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diff --git a/docs/sudo_plugin_python.mdoc.in b/docs/sudo_plugin_python.mdoc.in new file mode 100644 index 0000000..49299ea --- /dev/null +++ b/docs/sudo_plugin_python.mdoc.in @@ -0,0 +1,1556 @@ +.\" +.\" SPDX-License-Identifier: ISC +.\" +.\" Copyright (c) 2019-2021 Robert Manner <robert.manner@oneidentity.com> +.\" Copyright (c) 2019-2023 Todd C. Miller <Todd.Miller@sudo.ws> +.\" +.\" Permission to use, copy, modify, and distribute this software for any +.\" purpose with or without fee is hereby granted, provided that the above +.\" copyright notice and this permission notice appear in all copies. +.\" +.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES +.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF +.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR +.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES +.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN +.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF +.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. +.\" +.Dd January 16, 2023 +.Dt SUDO_PLUGIN_PYTHON @mansectform@ +.Os Sudo @PACKAGE_VERSION@ +.Sh NAME +.Nm sudo_plugin_python +.Nd Sudo Plugin API (Python) +.Sh DESCRIPTION +Starting with version 1.9, +.Nm sudo +plugins can be written in python. +The API closely follows the C +.Nm sudo +plugin API described by +.Xr sudo_plugin @mansectform@ . +.Pp +The supported plugins types are: +.Pp +.Bl -bullet -compact -offset 1n -width 1n +.It +Policy plugin +.It +I/O plugin +.It +Audit plugin +.It +Approval plugin +.It +Group provider plugin +.El +.Pp +Python plugin support needs to be explicitly enabled at build time +with the configure option +.Dq --enable-python . +Python version 3.0 or higher is required. +.Ss Sudo Python Plugin Base +A plugin written in Python should be a class in a python file that +inherits from +.Em sudo.Plugin . +The +.Em sudo.Plugin +base class has no real purpose other than to identify this class as a plugin. +.Pp +The only implemented method is a constructor, which stores the +keyword arguments it receives as fields (member variables) in the object. +This is intended as a convenience to allow you to avoid writing the +constructor yourself. +.Pp +For example: +.Bd -literal -offset 4n +import sudo + +class MySudoPlugin(sudo.Plugin): + # example constructor (optional) + def __init__(self, *args, **kwargs): + super().__init__(*args, **kwargs) + + # example destructor (optional) + def __del__(self): + pass +.Ed +.Pp +Both the constructor and destructor are optional and can be omitted. +.Pp +The customized Plugin class should define a few plugin-specific methods. +When the plugin loads, +.Nm sudo +will create an instance of this class and call the methods. +The actual methods required depent on the type of the plugin, +but most return an +.Vt int +result code, as documented in +.Xr sudo_plugin @mansectform@ , +that indicates whether or not the method was successful. +The Python sudo module defines the following constants to improve readability: +.Bl -column "sudo.RC.USAGE_ERROR" "XXX" -offset 4n +.It Sy Define Ta Sy Value +.It Dv sudo.RC.OK Ta 1 +.It Dv sudo.RC.ACCEPT Ta 1 +.It Dv sudo.RC.REJECT Ta 0 +.It Dv sudo.RC.ERROR Ta \-1 +.It Dv sudo.RC.USAGE_ERROR Ta \-2 +.El +.Pp +If a function returns +.Dv None +(for example, if it does not call return), +it will be considered to have returned +.Dv sudo.RC.OK . +If an exception is raised (other than sudo.PluginException), the +backtrace will be shown to the user and the plugin function will return +.Dv sudo.RC.ERROR . +If that is not acceptable, you must catch the exception and handle it yourself. +.Pp +Instead of just returning +.Dv sudo.RC.ERROR +or +.Dv sudo.RC.REJECT +result code the plugin can also provide a message describing the problem. +This can be done by raising one of the special exceptions: +.Bd -literal -offset 4n +raise sudo.PluginError("Message") +raise sudo.PluginReject("Message") +.Ed +.Pp +This added message will be used by the audit plugins. +Both exceptions inherit from +.Dv sudo.PluginException +.Ss Python Plugin Loader +Running the Python interpreter and bridging between C and Python is +handled by the +.Nm sudo +plugin +.Pa @python_plugin@ . +This shared object can be loaded like any other dynamic +.Nm sudo +plugin and should receive the path and the class name of the Python +plugin it is loading as arguments. +.Pp +Example usage in +.Xr sudo.conf @mansectform@ : +.Bd -literal -offset 4n +Plugin python_policy @python_plugin@ ModulePath=<path> ClassName=<class> +Plugin python_io @python_plugin@ ModulePath=<path> ClassName=<class> +Plugin python_audit @python_plugin@ ModulePath=<path> ClassName=<class> +Plugin python_approval @python_plugin@ ModulePath=<path> ClassName=<class> +.Ed +.Pp +Example group provider plugin usage in the +.Em sudoers +file: +.Bd -literal -offset 4n +Defaults group_plugin="@python_plugin@ ModulePath=<path> ClassName=<class>" +.Ed +.Pp +The plugin arguments are as follows: +.Bl -tag -width 4n +.It ModulePath +The path of a python file which contains the class of the sudo Python plugin. +It must be either an absolute path or a path relative to the sudo Python plugin +directory, +.Pa @plugindir@/python . +The parent directory of +.Em ModulePath +will be appended to Python's module search path (there is currently no +way to force Python to load a module from a fully-qualified path). +It is good practice to use a prefix for the module file that is unlikely +to conflict with other installed Python modules, for example, +.Pa sudo_policy.py . +Otherwise, if the there is an installed Python module with the same +file name as the sudo Python plugin file (without the directory), +the wrong file will be loaded. +.It ClassName +(Optional.) The name of the class implementing the sudo Python plugin. +If not supplied, the one and only sudo.Plugin that is present in the module +will be used. +If there are multiple such plugins in the module (or none), it +will result in an error. +.El +.Ss Policy plugin API +Policy plugins must be registered in +.Xr sudo.conf @mansectform@ . +For example: +.Bd -literal -offset 4n +Plugin python_policy @python_plugin@ ModulePath=<path> ClassName=<class> +.Ed +.Pp +Currently, only a single policy plugin may be specified in +.Xr sudo.conf @mansectform@ . +.Pp +A policy plugin may have the following member functions: +.Bl -tag -width 4n +.It Fa constructor +.Bd -literal -compact +__init__(self, user_env: Tuple[str, ...], settings: Tuple[str, ...], + version: str, user_info: Tuple[str, ...], + plugin_options: Tuple[str, ...]) +.Ed +.Pp +Implementing this function is optional. +The default constructor will set the keyword arguments it receives +as member variables in the object. +.Pp +The constructor matches the +.Fn open +function in the C +.Nm sudo +plugin API. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user_env +The user's environment as a tuple of strings in +.Dq key=value +format. +.It Fa settings +A tuple of user-supplied +.Em sudo +settings in the form of +.Dq key=value +strings. +.It Fa version +The version of the Python Policy Plugin API. +.It Fa user_info +A tuple of information about the user running the command in the form of +.Dq key=value +strings. +.It Fa plugin_options +The plugin options passed as arguments in the +.Xr sudo.conf @mansectform@ +plugin registration. +This is a tuple of strings, usually (but not necessarily) in +.Dq key=value +format. +.El +.Pp +The +.Fn sudo.options_as_dict +convenience function can be used to convert +.Dq key=value +pairs to a dictionary. +For a list of recognized keys and their supported values, +see the policy plugin +.Fn open +documentation in +.Xr sudo_plugin @mansectform@ . +.It Fa check_policy +.Bd -literal -compact +check_policy(self, argv: Tuple[str, ...], env_add: Tuple[str, ...]) +.Ed +.Pp +The +.Fn check_policy +function is called by +.Nm sudo +to determine whether the user is allowed to run the specified command. +Implementing this function is mandatory for a policy plugin. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa argv +A tuple describing the command the user wishes to run. +.It Fa env_add +Additional environment variables specified by the user on the command line in +the form of a tuple of +.Dq key=value +pairs. +The +.Fn sudo.options_as_dict +convenience function can be used to convert them to a dictionary. +.El +.Pp +This function should return a result code or a tuple in the following format: +.Bd -literal -offset 4n +return (rc, command_info_out, argv_out, user_env_out) +.Ed +.Pp +The tuple values are as follows: +.Bl -tag -width 4n +.It Fa rc +The result of the policy check, one of the +.Dv sudo.RC.* +constants. +.Dv sudo.RC.ACCEPT +if the command is allowed, +.Dv sudo.RC.REJECT +if not allowed, +.Dv sudo.RC.ERROR +for a general error, or +.Dv sudo.RC.USAGE_ERROR +for a usage error. +.It Fa command_info_out +Optional (only required when the command is accepted). +Information about the command being run in the form of +.Dq key=value +strings. +.Pp +To accept a command, at the very minimum the plugin must set in the +.Em command , +.Em runas_uid , +and +.Em runas_gid +keys. +.Pp +For a list of recognized keys and supported values, +see the +.Fn check_policy +documentation in +.Xr sudo_plugin @mansectform@ . +.It Fa argv_out +Optional (only required when the command is accepted). +The arguments to pass to the +.Xr execve 2 +system call when executing the command. +.It Fa user_env_out +Optional (only required when the command is accepted). +The environment to use when executing the command in the form of a +tuple of strings in +.Dq key=value +format. +.El +.It Fa init_session +.Bd -literal -compact +init_session(self, user_pwd: Tuple, user_env: Tuple[str, ...]) +.Ed +.Pp +Perform session setup (optional). +The +.Fn init_session +function is called before +.Nm sudo +sets up the +execution environment for the command before any user-ID or group-ID changes. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user_pwd +A tuple describing the user's passwd entry. +Convertible to +.Vt pwd.struct_passwd or +.Dv None +if the user is not present in the password database. +.Pp +Example conversion: +.Bd -literal -compact -offset indent +user_pwd = pwd.struct_passwd(user_pwd) if user_pwd else None +.Ed +.It Fa user_env +The environment the command will run in. +This is a tuple of strings in +.Dq key=value +format. +.El +.Pp +This function should return a result code or a tuple in the following format: +.Bd -literal -offset 4n +return (rc, user_env_out) +.Ed +.Pp +The tuple values are as follows: +.Bl -tag -width 4n +.It Fa rc +The result of the session init, one of the +.Dv sudo.RC.* +constants. +.Dv sudo.RC.OK +on success, 0 on failure, or +.Dv sudo.RC.ERROR +if an error occurred. +.It Fa user_env_out +Optional. +If the +.Fn init_session +function needs to modify the user environment, it can return the new +environment in +.Fa user_env_out . +If this is omitted, no changes will be made to +.Fa user_env . +.El +.It Fa list +.Bd -literal -compact +list(self, argv: Tuple[str, ...], is_verbose: int, user: str) +.Ed +.Pp +List available privileges for the invoking user. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa argv +If not set to +.Dv None , +an argument vector describing a command the user wishes to check +against the policy. +.It Fa is_verbose +Flag indicating whether to list in verbose mode or not. +.It Fa user +The name of a different user to list privileges for if the policy allows it. +If +.Dv None , +the plugin should list the privileges of the invoking user. +.El +.It Fa validate +.Bd -literal -compact +validate(self) +.Ed +.Pp +For policy plugins that cache authentication credentials, this function is used to validate and cache the credentials (optional). +.It Fa invalidate +.Bd -literal -compact +invalidate(self, remove: int) +.Ed +.Pp +For policy plugins that cache authentication credentials, this function is used to invalidate the credentials (optional). +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa remove +If this flag is set, the plugin may remove the credentials instead of simply +invalidating them. +.El +.It Fa show_version +.Bd -literal -compact +show_version(self, is_verbose: int) +.Ed +.Pp +Display the plugin version information to the user. +The +.Fn sudo.log_info +function should be used. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa is_verbose +A flag to indicate displaying more verbose information. +Currently this is 1 if +.Ql sudo -V +is run as the root user. +.El +.It Fa close +.Bd -literal -compact +close(self, exit_status: int, error: int) +.Ed +.Pp +Called when a command finishes executing. +.Pp +Works the same as the +.Fn close +function in the C +.Nm sudo +plugin API, except that it only gets called if +.Nm sudo +attempts to execute the command. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa exit_status +The exit status of the command if was executed, otherwise \-1. +.It Fa error +If the command could not be executed, this is set to the value of +errno set by the +.Xr execve 2 +system call, otherwise 0. +.El +.El +.Ss Policy plugin example +Sudo ships with an example Python policy plugin. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal +Plugin python_policy @python_plugin@ \e + ModulePath=@EXAMPLES@/example_policy_plugin.py \e + ClassName=SudoPolicyPlugin +.Ed +.Pp +Only one policy plugin can be enabled at a time so you must disable +any other policy plugin listed in +.Pa @sysconfdir@/sudo.conf , +such as +.Xr sudoers @mansectform@ . +.Ss I/O plugin API +I/O plugins must be registered in +.Xr sudo.conf @mansectform@ . +For example: +.Bd -literal -offset 4n +Plugin python_io @python_plugin@ ModulePath=<path> ClassName=<class> +.Ed +.Pp +Sudo supports loading multiple I/O plugins. +Currently only 8 python I/O plugins can be loaded at once. +.Pp +An I/O plugin may have the following member functions: +.Bl -tag -width 4n +.It Fa constructor +.Bd -literal -compact +__init__(self, user_env: Tuple[str, ...], settings: Tuple[str, ...], + version: str, user_info: Tuple[str, ...], + plugin_options: Tuple[str, ...]) +.Ed +.Pp +Implementing this function is optional. +The default constructor will set the keyword arguments it receives +as member variables in the object. +.Pp +The constructor matches the +.Fn open +function in the C +.Nm sudo +plugin API. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user_env +The user's environment as a tuple of strings in +.Dq key=value +format. +.It Fa settings +A tuple of user-supplied +.Em sudo +settings in the form of +.Dq key=value +strings. +.It Fa version +The version of the Python I/O Plugin API. +.It Fa user_info +A tuple of information about the user running the command in the form of +.Dq key=value +strings. +.It Fa plugin_options +The plugin options passed as arguments in the +.Xr sudo.conf @mansectform@ +plugin registration. +This is a tuple of strings, usually (but not necessarily) in +.Dq key=value +format. +.El +.Pp +The +.Fn sudo.options_as_dict +convenience function can be used to convert +.Dq key=value +pairs to a dictionary. +For a list of recognized keys and their supported values, +see the I/O plugin +.Fn open +documentation in +.Xr sudo_plugin @mansectform@ . +.It Fa open +.Bd -literal -compact +open(self, argv: Tuple[str, ...], + command_info: Tuple[str, ...]) -> int +.Ed +.Pp +Receives the command the user wishes to run. +.Pp +Works the same as the +.Fn open +function in the C +.Nm sudo +plugin API except that: +.Pp +.Bl -bullet -compact -offset 1n -width 1n +.It +It only gets called when there is a command to be executed +(and not for a version query for example). +.It +Other arguments of the C API +.Fn open +function are received through the constructor. +.El +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa argv +A tuple of the arguments describing the command the user wishes to run. +.It Fa command_info +Information about the command being run in the form of +.Dq key=value +strings. +.El +.Pp +The +.Fn sudo.options_as_dict +convenience function can be used to convert +.Dq key=value +pairs to a dictionary. +For a list of recognized keys and their supported values, +see the I/O plugin +.Fn open +documentation in +.Xr sudo_plugin @mansectform@ . +.Pp +The +.Fn open +function should return a result code, one of the +.Dv sudo.RC.* +constants. +If the function returns +.Dv sudo.RC.REJECT , +no I/O will be sent to the plugin. +.It Fa log_ttyin , log_ttyout , log_stdin , log_stdout , log_stderr +.Bd -literal -compact +log_ttyin(self, buf: str) -> int +log_ttyout(self, buf: str) -> int +log_stdin(self, buf: str) -> int +log_stdout(self, buf: str) -> int +log_stderr(self, buf: str) -> int +.Ed +.Pp +Receive the user input or output of the terminal device and +application standard input, standard output, or standard error. +See the matching calls in +.Xr sudo_plugin @mansectform@ . +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa buf +The input (or output) buffer in the form of a string. +.El +.Pp +The function should return a result code, one of the +.Dv sudo.RC.* +constants. +.Pp +If +.Dv sudo.RC.ERROR +is returned, the running command will be terminated and all of the +plugin's logging functions will be disabled. +Other I/O logging plugins will still receive any remaining +input or output that has not yet been processed. +.Pp +If an input logging function rejects the data by returning +.Dv sudo.RC.REJECT , +the command will be terminated and the data will not be passed to the +command, though it will still be sent to any other I/O logging plugins. +If an output logging function rejects the data by returning +.Dv sudo.RC.REJECT , +the command will be terminated and the data will not be written to the +terminal, though it will still be sent to any other I/O logging plugins. +.It Fa change_winsize +.Bd -literal -compact +change_winsize(self, line: int, cols: int) -> int +.Ed +.Pp +Called whenever the window size of the terminal changes. +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa line +The number of lines of the terminal. +.It Fa cols +The number of columns of the terminal. +.El +.It Fa log_suspend +.Bd -literal -compact +log_suspend(self, signo: int) -> int +.Ed +Called whenever a command is suspended or resumed. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa signo +The number of the signal that caused the command to be suspended or +.Dv SIGCONT +if the command was resumed. +.El +.It Fa show_version +.Bd -literal -compact +show_version(self, is_verbose: int) +.Ed +Display the plugin version information to the user. +The +.Fn sudo.log_info +function should be used. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa is_verbose +A flag to indicate displaying more verbose information. +Currently this is 1 if +.Ql sudo -V +is run as the root user. +.El +.It Fa close +.Bd -literal -compact +close(self, exit_status: int, error: int) -> None +.Ed +Called when a command finishes execution. +.Pp +Works the same as the +.Fn close +function in the C +.Nm sudo +plugin API, except that it only gets called if +.Nm sudo +attempts to execute the command. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa exit_status +The exit status of the command if was executed, otherwise \-1. +.It Fa error +If the command could not be executed, this is set to the value of +errno set by the +.Xr execve 2 +system call, otherwise 0. +.El +.El +.Ss I/O plugin example +Sudo ships with a Python I/O plugin example. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal -offset 4n +Plugin python_io @python_plugin@ \e + ModulePath=@EXAMPLES@/example_io_plugin.py \e + ClassName=SudoIOPlugin +.Ed +.Ss Audit plugin API +Audit plugins must be registered in +.Xr sudo.conf @mansectform@ . +For example: +.Bd -literal -offset 4n +Plugin python_audit @python_plugin@ ModulePath=<path> ClassName=<class> +.Ed +.Pp +Sudo supports loading multiple audit plugins. +Currently only 8 python audit plugins can be loaded at once. +.Pp +An audit plugin may have the following member functions (all of which are optional): +.Bl -tag -width 4n +.It Fa constructor +.Bd -literal -compact +__init__(self, user_env: Tuple[str, ...], settings: Tuple[str, ...], + version: str, user_info: Tuple[str, ...], plugin_options: Tuple[str, ...]) +.Ed +.Pp +The default constructor will set the keyword arguments it receives +as member variables in the object. +.Pp +The constructor matches the +.Fn open +function in the C +.Nm sudo +plugin API. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user_env +The user's environment as a tuple of strings in +.Dq key=value +format. +.It Fa settings +A tuple of user-supplied +.Em sudo +settings in the form of +.Dq key=value +strings. +.It Fa version +The version of the Python Audit Plugin API. +.It Fa user_info +A tuple of information about the user running the command in the form of +.Dq key=value +strings. +.It Fa plugin_options +The plugin options passed as arguments in the +.Xr sudo.conf @mansectform@ +plugin registration. +This is a tuple of strings, usually (but not necessarily) in +.Dq key=value +format. +.El +.It Fa open +.Bd -literal -compact +open(self, submit_optind: int, + submit_argv: Tuple[str, ...]) -> int +.Ed +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa submit_optind +The index into +.Fa submit_argv +that corresponds to the first entry that is not a command line option. +.It Fa submit_argv +The argument vector sudo was invoked with, including all command line options. +.El +.It Fa close +.Bd -literal -compact +close(self, status_type: int, status: int) -> None +.Ed +.Pp +Called when sudo is finished, shortly before it exits. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa status_type +The type of status being passed. +One of the +.Dv sudo.EXIT_REASON.* +constants. +.It Fa status +Depending on the value of +.Fa status_type , +this value is either +ignored, the command's exit status as returned by the +.Xr wait 2 +system call, the value of +.Va errno +set by the +.Xr execve 2 +system call, or the value of +.Va errno +resulting from an error in the +.Nm sudo +front-end. +.El +.It Fa show_version +.Bd -literal -compact +show_version(self, is_verbose: int) -> int +.Ed +.Pp +Display the plugin version information to the user. +The +.Fn sudo.log_info +function should be used. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa is_verbose +A flag to indicate displaying more verbose information. +Currently this is 1 if +.Ql sudo -V +is run as the root user. +.El +.It Fa accept +.Bd -literal -compact +accept(self, plugin_name: str, plugin_type: int, command_info: Tuple[str, ...], + run_argv: Tuple[str, ...], run_envp: Tuple[str, ...]) -> int +.Ed +.Pp +This function is called when a command or action is accepted by a policy +or approval plugin. +The function arguments are as follows: +.Bl -tag -width 4n +.It plugin_name +The name of the plugin that accepted the command or +.Dq sudo +for the +.Nm sudo +front-end. +.It plugin_type +The type of plugin that accepted the command, currently either +.Dv sudo.PLUGIN_TYPE.POLICY , +.Dv sudo.PLUGIN_TYPE.APPROVAL , +or +.Dv sudo.PLUGIN_TYPE.SUDO . +The +.Fn accept +function is called multiple times--once for each policy or approval +plugin that succeeds and once for the sudo front-end. +When called on behalf of the sudo front-end, +.Fa command_info +may include information from an I/O logging plugin as well. +.Pp +Typically, an audit plugin is interested in either the accept status from +the +.Nm sudo +front-end or from the various policy and approval plugins, but not both. +It is possible for the policy plugin to accept a command that is +later rejected by an approval plugin, in which case the audit +plugin's +.Fn accept +and +.Fn reject +functions will +.Em both +be called. +.It command_info +A vector of information describing the command being run. +See the +.Xr sudo_plugin @mansectform@ +manual for possible values. +.It run_argv +Argument vector describing a command that will be run. +.It run_envp +The environment the command will be run with. +.El +.It Fa reject +.Bd -literal -compact +reject(self, plugin_name: str, plugin_type: int, audit_msg: str, + command_info: Tuple[str, ...]) -> int +.Ed +.Pp +This function is called when a command or action is rejected by the policy +plugin. +The function arguments are as follows: +.Bl -tag -width 4n +.It plugin_name +The name of the plugin that rejected the command. +.It plugin_type +The type of plugin that rejected the command, currently either +.Dv sudo.PLUGIN_TYPE.POLICY , +.Dv sudo.PLUGIN_TYPE.APPROVAL , +or +.Dv sudo.PLUGIN_TYPE.IO . +.Pp +Unlike the +.Fn accept +function, the +.Fn reject +function is not called on behalf of the +.Nm sudo +front-end. +.It audit_msg +An optional string describing the reason the command was rejected by the plugin. +If the plugin did not provide a reason, audit_msg will be +.Dv None . +.It command_info +A vector of information describing the rejected command. +See the +.Xr sudo_plugin @mansectform@ +manual for possible values. +.El +.It Fa error +.Bd -literal -compact +error(self, plugin_name: str, plugin_type: int, audit_msg: str, + command_info: Tuple[str, ...]) -> int +.Ed +.Pp +This function is called when a plugin or the +.Nm sudo +front-end returns an error. +The function arguments are as follows: +.Bl -tag -width 4n +.It plugin_name +The name of the plugin that generated the error or +.Dq sudo +for the +.Nm sudo +front-end. +.It plugin_type +The type of plugin that generated the error, or +.Dv SUDO_FRONT_END +for the +.Nm sudo +front-end. +.It audit_msg +An optional string describing the plugin error. +If the plugin did not provide a description, it will be +.Dv None . +.It command_info +A vector of information describing the command. +See the +.Xr sudo_plugin @mansectform@ +manual for possible values. +.El +.El +.Ss Audit plugin example +Sudo ships with a Python Audit plugin example. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal -offset 4n +Plugin python_audit @python_plugin@ \e + ModulePath=@EXAMPLES@/example_audit_plugin.py \e + ClassName=SudoAuditPlugin +.Ed +.Pp +It will log the plugin accept / reject / error results to the output. +.Ss Approval plugin API +Approval plugins must be registered in +.Xr sudo.conf @mansectform@ . +For example: +.Bd -literal -offset 4n +Plugin python_approval @python_plugin@ ModulePath=<path> ClassName=<class> +.Ed +.Pp +Sudo supports loading multiple approval plugins. +Currently only 8 python approval plugins can be loaded at once. +.Pp +An approval plugin may have the following member functions: +.Bl -tag -width 4n +.It Fa constructor +.Bd -literal -compact +__init__(self, user_env: Tuple[str, ...], settings: Tuple[str, ...], + version: str, user_info: Tuple[str, ...], plugin_options: Tuple[str, ...], + submit_optind: int, submit_argv: Tuple[str, ...]) +.Ed +.Pp +Optional. +The default constructor will set the keyword arguments it receives +as member variables in the object. +.Pp +The constructor matches the +.Fn open +function in the C +.Nm sudo +plugin API. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user_env +The user's environment as a tuple of strings in +.Dq key=value +format. +.It Fa settings +A tuple of user-supplied +.Em sudo +settings in the form of +.Dq key=value +strings. +.It Fa version +The version of the Python Approval Plugin API. +.It Fa user_info +A tuple of information about the user running the command in the form of +.Dq key=value +strings. +.It Fa plugin_options +The plugin options passed as arguments in the +.Xr sudo.conf @mansectform@ +plugin registration. +This is a tuple of strings, usually (but not necessarily) in +.Dq key=value +format. +.It Fa submit_optind +The index into +.Fa submit_argv +that corresponds to the first entry that is not a command line option. +.It Fa submit_argv +The argument vector sudo was invoked with, including all command line options. +.El +.It Fa show_version +.Bd -literal -compact +show_version(self, is_verbose: int) -> int +.Ed +.Pp +Display the version. +(Same as for all the other plugins.) +.It Fa check +.Bd -literal -compact +check(self, command_info: Tuple[str, ...], run_argv: Tuple[str, ...], + run_env: Tuple[str, ...]) -> int +.Ed +.Pp +This function is called after policy plugin's check_policy has succeeded. +It can reject execution of the command by returning sudo.RC.REJECT or +raising the special exception: +.Bd -literal -offset 4n +raise sudo.PluginReject("some message") +.Ed +.Pp +with the message describing the problem. +In the latter case, the audit plugins will get the description. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It command_info +A vector of information describing the command that will run. +See the +.Xr sudo_plugin @mansectform@ +manual for possible values. +.It run_argv +Argument vector describing a command that will be run. +.It run_env +The environment the command will be run with. +.El +.El +.Ss Approval plugin example +Sudo ships with a Python Approval plugin example. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal -offset 4n +Plugin python_approval @python_plugin@ \e + ModulePath=@EXAMPLES@/example_approval_plugin.py \e + ClassName=BusinessHoursApprovalPlugin +.Ed +.Pp +It will only allow execution of commands in the "business hours" (from Monday +to Friday between 8:00 and 17:59:59). +.Ss Sudoers group provider plugin API +A group provider plugin is registered in the +.Xr sudoers @mansectform@ +file. +For example: +.Bd -literal -offset 4n +Defaults group_plugin="@python_plugin@ ModulePath=<path> ClassName=<class>" +.Ed +.Pp +Currently, only a single group plugin can be registered in +.Em sudoers . +.Pp +A group provider plugin may have the following member functions: +.Bl -tag -width 4n +.It Fa constructor +.Bd -literal -compact +__init__(self, args: Tuple[str, ...], version: str) +.Ed +.Pp +Implementing this function is optional. +The default constructor will set the keyword arguments it receives +as member variables in the object. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa args +The plugin options passed as arguments in the +.Em sudoers +file plugin registration. +All the arguments are free form strings (not necessarily in +.Dq key=value +format). +.It Fa version +The version of the Python Group Plugin API. +.El +.It Fa query +.Bd -literal -compact +query(self, user: str, group: str, user_pwd: Tuple) +.Ed +.Pp +The +.Fn query +function is used to ask the group plugin whether +.Fa user +is a member of +.Fa group . +This method is required. +.El +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa user +The name of the user being looked up in the external group database. +.It Fa group +The name of the group being queried. +.It Fa user_pwd +The password database entry for the user, if any. +If +.Fa user +is not present in the password database, +.Fa user_pwd +will be +.Dv NULL . +.El +.Ss Group plugin example +Sudo ships with a Python group plugin example. +To try it, register it in the +.Em sudoers +file by adding the following lines: +.Bd -literal -offset 4n +Defaults group_plugin="@python_plugin@ \e + ModulePath=@EXAMPLES@/example_group_plugin.py \e + ClassName=SudoGroupPlugin" +.Ed +.Pp +The example plugin will tell +.Nm sudo +that the user +.Em test +is part of the non-Unix group +.Em mygroup . +If you add a rule that uses this group, it will affect the +.Em test +user. +For example: +.Bd -literal -offset 4n +%:mygroup ALL=(ALL) NOPASSWD: ALL +.Ed +.Pp +Will allow user +.Em test +to run +.Nm sudo +without a password. +.Ss Hook function API +The hook function API is currently not supported for plugins +written in Python. +.Ss Conversation API +A Python plugin can interact with the user using the +.Fn sudo.conv +function which displays one or more messages described by the +.Dv sudo.ConvMessage +class. +This is the Python equivalent of the +.Fn conversation +function in the C +.Nm sudo +plugin API. +A plugin should not attempt to read directly from the standard input or +the user's tty (neither of which are guaranteed to exist). +.Pp +The +.Dv sudo.ConvMessage +class specifies how the user interaction should occur: +.Bd -literal -offset 4n +sudo.ConvMessage(msg_type: int, msg: str, timeout: int) +.Ed +.Pp +.Dv sudo.ConvMessage +member variables: +.Bl -tag -width 4n +.It Fa msg_type +Specifies the type of the conversation. +See the +.Dv sudo.CONV.* +constants below. +.It Fa msg +The message to display to the user. +The caller must include a trailing newline in +.Fa msg +if one is to be displayed. +.It Fa timeout +Optional. +The maximum amount of time for the conversation in seconds. +If the timeout is exceeded, the +.Fn sudo.conv +function will raise a +.Dv sudo.ConversationInterrupted +exception. +The default is to wait forever (no timeout). +.El +.Pp +To specify the message type, the following constants are available: +.Pp +.Bl -bullet -compact -offset 1n -width 1n +.It +.Dv sudo.CONV.PROMPT_ECHO_OFF +.It +.Dv sudo.CONV.PROMPT_ECHO_ON +.It +.Dv sudo.CONV.ERROR_MSG +.It +.Dv sudo.CONV.INFO_MSG +.It +.Dv sudo.CONV.PROMPT_MASK +.It +.Dv sudo.CONV.PROMPT_ECHO_OK +.It +.Dv sudo.CONV.PREFER_TTY +.El +.Pp +See the +.Xr sudo_plugin @mansectform@ +manual for a description of the message types. +.Pp +The +.Fn sudo.conv +function performs the actual user interaction: +.Bd -literal -offset 4n +sudo.conv(message(s), on_suspend=suspend_function, + on_resume=resume_function) +.Ed +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa message(s) +One of more messages (of type +.Dv sudo.ConvMessage ) , +each describing a conversation. +At least one message is required. +.It Fa on_suspend +An optional callback function which gets called if the conversation +is suspended, for example by the user pressing control-Z. +The specified function must take a single argument which will be filled +with the number of the signal that caused the process to be suspended. +.It Fa on_resume +An optional callback function which gets called when the previously +suspended conversation is resumed. +The specified function must take a single argument which will be filled +with the number of the signal that caused the process to be suspended. +.El +.Pp +The +.Fn sudo.conv +function can raise the following exceptions: +.Bl -tag -width 4n +.It Dv sudo.SudoException +If the conversation fails, for example when the conversation function is not +available. +.It Dv sudo.ConversationInterrupted +If the conversation function returns an error, e.g., the timeout passed +or the user interrupted the conversation by pressing control-C. +.El +.Ss Conversation example +Sudo ships with an example plugin demonstrating the Python conversation API. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal -offset 4n +Plugin python_io @python_plugin@ \e + ModulePath=@EXAMPLES@/example_conversation.py \e + ClassName=ReasonLoggerIOPlugin +.Ed +.Ss Information / error display API +.Bd -literal +sudo.log_info(string(s), sep=" ", end="\en") +sudo.log_error(string(s), sep=" ", end="\en") +.Ed +.Pp +To display information to the user, the +.Fn sudo.log_info +function can be used. +To display error messages, use +.Fn sudo.log_error . +The syntax is similar to the Python +.Fn print +function. +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa string(s) +One or more strings to display. +.It Fa sep +An optional string which will be used as the separator between the +specified strings. +The default is a space character, +.Pq Sq \ . +.It Fa end +An optional string which will be displayed at the end of the message. +The default is a new line character +.Pq Sq \en . +.El +.Ss Debug API +Debug messages are not visible to the user and are only logged debugging +is explicitly enabled in +.Xr sudo.conf @mansectform@ . +Python plugins can use the +.Fn sudo.debug +function to make use of +.Nm sudo Ns No 's +debug system. +.Pp +.Em Enabling debugging in sudo.conf +.Pp +To enable debug messages, add a +.Em Debug +line to +.Xr sudo.conf @mansectform@ +with the program set to +.Pa @python_plugin@ . +For example, to store debug output in +.Pa @log_dir@/sudo_python_debug , +use a line like the following: +.Bd -literal -offset 4n +Debug @python_plugin@ @log_dir@/sudo_python_debug \e + plugin@trace,c_calls@trace +.Ed +.Pp +The debug options are in the form of multiple +.Dq subsystem@level +strings, separated by commas +.Pq Sq \&, . +For example to just see the debug output of +.Fn sudo.debug +calls, use: +.Bd -literal -offset 4n +Debug @python_plugin@ @log_dir@/sudo_python_debug plugin@trace +.Ed +.Pp +See +.Xr sudo_conf @mansectform@ +for more details. +.Pp +The most interesting subsystems for Python plugin development are: +.Bl -tag -width 4n +.It Em plugin +Logs each +.Fn sudo.debug +API call. +.It Em py_calls +Logs whenever a C function calls into the python module. +For example, calling the +.Fn __init__ +function. +.It Em c_calls +Logs whenever python calls into a C +.Nm sudo +API function. +.It Em internal +Logs internal functions of the python language wrapper plugin. +.It Em sudo_cb +Logs when +.Nm sudo +calls into the python plugin API. +.It Em load +Logs python plugin loading / unloading events. +.El +.Pp +You can also specify +.Dq all +as the subsystem name to log debug messages for all subsystems. +.Pp +The +.Fn sudo.debug +function is defined as: +.Bd -literal -offset 4n +sudo.debug(level, message(s)) +.Ed +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa level +an integer, use one of the log level constants below +.It Fa message(s) +one or more messages to log +.El +.Pp +.Em Available log levels: +.Bl -column "name in sudo.conf" "Python constant" "only critical messages" +.It Sy sudo.conf name Ta Sy Python constant Ta Sy description +.It crit Ta Dv sudo.DEBUG.CRIT Ta only critical messages +.It err Ta Dv sudo.DEBUG.ERROR Ta +.It warn Ta Dv sudo.DEBUG.WARN Ta +.It notice Ta Dv sudo.DEBUG.NOTICE Ta +.It diag Ta Dv sudo.DEBUG.DIAG Ta +.It info Ta Dv sudo.DEBUG.INFO Ta +.It trace Ta Dv sudo.DEBUG.TRACE Ta +.It debug Ta Dv sudo.DEBUG.DEBUG Ta very extreme verbose debugging +.El +.Pp +.Em Using the logging module +.Pp +Alternatively, a plugin can use the built in logging module of Python as well. +Sudo adds its log handler to the root logger, so by default all output of a +logger will get forwarded to sudo log system, as it would call sudo.debug. +.Pp +The log handler of sudo will map each Python log level of a message to +the appropriate sudo debug level. +The sudo debug system will only receive messages that are not filtered +out by the Python loggers. +For example, the log level of the python logger will be an additional +filter for the log messages, and is usually very different from +what level is set in sudo.conf for the sudo debug system. +.Ss Debug example +Sudo ships with an example debug plugin. +To try it, register it by adding the following lines to +.Pa @sysconfdir@/sudo.conf : +.Bd -literal -offset 4n +Plugin python_io @python_plugin@ \e + ModulePath=@EXAMPLES@/example_debugging.py \e + ClassName=DebugDemoPlugin + +Debug @python_plugin@ \e + @log_dir@/sudo_python_debug plugin@trace,c_calls@trace +.Ed +.Ss Option conversion API +The Python plugin API includes two convenience functions to +convert options in +.Dq key=value +format to a dictionary and vice versa. +.Bl -tag -width 4n +.It options_as_dict +.Bd -literal -compact +options_as_dict(options) +.Ed +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa options +An iterable (tuple, list, etc.) of strings, each in +.Dq key=value +format. +This is how the plugin API passes options and settings to a Python plugin. +.El +.Pp +The function returns the resulting dictionary. +Each string of the passed in +.Fa options +will be split at the first equal sign +.Pq Sq \&= +into a +.Em key +and +.Em value . +Dictionary keys will never contain this symbol (but values may). +.It options_from_dict +.Bd -literal -compact +options_from_dict(options_dict) +.Ed +.Pp +The function arguments are as follows: +.Bl -tag -width 4n +.It Fa options_dict +A dictionary where both the key and the value are strings. +The key should not contain an equal sign +.Pq Sq \&= , +otherwise the resulting string will have a different meaning. +However, this is not currently enforced. +.El +.Pp +The function returns a tuple containing the strings in +.Dq key=value +form for each key and value in the +.Fa options_dict +dictionary passed in. +This is how the plugin API accepts options and settings. +.El +.Sh PLUGIN API CHANGELOG (Python) +None yet +.Sh LIMITATIONS +A maximum of 8 python I/O plugins can be loaded at once. +If +.Pa @sysconfdir@/sudo.conf +contains more, those will be rejected with a warning message. +.Pp +The Event API and the hook function API is currently not accessible +for Python plugins. +.Sh SEE ALSO +.Xr sudo.conf @mansectform@ , +.Xr sudo_plugin @mansectform@ , +.Xr sudoers @mansectform@ , +.Xr sudo @mansectsu@ +.Sh AUTHORS +Many people have worked on +.Nm sudo +over the years; this version consists of code written primarily by: +.Bd -ragged -offset indent +.An Todd C. Miller +.Ed +.Pp +See the CONTRIBUTORS.md file in the +.Nm sudo +distribution (https://www.sudo.ws/about/contributors/) for an +exhaustive list of people who have contributed to +.Nm sudo . +.Sh BUGS +Python plugin support is currently considered experimental. +.Pp +If you believe you have found a bug in +.Nm sudo , +you can submit a bug report at https://bugzilla.sudo.ws/ +.Sh SECURITY CONSIDERATIONS +All Python plugin handling is implemented inside the +.Pa @python_plugin@ +dynamic plugin. +Therefore, if no Python plugin is registered in +.Xr sudo.conf @mansectform@ +or the +.Em sudoers +file, +.Nm sudo +will not load the Python interpreter or the Python libraries. +.Pp +As +.Nm sudo +runs plugins as +.Sy root , +care must be taken when writing Python plugins to avoid creating +security vulnerabilities, just as one would when writing plugins +in C. +.Sh SUPPORT +Limited free support is available via the sudo-users mailing list, +see https://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or +search the archives. +.Sh DISCLAIMER +.Nm sudo +is provided +.Dq AS IS +and any express or implied warranties, including, but not limited +to, the implied warranties of merchantability and fitness for a +particular purpose are disclaimed. +See the LICENSE.md file distributed with +.Nm sudo +or https://www.sudo.ws/about/license/ for complete details. |