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.
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 plugin_printf, char * const settings[],
char * const user_info[], char * const user_env[],
char * const plugin_options[]);
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[]);
int (*list)(int argc, char * const argv[], int verbose,
const char *list_user);
int (*validate)(void);
void (*invalidate)(int remove);
int (*init_session)(struct passwd *pwd, char **user_env[]);
void (*register_hooks)(int version,
int (*register_hook)(struct sudo_hook *hook));
void (*deregister_hooks)(int version,
int (*deregister_hook)(struct sudo_hook *hook));
};
The policy_plugin struct has the following fields:
This allows sudo to determine the API version the plugin was built against.
int (*open)(unsigned int version, sudo_conv_t conversation,
sudo_printf_t plugin_printf, char * const settings[],
char * const user_info[], char * const user_env[],
char * const plugin_options[]);
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 Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
The function arguments are as follows:
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.
Additional settings may be added in the future so the plugin should silently ignore settings that it does not recognize.
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.
NOTE: 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.
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.
void (*close)(int exit_status, int error);
The Fn close function is called when the command being run by sudo finishes.
The function arguments are as follows:
If no Fn close function is defined, no I/O logging plugins are loaded, and neither the timeout not 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.
int (*show_version)(int verbose);
The Fn 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 Fn conversation or Fn plugin_printf function using SUDO_CONV_INFO_MSG If the user requests detailed version 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.
int (*check_policy)(int argc, char * const argv[],
char *env_add[], char **command_info[],
char **argv_out[], char **user_env_out[]);
The Fn 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 Fn 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 privileges. 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 should choose the editor to be used, potentially from a variable in the user's environment, such as EDITOR and include it in argv_out (note that environment variables may include command line flags). The files to be edited should be copied from argv into argv_out separated from the editor and its arguments by a ``-- '' element. The ``-- '' will be removed by sudo before the editor is executed. The plugin should also set sudoedit=true in the command_info list.
The Fn 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 unsupported 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 Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
The function arguments are as follows:
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.
For this to work seamlessly, the operating system must support the automatic restarting of system calls. Unfortunately, not all operating systems do this by default, and even those that do may have bugs. For example, macOS fails to restart the Fn tcgetattr and Fn 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) 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 enabled.
Unsupported values will be ignored.
int (*list)(int argc, char * const argv[],
int verbose, const char *list_user);
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 Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
Privileges should be output via the Fn conversation or Fn plugin_printf function using SUDO_CONV_INFO_MSG
int (*validate)(void);
The Fn validate function is called when sudo is run with the -v flag. For policy plugins such as sudoers that cache authentication credentials, this function will validate and cache the credentials.
The Fn 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 optionally call the Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
void (*invalidate)(int remove);
The Fn invalidate function is called when sudo is called with the -k or -K flag. For policy plugins such as sudoers that cache authentication credentials, this function will invalidate the credentials. If the remove flag is set, the plugin may remove the credentials instead of simply invalidating them.
The Fn invalidate function should be NULL if the plugin does not support credential caching.
int (*init_session)(struct passwd *pwd, char **user_envp[);
The Fn init_session function is called before sudo sets up the execution environment for the command. It is run in the parent sudo process and before any uid or gid changes. This can be used to perform session setup that is not supported by command_info such as opening the PAM session. The Fn close function can be used to tear down the session that was opened by init_session
The pwd argument points to a passwd struct for the user the command will be run as if the uid the command will run as was found in the password database, otherwise it will be NULL
The user_env argument points to the environment the command will run in, in the form of a NULL -terminated vector of ``name=value'' strings. This is the same string passed back to the front end via the Policy Plugin's user_env_out parameter. If the Fn init_session function needs to modify the user environment, it should update the pointer stored in user_env The expected use case is to merge the contents of the PAM environment (if any) with the contents of user_env NOTE: the user_env 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 Failure to do so may result in a crash.
Returns 1 on success, 0 on failure and -1 on error. On error, the plugin may optionally call the Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
void (*register_hooks)(int version, int (*register_hook)(struct sudo_hook *hook));
The Fn 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 Fn 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 major version in struct hook does not match the front end's major hook API version.
See the Sx Hook function API section below for more information about hooks.
NOTE: the Fn 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.
void (*deregister_hooks)(int version, int (*deregister_hook)(struct sudo_hook *hook));
The Fn 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 Fn deregister_hook function should be used to deregister any hooks that were put in place by the Fn 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 Sx Hook function API section below for more information about hooks.
NOTE: the Fn 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.
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)
#define SUDO_API_VERSION_SET_MINOR(vp, n) do { \
*(vp) = (*(vp) & 0xffff0000) | (n); \
} while(0)
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 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[]);
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);
int (*log_ttyout)(const char *buf, unsigned int len);
int (*log_stdin)(const char *buf, unsigned int len);
int (*log_stdout)(const char *buf, unsigned int len);
int (*log_stderr)(const char *buf, unsigned int len);
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);
int (*log_suspend)(int signo);
};
When an I/O plugin is loaded, sudo runs the command in a pseudo-tty. This makes it possible 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 capture the I/O for logging before passing it on.
The log_ttyin function receives the raw user input from the terminal device (note that this will include input even when echo is disabled, such as when a password is read). The log_ttyout function receives output from the pseudo-tty that is suitable for replaying the user's session at a later time. The Fn log_stdin , Fn log_stdout and Fn 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 receive 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.
The io_plugin struct has the following fields:
This allows sudo to determine the API version the plugin was built against.
int (*open)(unsigned int version, sudo_conv_t conversation,
sudo_printf_t 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 Fn open function is run before the Fn log_ttyin , Fn log_ttyout , Fn log_stdin , Fn log_stdout , Fn log_stderr , Fn log_suspend , Fn change_winsize , or Fn show_version functions are called. It is only called if the version is being requested or if the policy plugin's Fn 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 Fn conversation or Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
The function arguments are as follows:
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 Sx Policy plugin API section for a list of all possible settings.
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 Sx Policy plugin API section for a list of all possible 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.
NOTE: 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.
void (*close)(int exit_status, int error);
The Fn close function is called when the command being run by sudo finishes.
The function arguments are as follows:
int (*show_version)(int verbose);
The Fn 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 Fn conversation or Fn plugin_printf function using SUDO_CONV_INFO_MSG If the user requests detailed version 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.
int (*log_ttyin)(const char *buf, unsigned int len);
The Fn 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:
int (*log_ttyout)(const char *buf, unsigned int len);
The Fn log_ttyout function is called whenever data can be read from the command but before 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 running command) or -1 if an error occurred.
The function arguments are as follows:
int (*log_stdin)(const char *buf, unsigned int len);
The Fn 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:
int (*log_stdout)(const char *buf, unsigned int len);
The Fn 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 command) or -1 if an error occurred.
The function arguments are as follows:
int (*log_stderr)(const char *buf, unsigned int len);
The Fn 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 command) or -1 if an error occurred.
The function arguments are as follows:
int (*change_winsize)(unsigned int lines, unsigned int cols);
The Fn 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 error occurred, in which case no further calls to Fn change_winsize will be made,
int (*log_suspend)(int signo);
The Fn log_suspend function is called whenever a command is suspended or resumed. The Fa signo argument is either the signal that caused the command to be suspended or SIGCONT if the command was resumed. Logging 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 Fn log_suspend will be made,
I/O Plugin Version Macros
Same as for the Sx Policy plugin API .
If a fatal signal is received before the command is executed, sudo will call the plugin's Fn 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 Fn close function. An exception to this is SIGPIPE which is ignored until the command is executed.
A plugin may temporarily install its own signal handlers but must restore the original handler before the plugin function returns.
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;
};
The sudo_hook structure has the following fields:
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.
typedef int (*sudo_hook_fn_unsetenv_t)(const char *name, void *closure);
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.
typedef int (*sudo_hook_fn_putenv_t)(char *string, void *closure);
If the registered hook does not match the typedef the results are unspecified.
The hook_fn field should be set to the plugin's hook implementation. The actual function 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:
Note that it is very easy to create an infinite loop when hooking C library functions. For example, a getenv(3) hook that calls the snprintf(3) function may create a loop if the snprintf(3) implementation calls getenv(3) 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 example:
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 Sx Policy plugin API .
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.
Note that 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.
A Fn printf Ns -style function is also available that can be used to display informational or error 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 255
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 Fn conversation and Fn printf Ns -style functions are passed in to the plugin's Fn open function when the plugin is initialized. The following type definitions can be used in the declaration of the Fn 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 *fmt, ...);
To use the Fn conversation function, the plugin must pass an array of sudo_conv_message and sudo_conv_reply structures. 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 Fa on_suspend and Fa on_resume functions are called with the signal that caused sudo to be suspended and the Fa 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 conversation 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 reacquire them when the process is resumed. Note that the functions are not actually invoked from within a signal handler.
The msg_type must be set to one of the following values:
In addition to the above values, the following flag bits may also be set:
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. It is also useful as a maximum value for the Fn memset_s function when clearing passwords filled in by the conversation function.
The Fn printf Ns -style function uses the same underlying mechanism as the Fn 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 Fn conversation function if no user reply is needed and supports standard Fn printf escape sequences.
See the sample plugin for an example of the Fn conversation function usage.
A group plugin must declare and populate a sudoers_group_plugin struct 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_printf,
char *const argv[]);
void (*cleanup)(void);
int (*query)(const char *user, const char *group,
const struct passwd *pwd);
};
The sudoers_group_plugin struct has the following fields:
This allows sudoers to determine the API version the group plugin was built against.
int (*init)(int version, sudo_printf_t plugin_printf,
char *const argv[]);
The Fn 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 Fn plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user.
The function arguments are as follows:
void (*cleanup)();
The Fn cleanup function is called when sudoers has finished its group checks. The plugin should free any memory it has allocated and close open file handles.
int (*query)(const char *user, const char *group,
const struct passwd *pwd);
The Fn query function is used to ask the group plugin whether user is a member of group
The function arguments are as follows:
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
Sx Policy plugin API .
A simple hooks API has been introduced to allow plugins to hook in to the system's environment handling functions.
The init_session Policy plugin function is now passed a pointer to the user environment which can be updated as needed. This can be used to merge in environment variables stored in the PAM handle before a command is run.
The max_groups and plugin_dir entries were added to the settings list.
The Fn version and Fn close functions are now optional. Previously, a missing Fn version or Fn close function would result in a crash. If no policy plugin Fn close function is defined, a default Fn close function will be provided by the sudo front end that displays 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.
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 returned 0.
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.conf5file.
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 conversation function pointer that supports this argument.
An Todd C. Miller
See the CONTRIBUTORS file in the sudo distribution (https://www.sudo.ws/contributors.html) for an exhaustive list of people who have contributed to sudo