SSH agents¶

SSH Agent interface

class paramiko.agent.Agent¶

Client interface for using private keys from an SSH agent running on the local machine. If an SSH agent is running, this class can be used to connect to it and retrieve PKey objects which can be used when attempting to authenticate to remote SSH servers.

Upon initialization, a session with the local machine’s SSH agent is opened, if one is running. If no agent is running, initialization will succeed, but get_keys will return an empty tuple.

Raises: SSHException – if an SSH agent is found, but speaks an incompatible protocol

Changed in version 2.10: Added support for native openssh agent on windows (extending previous putty pageant support)

close()¶: Close the SSH agent connection.

get_keys()¶

Return the list of keys available through the SSH agent, if any. If no SSH agent was running (or it couldn’t be contacted), an empty list will be returned.

This method performs no IO, just returns the list of keys retrieved when the connection was made.

Returns: a tuple of AgentKey objects representing keys available on the SSH agent

class paramiko.agent.AgentClientProxy(chanRemote)¶

Class proxying request as a client:

client ask for a request_forward_agent()
server creates a proxy and a fake SSH Agent
server ask for establishing a connection when needed, calling the forward_agent_handler at client side.
the forward_agent_handler launch a thread for connecting the remote fake agent and the local agent
Communication occurs …

close()¶: Close the current connection and terminate the agent Should be called manually

connect()¶: Method automatically called by AgentProxyThread.run.

class paramiko.agent.AgentKey(agent, blob, comment='')¶

Private key held in a local SSH agent. This type of key can be used for authenticating to a remote server (signing). Most other key operations work as expected.

Changed in version 3.2: Added the comment kwarg and attribute.

Changed in version 3.2: Added the .inner_key attribute holding a reference to the ‘real’ key instance this key is a proxy for, if one was obtainable, else None.

property algorithm_name¶

Return the key algorithm identifier for this key.

Similar to get_name, but aimed at pure algorithm name instead of SSH protocol field value.

asbytes()¶: Return a string of an SSH Message made up of the public part(s) of this key. This string is suitable for passing to __init__ to re-create the key object later.

can_sign()¶: Return True if this key has the private part necessary for signing data.

property fingerprint¶

Modern fingerprint property designed to be comparable to OpenSSH.

Currently only does SHA256 (the OpenSSH default).

New in version 3.2.

static from_path(path, passphrase=None)¶

Attempt to instantiate appropriate key subclass from given file path.

Parameters: path (Path) – The path to load (may also be a str).
Returns: A PKey subclass instance.
Raises: UnknownKeyType, if our crypto backend doesn’t know this key type.

New in version 3.2.

classmethod from_private_key(file_obj, password=None)¶

Create a key object by reading a private key from a file (or file-like) object. If the private key is encrypted and password is not None, the given password will be used to decrypt the key (otherwise PasswordRequiredException is thrown).

Parameters

file_obj – the file-like object to read from
password (str) – an optional password to use to decrypt the key, if it’s encrypted

Returns

a new PKey based on the given private key

Raises

IOError – if there was an error reading the key

Raises

PasswordRequiredException – if the private key file is encrypted, and password is None

Raises

SSHException – if the key file is invalid

classmethod from_private_key_file(filename, password=None)¶

Create a key object by reading a private key file. If the private key is encrypted and password is not None, the given password will be used to decrypt the key (otherwise PasswordRequiredException is thrown). Through the magic of Python, this factory method will exist in all subclasses of PKey (such as RSAKey or DSSKey), but is useless on the abstract PKey class.

Parameters

filename (str) – name of the file to read
password (str) – an optional password to use to decrypt the key file, if it’s encrypted

Returns

a new PKey based on the given private key

Raises

IOError – if there was an error reading the file

Raises

PasswordRequiredException – if the private key file is encrypted, and password is None

Raises

SSHException – if the key file is invalid

static from_type_string(key_type, key_bytes)¶

Given type str & raw bytes, return a PKey subclass instance.

For example, PKey.from_type_string("ssh-ed25519", <public bytes>) will (if successful) return a new Ed25519Key.

Parameters

key_type (str) – The key type, eg "ssh-ed25519".
key_bytes (bytes) – The raw byte data forming the key material, as expected by subclasses’ data parameter.

Returns

A PKey subclass instance.

Raises

UnknownKeyType, if no registered classes knew about this type.

New in version 3.2.

get_base64()¶

Return a base64 string containing the public part of this key. Nothing secret is revealed. This format is compatible with that used to store public key files or recognized host keys.

Returns: a base64 string containing the public part of the key.

get_bits()¶

Return the number of significant bits in this key. This is useful for judging the relative security of a key.

Returns: bits in the key (as an int)

get_fingerprint()¶

Return an MD5 fingerprint of the public part of this key. Nothing secret is revealed.

Returns: a 16-byte string (binary) of the MD5 fingerprint, in SSH format.

get_name()¶

Return the name of this private key implementation.

Returns: name of this private key type, in SSH terminology, as a str (for example, "ssh-rsa").

classmethod identifiers()¶

returns an iterable of key format/name strings this class can handle.

Most classes only have a single identifier, and thus this default implementation suffices; see ECDSAKey for one example of an override.

load_certificate(value)¶

Supplement the private key contents with data loaded from an OpenSSH public key (.pub) or certificate (-cert.pub) file, a string containing such a file, or a Message object.

The .pub contents adds no real value, since the private key file includes sufficient information to derive the public key info. For certificates, however, this can be used on the client side to offer authentication requests to the server based on certificate instead of raw public key.

See: https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.certkeys

Note: very little effort is made to validate the certificate contents, that is for the server to decide if it is good enough to authenticate successfully.

sign_ssh_data(data, algorithm=None)¶

Sign a blob of data with this private key, and return a Message representing an SSH signature message.

Parameters

data (bytes) – the data to sign.
algorithm (str) – the signature algorithm to use, if different from the key’s internal name. Default: None.

Returns

an SSH signature message.

Changed in version 2.9: Added the algorithm kwarg.

verify_ssh_sig(data, msg)¶

Given a blob of data, and an SSH message representing a signature of that data, verify that it was signed with this key.

Parameters

data (bytes) – the data that was signed.
msg (Message) – an SSH signature message

Returns

True if the signature verifies correctly; False otherwise.

write_private_key(file_obj, password=None)¶

Write private key contents into a file (or file-like) object. If the password is not None, the key is encrypted before writing.

Parameters

file_obj – the file-like object to write into
password (str) – an optional password to use to encrypt the key

Raises

IOError – if there was an error writing to the file

Raises

SSHException – if the key is invalid

write_private_key_file(filename, password=None)¶

Write private key contents into a file. If the password is not None, the key is encrypted before writing.

Parameters

filename (str) – name of the file to write
password (str) – an optional password to use to encrypt the key file

Raises

IOError – if there was an error writing the file

Raises

SSHException – if the key is invalid

class paramiko.agent.AgentLocalProxy(agent)¶

Class to be used when wanting to ask a local SSH Agent being asked from a remote fake agent (so use a unix socket for ex.)

property daemon¶

A boolean value indicating whether this thread is a daemon thread.

This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

The entire Python program exits when only daemon threads are left.

get_connection()¶

Return a pair of socket object and string address.

May block!

property ident¶

Thread identifier of this thread or None if it has not been started.

This is a nonzero integer. See the get_ident() function. Thread identifiers may be recycled when a thread exits and another thread is created. The identifier is available even after the thread has exited.

isAlive()¶

Return whether the thread is alive.

This method is deprecated, use is_alive() instead.

is_alive()¶

Return whether the thread is alive.

This method returns True just before the run() method starts until just after the run() method terminates. The module function enumerate() returns a list of all alive threads.

join(timeout=None)¶

Wait until the thread terminates.

This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception or until the optional timeout occurs.

When the timeout argument is present and not None, it should be a floating point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

When the timeout argument is not present or None, the operation will block until the thread terminates.

A thread can be join()ed many times.

join() raises a RuntimeError if an attempt is made to join the current thread as that would cause a deadlock. It is also an error to join() a thread before it has been started and attempts to do so raises the same exception.

property name¶

A string used for identification purposes only.

It has no semantics. Multiple threads may be given the same name. The initial name is set by the constructor.

run()¶

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

start()¶

Start the thread’s activity.

It must be called at most once per thread object. It arranges for the object’s run() method to be invoked in a separate thread of control.

This method will raise a RuntimeError if called more than once on the same thread object.

class paramiko.agent.AgentProxyThread(agent)¶

Class in charge of communication between two channels.

property daemon¶

A boolean value indicating whether this thread is a daemon thread.

This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

The entire Python program exits when only daemon threads are left.

property ident¶

Thread identifier of this thread or None if it has not been started.

This is a nonzero integer. See the get_ident() function. Thread identifiers may be recycled when a thread exits and another thread is created. The identifier is available even after the thread has exited.

isAlive()¶

Return whether the thread is alive.

This method is deprecated, use is_alive() instead.

is_alive()¶

Return whether the thread is alive.

This method returns True just before the run() method starts until just after the run() method terminates. The module function enumerate() returns a list of all alive threads.

join(timeout=None)¶

Wait until the thread terminates.

This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception or until the optional timeout occurs.

When the timeout argument is present and not None, it should be a floating point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

When the timeout argument is not present or None, the operation will block until the thread terminates.

A thread can be join()ed many times.

join() raises a RuntimeError if an attempt is made to join the current thread as that would cause a deadlock. It is also an error to join() a thread before it has been started and attempts to do so raises the same exception.

property name¶

A string used for identification purposes only.

It has no semantics. Multiple threads may be given the same name. The initial name is set by the constructor.

run()¶

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

start()¶

Start the thread’s activity.

It must be called at most once per thread object. It arranges for the object’s run() method to be invoked in a separate thread of control.

This method will raise a RuntimeError if called more than once on the same thread object.

class paramiko.agent.AgentRemoteProxy(agent, chan)¶

Class to be used when wanting to ask a remote SSH Agent

property daemon¶

A boolean value indicating whether this thread is a daemon thread.

This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

The entire Python program exits when only daemon threads are left.

property ident¶

Thread identifier of this thread or None if it has not been started.

This is a nonzero integer. See the get_ident() function. Thread identifiers may be recycled when a thread exits and another thread is created. The identifier is available even after the thread has exited.

isAlive()¶

Return whether the thread is alive.

This method is deprecated, use is_alive() instead.

is_alive()¶

Return whether the thread is alive.

This method returns True just before the run() method starts until just after the run() method terminates. The module function enumerate() returns a list of all alive threads.

join(timeout=None)¶

Wait until the thread terminates.

This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception or until the optional timeout occurs.

When the timeout argument is present and not None, it should be a floating point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

When the timeout argument is not present or None, the operation will block until the thread terminates.

A thread can be join()ed many times.

join() raises a RuntimeError if an attempt is made to join the current thread as that would cause a deadlock. It is also an error to join() a thread before it has been started and attempts to do so raises the same exception.

property name¶

A string used for identification purposes only.

It has no semantics. Multiple threads may be given the same name. The initial name is set by the constructor.

run()¶

Method representing the thread’s activity.

You may override this method in a subclass. The standard run() method invokes the callable object passed to the object’s constructor as the target argument, if any, with sequential and keyword arguments taken from the args and kwargs arguments, respectively.

start()¶

Start the thread’s activity.

It must be called at most once per thread object. It arranges for the object’s run() method to be invoked in a separate thread of control.

This method will raise a RuntimeError if called more than once on the same thread object.

class paramiko.agent.AgentRequestHandler(chanClient)¶

Primary/default implementation of SSH agent forwarding functionality.

Simply instantiate this class, handing it a live command-executing session object, and it will handle forwarding any local SSH agent processes it finds.

For example:

# Connect
client = SSHClient()
client.connect(host, port, username)
# Obtain session
session = client.get_transport().open_session()
# Forward local agent
AgentRequestHandler(session)
# Commands executed after this point will see the forwarded agent on
# the remote end.
session.exec_command("git clone https://my.git.repository/")

class paramiko.agent.AgentServerProxy(t)¶

Allows an SSH server to access a forwarded agent.

This also creates a unix domain socket on the system to allow external programs to also access the agent. For this reason, you probably only want to create one of these.

connect() must be called before it is usable. This will also load the list of keys the agent contains. You must also call close() in order to clean up the unix socket and the thread that maintains it. (contextlib.closing might be helpful to you.)

Parameters: t (Transport) – Transport used for SSH Agent communication forwarding
Raises: SSHException – mostly if we lost the agent

close()¶: Terminate the agent, clean the files, close connections Should be called manually

get_env()¶

Helper for the environment under unix

Returns: a dict containing the SSH_AUTH_SOCK environment variables

get_keys()¶

Return the list of keys available through the SSH agent, if any. If no SSH agent was running (or it couldn’t be contacted), an empty list will be returned.

This method performs no IO, just returns the list of keys retrieved when the connection was made.

Returns: a tuple of AgentKey objects representing keys available on the SSH agent

paramiko.agent.get_agent_connection()¶: Returns some SSH agent object, or None if none were found/supported.

New in version 2.10.

SSH agents¶

Paramiko

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