Collaboration diagram for The SSH authentication functions:

Typedefs
typedef int(*	ssh_auth_callback) (const char prompt, char buf, size_t len, int echo, int verify, void *userdata)
	SSH authentication callback for password and publickey auth.

Enumerations
enum	ssh_agent_state_e { SSH_AGENT_STATE_NONE = 0 , SSH_AGENT_STATE_PUBKEY , SSH_AGENT_STATE_CERT , SSH_AGENT_STATE_AUTH }

enum	ssh_auth_auto_state_e { SSH_AUTH_AUTO_STATE_NONE = 0 , SSH_AUTH_AUTO_STATE_PUBKEY , SSH_AUTH_AUTO_STATE_KEY_IMPORTED , SSH_AUTH_AUTO_STATE_CERTIFICATE_FILE , SSH_AUTH_AUTO_STATE_CERTIFICATE_OPTION , SSH_AUTH_AUTO_STATE_PUBKEY_ACCEPTED }

Functions
int	ssh_set_agent_channel (ssh_session session, ssh_channel channel)
	sets the SSH agent channel. The SSH agent channel will be used to authenticate this client using an agent through a channel, from another session. The most likely use is to implement SSH Agent forwarding into a SSH proxy.

int	ssh_set_agent_socket (ssh_session session, socket_t fd)
	sets the SSH agent socket. The SSH agent will be used to authenticate this client using the given socket to communicate with the ssh-agent. The caller is responsible for connecting to the socket prior to calling this function.

	SSH_PACKET_CALLBACK (ssh_packet_userauth_banner)

	SSH_PACKET_CALLBACK (ssh_packet_userauth_failure)

	SSH_PACKET_CALLBACK (ssh_packet_userauth_success)

	SSH_PACKET_CALLBACK (ssh_packet_userauth_pk_ok)

int	ssh_userauth_list (ssh_session session, const char *username)
	Get available authentication methods from the server.

int	ssh_userauth_none (ssh_session session, const char *username)
	Try to authenticate through the "none" method.

int	ssh_userauth_try_publickey (ssh_session session, const char *username, const ssh_key pubkey)
	Try to authenticate with the given public key.

int	ssh_userauth_publickey (ssh_session session, const char *username, const ssh_key privkey)
	Authenticate with public/private key or certificate.

void	ssh_agent_state_free (void *data)

int	ssh_userauth_agent (ssh_session session, const char *username)
	Try to do public key authentication with ssh agent.

int	ssh_userauth_publickey_auto_get_current_identity (ssh_session session, char **value)
	Get the identity that is currently being processed by ssh_userauth_publickey_auto()

int	ssh_userauth_publickey_auto (ssh_session session, const char username, const char passphrase)
	Tries to automatically authenticate with public key and "none".

int	ssh_userauth_password (ssh_session session, const char username, const char password)
	Try to authenticate by password.

int	ssh_userauth_agent_pubkey (ssh_session session, const char *username, ssh_public_key publickey)

ssh_kbdint	ssh_kbdint_new (void)

void	ssh_kbdint_free (ssh_kbdint kbd)

void	ssh_kbdint_clean (ssh_kbdint kbd)

	SSH_PACKET_CALLBACK (ssh_packet_userauth_info_request)

int	ssh_userauth_kbdint (ssh_session session, const char user, const char submethods)
	Try to authenticate through the "keyboard-interactive" method.

int	ssh_userauth_kbdint_getnprompts (ssh_session session)
	Get the number of prompts (questions) the server has given.

const char *	ssh_userauth_kbdint_getname (ssh_session session)
	Get the "name" of the message block.

const char *	ssh_userauth_kbdint_getinstruction (ssh_session session)
	Get the "instruction" of the message block.

const char *	ssh_userauth_kbdint_getprompt (ssh_session session, unsigned int i, char *echo)
	Get a prompt from a message block.

int	ssh_userauth_kbdint_getnanswers (ssh_session session)
	Get the number of answers the client has given.

const char *	ssh_userauth_kbdint_getanswer (ssh_session session, unsigned int i)
	Get the answer to a question from a message block.

int	ssh_userauth_kbdint_setanswer (ssh_session session, unsigned int i, const char *answer)
	Set the answer for a question from a message block.

int	ssh_userauth_gssapi (ssh_session session)
	Try to authenticate through the "gssapi-with-mic" method.

Detailed Description

Functions to authenticate with a server.

Typedef Documentation

◆ ssh_auth_callback

typedef int(* ssh_auth_callback) (const char *prompt, char *buf, size_t len, int echo, int verify, void *userdata)

SSH authentication callback for password and publickey auth.

Parameters

prompt	Prompt to be displayed.
buf	Buffer to save the password. You should null-terminate it.
len	Length of the buffer.
echo	Enable or disable the echo of what you type.
verify	Should the password be verified?
userdata	Userdata to be passed to the callback function. Useful for GUI applications.

Returns: 0 on success, < 0 on error.

Function Documentation

◆ ssh_set_agent_channel()

int ssh_set_agent_channel	(	ssh_session	session,
		ssh_channel	channel )

sets the SSH agent channel. The SSH agent channel will be used to authenticate this client using an agent through a channel, from another session. The most likely use is to implement SSH Agent forwarding into a SSH proxy.

Parameters

	session	the session
[in]	channel	a SSH channel from another session.

Returns: SSH_OK in case of success SSH_ERROR in case of an error

◆ ssh_set_agent_socket()

int ssh_set_agent_socket	(	ssh_session	session,
		socket_t	fd )

sets the SSH agent socket. The SSH agent will be used to authenticate this client using the given socket to communicate with the ssh-agent. The caller is responsible for connecting to the socket prior to calling this function.

Returns: SSH_OK in case of success SSH_ERROR in case of an error

◆ ssh_userauth_agent()

int ssh_userauth_agent	(	ssh_session	session,
		const char *	username )

Try to do public key authentication with ssh agent.

Parameters

[in]	session	The ssh session to use.
[in]	username	The username, this SHOULD be NULL.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: The server doesn't accept that public key as an authentication token. Try another key or another method.
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method.
SSH_AUTH_SUCCESS: The public key is accepted, you want now to use ssh_userauth_publickey().
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

◆ ssh_userauth_gssapi()

int ssh_userauth_gssapi ( ssh_session session )

Try to authenticate through the "gssapi-with-mic" method.

Parameters

[in] session The ssh session to use.

Returns: SSH_AUTH_ERROR: A serious error happened
SSH_AUTH_DENIED: Authentication failed : use another method
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method
SSH_AUTH_SUCCESS: Authentication success
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

◆ ssh_userauth_kbdint()

int ssh_userauth_kbdint	(	ssh_session	session,
		const char *	user,
		const char *	submethods )

Try to authenticate through the "keyboard-interactive" method.

Parameters

[in]	session	The ssh session to use.
[in]	user	The username to authenticate. You can specify NULL if ssh_option_set_username() has been used. You cannot try two different logins in a row.
[in]	submethods	Undocumented. Set it to NULL.

Returns: SSH_AUTH_ERROR: A serious error happened
SSH_AUTH_DENIED: Authentication failed : use another method
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method
SSH_AUTH_SUCCESS: Authentication success
SSH_AUTH_INFO: The server asked some questions. Use ssh_userauth_kbdint_getnprompts() and such.
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

See also: ssh_userauth_kbdint_getnprompts(); ssh_userauth_kbdint_getname(); ssh_userauth_kbdint_getinstruction(); ssh_userauth_kbdint_getprompt(); ssh_userauth_kbdint_setanswer()

◆ ssh_userauth_kbdint_getanswer()

const char * ssh_userauth_kbdint_getanswer	(	ssh_session	session,
		unsigned int	i )

Get the answer to a question from a message block.

Parameters

[in]	session	The ssh session to use.
[in]	i	index The number of the ith answer.

Returns: The answer string, or NULL if the answer is not available. Do not free the string.

◆ ssh_userauth_kbdint_getinstruction()

const char * ssh_userauth_kbdint_getinstruction ( ssh_session session )

Get the "instruction" of the message block.

Once you have called ssh_userauth_kbdint() and received SSH_AUTH_INFO return code, this function can be used to retrieve information about the keyboard interactive authentication questions sent by the remote host.

Parameters

[in] session The ssh session to use.

Returns: The instruction of the message block.

◆ ssh_userauth_kbdint_getname()

const char * ssh_userauth_kbdint_getname ( ssh_session session )

Get the "name" of the message block.

Once you have called ssh_userauth_kbdint() and received SSH_AUTH_INFO return code, this function can be used to retrieve information about the keyboard interactive authentication questions sent by the remote host.

Parameters

[in] session The ssh session to use.

Returns: The name of the message block. Do not free it.

◆ ssh_userauth_kbdint_getnanswers()

int ssh_userauth_kbdint_getnanswers ( ssh_session session )

Get the number of answers the client has given.

Parameters

[in] session The ssh session to use.

Returns: The number of answers.

◆ ssh_userauth_kbdint_getnprompts()

int ssh_userauth_kbdint_getnprompts ( ssh_session session )

Get the number of prompts (questions) the server has given.

Once you have called ssh_userauth_kbdint() and received SSH_AUTH_INFO return code, this function can be used to retrieve information about the keyboard interactive authentication questions sent by the remote host.

Parameters

[in] session The ssh session to use.

Returns: The number of prompts.

◆ ssh_userauth_kbdint_getprompt()

const char * ssh_userauth_kbdint_getprompt	(	ssh_session	session,
		unsigned int	i,
		char *	echo )

Get a prompt from a message block.

Once you have called ssh_userauth_kbdint() and received SSH_AUTH_INFO return code, this function can be used to retrieve information about the keyboard interactive authentication questions sent by the remote host.

Parameters

[in]	session	The ssh session to use.
[in]	i	The index number of the i'th prompt.
[out]	echo	This is an optional variable. You can obtain a boolean if the user input should be echoed or hidden. For passwords it is usually hidden.

Returns: A pointer to the prompt. Do not free it.

const char prompt;
char echo;
 
prompt = ssh_userauth_kbdint_getprompt(session, 0, &echo);
if (echo) ...

◆ ssh_userauth_kbdint_setanswer()

int ssh_userauth_kbdint_setanswer	(	ssh_session	session,
		unsigned int	i,
		const char *	answer )

Set the answer for a question from a message block.

If you have called ssh_userauth_kbdint() and got SSH_AUTH_INFO, this function returns the questions from the server.

Parameters

[in]	session	The ssh session to use.
[in]	i	index The number of the ith prompt.
[in]	answer	The answer to give to the server. The answer MUST be encoded UTF-8. It is up to the server how to interpret the value and validate it. However, if you read the answer in some other encoding, you MUST convert it to UTF-8.

Returns: 0 on success, < 0 on error.

◆ ssh_userauth_list()

int ssh_userauth_list	(	ssh_session	session,
		const char *	username )

Get available authentication methods from the server.

This requires the function ssh_userauth_none() to be called before the methods are available. The server MAY return a list of methods that may continue.

Parameters

[in]	session	The SSH session.
[in]	username	Deprecated, set to NULL.

Returns

A bitfield of the following values:

SSH_AUTH_METHOD_PASSWORD
SSH_AUTH_METHOD_PUBLICKEY
SSH_AUTH_METHOD_HOSTBASED
SSH_AUTH_METHOD_INTERACTIVE

Warning: Other reserved flags may appear in future versions.

See also: ssh_userauth_none()

◆ ssh_userauth_none()

int ssh_userauth_none	(	ssh_session	session,
		const char *	username )

Try to authenticate through the "none" method.

Parameters

[in]	session	The ssh session to use.
[in]	username	The username, this SHOULD be NULL.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: Authentication failed: use another method
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method
SSH_AUTH_SUCCESS: Authentication success
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

◆ ssh_userauth_password()

int ssh_userauth_password	(	ssh_session	session,
		const char *	username,
		const char *	password )

Try to authenticate by password.

This authentication method is normally disabled on SSHv2 server. You should use keyboard-interactive mode.

The 'password' value MUST be encoded UTF-8. It is up to the server how to interpret the password and validate it against the password database. However, if you read the password in some other encoding, you MUST convert the password to UTF-8.

Parameters

[in]	session	The ssh session to use.
[in]	username	The username, this SHOULD be NULL.
[in]	password	The password to authenticate in UTF-8.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: Authentication failed: use another method
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method
SSH_AUTH_SUCCESS: Authentication success
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

See also: ssh_userauth_none(); ssh_userauth_kbdint()

◆ ssh_userauth_publickey()

int ssh_userauth_publickey	(	ssh_session	session,
		const char *	username,
		const ssh_key	privkey )

Authenticate with public/private key or certificate.

Parameters

[in]	session	The SSH session.
[in]	username	The username, this SHOULD be NULL.
[in]	privkey	The private key for authentication.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: The server doesn't accept that public key as an authentication token. Try another key or another method.
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method.
SSH_AUTH_SUCCESS: The public key is accepted.
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

◆ ssh_userauth_publickey_auto()

int ssh_userauth_publickey_auto	(	ssh_session	session,
		const char *	username,
		const char *	passphrase )

Tries to automatically authenticate with public key and "none".

It may fail, for instance it doesn't ask for a password and uses a default asker for passphrases (in case the private key is encrypted).

Parameters

[in]	session	The SSH session.
[in]	username	The username, this SHOULD be NULL.
[in]	passphrase	Use this passphrase to unlock the privatekey. Use NULL if you don't want to use a passphrase or the user should be asked.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: The server doesn't accept that public key as an authentication token. Try another key or another method.
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method.
SSH_AUTH_SUCCESS: Authentication success
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

The OpenSSH iterates over the identities and first try the plain public key and then the certificate if it is in place.

◆ ssh_userauth_publickey_auto_get_current_identity()

int ssh_userauth_publickey_auto_get_current_identity	(	ssh_session	session,
		char **	value )

Get the identity that is currently being processed by ssh_userauth_publickey_auto()

This is meant to be used by a callback that happens as part of the execution of ssh_userauth_publickey_auto(). The auth_function callback might want to know which key a passphrase is needed for, for example.

Parameters

[in]	session	The SSH session.
[out]	value	The value to get into. As a char**, space will be allocated by the function for the value, it is your responsibility to free the memory using ssh_string_free_char().

Returns: SSH_OK on success, SSH_ERROR on error.

◆ ssh_userauth_try_publickey()

int ssh_userauth_try_publickey	(	ssh_session	session,
		const char *	username,
		const ssh_key	pubkey )

Try to authenticate with the given public key.

To avoid unnecessary processing and user interaction, the following method is provided for querying whether authentication using the 'pubkey' would be possible.

Parameters

[in]	session	The SSH session.
[in]	username	The username, this SHOULD be NULL.
[in]	pubkey	The public key to try.

Returns: SSH_AUTH_ERROR: A serious error happened.
SSH_AUTH_DENIED: The server doesn't accept that public key as an authentication token. Try another key or another method.
SSH_AUTH_PARTIAL: You've been partially authenticated, you still have to use another method.
SSH_AUTH_SUCCESS: The public key is accepted, you want now to use ssh_userauth_publickey().
SSH_AUTH_AGAIN: In nonblocking mode, you've got to call this again later.

Note: Most server implementations do not permit changing the username during authentication. The username should only be set with ssh_options_set() only before you connect to the server.

Typedefs

Enumerations

Functions

Detailed Description

Typedef Documentation

◆ ssh_auth_callback

Function Documentation

◆ ssh_set_agent_channel()

◆ ssh_set_agent_socket()

◆ ssh_userauth_agent()

◆ ssh_userauth_gssapi()

◆ ssh_userauth_kbdint()

◆ ssh_userauth_kbdint_getanswer()

◆ ssh_userauth_kbdint_getinstruction()

◆ ssh_userauth_kbdint_getname()

◆ ssh_userauth_kbdint_getnanswers()

◆ ssh_userauth_kbdint_getnprompts()

◆ ssh_userauth_kbdint_getprompt()

◆ ssh_userauth_kbdint_setanswer()

◆ ssh_userauth_list()

◆ ssh_userauth_none()

◆ ssh_userauth_password()

◆ ssh_userauth_publickey()

◆ ssh_userauth_publickey_auto()

◆ ssh_userauth_publickey_auto_get_current_identity()

◆ ssh_userauth_try_publickey()