SUDO_PLUGIN(1m) MAINTENANCE COMMANDS SUDO_PLUGIN(1m) NNAAMMEE sudo_plugin - Sudo Plugin API DDEESSCCRRIIPPTTIIOONN Starting with version 1.8, ssuuddoo supports a plugin API for policy and session logging. By default, the _s_u_d_o_e_r_s policy plugin and an associated I/O logging plugin are used. Via the plugin API, ssuuddoo can be configured to use alternate policy and/or I/O logging plugins provided by third parties. The plugins to be used are specified via the _/_e_t_c_/_s_u_d_o_._c_o_n_f 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. TThhee ssuuddoo..ccoonnff FFiillee The _/_e_t_c_/_s_u_d_o_._c_o_n_f file contains plugin configuration directives. Currently, the only supported keyword is the Plugin directive, which causes a plugin plugin to be loaded. A Plugin line consists of the Plugin keyword, followed by the _s_y_m_b_o_l___n_a_m_e and the _p_a_t_h to the shared object containing the plugin. The _s_y_m_b_o_l___n_a_m_e is the name of the struct policy_plugin or struct io_plugin in the plugin shared object. The _p_a_t_h may be fully qualified or relative. If not fully qualified it is relative to the _/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c directory. Any additional parameters after the _p_a_t_h are ignored. Lines that don't begin with Plugin or Path are silently ignored. The same shared object may contain multiple plugins, each with a different symbol name. The shared object file must be owned by uid 0 and only writable by its owner. Because of ambiguities that arise from composite policies, only a single policy plugin may be specified. This limitation does not apply to I/O plugins. # # Default /etc/sudo.conf file # # Format: # Plugin plugin_name plugin_path # Path askpass /path/to/askpass # # The plugin_path is relative to /usr/local/libexec unless # fully qualified. # The plugin_name corresponds to a global symbol in the plugin # that contains the plugin interface structure. # Plugin sudoers_policy sudoers.so Plugin sudoers_io sudoers.so PPoolliiccyy PPlluuggiinn AAPPII A policy plugin must declare and populate a policy_plugin struct in the global scope. This structure contains pointers to the functions that implement the ssuuddoo policy checks. The name of the symbol should be specified in _/_e_t_c_/_s_u_d_o_._c_o_n_f along with a path to the plugin so that ssuuddoo 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 plugin_printf, char * const settings[], char * const user_info[], char * const user_env[]); 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); }; The policy_plugin struct 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 ssuuddoo to determine the API version the plugin was built against. open 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[]); 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, ssuuddoo 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 ssuuddoo allows the plugin to determine the major and minor version number of the plugin API supported by ssuuddoo. conversation A pointer to the conversation function that can be used by the plugin to interact with the user (see below). 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 below). Returns the number of characters printed on success and -1 on failure. settings A vector of user-supplied ssuuddoo settings in the form of "name=value" strings. The vector is terminated by a NULL pointer. These settings correspond to flags the user specified when running ssuuddoo. As such, they will only be present when the corresponding flag has been specified on the command line. When parsing _s_e_t_t_i_n_g_s, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. debug_level=number A numeric debug level, from 1-9, if specified via the -D flag. runas_user=string The user name or uid to to run the command as, if specified via the -u flag. runas_group=string The group name or gid to to run the command as, if specified via the -g flag. prompt=string The prompt to use when requesting a password, if specified via the -p flag. set_home=bool Set to true if the user specified the -H flag. If true, set the HOME environment variable to the target user's home directory. preserve_environment=bool Set to true if the user specified the -E flag, indicating that the user wishes to preserve the environment. run_shell=bool Set to true if the user specified the -s flag, indicating that the user wishes to run a shell. login_shell=bool Set to true if the user specified the -i flag, indicating that the user wishes to run a login shell. implied_shell=bool If the user does not specify a program on the command line, ssuuddoo will pass the plugin the path to the user's shell and set _i_m_p_l_i_e_d___s_h_e_l_l to true. This allows ssuuddoo with no arguments to be used similarly to _s_u(1). If the plugin does not to support this usage, it may return a value of -2 from the check_policy function, which will cause ssuuddoo to print a usage message and exit. preserve_groups=bool Set to true if the user specified the -P flag, indicating that the user wishes to preserve the group vector instead of setting it based on the runas user. ignore_ticket=bool Set to true if the user specified the -k flag along with a command, indicating that the user wishes to ignore any cached authentication credentials. noninteractive=bool Set to true if the user specified the -n flag, indicating that ssuuddoo should operate in non-interactive mode. The plugin may reject a command run in non-interactive mode if user interaction is required. login_class=string BSD login class to use when setting resource limits and nice value, if specified by the -c flag. selinux_role=string SELinux role to use when executing the command, if specified by the -r flag. selinux_type=string SELinux type to use when executing the command, if specified by the -t flag. bsdauth_type=string Authentication type, if specified by the -a flag, to use on systems where BSD authentication is supported. 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. progname=string The command name that sudo was run as, typically "sudo" or "sudoedit". sudoedit=bool Set to true when the -e flag is is specified or if invoked as ssuuddooeeddiitt. The plugin shall substitute an editor into _a_r_g_v in the _c_h_e_c_k___p_o_l_i_c_y function or return -2 with a usage error if the plugin does not support _s_u_d_o_e_d_i_t. For more information, see the _c_h_e_c_k___p_o_l_i_c_y section. closefrom=number If specified, the user has requested via the -C flag that ssuuddoo close all files descriptors with a value of _n_u_m_b_e_r or higher. The plugin may optionally pass this, or another value, back in the _c_o_m_m_a_n_d___i_n_f_o list. Additional settings may be added in the future so the plugin should silently ignore 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 _u_s_e_r___i_n_f_o, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. user=string The name of the user invoking ssuuddoo. uid=uid_t The real user ID of the user invoking ssuuddoo. gid=gid_t The real group ID of the user invoking ssuuddoo. groups=list The user's supplementary group list formatted as a string of comma-separated group IDs. cwd=string The user's current working directory. 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=. host=string The local machine's hostname as returned by the gethostname() 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. cols=int The number of columns the user's terminal supports. If there is no terminal device available, a default value of 80 is used. user_env The user's environment in the form of a NULL-terminated vector of "name=value" strings. When parsing _u_s_e_r___e_n_v, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. close void (*close)(int exit_status, int error); The close function is called when the command being run by ssuuddoo finishes. The function arguments are as follows: exit_status The command's exit status, as returned by the _w_a_i_t(2) system call. 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 _e_x_e_c_v_e(2) system call. The plugin is responsible for displaying error information via the conversation or plugin_printf function. If the command was successfully executed, the value of error is 0. show_version int (*show_version)(int verbose); The show_version function is called by ssuuddoo 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 version information, the verbose flag will be set. check_policy int (*check_policy)(int argc, char * const argv[] char *env_add[], char **command_info[], char **argv_out[], char **user_env_out[]); The _c_h_e_c_k___p_o_l_i_c_y function is called by ssuuddoo to determine whether the user is allowed to run the specified commands. If the _s_u_d_o_e_d_i_t option was enabled in the _s_e_t_t_i_n_g_s array passed to the _o_p_e_n function, the user has requested _s_u_d_o_e_d_i_t mode. _s_u_d_o_e_d_i_t is a mechanism for editing one or more files where an editor is run with the user's credentials instead of with elevated privileges. ssuuddoo 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 ssuuddooeeddiitt, it should choose the editor to be used, potentially from a variable in the user's environment, such as EDITOR, and include it in _a_r_g_v___o_u_t (note that environment variables may include command line flags). The files to be edited should be copied from _a_r_g_v into _a_r_g_v___o_u_t, separated from the editor and its arguments by a "--" element. The "--" will be removed by ssuuddoo before the editor is executed. The plugin should also set _s_u_d_o_e_d_i_t_=_t_r_u_e in the _c_o_m_m_a_n_d___i_n_f_o list. The _c_h_e_c_k___p_o_l_i_c_y 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 ssuuddooeeddiitt was specified but is unsupported by the plugin. In the latter case, ssuuddoo 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: argc The number of elements in _a_r_g_v, 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 _e_x_e_c_v_e_(_) system call. The vector is terminated 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 _e_n_v___a_d_d, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. command_info Information about the command being run in the form of "name=value" strings. These values are used by ssuuddoo 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 ssuuddoo: command=string Fully qualified path to the command to be executed. runas_uid=uid User ID to run the command as. runas_euid=uid Effective user ID to run the command as. If not specified, the value of _r_u_n_a_s___u_i_d is used. runas_gid=gid Group ID to run the command as. runas_egid=gid Effective group ID to run the command as. If not specified, the value of _r_u_n_a_s___g_i_d is used. runas_groups=list The supplementary group vector to use for the command in the form of a comma-separated list of group IDs. If _p_r_e_s_e_r_v_e___g_r_o_u_p_s is set, this option is ignored. login_class=string BSD login class to use when setting resource limits and nice value (optional). This option is only set on systems that support login classes. preserve_groups=bool If set, ssuuddoo will preserve the user's group vector instead of initializing the group vector based on runas_user. cwd=string The current working directory to change to when executing the command. noexec=bool If set, prevent the command from executing other programs. chroot=string The root directory to use when running the command. nice=int Nice value (priority) to use when executing the command. The nice value, if specified, overrides the priority associated with the _l_o_g_i_n___c_l_a_s_s on BSD systems. umask=octal The file creation mask to use 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. timeout=int Command timeout. If non-zero then when the timeout expires the command will be killed. sudoedit=bool Set to true when in _s_u_d_o_e_d_i_t mode. The plugin may enable _s_u_d_o_e_d_i_t mode even if ssuuddoo was not invoked as ssuuddooeeddiitt. This allows the plugin to perform command substitution and transparently enable _s_u_d_o_e_d_i_t when the user attempts to run an editor. closefrom=number If specified, ssuuddoo will close all files descriptors with a value of _n_u_m_b_e_r or higher. 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_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 ignore 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 input 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 error 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 input. 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. use_pty=bool Allocate a pseudo-tty to run the command in, regardless of whether or not I/O logging is in use. By default, ssuuddoo will only run the command in a pty when an I/O log plugin is loaded. set_utmp=bool Create a utmp (or utmpx) entry when a pseudo-tty is allocated. By default, 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. utmp_user=string User name to use when constructing a new utmp (or utmpx) entry when _s_e_t___u_t_m_p 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, ssuuddoo 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 _e_x_e_c_v_e_(_) system call when executing 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. list int (*list)(int verbose, const char *list_user, int argc, char * const argv[]); 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 plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user. Privileges should be output via the conversation or plugin_printf function using SUDO_CONV_INFO_MSG. verbose Flag indicating whether to list in verbose mode or not. list_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. argc The number of elements in _a_r_g_v, 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 _e_x_e_c_v_e_(_) system 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. validate int (*validate)(void); The validate function is called when ssuuddoo is run with the -v flag. For policy plugins such as _s_u_d_o_e_r_s 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 optionally call the conversation or plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user. invalidate void (*invalidate)(int remove); The invalidate function is called when ssuuddoo is called with the -k or -K flag. For policy plugins such as _s_u_d_o_e_r_s that cache authentication credentials, this function will invalidate the credentials. If the _r_e_m_o_v_e flag is set, 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); The init_session function is called when ssuuddoo sets up the execution environment for the command, immediately before the contents of the _c_o_m_m_a_n_d___i_n_f_o list are applied (before the uid changes). This can be used to do session setup that is not supported by _c_o_m_m_a_n_d___i_n_f_o, such as opening the PAM session. The _p_w_d 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. Returns 1 on success, 0 on failure and -1 on error. On error, the plugin may optionally call the conversation or plugin_printf function with SUDO_CONF_ERROR_MSG to present additional error information to the user. _V_e_r_s_i_o_n _m_a_c_r_o_s #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_VERSION_SET_MINOR(vp, n) do { \ *(vp) = (*(vp) & 0xffff0000) | (n); \ } while(0) #define SUDO_API_VERSION_MAJOR 1 #define SUDO_API_VERSION_MINOR 0 #define SUDO_API_VERSION ((SUDO_API_VERSION_MAJOR << 16) | \ SUDO_API_VERSION_MINOR) II//OO PPlluuggiinn AAPPII 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[], int argc, char * const argv[], char * const user_env[]); 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); }; When an I/O plugin is loaded, ssuuddoo 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, ssuuddoo 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 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. The io_plugin struct 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 ssuuddoo to determine the API version the plugin was built against. open int (*open)(unsigned int version, sudo_conv_t conversation sudo_printf_t plugin_printf, char * const settings[], char * const user_info[], int argc, char * const argv[], char * const user_env[]); The _o_p_e_n function is run before the _l_o_g___i_n_p_u_t, _l_o_g___o_u_t_p_u_t or _s_h_o_w___v_e_r_s_i_o_n functions are called. It is only called if the version is being requested or the _c_h_e_c_k___p_o_l_i_c_y 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, ssuuddoo 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 ssuuddoo allows the plugin to determine the major and minor version number of the plugin API supported by ssuuddoo. conversation A pointer to the conversation function that may be used by the _s_h_o_w___v_e_r_s_i_o_n 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 _s_h_o_w___v_e_r_s_i_o_n 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 ssuuddoo settings in the form of "name=value" strings. The vector is terminated by a NULL pointer. These settings correspond to flags the user specified when running ssuuddoo. As such, they will only be present when the corresponding flag has been specified on the command line. When parsing _s_e_t_t_i_n_g_s, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e 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 _u_s_e_r___i_n_f_o, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. See the "Policy Plugin API" section for a list of all possible strings. argc The number of elements in _a_r_g_v, not counting the final NULL pointer. 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 _e_x_e_c_v_e_(_) system call. user_env The user's environment in the form of a NULL-terminated vector of "name=value" strings. When parsing _u_s_e_r___e_n_v, the plugin should split on the ffiirrsstt equal sign ('=') since the _n_a_m_e field will never include one itself but the _v_a_l_u_e might. close void (*close)(int exit_status, int error); The close function is called when the command being run by ssuuddoo finishes. The function arguments are as follows: exit_status The command's exit status, as returned by the _w_a_i_t(2) system call. 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 _e_x_e_c_v_e(2) system call. If the command was successfully executed, the value of error is 0. show_version int (*show_version)(int verbose); The show_version function is called by ssuuddoo 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 version information, the verbose flag will be set. log_ttyin int (*log_ttyin)(const char *buf, unsigned int len); The _l_o_g___t_t_y_i_n 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 command) or -1 if an error occurred. The function arguments are as follows: buf The buffer containing user input. len The length of _b_u_f in bytes. log_ttyout int (*log_ttyout)(const char *buf, unsigned int len); The _l_o_g___t_t_y_o_u_t 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 command) or -1 if an error occurred. The function arguments are as follows: buf The buffer containing command output. len The length of _b_u_f in bytes. log_stdin int (*log_stdin)(const char *buf, unsigned int len); The _l_o_g___s_t_d_i_n 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 command) or -1 if an error occurred. The function arguments are as follows: buf The buffer containing user input. len The length of _b_u_f in bytes. log_stdout int (*log_stdout)(const char *buf, unsigned int len); The _l_o_g___s_t_d_o_u_t 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 command) or -1 if an error occurred. The function arguments are as follows: buf The buffer containing command output. len The length of _b_u_f in bytes. log_stderr int (*log_stderr)(const char *buf, unsigned int len); The _l_o_g___s_t_d_e_r_r 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 command) or -1 if an error occurred. The function arguments are as follows: buf The buffer containing command output. len The length of _b_u_f in bytes. _V_e_r_s_i_o_n _m_a_c_r_o_s Same as for the "Policy Plugin API". CCoonnvveerrssaattiioonn AAPPII 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 tty (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 error messages to the user, which is usually more convenient for simple messages where no use input is required. 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 */ int msg_type; int timeout; const char *msg; }; struct sudo_conv_reply { char *reply; }; typedef int (*sudo_conv_t)(int num_msgs, const struct sudo_conv_message msgs[], struct sudo_conv_reply replies[]); typedef int (*sudo_printf_t)(int msg_type, const char *fmt, ...); Pointers to the conversation and printf-style functions are passed in to the plugin's open function when the plugin is initialized. To use the 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. The plugin is responsible for freeing the reply buffer filled in to the struct sudo_conv_reply, if any. 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 _m_s_g___t_y_p_e parameter. It can be more convenient than using the conversation function if no user reply is needed and supports standard _p_r_i_n_t_f_(_) escape sequences. See the sample plugin for an example of the conversation function usage. SSuuddooeerrss GGrroouupp PPlluuggiinn AAPPII The _s_u_d_o_e_r_s module supports a plugin interface to allow non-Unix group lookups. This can be used to query a group source other than the standard Unix group database. A sample group plugin is bundled with ssuuddoo that implements file-based lookups. Third party group plugins include a QAS AD plugin available from Quest Software. 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: version The version field should be set to GROUP_API_VERSION. This allows _s_u_d_o_e_r_s to determine the API version the group plugin was built against. init int (*init)(int version, sudo_printf_t plugin_printf, char *const argv[]); The _i_n_i_t function is called after _s_u_d_o_e_r_s 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 information to the user. The function arguments are as follows: version The version passed in by _s_u_d_o_e_r_s allows the plugin to determine the major and minor version number of the group plugin API supported by _s_u_d_o_e_r_s. 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 success and -1 on failure. argv A NULL-terminated array of arguments generated from the _g_r_o_u_p___p_l_u_g_i_n option in _s_u_d_o_e_r_s. If no arguments were given, _a_r_g_v will be NULL. cleanup void (*cleanup)(); The _c_l_e_a_n_u_p function is called when _s_u_d_o_e_r_s has finished its group checks. The plugin 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 _q_u_e_r_y function is used to ask the group plugin whether _u_s_e_r is a member of _g_r_o_u_p. 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 _u_s_e_r, if any. If _u_s_e_r is not present in the password database, _p_w_d will be NULL. _V_e_r_s_i_o_n _M_a_c_r_o_s /* 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) /* Getters and setters for group version */ #define GROUP_API_VERSION_GET_MAJOR(v) ((v) >> 16) #define GROUP_API_VERSION_GET_MINOR(v) ((v) & 0xffff) #define GROUP_API_VERSION_SET_MAJOR(vp, n) do { \ *(vp) = (*(vp) & 0x0000ffff) | ((n) << 16); \ } while(0) #define GROUP_API_VERSION_SET_MINOR(vp, n) do { \ *(vp) = (*(vp) & 0xffff0000) | (n); \ } while(0) SSEEEE AALLSSOO _s_u_d_o_e_r_s(4), _s_u_d_o(1m) BBUUGGSS If you feel you have found a bug in ssuuddoo, please submit a bug report at http://www.sudo.ws/sudo/bugs/ SSUUPPPPOORRTT Limited free support is available via the sudo-workers mailing list, see http://www.sudo.ws/mailman/listinfo/sudo-workers to subscribe or search the archives. DDIISSCCLLAAIIMMEERR ssuuddoo 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 disclaimed. See the LICENSE file distributed with ssuuddoo or http://www.sudo.ws/sudo/license.html for complete details. 1.8.3 September 16, 2011 SUDO_PLUGIN(1m)