# sudo_plugin - Sudo Plugin API - man(5) - [phpMan] [_SUDO_PLUGIN_(5)](https://www.chedong.com/phpMan.php/man/SUDOPLUGIN/5/markdown) File Formats Manual [_SUDO_PLUGIN_(5)](https://www.chedong.com/phpMan.php/man/SUDOPLUGIN/5/markdown) ## NAME sudo_plugin — Sudo Plugin API ## DESCRIPTION Starting with version 1.8, **sudo **supports a plugin API for policy and session logging. Plug‐ ins may be compiled as dynamic shared objects (the default on systems that support them) or compiled statically into the **sudo **binary itself. By default, the **sudoers **plugin provides au‐ dit, security policy and I/O logging capabilities. Via the plugin API, **sudo **can be config‐ ured to use alternate plugins provided by third parties. The plugins to be used are speci‐ fied in the [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown) file. The API is versioned with a major and minor number. The minor version number is incremented when additions are made. The major number is incremented when incompatible changes are made. A plugin should be check the version passed to it and make sure that the major version matches. The plugin API is defined by the <_sudo_plugin.h_> header file. ### Policy plugin API A policy plugin must declare and populate a _struct_ _policy_plugin_ in the global scope. This structure contains pointers to the functions that implement the **sudo **policy checks. The name of the symbol should be specified in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown) along with a path to the plugin so that **sudo **can load it. struct policy_plugin { #define SUDO_POLICY_PLUGIN 1 unsigned int type; /* always SUDO_POLICY_PLUGIN */ unsigned int version; /* always SUDO_API_VERSION */ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], char * const user_env[], char * const plugin_options[], const char **errstr); void (*close)(int exit_status, int error); int (*show_version)(int verbose); int (*check_policy)(int argc, char * const argv[], char *env_add[], char **command_info[], char **argv_out[], char **user_env_out[], const char **errstr); int (*list)(int argc, char * const argv[], int verbose, const char *user, const char **errstr); int (*validate)(const char **errstr); void (*invalidate)(int rmcred); int (*init_session)(struct passwd *pwd, char **user_env[], const char **errstr); void (*register_hooks)(int version, int (*register_hook)(struct sudo_hook *hook)); void (*deregister_hooks)(int version, int (*deregister_hook)(struct sudo_hook *hook)); struct sudo_plugin_event * (*event_alloc)(void); }; A _struct_ _policy_plugin_ has the following fields: _type_ The _type_ field should always be set to SUDO_POLICY_PLUGIN. _version_ The _version_ field should be set to SUDO_API_VERSION. This allows **sudo **to determine the API version the plugin was built against. _open_ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], char * const user_env[], char * const plugin_options[], const char **errstr); Returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error in‐ formation to the user. The function arguments are as follows: _version_ The version passed in by **sudo **allows the plugin to determine the major and minor version number of the plugin API supported by **sudo**. _conversation_ A pointer to the **conversation**() function that can be used by the plugin to inter‐ act with the user (see “Conversation API” for details). Returns 0 on success and -1 on failure. _sudo_plugin_printf_ A pointer to a **printf**()-style function that may be used to display informational or error messages (see “Conversation API” for details). Returns the number of characters printed on success and -1 on failure. _settings_ A vector of user-supplied **sudo **settings in the form of “name=value” strings. The vector is terminated by a NULL pointer. These settings correspond to options the user specified when running **sudo**. As such, they will only be present when the corresponding option has been specified on the command line. When parsing _settings_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. The following values may be set by **sudo**: bsdauth_type=string Authentication type, if specified by the **-a **option, to use on systems where BSD authentication is supported. closefrom=number If specified, the user has requested via the **-C **option that **sudo **close all files descriptors with a value of _number_ or higher. The plugin may option‐ ally pass this, or another value, back in the _command_info_ list. cmnd_chroot=string The root directory (see [_chroot_(2)](https://www.chedong.com/phpMan.php/man/chroot/2/markdown)) to run the command in, as specified by the user via the **-R **option. The plugin may ignore or restrict the user's ability to specify a new root directory. Only available starting with API version 1.16. cmnd_cwd=string The working directory to run the command in, as specified by the user via the **-D **option. The plugin may ignore or restrict the user's ability to specify a new working directory. Only available starting with API version 1.16. debug_flags=string A debug file path name followed by a space and a comma-separated list of debug flags that correspond to the plugin's _Debug_ entry in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown), if there is one. The flags are passed to the plugin exactly as they appear in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown). The syntax used by **sudo **and the **sudoers **plugin is _subsystem_@_priority_ but a plugin is free to use a different format so long as it does not include a comma (‘,’). Prior to **sudo **1.8.12, there was no way to specify plugin-specific _debug_flags_ so the value was always the same as that used by the **sudo **front-end and did not include a path name, only the flags themselves. As of version 1.7 of the plugin interface, **sudo **will only pass _debug_flags_ if [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown) contains a plugin-specific _Debug_ en‐ try. ignore_ticket=bool Set to true if the user specified the **-k **option along with a command, indi‐ cating that the user wishes to ignore any cached authentication creden‐ tials. _implied_shell_ to true. This allows **sudo **with no arguments to be used similarly to [_su_(1)](https://www.chedong.com/phpMan.php/man/su/1/markdown). If the plugin does not to support this usage, it may return a value of -2 from the **check_policy**() function, which will cause **sudo **to print a usage message and exit. implied_shell=bool If the user does not specify a program on the command line, **sudo **will pass the plugin the path to the user's shell and set _implied_shell_. intercept_ptrace=bool Indicates whether or not the system supports intercept mode using [_ptrace_(2)](https://www.chedong.com/phpMan.php/man/ptrace/2/markdown). This is currently only true for Linux systems that support [_seccomp_(2)](https://www.chedong.com/phpMan.php/man/seccomp/2/markdown) filtering and the “trap” action. Other systems will use a dy‐ namic shared object to implement intercept. Only available starting with API version 1.19. intercept_setid=bool Indicates whether or not the system supports running set-user-ID and set- group-ID binaries in intercept mode. This is currently only true for Linux systems that support [_seccomp_(2)](https://www.chedong.com/phpMan.php/man/seccomp/2/markdown) filtering and the “trap” action. On sys‐ tems that use a dynamic shared object to implement intercept, the dynamic linker (ld.so or the equivalent) will disable preloading of shared objects when executing a set-user-ID or set-group-ID binary. This will disable in‐ tercept mode for that program and any other programs that it executes. The policy plugin may refuse to execute a set-user-ID or set-group-ID binary in intercept mode to avoid this. Only available starting with API version 1.19. login_class=string BSD login class to use when setting resource limits and nice value, if specified by the **-c **option. login_shell=bool Set to true if the user specified the **-i **option, indicating that the user wishes to run a login shell. max_groups=int The maximum number of groups a user may belong to. This will only be present if there is a corresponding setting in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown). network_addrs=list A space-separated list of IP network addresses and netmasks in the form “addr/netmask”, e.g., “192.168.1.2/255.255.255.0”. The address and netmask pairs may be either IPv4 or IPv6, depending on what the operating system supports. If the address contains a colon (‘:’), it is an IPv6 address, else it is IPv4. noninteractive=bool Set to true if the user specified the **-n **option, indicating that **sudo** should operate in non-interactive mode. The plugin may reject a command run in non-interactive mode if user interaction is required. plugin_dir=string The default plugin directory used by the **sudo **front-end. This is the de‐ fault directory set at compile time and may not correspond to the directory the running plugin was loaded from. It may be used by a plugin to locate support files. plugin_path=string The path name of plugin loaded by the **sudo **front-end. The path name will be a fully-qualified unless the plugin was statically compiled into **sudo**. preserve_environment=bool Set to true if the user specified the **-E **option, indicating that the user wishes to preserve the environment. preserve_groups=bool Set to true if the user specified the **-P **option, indicating that the user wishes to preserve the group vector instead of setting it based on the runas user. progname=string The command name that sudo was run as, typically “sudo” or “sudoedit”. prompt=string The prompt to use when requesting a password, if specified via the **-p **op‐ tion. remote_host=string The name of the remote host to run the command on, if specified via the **-h** option. Support for running the command on a remote host is meant to be implemented via a helper program that is executed in place of the user- specified command. The **sudo **front-end is only capable of executing com‐ mands on the local host. Only available starting with API version 1.4. run_shell=bool Set to true if the user specified the **-s **option, indicating that the user wishes to run a shell. runas_group=string The group name or group-ID to run the command as, if specified via the **-g** option. runas_user=string The user name or user-ID to run the command as, if specified via the **-u **op‐ tion. selinux_role=string SELinux role to use when executing the command, if specified by the **-r **op‐ tion. selinux_type=string SELinux type to use when executing the command, if specified by the **-t **op‐ tion. set_home=bool Set to true if the user specified the **-H **option. If true, set the HOME en‐ vironment variable to the target user's home directory. sudoedit=bool Set to true when the **-e **option is specified or if invoked as **sudoedit**. The plugin shall substitute an editor into _argv_ in the **check_policy**() function or return -2 with a usage error if the plugin does not support _sudoedit_. For more information, see the **check_policy**() section. timeout=string Command timeout specified by the user via the **-T **option. Not all plugins support command timeouts and the ability of the user to set a timeout may be restricted by policy. The format of the timeout string is plugin-spe‐ cific. update_ticket=bool Set to false if the user specified the **-N **option, indicating that the user wishes to avoid updating any cached authentication credentials. Only available starting with API version 1.20. Additional settings may be added in the future so the plugin should silently ig‐ nore settings that it does not recognize. _user_info_ A vector of information about the user running the command in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _user_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. The following values may be set by **sudo**: cols=int The number of columns the user's terminal supports. If there is no termi‐ nal device available, a default value of 80 is used. cwd=string The user's current working directory. egid=gid_t The effective group-ID of the user invoking **sudo**. euid=uid_t The effective user-ID of the user invoking **sudo**. gid=gid_t The real group-ID of the user invoking **sudo**. groups=list The user's supplementary group list formatted as a string of comma-sepa‐ rated group-IDs. host=string The local machine's hostname as returned by the [_gethostname_(2)](https://www.chedong.com/phpMan.php/man/gethostname/2/markdown) system call. lines=int The number of lines the user's terminal supports. If there is no terminal device available, a default value of 24 is used. pgid=int The ID of the process group that the running **sudo **process is a member of. Only available starting with API version 1.2. pid=int The process ID of the running **sudo **process. Only available starting with API version 1.2. ppid=int The parent process ID of the running **sudo **process. Only available starting with API version 1.2. rlimit_as=soft,hard The maximum size to which the process's address space may grow (in bytes), if supported by the operating system. The soft and hard limits are sepa‐ rated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_core=soft,hard The largest size core dump file that may be created (in bytes). The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_cpu=soft,hard The maximum amount of CPU time that the process may use (in seconds). The soft and hard limits are separated by a comma. A value of “infinity” indi‐ cates that there is no limit. Only available starting with API version 1.16. rlimit_data=soft,hard The maximum size of the data segment for the process (in bytes). The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_fsize=soft,hard The largest size file that the process may create (in bytes). The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_locks=soft,hard The maximum number of locks that the process may establish, if supported by the operating system. The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_memlock=soft,hard The maximum size that the process may lock in memory (in bytes), if sup‐ ported by the operating system. The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_nofile=soft,hard The maximum number of files that the process may have open. The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_nproc=soft,hard The maximum number of processes that the user may run simultaneously. The soft and hard limits are separated by a comma. A value of “infinity” indi‐ cates that there is no limit. Only available starting with API version 1.16. rlimit_rss=soft,hard The maximum size to which the process's resident set size may grow (in bytes). The soft and hard limits are separated by a comma. A value of “infinity” indicates that there is no limit. Only available starting with API version 1.16. rlimit_stack=soft,hard The maximum size to which the process's stack may grow (in bytes). The soft and hard limits are separated by a comma. A value of “infinity” indi‐ cates that there is no limit. Only available starting with API version 1.16. sid=int The session ID of the running **sudo **process or 0 if **sudo **is not part of a POSIX job control session. Only available starting with API version 1.2. tcpgid=int The ID of the foreground process group associated with the terminal device associated with the **sudo **process or 0 if there is no terminal present. Only available starting with API version 1.2. tty=string The path to the user's terminal device. If the user has no terminal device associated with the session, the value will be empty, as in ‘tty=’. uid=uid_t The real user-ID of the user invoking **sudo**. umask=octal The invoking user's file creation mask. Only available starting with API version 1.10. user=string The name of the user invoking **sudo**. _user_env_ The user's environment in the form of a NULL-terminated vector of “name=value” strings. When parsing _user_env_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _plugin_options_ Any (non-comment) strings immediately after the plugin path are passed as argu‐ ments to the plugin. These arguments are split on a white space boundary and are passed to the plugin in the form of a NULL-terminated array of strings. If no arguments were specified, _plugin_options_ will be the NULL pointer. The _plugin_options_ parameter is only available starting with API version 1.2. A plugin **must **check the API version specified by the **sudo **front-end before using _plugin_options_. Failure to do so may result in a crash. _errstr_ If the **open**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _close_ void (*close)(int exit_status, int error); The **close**() function is called when **sudo **is finished, shortly before it exits. Start‐ ing with API version 1.15, **close**() is called regardless of whether or not a command was actually executed. This makes it possible for plugins to perform cleanup even when a command was not run. It is not possible to tell whether a command was run based solely on the arguments passed to the **close**() function. To determine if a command was actu‐ ally run, the plugin must keep track of whether or not the **check_policy**() function re‐ turned successfully. The function arguments are as follows: _exit_status_ The command's exit status, as returned by the [_wait_(2)](https://www.chedong.com/phpMan.php/man/wait/2/markdown) system call, or zero if no command was run. The value of _exit_status_ is undefined if _error_ is non-zero. _error_ If the command could not be executed, this is set to the value of _errno_ set by the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. The plugin is responsible for displaying error infor‐ mation via the **conversation**() or **sudo_plugin_printf**() function. If the command was successfully executed, the value of _error_ is zero. If no **close**() function is defined, no I/O logging plugins are loaded, and neither the _timeout_ nor _use_pty_ options are set in the _command_info_ list, the **sudo **front-end may execute the command directly instead of running it as a child process. _show_version_ int (*show_version)(int verbose); The **show_version**() function is called by **sudo **when the user specifies the **-V **option. The plugin may display its version information to the user via the **conversation**() or **sudo_plugin_printf**() function using SUDO_CONV_INFO_MSG. If the user requests detailed version information, the _verbose_ flag will be non-zero. Returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error, although the return value is currently ignored. _check_policy_ int (*check_policy)(int argc, char * const argv[], char *env_add[], char **command_info[], char **argv_out[], char **user_env_out[], const char **errstr); The **check_policy**() function is called by **sudo **to determine whether the user is allowed to run the specified commands. If the _sudoedit_ option was enabled in the _settings_ array passed to the **open**() function, the user has requested _sudoedit_ mode. _sudoedit_ is a mechanism for editing one or more files where an editor is run with the user's credentials instead of with elevated priv‐ ileges. **sudo **achieves this by creating user-writable temporary copies of the files to be edited and then overwriting the originals with the temporary copies after editing is complete. If the plugin supports _sudoedit_, it must set _sudoedit=true_ in the _command_info_ list. The plugin is responsible for choosing the editor to be used, po‐ tentially from a variable in the user's environment, such as EDITOR, and should be stored in _argv_out_ (environment variables may include command line options). The files to be edited should be copied from _argv_ to _argv_out_, separated from the editor and its arguments by a ‘--’ element. The ‘--’ will be removed by **sudo **before the editor is ex‐ ecuted. The plugin may also set _sudoedit_nfiles_ to the number of files to be edited in the _command_info_ list; this will only be used by the **sudo **front-end starting with API version 1.21. The **check_policy**() function returns 1 if the command is allowed, 0 if not allowed, -1 for a general error, or -2 for a usage error or if _sudoedit_ was specified but is unsup‐ ported by the plugin. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error in‐ formation to the user. The function arguments are as follows: _argc_ The number of elements in _argv_, not counting the final NULL pointer. _argv_ The argument vector describing the command the user wishes to run, in the same form as what would be passed to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. The vector is termi‐ nated by a NULL pointer. _env_add_ Additional environment variables specified by the user on the command line in the form of a NULL-terminated vector of “name=value” strings. The plugin may reject the command if one or more variables are not allowed to be set, or it may silently ignore such variables. When parsing _env_add_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _command_info_ Information about the command being run in the form of “name=value” strings. These values are used by **sudo **to set the execution environment when running a command. The plugin is responsible for creating and populating the vector, which must be terminated with a NULL pointer. The following values are recognized by **sudo**: apparmor_profile=string AppArmor profile to transition to when executing the command. Only avail‐ able starting with API version 1.19. chroot=string The root directory to use when running the command. closefrom=number If specified, **sudo **will close all files descriptors with a value of _number_ or higher. command=string Fully qualified path to the command to be executed. cwd=string The current working directory to change to when executing the command. If **sudo **is unable to change to the new working directory, the command will not be run unless _cwd_optional_ is also set (see below). cwd_optional=bool If set, **sudo **will treat an inability to change to the new working directory as a non-fatal error. This setting has no effect unless _cwd_ is also set. exec_background=bool By default, **sudo **runs a command as the foreground process as long as **sudo** itself is running in the foreground. When _exec_background_ is enabled and the command is being run in a pseudo-terminal (due to I/O logging or the _use_pty_ setting), the command will be run as a background process. At‐ tempts to read from the controlling terminal (or to change terminal set‐ tings) will result in the command being suspended with the SIGTTIN signal (or SIGTTOU in the case of terminal settings). If this happens when **sudo** is a foreground process, the command will be granted the controlling termi‐ nal and resumed in the foreground with no user intervention required. The advantage of initially running the command in the background is that **sudo** need not read from the terminal unless the command explicitly requests it. Otherwise, any terminal input must be passed to the command, whether it has required it or not (the kernel buffers terminals so it is not possible to tell whether the command really wants the input). This is different from historic **sudo **behavior or when the command is not being run in a pseudo- terminal. For this to work seamlessly, the operating system must support the auto‐ matic restarting of system calls. Unfortunately, not all operating systems do this by default, and even those that do may have bugs. For example, ma‐ cOS fails to restart the **tcgetattr**() and **tcsetattr**() system calls (this is a bug in macOS). Furthermore, because this behavior depends on the command stopping with the SIGTTIN or SIGTTOU signals, programs that catch these signals and suspend themselves with a different signal (usually SIGTOP) will not be automatically foregrounded. Some versions of the linux [_su_(1)](https://www.chedong.com/phpMan.php/man/su/1/markdown) command behave this way. Because of this, a plugin should not set _exec_background_ unless it is explicitly enabled by the administrator and there should be a way to enabled or disable it on a per-command basis. This setting has no effect unless I/O logging is enabled or _use_pty_ is en‐ abled. execfd=number If specified, **sudo **will use the [_fexecve_(2)](https://www.chedong.com/phpMan.php/man/fexecve/2/markdown) system call to execute the com‐ mand instead of [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown). The specified _number_ must refer to an open file descriptor. intercept=bool If set, **sudo **will intercept attempts to execute a subsequent command and perform a policy check via the policy plugin's **check_policy**() function to determine whether or not the command is permitted. This can be used to prevent shell escapes on supported platforms but it has a number of limita‐ tions. See **Preventing shell escapes **in [_sudoers_(5)](https://www.chedong.com/phpMan.php/man/sudoers/5/markdown) for details. Only available starting with API version 1.18. intercept_verify=bool If set, **sudo **will attempt to verify that a command run in intercept mode has the expected path name, command line arguments and environment. This setting has no effect unless _use_ptrace_ is also enabled. Only available starting with API version 1.20. iolog_compress=bool Set to true if the I/O logging plugins, if any, should compress the log data. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_group=string The group that will own newly created I/O log files and directories. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_mode=octal The file permission mode to use when creating I/O log files and directo‐ ries. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_user=string The user that will own newly created I/O log files and directories. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_path=string Fully qualified path to the file or directory in which I/O log is to be stored. This is a hint to the I/O logging plugin which may choose to ig‐ nore it. If no I/O logging plugin is loaded, this setting has no effect. iolog_stdin=bool Set to true if the I/O logging plugins, if any, should log the standard in‐ put if it is not connected to a terminal device. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_stdout=bool Set to true if the I/O logging plugins, if any, should log the standard output if it is not connected to a terminal device. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_stderr=bool Set to true if the I/O logging plugins, if any, should log the standard er‐ ror if it is not connected to a terminal device. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_ttyin=bool Set to true if the I/O logging plugins, if any, should log all terminal in‐ put. This only includes input typed by the user and not from a pipe or redirected from a file. This is a hint to the I/O logging plugin which may choose to ignore it. iolog_ttyout=bool Set to true if the I/O logging plugins, if any, should log all terminal output. This only includes output to the screen, not output to a pipe or file. This is a hint to the I/O logging plugin which may choose to ignore it. login_class=string BSD login class to use when setting resource limits and nice value (op‐ tional). This option is only set on systems that support login classes. nice=int Nice value (priority) to use when executing the command. The nice value, if specified, overrides the priority associated with the _login_class_ on BSD systems. log_subcmds=bool If set, **sudo **will call the audit plugin's **accept**() function to log when the command runs a subsequent command, if supported by the system. If _intercept_ is also specified, _log_subcmds_ will be ignored. See **Preventing** **shell escapes **in [_sudoers_(5)](https://www.chedong.com/phpMan.php/man/sudoers/5/markdown) for more information. Only available starting with API version 1.18. noexec=bool If set, prevent the command from executing other programs. preserve_fds=list A comma-separated list of file descriptors that should be preserved, re‐ gardless of the value of the _closefrom_ setting. Only available starting with API version 1.5. preserve_groups=bool If set, **sudo **will preserve the user's group vector instead of initializing the group vector based on _runas_user_. rlimit_as=soft,hard The maximum size to which the process's address space may grow (in bytes), if supported by the operating system. The soft and hard limits are sepa‐ rated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only available starting with API version 1.18. rlimit_core=soft,hard The largest size core dump file that may be created (in bytes). The soft and hard limits are separated by a comma. If only a single value is speci‐ fied, both the hard and soft limits are set. A value of “infinity” indi‐ cates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per- user resource limits to be configured. Only available starting with API version 1.18. rlimit_cpu=soft,hard The maximum amount of CPU time that the process may use (in seconds). The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invok‐ ing user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only available starting with API version 1.18. rlimit_data=soft,hard The maximum size of the data segment for the process (in bytes). The soft and hard limits are separated by a comma. If only a single value is speci‐ fied, both the hard and soft limits are set. A value of “infinity” indi‐ cates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per- user resource limits to be configured. Only available starting with API version 1.18. rlimit_fsize=soft,hard The largest size file that the process may create (in bytes). The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user re‐ source limits to be configured. Only available starting with API version 1.18. rlimit_locks=soft,hard The maximum number of locks that the process may establish, if supported by the operating system. The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only avail‐ able starting with API version 1.18. rlimit_memlock=soft,hard The maximum size that the process may lock in memory (in bytes), if sup‐ ported by the operating system. The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft lim‐ its are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be pre‐ served. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be con‐ figured. Only available starting with API version 1.18. rlimit_nofile=soft,hard The maximum number of files that the process may have open. The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user re‐ source limits to be configured. Only available starting with API version 1.18. rlimit_nproc=soft,hard The maximum number of processes that the user may run simultaneously. The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invok‐ ing user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only available starting with API version 1.18. rlimit_rss=soft,hard The maximum size to which the process's resident set size may grow (in bytes). The soft and hard limits are separated by a comma. If only a sin‐ gle value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invoking user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only available starting with API version 1.18. rlimit_stack=soft,hard The maximum size to which the process's stack may grow (in bytes). The soft and hard limits are separated by a comma. If only a single value is specified, both the hard and soft limits are set. A value of “infinity” indicates that there is no limit. A value of “user” will cause the invok‐ ing user's resource limit to be preserved. A value of “default” will cause the target user's default resource limit to be used on systems that allow per-user resource limits to be configured. Only available starting with API version 1.18. runas_egid=gid Effective group-ID to run the command as. If not specified, the value of _runas_gid_ is used. runas_euid=uid Effective user-ID to run the command as. If not specified, the value of _runas_uid_ is used. runas_gid=gid Group-ID to run the command as. runas_group=string The name of the group the command will run as, if it is different from the _runas_user_'s default group. This value is provided for auditing purposes only, the **sudo **front-end uses _runas_egid_ and _runas_gid_ when executing the command. runas_groups=list The supplementary group vector to use for the command in the form of a comma-separated list of group-IDs. If _preserve_groups_ is set, this option is ignored. runas_uid=uid User-ID to run the command as. runas_user=string The name of the user the command will run as, which should correspond to _runas_euid_ (or _runas_uid_ if _runas_euid_ is not set). This value is provided for auditing purposes only, the **sudo **front-end uses _runas_euid_ and _runas_uid_ when executing the command. selinux_role=string SELinux role to use when executing the command. selinux_type=string SELinux type to use when executing the command. set_utmp=bool Create a utmp (or utmpx) entry when a pseudo-terminal is allocated. By de‐ fault, the new entry will be a copy of the user's existing utmp entry (if any), with the tty, time, type, and pid fields updated. sudoedit=bool Set to true when in _sudoedit_ mode. The plugin may enable _sudoedit_ mode even if **sudo **was not invoked as **sudoedit**. This allows the plugin to per‐ form command substitution and transparently enable _sudoedit_ when the user attempts to run an editor. sudoedit_checkdir=bool Set to false to disable directory writability checks in **sudoedit**. By de‐ fault, **sudoedit **1.8.16 and higher will check all directory components of the path to be edited for writability by the invoking user. Symbolic links will not be followed in writable directories and **sudoedit **will refuse to edit a file located in a writable directory. These restrictions are not enforced when **sudoedit **is run by root. The _sudoedit_checkdir_ option can be set to false to disable this check. Only available starting with API ver‐ sion 1.8. sudoedit_follow=bool Set to true to allow **sudoedit **to edit files that are symbolic links. By default, **sudoedit **1.8.15 and higher will refuse to open a symbolic link. The _sudoedit_follow_ option can be used to restore the older behavior and allow **sudoedit **to open symbolic links. Only available starting with API version 1.8. sudoedit_nfiles=number The number of files to be edited by the user. If present, this is will be used by the **sudo **front-end to determine which elements of the _argv_out_ vec‐ tor are files to be edited. The ‘--’ element must immediately precede the first file to be editied. If _sudoedit_nfiles_ is not specified, the **sudo** front-end will use the position of the ‘--’ element to determine where the file list begins. Only available starting with API version 1.21. timeout=int Command timeout. If non-zero then when the timeout expires the command will be killed. umask=octal The file creation mask to use when executing the command. This value may be overridden by PAM or login.conf on some systems unless the _umask_override_ option is also set. umask_override=bool Force the value specified by the _umask_ option to override any umask set by PAM or login.conf. use_ptrace=bool If set, **sudo **will use [_ptrace_(2)](https://www.chedong.com/phpMan.php/man/ptrace/2/markdown) to implement intercept mode if supported by the system. This setting has no effect unless _intercept_ is also set. Only available starting with API version 1.19. use_pty=bool Allocate a pseudo-terminal to run the command in, regardless of whether or not I/O logging is in use. By default, **sudo **will only run the command in a pseudo-terminal when an I/O log plugin is loaded. utmp_user=string User name to use when constructing a new utmp (or utmpx) entry when _set_utmp_ is enabled. This option can be used to set the user field in the utmp entry to the user the command runs as rather than the invoking user. If not set, **sudo **will base the new entry on the invoking user's existing entry. Unsupported values will be ignored. _argv_out_ The NULL-terminated argument vector to pass to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call when ex‐ ecuting the command. The plugin is responsible for allocating and populating the vector. _user_env_out_ The NULL-terminated environment vector to use when executing the command. The plugin is responsible for allocating and populating the vector. _errstr_ If the **check_policy**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _list_ int (*list)(int argc, char * const argv[], int verbose, const char *user, const char **errstr); List available privileges for the invoking user. Returns 1 on success, 0 on failure, and -1 on error. On error, the plugin may optionally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error in‐ formation to the user. Privileges should be output via the **conversation**() or **sudo_plugin_printf**() function us‐ ing SUDO_CONV_INFO_MSG. The function arguments are as follows: _argc_ The number of elements in _argv_, not counting the final NULL pointer. _argv_ If non-NULL, an argument vector describing a command the user wishes to check against the policy in the same form as what would be passed to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) sys‐ tem call. If the command is permitted by the policy, the fully-qualified path to the command should be displayed along with any command line arguments. _verbose_ Flag indicating whether to list in verbose mode or not. _user_ The name of a different user to list privileges for if the policy allows it. If NULL, the plugin should list the privileges of the invoking user. _errstr_ If the **list**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _validate_ int (*validate)(const char **errstr); The **validate**() function is called when **sudo **is run with the **-v **option. For policy plu‐ gins such as **sudoers **that cache authentication credentials, this function will validate and cache the credentials. The **validate**() function should be NULL if the plugin does not support credential caching. Returns 1 on success, 0 on failure, and -1 on error. On error, the plugin may option‐ ally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _errstr_ If the **validate**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _invalidate_ void (*invalidate)(int rmcred); The **invalidate**() function is called when **sudo **is run with the **-k **or **-K **option. For policy plugins such as **sudoers **that cache authentication credentials, this function will invalidate the credentials. If the _rmcred_ flag is non-zero, the plugin may remove the credentials instead of simply invalidating them. The **invalidate**() function should be NULL if the plugin does not support credential caching. _init_session_ int (*init_session)(struct passwd *pwd, char **user_env[], const char **errstr); The **init_session**() function is called before **sudo **sets up the execution environment for the command. It is run in the parent **sudo **process before any user-ID or group-ID changes. This can be used to perform session setup that is not supported by _command_info_, such as opening the PAM session. The **close**() function can be used to tear down the session that was opened by **init_session**(). Returns 1 on success, 0 on failure, and -1 on error. On error, the plugin may option‐ ally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _pwd_ If the user-ID the command will run as was found in the password database, _pwd_ will describe that user, otherwise it will be NULL. _user_env_out_ The NULL-terminated environment vector to use when executing the command. This is the same string passed back to the front-end via the Policy Plugin's _user_env_out_ parameter. If the **init_session**() function needs to modify the user environment, it should update the pointer stored in _user_env_out_. The expected use case is to merge the contents of the PAM environment (if any) with the con‐ tents of _user_env_out_. The _user_env_out_ parameter is only available starting with API version 1.2. A plugin **must **check the API version specified by the **sudo** front-end before using _user_env_out_. Failure to do so may result in a crash. _errstr_ If the **init_session**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _register_hooks_ void (*register_hooks)(int version, int (*register_hook)(struct sudo_hook *hook)); The **register_hooks**() function is called by the sudo front-end to register any hooks the plugin needs. If the plugin does not support hooks, _register_hooks_ should be set to the NULL pointer. The _version_ argument describes the version of the hooks API supported by the **sudo** front-end. The **register_hook**() function should be used to register any supported hooks the plugin needs. It returns 0 on success, 1 if the hook type is not supported, and -1 if the ma‐ jor version in _struct_ _sudo_hook_ does not match the front-end's major hook API version. See the “Hook function API” section below for more information about hooks. The **register_hooks**() function is only available starting with API version 1.2. If the **sudo **front-end doesn't support API version 1.2 or higher, **register_hooks**() will not be called. _deregister_hooks_ void (*deregister_hooks)(int version, int (*deregister_hook)(struct sudo_hook *hook)); The **deregister_hooks**() function is called by the sudo front-end to deregister any hooks the plugin has registered. If the plugin does not support hooks, _deregister_hooks_ should be set to the NULL pointer. The _version_ argument describes the version of the hooks API supported by the **sudo** front-end. The **deregister_hook**() function should be used to deregister any hooks that were put in place by the **register_hook**() function. If the plugin tries to deregister a hook that the front-end does not support, **deregister_hook**() will return an error. See the “Hook function API” section below for more information about hooks. The **deregister_hooks**() function is only available starting with API version 1.2. If the **sudo **front-end doesn't support API version 1.2 or higher, **deregister_hooks**() will not be called. _event_alloc_ struct sudo_plugin_event * (*event_alloc)(void); The **event_alloc**() function is used to allocate a _struct_ _sudo_plugin_event_ which pro‐ vides access to the main **sudo **event loop. Unlike the other fields, the _event_alloc_ pointer is filled in by the **sudo **front-end, not by the plugin. See the “Event API” section below for more information about events. The **event_alloc**() function is only available starting with API version 1.15. If the **sudo **front-end doesn't support API version 1.15 or higher, _event_alloc_ will not be set. _Policy_ _Plugin_ _Version_ _Macros_ /* Plugin API version major/minor. */ #define SUDO_API_VERSION_MAJOR 1 #define SUDO_API_VERSION_MINOR 13 #define SUDO_API_MKVERSION(x, y) ((x << 16) | y) #define SUDO_API_VERSION SUDO_API_MKVERSION(SUDO_API_VERSION_MAJOR,\ SUDO_API_VERSION_MINOR) /* Getters and setters for API version */ #define SUDO_API_VERSION_GET_MAJOR(v) ((v) >> 16) #define SUDO_API_VERSION_GET_MINOR(v) ((v) & 0xffff) #define SUDO_API_VERSION_SET_MAJOR(vp, n) do { \ *(vp) = (*(vp) & 0x0000ffff) | ((n) << 16); \ } [while(0)](https://www.chedong.com/phpMan.php/man/while/0/markdown) #define SUDO_API_VERSION_SET_MINOR(vp, n) do { \ *(vp) = (*(vp) & 0xffff0000) | (n); \ } [while(0)](https://www.chedong.com/phpMan.php/man/while/0/markdown) ### I/O plugin API struct io_plugin { #define SUDO_IO_PLUGIN 2 unsigned int type; /* always SUDO_IO_PLUGIN */ unsigned int version; /* always SUDO_API_VERSION */ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], char * const command_info[], int argc, char * const argv[], char * const user_env[], char * const plugin_options[], const char **errstr); void (*close)(int exit_status, int error); /* wait status or error */ int (*show_version)(int verbose); int (*log_ttyin)(const char *buf, unsigned int len, const char **errstr); int (*log_ttyout)(const char *buf, unsigned int len, const char **errstr); int (*log_stdin)(const char *buf, unsigned int len, const char **errstr); int (*log_stdout)(const char *buf, unsigned int len, const char **errstr); int (*log_stderr)(const char *buf, unsigned int len, const char **errstr); void (*register_hooks)(int version, int (*register_hook)(struct sudo_hook *hook)); void (*deregister_hooks)(int version, int (*deregister_hook)(struct sudo_hook *hook)); int (*change_winsize)(unsigned int lines, unsigned int cols, const char **errstr); int (*log_suspend)(int signo, const char **errstr); struct sudo_plugin_event * (*event_alloc)(void); }; When an I/O plugin is loaded, **sudo **runs the command in a pseudo-terminal. This makes it pos‐ sible to log the input and output from the user's session. If any of the standard input, standard output, or standard error do not correspond to a tty, **sudo **will open a pipe to cap‐ ture the I/O for logging before passing it on. The **log_ttyin**() function receives the raw user input from the terminal device (this will in‐ clude input even when echo is disabled, such as when a password is read). The **log_ttyout**() function receives output from the pseudo-terminal that is suitable for replaying the user's session at a later time. The **log_stdin**(), **log_stdout**(), and **log_stderr**() functions are only called if the standard input, standard output, or standard error respectively correspond to something other than a tty. Any of the logging functions may be set to the NULL pointer if no logging is to be performed. If the open function returns 0, no I/O will be sent to the plugin. If a logging function returns an error (-1), the running command will be terminated and all of the plugin's logging functions will be disabled. Other I/O logging plugins will still re‐ ceive any remaining input or output that has not yet been processed. If an input logging function rejects the data by returning 0, 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 0, 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. A _struct_ _audit_plugin_ has the following fields: _type_ The _type_ field should always be set to SUDO_IO_PLUGIN. _version_ The _version_ field should be set to SUDO_API_VERSION. This allows **sudo **to determine the API version the plugin was built against. _open_ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], char * const command_info[], int argc, char * const argv[], char * const user_env[], char * const plugin_options[]); The **open**() function is run before the **log_ttyin**(), **log_ttyout**(), **log_stdin**(), **log_stdout**(), **log_stderr**(), **log_suspend**(), **change_winsize**(), or **show_version**() func‐ tions are called. It is only called if the version is being requested or if the policy plugin's **check_policy**() function has returned successfully. It returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **sudo_plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _version_ The version passed in by **sudo **allows the plugin to determine the major and minor version number of the plugin API supported by **sudo**. _conversation_ A pointer to the **conversation**() function that may be used by the **Fa**(_show_version_) function to display version information (see **show_version**() below). The **conversation**() function may also be used to display additional error message to the user. The **conversation**() function returns 0 on success and -1 on failure. _sudo_plugin_printf_ A pointer to a **printf**()-style function that may be used by the **show_version**() function to display version information (see show_version below). The **sudo_plugin_printf**() function may also be used to display additional error mes‐ sage to the user. The **sudo_plugin_printf**() function returns number of characters printed on success and -1 on failure. _settings_ A vector of user-supplied **sudo **settings in the form of “name=value” strings. The vector is terminated by a NULL pointer. These settings correspond to options the user specified when running **sudo**. As such, they will only be present when the corresponding option has been specified on the command line. When parsing _settings_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible settings. _user_info_ A vector of information about the user running the command in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _user_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _command_info_ A vector of information describing the command being run in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _command_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _argc_ The number of elements in _argv_, not counting the final NULL pointer. It can be zero, such as when **sudo **is called with the **-V **option. _argv_ If non-NULL, an argument vector describing a command the user wishes to run in the same form as what would be passed to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. _user_env_ The user's environment in the form of a NULL-terminated vector of “name=value” strings. When parsing _user_env_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _plugin_options_ Any (non-comment) strings immediately after the plugin path are treated as argu‐ ments to the plugin. These arguments are split on a white space boundary and are passed to the plugin in the form of a NULL-terminated array of strings. If no arguments were specified, _plugin_options_ will be the NULL pointer. The _plugin_options_ parameter is only available starting with API version 1.2. A plugin **must **check the API version specified by the **sudo **front-end before using _plugin_options_. Failure to do so may result in a crash. _errstr_ If the **open**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _close_ void (*close)(int exit_status, int error); The **close**() function is called when **sudo **is finished, shortly before it exits. The function arguments are as follows: _exit_status_ The command's exit status, as returned by the [_wait_(2)](https://www.chedong.com/phpMan.php/man/wait/2/markdown) system call, or zero if no command was run. The value of _exit_status_ is undefined if _error_ is non-zero. _error_ If the command could not be executed, this is set to the value of _errno_ set by the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. If the command was successfully executed, the value of _error_ is zero. _show_version_ int (*show_version)(int verbose); The **show_version**() function is called by **sudo **when the user specifies the **-V **option. The plugin may display its version information to the user via the **conversation**() or **sudo_plugin_printf**() function using SUDO_CONV_INFO_MSG. If the user requests detailed version information, the _verbose_ flag will be non-zero. Returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error, although the return value is currently ignored. _log_ttyin_ int (*log_ttyin)(const char *buf, unsigned int len, const char **errstr); The **log_ttyin**() function is called whenever data can be read from the user but before it is passed to the running command. This allows the plugin to reject data if it chooses to (for instance if the input contains banned content). Returns 1 if the data should be passed to the command, 0 if the data is rejected (which will terminate the running command), or -1 if an error occurred. The function arguments are as follows: _buf_ The buffer containing user input. _len_ The length of _buf_ in bytes. _errstr_ If the **log_ttyin**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _log_ttyout_ int (*log_ttyout)(const char *buf, unsigned int len, const char **errstr); The **log_ttyout**() function is called whenever data can be read from the command but be‐ fore it is written to the user's terminal. This allows the plugin to reject data if it chooses to (for instance if the output contains banned content). Returns 1 if the data should be passed to the user, 0 if the data is rejected (which will terminate the run‐ ning command), or -1 if an error occurred. The function arguments are as follows: _buf_ The buffer containing command output. _len_ The length of _buf_ in bytes. _errstr_ If the **log_ttyout**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _log_stdin_ int (*log_stdin)(const char *buf, unsigned int len, const char **errstr); The **log_stdin**() function is only used if the standard input does not correspond to a tty device. It is called whenever data can be read from the standard input but before it is passed to the running command. This allows the plugin to reject data if it chooses to (for instance if the input contains banned content). Returns 1 if the data should be passed to the command, 0 if the data is rejected (which will terminate the running command), or -1 if an error occurred. The function arguments are as follows: _buf_ The buffer containing user input. _len_ The length of _buf_ in bytes. _errstr_ If the **log_stdin**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _log_stdout_ int (*log_stdout)(const char *buf, unsigned int len, const char **errstr); The **log_stdout**() function is only used if the standard output does not correspond to a tty device. It is called whenever data can be read from the command but before it is written to the standard output. This allows the plugin to reject data if it chooses to (for instance if the output contains banned content). Returns 1 if the data should be passed to the user, 0 if the data is rejected (which will terminate the running com‐ mand), or -1 if an error occurred. The function arguments are as follows: _buf_ The buffer containing command output. _len_ The length of _buf_ in bytes. _errstr_ If the **log_stdout**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _log_stderr_ int (*log_stderr)(const char *buf, unsigned int len, const char **errstr); The **log_stderr**() function is only used if the standard error does not correspond to a tty device. It is called whenever data can be read from the command but before it is written to the standard error. This allows the plugin to reject data if it chooses to (for instance if the output contains banned content). Returns 1 if the data should be passed to the user, 0 if the data is rejected (which will terminate the running com‐ mand), or -1 if an error occurred. The function arguments are as follows: _buf_ The buffer containing command output. _len_ The length of _buf_ in bytes. _errstr_ If the **log_stderr**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _register_hooks_ See the “Policy plugin API” section for a description of **register_hooks**(). _deregister_hooks_ See the “Policy plugin API” section for a description of **deregister_hooks**(). _change_winsize_ int (*change_winsize)(unsigned int lines, unsigned int cols, const char **errstr); The **change_winsize**() function is called whenever the window size of the terminal changes from the initial values specified in the _user_info_ list. Returns -1 if an er‐ ror occurred, in which case no further calls to **change_winsize**() will be made, The function arguments are as follows: _lines_ The number of lines (rows) in the re-sized terminal. _cols_ The number of columns in the re-sized terminal. _errstr_ If the **change_winsize**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _log_suspend_ int (*log_suspend)(int signo, const char **errstr); The **log_suspend**() function is called whenever a command is suspended or resumed. Log‐ ging this information makes it possible to skip the period of time when the command was suspended during playback of a session. Returns -1 if an error occurred, in which case no further calls to **log_suspend**() will be made, The function arguments are as follows: _signo_ The signal that caused the command to be suspended, or SIGCONT if the command was resumed. _errstr_ If the **log_suspend**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. The _errstr_ parameter is only available starting with API version 1.15. A plugin **must **check the API version specified by the **sudo **front-end before using _errstr_. Failure to do so may result in a crash. _event_alloc_ struct sudo_plugin_event * (*event_alloc)(void); The **event_alloc**() function is used to allocate a _struct_ _sudo_plugin_event_ which provides access to the main **sudo **event loop. Unlike the other fields, the **event_alloc**() pointer is filled in by the **sudo **front-end, not by the plugin. See the “Event API” section below for more information about events. The **event_alloc**() function is only available starting with API version 1.15. If the **sudo **front-end doesn't support API version 1.15 or higher, **event_alloc**() will not be set. _I/O_ _Plugin_ _Version_ _Macros_ Same as for the “Policy plugin API”. ### Audit plugin API /* Audit plugin close function status types. */ #define SUDO_PLUGIN_NO_STATUS 0 #define SUDO_PLUGIN_WAIT_STATUS 1 #define SUDO_PLUGIN_EXEC_ERROR 2 #define SUDO_PLUGIN_SUDO_ERROR 3 #define SUDO_AUDIT_PLUGIN 3 struct audit_plugin { unsigned int type; /* always SUDO_AUDIT_PLUGIN */ unsigned int version; /* always SUDO_API_VERSION */ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], int submit_optind, char * const submit_argv[], char * const submit_envp[], char * const plugin_options[], const char **errstr); void (*close)(int status_type, int status); int (*accept)(const char *plugin_name, unsigned int plugin_type, char * const command_info[], char * const run_argv[], char * const run_envp[], const char **errstr); int (*reject)(const char *plugin_name, unsigned int plugin_type, const char *audit_msg, char * const command_info[], const char **errstr); int (*error)(const char *plugin_name, unsigned int plugin_type, const char *audit_msg, char * const command_info[], const char **errstr); int (*show_version)(int verbose); void (*register_hooks)(int version, int (*register_hook)(struct sudo_hook *hook)); void (*deregister_hooks)(int version, int (*deregister_hook)(struct sudo_hook *hook)); struct sudo_plugin_event * (*event_alloc)(void); } An audit plugin can be used to log successful and unsuccessful attempts to run **sudo **indepen‐ dent of the policy or any I/O plugins. Multiple audit plugins may be specified in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown). A _struct_ _audit_plugin_ has the following fields: _type_ The _type_ field should always be set to SUDO_AUDIT_PLUGIN. _version_ The _version_ field should be set to SUDO_API_VERSION. This allows **sudo **to determine the API version the plugin was built against. _open_ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], int submit_optind, char * const submit_argv[], char * const submit_envp[], char * const plugin_options[], const char **errstr); The audit **open**() function is run before any other **sudo **plugin API functions. This makes it possible to audit failures in the other plugins. It returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _version_ The version passed in by **sudo **allows the plugin to determine the major and minor version number of the plugin API supported by **sudo**. _conversation_ A pointer to the **conversation**() function that may be used by the **show_version**() function to display version information (see **show_version**() below). The **conversation**() function may also be used to display additional error message to the user. The **conversation**() function returns 0 on success, and -1 on failure. _plugin_printf_ A pointer to a **printf**()-style function that may be used by the **show_version**() function to display version information (see show_version below). The **plugin_printf**() function may also be used to display additional error message to the user. The **plugin_printf**() function returns number of characters printed on success and -1 on failure. _settings_ A vector of user-supplied **sudo **settings in the form of “name=value” strings. The vector is terminated by a NULL pointer. These settings correspond to options the user specified when running **sudo**. As such, they will only be present when the corresponding option has been specified on the command line. When parsing _settings_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible settings. _user_info_ A vector of information about the user running the command in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _user_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _submit_optind_ The index into _submit_argv_ that corresponds to the first entry that is not a com‐ mand line option. If _submit_argv_ only consists of options, which may be the case with the **-l **or **-v **options, _submit_argv_[_submit_optind_] will evaluate to the NULL pointer. _submit_argv_ The argument vector **sudo **was invoked with, including all command line options. The _submit_optind_ argument can be used to determine the end of the command line options. _submit_envp_ The invoking user's environment in the form of a NULL-terminated vector of “name=value” strings. When parsing _submit_envp_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _plugin_options_ Any (non-comment) strings immediately after the plugin path are treated as argu‐ ments to the plugin. These arguments are split on a white space boundary and are passed to the plugin in the form of a NULL-terminated array of strings. If no arguments were specified, _plugin_options_ will be the NULL pointer. _errstr_ If the **open**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _close_ void (*close)(int status_type, int status); The **close**() function is called when **sudo **is finished, shortly before it exits. The function arguments are as follows: _status_type_ The type of status being passed. One of SUDO_PLUGIN_NO_STATUS, SUDO_PLUGIN_WAIT_STATUS, SUDO_PLUGIN_EXEC_ERROR or SUDO_PLUGIN_SUDO_ERROR. _status_ Depending on the value of _status_type_, this value is either ignored, the com‐ mand's exit status as returned by the [_wait_(2)](https://www.chedong.com/phpMan.php/man/wait/2/markdown) system call, the value of _errno_ set by the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call, or the value of _errno_ resulting from an error in the **sudo **front-end. _accept_ int (*accept)(const char *plugin_name, unsigned int plugin_type, char * const command_info[], char * const run_argv[], char * const run_envp[], const char **errstr); The **accept**() function is called when a command or action is accepted by a policy or ap‐ proval plugin. The function arguments are as follows: _plugin_name_ The name of the plugin that accepted the command or “sudo” for the **sudo **front- end. _plugin_type_ The type of plugin that accepted the command, currently either SUDO_POLICY_PLUGIN, SUDO_POLICY_APPROVAL, or SUDO_FRONT_END. The **accept**() func‐ tion is called multiple times--once for each policy or approval plugin that suc‐ ceeds and once for the sudo front-end. When called on behalf of the sudo front- end, _command_info_ may include information from an I/O logging plugin as well. Typically, an audit plugin is interested in either the accept status from the **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 **accept**() and **reject**() func‐ tions will _both_ be called. _command_info_ An optional vector of information describing the command being run in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _command_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _run_argv_ A NULL-terminated argument vector describing a command that will be run in the same form as what would be passed to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. _run_envp_ The environment the command will be run with in the form of a NULL-terminated vector of “name=value” strings. When parsing _run_envp_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _errstr_ If the **accept**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _reject_ int (*reject)(const char *plugin_name, unsigned int plugin_type, const char *audit_msg, char * const command_info[], const char **errstr); The **reject**() function is called when a command or action is rejected by a plugin. The function arguments are as follows: _plugin_name_ The name of the plugin that rejected the command. _plugin_type_ The type of plugin that rejected the command, currently either SUDO_POLICY_PLUGIN, SUDO_APPROVAL_PLUGIN, or SUDO_IO_PLUGIN. Unlike the **accept**() function, the **reject**() function is not called on behalf of the **sudo **front-end. _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 the NULL pointer. _command_info_ An optional vector of information describing the command being run in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _command_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _errstr_ If the **reject**() function returns a value other than 1, the plugin may store a message describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _error_ int (*error)(const char *plugin_name, unsigned int plugin_type, const char *audit_msg, char * const command_info[], const char **errstr); The **error**() function is called when a plugin or the **sudo **front-end returns an error. The function arguments are as follows: _plugin_name_ The name of the plugin that generated the error or “sudo” for the **sudo **front-end. _plugin_type_ The type of plugin that generated the error, or SUDO_FRONT_END for the **sudo** front-end. _audit_msg_ An optional string describing the plugin error. If the plugin did not provide a description, _audit_msg_ will be the NULL pointer. _command_info_ An optional vector of information describing the command being run in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _command_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _errstr_ If the **error**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _show_version_ int (*show_version)(int verbose); The **show_version**() function is called by **sudo **when the user specifies the **-V **option. The plugin may display its version information to the user via the **conversation**() or **plugin_printf**() function using SUDO_CONV_INFO_MSG. If the user requests detailed ver‐ sion information, the verbose flag will be set. Returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error, although the return value is currently ignored. _register_hooks_ See the “Policy plugin API” section for a description of **register_hooks**(). _deregister_hooks_ See the “Policy plugin API” section for a description of **deregister_hooks**(). _event_alloc_ struct sudo_plugin_event * (*event_alloc)(void); The **event_alloc**() function is used to allocate a _struct_ _sudo_plugin_event_ which pro‐ vides access to the main **sudo **event loop. Unlike the other fields, the _event_alloc_ pointer is filled in by the **sudo **front-end, not by the plugin. See the “Event API” section below for more information about events. The **event_alloc**() function is only available starting with API version 1.17. If the **sudo **front-end doesn't support API version 1.17 or higher, **event_alloc**() will not be set. ### Approval plugin API struct approval_plugin { #define SUDO_APPROVAL_PLUGIN 4 unsigned int type; /* always SUDO_APPROVAL_PLUGIN */ unsigned int version; /* always SUDO_API_VERSION */ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], int submit_optind, char * const submit_argv[], char * const submit_envp[], char * const plugin_options[], const char **errstr); void (*close)(void); int (*check)(char * const command_info[], char * const run_argv[], char * const run_envp[], const char **errstr); int (*show_version)(int verbose); }; An approval plugin can be used to apply extra constraints after a command has been accepted by the policy plugin. Unlike the other plugin types, it does not remain open until the com‐ mand completes. The plugin is opened before a call to **check**() or **show_version**() and closed shortly thereafter (audit plugin functions must be called before the plugin is closed). Mul‐ tiple approval plugins may be specified in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown). A _struct_ _approval_plugin_ has the following fields: _type_ The _type_ field should always be set to SUDO_APPROVAL_PLUGIN. _version_ The _version_ field should be set to SUDO_API_VERSION. This allows **sudo **to determine the API version the plugin was built against. _open_ int (*open)(unsigned int version, sudo_conv_t conversation, sudo_printf_t sudo_plugin_printf, char * const settings[], char * const user_info[], int submit_optind, char * const submit_argv[], char * const submit_envp[], char * const plugin_options[], const char **errstr); The approval **open**() function is run immediately before a call to the plugin's **check**() or **show_version**() functions. It is only called if the version is being requested or if the policy plugin's **check_policy**() function has returned successfully. It returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage er‐ ror. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _version_ The version passed in by **sudo **allows the plugin to determine the major and minor version number of the plugin API supported by **sudo**. _conversation_ A pointer to the **conversation**() function that can be used by the plugin to inter‐ act with the user (see “Conversation API” for details). Returns 0 on success and -1 on failure. _plugin_printf_ A pointer to a **printf**()-style function that may be used to display informational or error messages (see “Conversation API” for details). Returns the number of characters printed on success and -1 on failure. _settings_ A vector of user-supplied **sudo **settings in the form of “name=value” strings. The vector is terminated by a NULL pointer. These settings correspond to options the user specified when running **sudo**. As such, they will only be present when the corresponding option has been specified on the command line. When parsing _settings_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible settings. _user_info_ A vector of information about the user running the command in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _user_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _submit_optind_ The index into _submit_argv_ that corresponds to the first entry that is not a com‐ mand line option. If _submit_argv_ only consists of options, which may be the case with the **-l **or **-v **options, _submit_argv_[_submit_optind_] will evaluate to the NULL pointer. _submit_argv_ The argument vector **sudo **was invoked with, including all command line options. The _submit_optind_ argument can be used to determine the end of the command line options. _submit_envp_ The invoking user's environment in the form of a NULL-terminated vector of “name=value” strings. When parsing _submit_envp_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _plugin_options_ Any (non-comment) strings immediately after the plugin path are treated as argu‐ ments to the plugin. These arguments are split on a white space boundary and are passed to the plugin in the form of a NULL-terminated array of strings. If no arguments were specified, _plugin_options_ will be the NULL pointer. _errstr_ If the **open**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _close_ void (*close)(void); The **close**() function is called after the approval plugin's **check**() or **show_version**() functions have been called. It takes no arguments. The **close**() function is typically used to perform plugin-specific cleanup, such as the freeing of memory objects allo‐ cated by the plugin. If the plugin does not need to perform any cleanup, **close**() may be set to the NULL pointer. _check_ int (*check)(char * const command_info[], char * const run_argv[], char * const run_envp[], const char **errstr); The approval **check**() function is run after the policy plugin **check_policy**() function and before any I/O logging plugins. If multiple approval plugins are loaded, they must all succeed for the command to be allowed. It returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error. In the latter case, **sudo **will print a usage message before it exits. If an error occurs, the plugin may optionally call the **conversation**() or **plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error information to the user. The function arguments are as follows: _command_info_ A vector of information describing the command being run in the form of “name=value” strings. The vector is terminated by a NULL pointer. When parsing _command_info_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. See the “Policy plugin API” section for a list of all possible strings. _run_argv_ A NULL-terminated argument vector describing a command that will be run in the same form as what would be passed to the [_execve_(2)](https://www.chedong.com/phpMan.php/man/execve/2/markdown) system call. _run_envp_ The environment the command will be run with in the form of a NULL-terminated vector of “name=value” strings. When parsing _run_envp_, the plugin should split on the **first **equal sign (‘=’) since the _name_ field will never include one itself but the _value_ might. _errstr_ If the **open**() function returns a value other than 1, the plugin may store a mes‐ sage describing the failure or error in _errstr_. The **sudo **front-end will then pass this value to any registered audit plugins. The string stored in _errstr_ must remain valid until the plugin's **close**() function is called. _show_version_ int (*show_version)(int verbose); The **show_version**() function is called by **sudo **when the user specifies the **-V **option. The plugin may display its version information to the user via the **conversation**() or **plugin_printf**() function using SUDO_CONV_INFO_MSG. If the user requests detailed ver‐ sion information, the verbose flag will be set. Returns 1 on success, 0 on failure, -1 if a general error occurred, or -2 if there was a usage error, although the return value is currently ignored. ### Signal handlers The **sudo **front-end installs default signal handlers to trap common signals while the plugin functions are run. The following signals are trapped by default before the command is exe‐ cuted: **• **SIGALRM **• **SIGHUP **• **SIGINT **• **SIGPIPE **• **SIGQUIT **• **SIGTERM **• **SIGTSTP **• **SIGUSR1 **• **SIGUSR2 If a fatal signal is received before the command is executed, **sudo **will call the plugin's **close**() function with an exit status of 128 plus the value of the signal that was received. This allows for consistent logging of commands killed by a signal for plugins that log such information in their **close**() function. An exception to this is SIGPIPE, which is ignored un‐ til the command is executed. A plugin may temporarily install its own signal handlers but must restore the original han‐ dler before the plugin function returns. ### Hook function API Beginning with plugin API version 1.2, it is possible to install hooks for certain functions called by the **sudo **front-end. Currently, the only supported hooks relate to the handling of environment variables. Hooks can be used to intercept attempts to get, set, or remove environment variables so that these changes can be reflected in the version of the environment that is used to execute a command. A future version of the API will support hooking internal **sudo **front-end functions as well. _Hook_ _structure_ Hooks in **sudo **are described by the following structure: typedef int (*sudo_hook_fn_t)(); struct sudo_hook { unsigned int hook_version; unsigned int hook_type; sudo_hook_fn_t hook_fn; void *closure; }; A _struct_ _sudo_hook_ has the following fields: _hook_version_ The _hook_version_ field should be set to SUDO_HOOK_VERSION. _hook_type_ The _hook_type_ field may be one of the following supported hook types: SUDO_HOOK_SETENV The C library [_setenv_(3)](https://www.chedong.com/phpMan.php/man/setenv/3/markdown) function. Any registered hooks will run before the C li‐ brary implementation. The _hook_fn_ field should be a function that matches the following typedef: typedef int (*sudo_hook_fn_setenv_t)(const char *name, const char *value, int overwrite, void *closure); If the registered hook does not match the typedef the results are unspecified. SUDO_HOOK_UNSETENV The C library [_unsetenv_(3)](https://www.chedong.com/phpMan.php/man/unsetenv/3/markdown) function. Any registered hooks will run before the C library implementation. The _hook_fn_ field should be a function that matches the following typedef: typedef int (*sudo_hook_fn_unsetenv_t)(const char *name, void *closure); SUDO_HOOK_GETENV The C library [_getenv_(3)](https://www.chedong.com/phpMan.php/man/getenv/3/markdown) function. Any registered hooks will run before the C li‐ brary implementation. The _hook_fn_ field should be a function that matches the following typedef: typedef int (*sudo_hook_fn_getenv_t)(const char *name, char **value, void *closure); If the registered hook does not match the typedef the results are unspecified. SUDO_HOOK_PUTENV The C library [_putenv_(3)](https://www.chedong.com/phpMan.php/man/putenv/3/markdown) function. Any registered hooks will run before the C li‐ brary implementation. The _hook_fn_ field should be a function that matches the following typedef: typedef int (*sudo_hook_fn_putenv_t)(char *string, void *closure); If the registered hook does not match the typedef the results are unspecified. _hook_fn_ sudo_hook_fn_t hook_fn; The _hook_fn_ field should be set to the plugin's hook implementation. The actual func‐ tion arguments will vary depending on the _hook_type_ (see _hook_type_ above). In all cases, the _closure_ field of _struct_ _sudo_hook_ is passed as the last function parameter. This can be used to pass arbitrary data to the plugin's hook implementation. The function return value may be one of the following: SUDO_HOOK_RET_ERROR The hook function encountered an error. SUDO_HOOK_RET_NEXT The hook completed without error, go on to the next hook (including the system implementation if applicable). For example, a [_getenv_(3)](https://www.chedong.com/phpMan.php/man/getenv/3/markdown) hook might return SUDO_HOOK_RET_NEXT if the specified variable was not found in the private copy of the environment. SUDO_HOOK_RET_STOP The hook completed without error, stop processing hooks for this invocation. This can be used to replace the system implementation. For example, a _setenv_ hook that operates on a private copy of the environment but leaves _environ_ un‐ changed. Care must be taken when hooking C library functions, it is very easy to create an infinite loop. For example, a [_getenv_(3)](https://www.chedong.com/phpMan.php/man/getenv/3/markdown) hook that calls the [_snprintf_(3)](https://www.chedong.com/phpMan.php/man/snprintf/3/markdown) function may create a loop if the [_snprintf_(3)](https://www.chedong.com/phpMan.php/man/snprintf/3/markdown) implementation calls [_getenv_(3)](https://www.chedong.com/phpMan.php/man/getenv/3/markdown) to check the locale. To prevent this, you may wish to use a static variable in the hook function to guard against nested calls. For exam‐ ple: static int in_progress = 0; /* avoid recursion */ if (in_progress) return SUDO_HOOK_RET_NEXT; in_progress = 1; ... in_progress = 0; return SUDO_HOOK_RET_STOP; _Hook_ _API_ _Version_ _Macros_ /* Hook API version major/minor */ #define SUDO_HOOK_VERSION_MAJOR 1 #define SUDO_HOOK_VERSION_MINOR 0 #define SUDO_HOOK_VERSION SUDO_API_MKVERSION(SUDO_HOOK_VERSION_MAJOR,\ SUDO_HOOK_VERSION_MINOR) For getters and setters see the “Policy plugin API”. ### Event API When **sudo **runs a command, it uses an event loop to service signals and I/O. Events may be triggered based on time, a file or socket descriptor becoming ready, or due to receipt of a signal. Starting with API version 1.15, it is possible for a plugin to participate in this event loop by calling the **event_alloc**() function. _Event_ _structure_ Events are described by the following structure: typedef void (*sudo_plugin_ev_callback_t)(int fd, int what, void *closure); struct sudo_plugin_event { int (*set)(struct sudo_plugin_event *pev, int fd, int events, sudo_plugin_ev_callback_t callback, void *closure); int (*add)(struct sudo_plugin_event *pev, struct timespec *timeout); int (*del)(struct sudo_plugin_event *pev); int (*pending)(struct sudo_plugin_event *pev, int events, struct timespec *ts); int (*fd)(struct sudo_plugin_event *pev); void (*setbase)(struct sudo_plugin_event *pev, void *base); void (*loopbreak)(struct sudo_plugin_event *pev); void (*free)(struct sudo_plugin_event *pev); }; A _struct_ _sudo_plugin_event_ contains the following function pointers: _set_ int (*set)(struct sudo_plugin_event *pev, int fd, int events, sudo_plugin_ev_callback_t callback, void *closure); The **set**() function takes the following arguments: _struct_ _sudo_plugin_event_ _*pev_ A pointer to the _struct_ _sudo_plugin_event_ itself. _fd_ The file or socket descriptor for I/O-based events or the signal number for sig‐ nal events. For time-based events, _fd_ must be -1. _events_ The following values determine what will trigger the event callback: SUDO_PLUGIN_EV_TIMEOUT callback is run after the specified timeout expires SUDO_PLUGIN_EV_READ callback is run when the file descriptor is readable SUDO_PLUGIN_EV_WRITE callback is run when the file descriptor is writable SUDO_PLUGIN_EV_PERSIST event is persistent and remains enabled until explicitly deleted SUDO_PLUGIN_EV_SIGNAL callback is run when the specified signal is received The SUDO_PLUGIN_EV_PERSIST flag may be ORed with any of the event types. It is also possible to OR SUDO_PLUGIN_EV_READ and SUDO_PLUGIN_EV_WRITE together to run the callback when a descriptor is ready to be either read from or written to. All other event values are mutually exclusive. _sudo_plugin_ev_callback_t_ _callback_ typedef void (*sudo_plugin_ev_callback_t)(int fd, int what, void *closure); The function to call when an event is triggered. The **callback**() function is run with the following arguments: _fd_ The file or socket descriptor for I/O-based events or the signal number for signal events. _what_ The event type that triggered that callback. For events that have multiple event types (for example SUDO_PLUGIN_EV_READ and SUDO_PLUGIN_EV_WRITE) or have an associated timeout, _what_ can be used to determine why the callback was run. _closure_ The generic pointer that was specified in the **set**() function. _closure_ A generic pointer that will be passed to the callback function. The **set**() function returns 1 on success, and -1 if a error occurred. _add_ int (*add)(struct sudo_plugin_event *pev, struct timespec *timeout); The **add**() function adds the event _pev_ to **sudo**'s event loop. The event must have previ‐ ously been initialized via the **set**() function. If the _timeout_ argument is not NULL, it should specify a (relative) timeout after which the event will be triggered if the main event criteria has not been met. This is often used to implement an I/O timeout where the event will fire if a descriptor is not ready within a certain time period. If the event is already present in the event loop, its _timeout_ will be adjusted to match the new value, if any. The **add**() function returns 1 on success, and -1 if a error occurred. _del_ int (*del)(struct sudo_plugin_event *pev); The **del**() function deletes the event _pev_ from **sudo**'s event loop. Deleted events can be added back via the **add**() function. The **del**() function returns 1 on success, and -1 if a error occurred. _pending_ int (*pending)(struct sudo_plugin_event *pev, int events, struct timespec *ts); The **pending**() function can be used to determine whether one or more events is pending. The _events_ argument specifies which events to check for. See the **set**() function for a list of valid event types. If SUDO_PLUGIN_EV_TIMEOUT is specified in _events_, the event has an associated timeout and the _ts_ pointer is non-NULL, it will be filled in with the remaining time. _fd_ int (*fd)(struct sudo_plugin_event *pev); The **fd**() function returns the descriptor or signal number associated with the event _pev_. _setbase_ void (*setbase)(struct sudo_plugin_event *pev, void *base); The **setbase**() function sets the underlying event _base_ for _pev_ to the specified value. This can be used to move an event created via **event_alloc**() to a new event loop allo‐ cated by sudo's event subsystem. If _base_ is NULL, _pev_'s event base is reset to the de‐ fault value, which corresponds to **sudo**'s main event loop. Using this function requires linking the plugin with the sudo_util library. It is unlikely to be used outside of the **sudoers **plugin. _loopbreak_ void (*loopbreak)(struct sudo_plugin_event *pev); The **loopbreak**() function causes **sudo**'s event loop to exit immediately and the running command to be terminated. _free_ void (*free)(struct sudo_plugin_event *pev); The **free**() function deletes the event _pev_ from the event loop and frees the memory as‐ sociated with it. ### Remote command execution The **sudo **front-end does not support running remote commands. However, starting with **sudo** 1.8.8, the **-h **option may be used to specify a remote host that is passed to the policy plu‐ gin. A plugin may also accept a _runas_user_ in the form of “user@hostname” which will work with older versions of **sudo**. It is anticipated that remote commands will be supported by ex‐ ecuting a “helper” program. The policy plugin should setup the execution environment such that the **sudo **front-end will run the helper which, in turn, will connect to the remote host and run the command. For example, the policy plugin could utilize **ssh **to perform remote command execution. The helper program would be responsible for running **ssh **with the proper options to use a private key or certificate that the remote host will accept and run a program on the remote host that would setup the execution environment accordingly. Remote **sudoedit **functionality must be handled by the policy plugin, not **sudo **itself as the front-end has no knowledge that a remote command is being executed. This may be addressed in a future revision of the plugin API. ### Conversation API If the plugin needs to interact with the user, it may do so via the **conversation**() function. A plugin should not attempt to read directly from the standard input or the user's terminal (neither of which are guaranteed to exist). The caller must include a trailing newline in _msg_ if one is to be printed. A **printf**()-style function is also available that can be used to display informational or er‐ ror messages to the user, which is usually more convenient for simple messages where no use input is required. _Conversation_ _function_ _structures_ The conversation function takes as arguments pointers to the following structures: struct sudo_conv_message { #define SUDO_CONV_PROMPT_ECHO_OFF 0x0001 /* do not echo user input */ #define SUDO_CONV_PROMPT_ECHO_ON 0x0002 /* echo user input */ #define SUDO_CONV_ERROR_MSG 0x0003 /* error message */ #define SUDO_CONV_INFO_MSG 0x0004 /* informational message */ #define SUDO_CONV_PROMPT_MASK 0x0005 /* mask user input */ #define SUDO_CONV_PROMPT_ECHO_OK 0x1000 /* flag: allow echo if no tty */ #define SUDO_CONV_PREFER_TTY 0x2000 /* flag: use tty if possible */ int msg_type; int timeout; const char *msg; }; #define SUDO_CONV_REPL_MAX 1023 struct sudo_conv_reply { char *reply; }; typedef int (*sudo_conv_callback_fn_t)(int signo, void *closure); struct sudo_conv_callback { unsigned int version; void *closure; sudo_conv_callback_fn_t on_suspend; sudo_conv_callback_fn_t on_resume; }; Pointers to the **conversation**() and **printf**()-style functions are passed in to the plugin's **open**() function when the plugin is initialized. The following type definitions can be used in the declaration of the **open**() function: typedef int (*sudo_conv_t)(int num_msgs, const struct sudo_conv_message msgs[], struct sudo_conv_reply replies[], struct sudo_conv_callback *callback); typedef int (*sudo_printf_t)(int msg_type, const char * restrict fmt, ...); To use the **conversation**() function, the plugin must pass an array of _struct_ _sudo_conv_message_ and _struct_ _sudo_conv_reply_. There must be a _struct_ _sudo_conv_message_ and _struct_ _sudo_conv_reply_ for each message in the conversation, that is, both arrays must have the same number of elements. Each _struct_ _sudo_conv_reply_ must have its _reply_ member initialized to NULL. The _struct_ _sudo_conv_callback_ pointer, if not NULL, should contain function pointers to be called when the **sudo **process is suspended and/or resumed during conversation input. The _on_suspend_ and _on_resume_ functions are called with the signal that caused **sudo **to be sus‐ pended and the _closure_ pointer from the _struct_ _sudo_conv_callback_. These functions should return 0 on success and -1 on error. On error, the conversation will end and the conversa‐ tion function will return a value of -1. The intended use is to allow the plugin to release resources, such as locks, that should not be held indefinitely while suspended and then reac‐ quire them when the process is resumed. The functions are not actually invoked from within a signal handler. The _msg_type_ must be set to one of the following values: SUDO_CONV_PROMPT_ECHO_OFF Prompt the user for input with echo disabled; this is generally used for passwords. The reply will be stored in the _replies_ array, and it will never be NULL. SUDO_CONV_PROMPT_ECHO_ON Prompt the user for input with echo enabled. The reply will be stored in the _replies_ array, and it will never be NULL. SUDO_CONV_ERROR_MSG Display an error message. The message is written to the standard error unless the SUDO_CONV_PREFER_TTY flag is set, in which case it is written to the user's terminal if possible. SUDO_CONV_INFO_MSG Display a message. The message is written to the standard output unless the SUDO_CONV_PREFER_TTY flag is set, in which case it is written to the user's terminal if possible. SUDO_CONV_PROMPT_MASK Prompt the user for input but echo an asterisk character for each character read. The reply will be stored in the _replies_ array, and it will never be NULL. This can be used to provide visual feedback to the user while reading sensitive information that should not be displayed. In addition to the above values, the following flag bits may also be set: SUDO_CONV_PROMPT_ECHO_OK Allow input to be read when echo cannot be disabled when the message type is SUDO_CONV_PROMPT_ECHO_OFF or SUDO_CONV_PROMPT_MASK. By default, **sudo **will refuse to read input if the echo cannot be disabled for those message types. SUDO_CONV_PREFER_TTY When displaying a message via SUDO_CONV_ERROR_MSG or SUDO_CONV_INFO_MSG, try to write the message to the user's terminal. If the terminal is unavailable, the standard error or standard output will be used, depending upon whether SUDO_CONV_ERROR_MSG or SUDO_CONV_INFO_MSG was used. The user's terminal is always used when possible for in‐ put, this flag is only used for output. The _timeout_ in seconds until the prompt will wait for no more input. A zero value implies an infinite timeout. The plugin is responsible for freeing the reply buffer located in each _struct_ _sudo_conv_reply_, if it is not NULL. SUDO_CONV_REPL_MAX represents the maximum length of the reply buffer (not including the trailing NUL character). In practical terms, this is the longest password **sudo **will support. The **printf**()-style function uses the same underlying mechanism as the **conversation**() function but only supports SUDO_CONV_INFO_MSG and SUDO_CONV_ERROR_MSG for the _msg_type_ parameter. It can be more convenient than using the **conversation**() function if no user reply is needed and supports standard **printf**() escape sequences. See the sample plugin for an example of the **conversation**() function usage. ### Plugin invocation order As of **sudo **1.9.0, the plugin **open**() and **close**() functions are called in the following order: 1. audit open 2. policy open 3. approval open 4. approval close 5. I/O log open 6. command runs 7. command exits 8. I/O log close 9. policy close 10. audit close 11. sudo exits Prior to **sudo **1.9.0, the I/O log **close**() function was called _after_ the policy **close**() func‐ tion. ### Sudoers group plugin API The **sudoers **plugin supports its own plugin interface to allow non-Unix group lookups. This can be used to query a group source other than the standard Unix group database. Two sample group plugins are bundled with **sudo**, _group_file_, and _system_group_, are detailed in [_sudoers_(5)](https://www.chedong.com/phpMan.php/man/sudoers/5/markdown). Third party group plugins include a QAS AD plugin available from Quest Software. A group plugin must declare and populate a _struct_ _sudoers_group_plugin_ in the global scope. This structure contains pointers to the functions that implement plugin initialization, cleanup, and group lookup. struct sudoers_group_plugin { unsigned int version; int (*init)(int version, sudo_printf_t sudo_plugin_printf, char *const argv[]); void (*cleanup)(void); int (*query)(const char *user, const char *group, const struct passwd *pwd); }; A _struct_ _sudoers_group_plugin_ has the following fields: _version_ The _version_ field should be set to GROUP_API_VERSION. This allows **sudoers **to determine the API version the group plugin was built against. _init_ int (*init)(int version, sudo_printf_t sudo_plugin_printf, char *const argv[]); The **init**() function is called after _sudoers_ has been parsed but before any policy checks. It returns 1 on success, 0 on failure (or if the plugin is not configured), and -1 if a error occurred. If an error occurs, the plugin may call the **plugin_printf**() function with SUDO_CONF_ERROR_MSG to present additional error informa‐ tion to the user. The function arguments are as follows: _version_ The version passed in by **sudoers **allows the plugin to determine the major and mi‐ nor version number of the group plugin API supported by **sudoers**. _plugin_printf_ A pointer to a **printf**()-style function that may be used to display informational or error message to the user. Returns the number of characters printed on suc‐ cess and -1 on failure. _argv_ A NULL-terminated array of arguments generated from the _group_plugin_ option in _sudoers_. If no arguments were given, _argv_ will be NULL. _cleanup_ void (*cleanup)(); The **cleanup**() function is called when **sudoers **has finished its group checks. The plu‐ gin should free any memory it has allocated and close open file handles. _query_ int (*query)(const char *user, const char *group, const struct passwd *pwd); The **query**() function is used to ask the group plugin whether _user_ is a member of _group_. The function arguments are as follows: _user_ The name of the user being looked up in the external group database. _group_ The name of the group being queried. _pwd_ The password database entry for _user_, if any. If _user_ is not present in the password database, _pwd_ will be NULL. _Group_ _API_ _Version_ _Macros_ /* Sudoers group plugin version major/minor */ #define GROUP_API_VERSION_MAJOR 1 #define GROUP_API_VERSION_MINOR 0 #define GROUP_API_VERSION ((GROUP_API_VERSION_MAJOR << 16) | \ GROUP_API_VERSION_MINOR) For getters and setters see the “Policy plugin API”. ## PLUGIN API CHANGELOG The following revisions have been made to the Sudo Plugin API. Version 1.0 Initial API version. Version 1.1 (sudo 1.8.0) The I/O logging plugin's **open**() function was modified to take the _command_info_ list as an argument. Version 1.2 (sudo 1.8.5) The Policy and I/O logging plugins' **open**() functions are now passed a list of plugin parameters if any are specified in [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown). A simple hooks API has been introduced to allow plugins to hook in to the system's en‐ vironment handling functions. The **init_session**() Policy plugin function is now passed a pointer to the user environ‐ ment which can be updated as needed. This can be used to merge in environment vari‐ ables stored in the PAM handle before a command is run. Version 1.3 (sudo 1.8.7) Support for the _exec_background_ entry has been added to the _command_info_ list. The _max_groups_ and _plugin_dir_ entries were added to the _settings_ list. The **version**() and **close**() functions are now optional. Previously, a missing **version**() or **close**() function would result in a crash. If no policy plugin **close**() function is defined, a default **close**() function will be provided by the **sudo **front-end that dis‐ plays a warning if the command could not be executed. The **sudo **front-end now installs default signal handlers to trap common signals while the plugin functions are run. Version 1.4 (sudo 1.8.8) The _remote_host_ entry was added to the _settings_ list. Version 1.5 (sudo 1.8.9) The _preserve_fds_ entry was added to the _command_info_ list. Version 1.6 (sudo 1.8.11) The behavior when an I/O logging plugin returns an error (-1) has changed. Previously, the **sudo **front-end took no action when the **log_ttyin**(), **log_ttyout**(), **log_stdin**(), **log_stdout**(), or **log_stderr**() function returned an error. The behavior when an I/O logging plugin returns 0 has changed. Previously, output from the command would be displayed to the terminal even if an output logging function re‐ turned 0. Version 1.7 (sudo 1.8.12) The _plugin_path_ entry was added to the _settings_ list. The _debug_flags_ entry now starts with a debug file path name and may occur multiple times if there are multiple plugin-specific Debug lines in the [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown) file. Version 1.8 (sudo 1.8.15) The _sudoedit_checkdir_ and _sudoedit_follow_ entries were added to the _command_info_ list. The default value of _sudoedit_checkdir_ was changed to true in sudo 1.8.16. The sudo **conversation**() function now takes a pointer to a _struct_ _sudo_conv_callback_ as its fourth argument. The _sudo_conv_t_ definition has been updated to match. The plugin must specify that it supports plugin API version 1.8 or higher to receive a conversa‐ tion function pointer that supports this argument. Version 1.9 (sudo 1.8.16) The _execfd_ entry was added to the _command_info_ list. Version 1.10 (sudo 1.8.19) The _umask_ entry was added to the _user_info_ list. The _iolog_group_, _iolog_mode_, and _iolog_user_ entries were added to the _command_info_ list. Version 1.11 (sudo 1.8.20) The _timeout_ entry was added to the _settings_ list. Version 1.12 (sudo 1.8.21) The **change_winsize**() function was added to _struct_ _io_plugin_. Version 1.13 (sudo 1.8.26) The **log_suspend**() function was added to _struct_ _io_plugin_. Version 1.14 (sudo 1.8.29) The _umask_override_ entry was added to the _command_info_ list. Version 1.15 (sudo 1.9.0) The _cwd_optional_ entry was added to the _command_info_ list. The **event_alloc**() function was added to _struct_ _policy_plugin_ and _struct_ _io_plugin_. The _errstr_ argument was added to the policy and I/O plugin functions which the plugin function can use to return an error string. This string may be used by the audit plu‐ gin to report failure or error conditions set by the other plugins. The **close**() function is now is called regardless of whether or not a command was actu‐ ally executed. This makes it possible for plugins to perform cleanup even when a com‐ mand was not run. SUDO_CONV_REPL_MAX has increased from 255 to 1023 bytes. Support for audit and approval plugins was added. Version 1.16 (sudo 1.9.3) Initial resource limit values were added to the _user_info_ list. The _cmnd_chroot_ and _cmnd_cwd_ entries were added to the _settings_ list. Version 1.17 (sudo 1.9.4) The **event_alloc**() function was added to _struct_ _audit_plugin_ and _struct_ _approval_plugin_. Version 1.18 (sudo 1.9.9) The policy may now set resource limit values in the _command_info_ list. The _intercept_ and _log_subcmds_ entries were added to the _command_info_ list. Version 1.19 (sudo 1.9.11) The _intercept_ptrace_ and _intercept_setid_ entries were added to the _settings_ list. The _apparmor_profile_ and _use_ptrace_ entries were added to the _command_info_ list. Version 1.20 (sudo 1.9.12) The _update_ticket_ entry was added to the _settings_ list. The _intercept_verify_ entry was added to the _command_info_ list. Version 1.21 (sudo 1.9.13) The _sudoedit_nfiles_ entry was added to the _command_info_ list. ## SEE ALSO [_sudo.conf_(5)](https://www.chedong.com/phpMan.php/man/sudo.conf/5/markdown), [_sudoers_(5)](https://www.chedong.com/phpMan.php/man/sudoers/5/markdown), [_sudo_(8)](https://www.chedong.com/phpMan.php/man/sudo/8/markdown) ## AUTHORS Many people have worked on **sudo **over the years; this version consists of code written primar‐ ily by: Todd C. Miller See the CONTRIBUTORS.md file in the **sudo **distribution (‐ tors/) for an exhaustive list of people who have contributed to **sudo**. ## BUGS If you believe you have found a bug in **sudo**, you can submit a bug report at ## SUPPORT Limited free support is available via the sudo-users mailing list, see to subscribe or search the archives. ## DISCLAIMER **sudo **is provided “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 dis‐ claimed. See the LICENSE.md file distributed with **sudo **or for complete details. Sudo 1.9.15p5 July 10, 2023 [_SUDO_PLUGIN_(5)](https://www.chedong.com/phpMan.php/man/SUDOPLUGIN/5/markdown)