value, if known, or NULL if no value known.

Since 0.2.0

### 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.

If no value is known, and no callback is specified or if the callback fail to return data, and if any obsolete callback functions has been set by the application, this function will try to call these obsolete callbacks, and store the returned data as the corresponding property. This behaviour of this function will be removed when the obsolete callback interfaces are removed.

`sctx` : | session handle.
`prop` : | enumerated value of Gsasl_property type, indicating the type of data in `data`.
Returns : | Return data for property, or NULL if no value known.

Since 0.2.0

### gsasl_property_set ()

    void                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.

`sctx` : | session handle.
`prop` : | enumerated value of Gsasl_property type, indicating the type of data in `data`.
`data` : | zero terminated character string to store.

Since 0.2.0

### gsasl_property_set_raw ()

    void                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.

`sctx` : | session handle.
`prop` : | enumerated value of Gsasl_property type, indicating the type of data in `data`.
`data` : | character string to store.
`len` : | length of character string to store.

Since 0.2.0

### gsasl_random ()

    int                 gsasl_random                        (char *data,
                                                             size_t datalen);

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

`data` : | output array to be filled with strong random data.
`datalen` : | size of output array.
Returns : | Returns `GSASL_OK` iff successful.

### 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.

`in` : | a UTF-8 encoded string.
`flags` : | any SASLprep flag, e.g., `GSASL_ALLOW_UNASSIGNED`.
`out` : | on exit, contains newly allocated output string.
`stringpreprc` : | if non-NULL, will hold precise stringprep return code.
Returns : | Returns `GSASL_OK` on success, or `GSASL_SASLPREP_ERROR` on error.

Since 0.2.3

### 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.

`ctx` : | libgsasl handle.
`out` : | newly allocated output character array.
Returns : | Returns `GSASL_OK` if successful, or error code.

### 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.

`ctx` : | libgsasl handle.
`mech` : | name of SASL mechanism.
`sctx` : | pointer to server handle.
Returns : | Returns `GSASL_OK` if successful, or error code.

### 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.

`ctx` : | libgsasl handle.
`name` : | name of SASL mechanism.
Returns : | Returns 1 if the libgsasl server supports the named mechanism, otherwise 0.

### 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.

`sctx` : | libgsasl session handle.
Returns : | Returns the application specific data, or NULL.

Since 0.2.14

### 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.

`sctx` : | libgsasl session handle.
`hook` : | opaque pointer to application specific data.

Since 0.2.14

### gsasl_sha1 ()

    int                 gsasl_sha1                          (const char *in,
                                                             size_t inlen,
                                                             char *out[20]);

Compute hash of data using SHA1. The `out` buffer must be deallocated by the caller.

`in` : | input character array of data to hash.
`inlen` : | length of input character array of data to hash.
`out` : | newly allocated character array with hash of data.
Returns : | Returns `GSASL_OK` iff successful.

Since 1.3

### 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.

`filename` : | filename of file containing passwords.
`username` : | username string.
`key` : | newly allocated output character array.
Returns : | Return `GSASL_OK` if output buffer contains the password, `GSASL_AUTHENTICATION_ERROR` if the user could not be found, or other error code.

### 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 free (`output`).

`sctx` : | libgsasl session handle.
`input` : | input byte array.
`input_len` : | size of input byte array.
`output` : | newly allocated output byte array.
`output_len` : | pointer to output variable with size of output byte array.
Returns : | Returns `GSASL_OK` if authenticated terminated successfully, `GSASL_NEEDS_MORE` if more data is needed, or error code.

### 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 free (`b64output`).

`sctx` : | libgsasl client handle.
`b64input` : | input base64 encoded byte array.
`b64output` : | newly allocated output base64 encoded byte array.
Returns : | Returns `GSASL_OK` if authenticated terminated successfully, `GSASL_NEEDS_MORE` if more data is needed, or error code.

### 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()`.

`err` : | libgsasl error code
Returns : | Returns a pointer to a statically allocated string containing an explanation of the error code `err`.

### 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()`.

`err` : | libgsasl error code
Returns : | Returns a pointer to a statically allocated string containing a string version of the error code `err`, or NULL if the error code is not known.

Since 0.2.29