applets/applets.c - codeaurora/busybox - Gitiles

 /* vi: set sw=4 ts=4: */
 /*
  * Utility routines.
  *
  * Copyright (C) tons of folks.  Tracking down who wrote what
  * isn't something I'm going to worry about...  If you wrote something
  * here, please feel free to acknowledge your work.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  *
  * Based in part on code from sash, Copyright (c) 1999 by David I. Bell
  * Permission has been granted to redistribute this code under the GPL.
  *
  */

 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "busybox.h"

 #undef APPLET
 #undef APPLET_NOUSAGE
 #undef PROTOTYPES
 #include "applets.h"

 struct BB_applet *applet_using;

 /* The -1 arises because of the {0,NULL,0,-1} entry above. */
 const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);


 #ifdef CONFIG_FEATURE_SUID

 static void check_suid ( struct BB_applet *app );

 #ifdef CONFIG_FEATURE_SUID_CONFIG

 #include <sys/stat.h>
 #include <ctype.h>
 #include "pwd.h"
 #include "grp.h"

 static void parse_error ( int line, const char *err );
 static void parse_config_file ( void );

 #define CONFIG_FILE "/etc/busybox.conf"

 // applets [] is const, so we have to define this "override" structure
 struct BB_suid_config {
 	struct BB_applet *m_applet;

 	uid_t  m_uid;
 	gid_t  m_gid;
 	mode_t m_mode;

 	struct BB_suid_config *m_next;
 };

 static struct BB_suid_config *suid_config;

 #endif // CONFIG_FEATURE_SUID_CONFIG

 #endif // CONFIG_FEATURE_SUID


 extern void show_usage(void)
 {
 	const char *format_string;
 	const char *usage_string = usage_messages;
 	int i;

 	for (i = applet_using - applets; i > 0; ) {
 		if (!*usage_string++) {
 			--i;
 		}
 	}
 	format_string = "%s\n\nUsage: %s %s\n\n";
 	if(*usage_string == 0)
 		format_string = "%s\n\nNo help available.\n\n";
 	fprintf(stderr, format_string,
 			full_version, applet_using->name, usage_string);
 	exit(EXIT_FAILURE);
 }

 static int applet_name_compare(const void *x, const void *y)
 {
 	const char *name = x;
 	const struct BB_applet *applet = y;

 	return strcmp(name, applet->name);
 }

 extern const size_t NUM_APPLETS;

 struct BB_applet *find_applet_by_name(const char *name)
 {
 	return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
 			applet_name_compare);
 }

 void run_applet_by_name(const char *name, int argc, char **argv)
 {
 	static int recurse_level = 0;
 	extern int been_there_done_that; /* From busybox.c */

 #ifdef CONFIG_FEATURE_SUID_CONFIG
 	if ( recurse_level == 0 )
 		parse_config_file ( );
 #endif

 	recurse_level++;
 	/* Do a binary search to find the applet entry given the name. */
 	if ((applet_using = find_applet_by_name(name)) != NULL) {
 		applet_name = applet_using->name;
 		if (argv[1] && strcmp(argv[1], "--help") == 0) {
 			if (strcmp(applet_using->name, "busybox")==0) {
 				if(argv[2])
 				  applet_using = find_applet_by_name(argv[2]);
 				 else
 				  applet_using = NULL;
 			}
 			if(applet_using)
 				show_usage();
 			been_there_done_that=1;
 			busybox_main(0, NULL);
 		}
 #ifdef CONFIG_FEATURE_SUID
 		check_suid ( applet_using );
 #endif

 		exit((*(applet_using->main)) (argc, argv));
 	}
 	/* Just in case they have renamed busybox - Check argv[1] */
 	if (recurse_level == 1) {
 		run_applet_by_name("busybox", argc, argv);
 	}
 	recurse_level--;
 }


 #ifdef CONFIG_FEATURE_SUID

 #ifdef CONFIG_FEATURE_SUID_CONFIG

 // check if u is member of group g
 static int ingroup ( uid_t u, gid_t g )
 {
 	struct group *grp = getgrgid ( g );

 	if ( grp ) {
 		char **mem;

 		for ( mem = grp-> gr_mem; *mem; mem++ ) {
 			struct passwd *pwd = getpwnam ( *mem );

 			if ( pwd && ( pwd-> pw_uid == u ))
 				return 1;
 		}
 	}
 	return 0;
 }

 #endif


 void check_suid ( struct BB_applet *applet )
 {
 	uid_t ruid = getuid ( ); // real [ug]id
 	uid_t rgid = getgid ( );

 #ifdef CONFIG_FEATURE_SUID_CONFIG
 	struct BB_suid_config *sct;

 	for ( sct = suid_config; sct; sct = sct-> m_next ) {
 		if ( sct-> m_applet == applet )
 			break;
 	}
 	if ( sct ) {
 		mode_t m = sct-> m_mode;

 		if ( sct-> m_uid == ruid ) // same uid
 			m >>= 6;
 		else if (( sct-> m_gid == rgid ) || ingroup ( ruid, sct-> m_gid )) // same group / in group
 			m >>= 3;

 		if (!( m & S_IXOTH ))   // is x bit not set ?
 			error_msg_and_die ( "You have no permission to run this applet!" );

 		if (( sct-> m_mode & ( S_ISGID | S_IXGRP )) == ( S_ISGID | S_IXGRP )) { // *both* have to be set for sgid
 			if ( setegid ( sct-> m_gid ))
 				error_msg_and_die ( "BusyBox binary has insufficient rights to set proper GID for applet!" );
 		}
 		else
 			setgid ( rgid ); // no sgid -> drop

 		if ( sct-> m_mode & S_ISUID ) {
 			if ( seteuid ( sct-> m_uid ))
 				error_msg_and_die ( "BusyBox binary has insufficient rights to set proper UID for applet!" );
 		}
 		else
 			setuid ( ruid ); // no suid -> drop
 	}
 	else { // default: drop all priviledges
 		setgid ( rgid );
 		setuid ( ruid );
 	}
 #else

 	if ( applet-> need_suid == _BB_SUID_ALWAYS ) {
 		if ( geteuid ( ) != 0 )
 			error_msg_and_die ( "This applet requires root priviledges!" );
 	}
 	else if ( applet-> need_suid == _BB_SUID_NEVER ) {
 		setgid ( rgid ); // drop all priviledges
 		setuid ( ruid );
 	}
 #endif
 }

 #ifdef CONFIG_FEATURE_SUID_CONFIG

 void parse_error ( int line, const char *err )
 {
 	char msg [512];
 	snprintf ( msg, sizeof( msg ) - 1, "Parse error in %s, line %d: %s", CONFIG_FILE, line, err );

 	error_msg_and_die ( msg );
 }


 void parse_config_file ( void )
 {
 	struct stat st;

 	suid_config = 0;

 	// is there a config file ?
 	if ( stat ( CONFIG_FILE, &st ) == 0 ) {
 		// is it owned by root with no write perm. for group and others ?
 		if ( S_ISREG( st. st_mode ) && ( st. st_uid == 0 )	&& (!( st. st_mode & ( S_IWGRP | S_IWOTH )))) {
 			// that's ok .. then try to open it
 			FILE *f = fopen ( CONFIG_FILE, "r" );

 			if ( f ) {
 				char buffer [4096];
 				int section = 0;
 				int lc = 0;

 				while ( fgets ( buffer, sizeof( buffer ) - 1, f )) {
 					char c = buffer [0];
 					char *p;

 					lc++;

 					p = strchr ( buffer, '#' );
 					if ( p )
 						*p = 0;
 					p = buffer + xstrlen ( buffer );
 					while (( p > buffer ) && isspace ( *--p ))
 						*p = 0;

 					if ( p == buffer )
 						continue;

 					if ( c == '[' ) {
 						p = strchr ( buffer, ']' );

 						if ( !p || ( p == ( buffer + 1 )))  // no matching ] or empty []
 							parse_error ( lc, "malformed section header" );

 						*p = 0;

 						if ( strcasecmp ( buffer + 1, "SUID" ) == 0 )
 							section = 1;
 						else
 							section = -1; // unknown section - just skip
 					}
 					else if ( section ) {
 						switch ( section ) {
 							case 1: { // SUID
 								int l;
 								struct BB_applet *applet;

 								p = strchr ( buffer, '=' ); // <key>[::space::]*=[::space::]*<value>

 								if ( !p || ( p == ( buffer + 1 ))) // no = or key is empty
 									parse_error ( lc, "malformed keyword" );

 								l = p - buffer;
 								while ( isspace ( buffer [--l] )) { } // skip whitespace

 								buffer [l+1] = 0;

 								if (( applet = find_applet_by_name ( buffer ))) {
 									struct BB_suid_config *sct = xmalloc ( sizeof( struct BB_suid_config ));

 									sct-> m_applet = applet;
 									sct-> m_next = suid_config;
 									suid_config = sct;

 									while ( isspace ( *++p )) { } // skip whitespace

 									sct-> m_mode = 0;

 									switch ( *p++ ) {
 										case 'S': sct-> m_mode |= S_ISUID; break;
 										case 's': sct-> m_mode |= S_ISUID; // no break
 										case 'x': sct-> m_mode |= S_IXUSR; break;
 										case '-': break;
 										default : parse_error ( lc, "invalid user mode" );
 									}

 									switch ( *p++ ) {
 										case 's': sct-> m_mode |= S_ISGID; // no break
 										case 'x': sct-> m_mode |= S_IXGRP; break;
 										case 'S': break;
 										case '-': break;
 										default : parse_error ( lc, "invalid group mode" );
 									}

 									switch ( *p ) {
 										case 't':
 										case 'x': sct-> m_mode |= S_IXOTH; break;
 										case 'T':
 										case '-': break;
 										default : parse_error ( lc, "invalid other mode" );
 									}

 									while ( isspace ( *++p )) { } // skip whitespace

 									if ( isdigit ( *p )) {
 										sct-> m_uid = strtol ( p, &p, 10 );
 										if ( *p++ != '.' )
 											parse_error ( lc, "parsing <uid>.<gid>" );
 									}
 									else {
 										struct passwd *pwd;
 										char *p2 = strchr ( p, '.' );

 										if ( !p2 )
 											parse_error ( lc, "parsing <uid>.<gid>" );

 										*p2 = 0;
 										pwd = getpwnam ( p );

 										if ( !pwd )
 											parse_error ( lc, "invalid user name" );

 										sct-> m_uid = pwd-> pw_uid;
 										p = p2 + 1;
 									}
 									if ( isdigit ( *p ))
 										sct-> m_gid = strtol ( p, &p, 10 );
 									else {
 										struct group *grp = getgrnam ( p );

 										if ( !grp )
 											parse_error ( lc, "invalid group name" );

 										sct-> m_gid = grp-> gr_gid;
 									}
 								}
 								break;
 							}
 							default: // unknown - skip
 								break;
 						}
 					}
 					else
 						parse_error ( lc, "keyword not within section" );
 				}
 				fclose ( f );
 			}
 		}
 	}
 }

 #endif

 #endif

 /* END CODE */
 /*
 Local Variables:
 c-file-style: "linux"
 c-basic-offset: 4
 tab-width: 4
 End:
 */
	/* vi: set sw=4 ts=4: */
	/*
	* Utility routines.
	*
	* Copyright (C) tons of folks. Tracking down who wrote what
	* isn't something I'm going to worry about... If you wrote something
	* here, please feel free to acknowledge your work.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
	* Permission has been granted to redistribute this code under the GPL.
	*
	*/

	#include <unistd.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include "busybox.h"

	#undef APPLET
	#undef APPLET_NOUSAGE
	#undef PROTOTYPES
	#include "applets.h"

	struct BB_applet *applet_using;

	/* The -1 arises because of the {0,NULL,0,-1} entry above. */
	const size_t NUM_APPLETS = (sizeof (applets) / sizeof (struct BB_applet) - 1);


	#ifdef CONFIG_FEATURE_SUID

	static void check_suid ( struct BB_applet *app );

	#ifdef CONFIG_FEATURE_SUID_CONFIG

	#include <sys/stat.h>
	#include <ctype.h>
	#include "pwd.h"
	#include "grp.h"

	static void parse_error ( int line, const char *err );
	static void parse_config_file ( void );

	#define CONFIG_FILE "/etc/busybox.conf"

	// applets [] is const, so we have to define this "override" structure
	struct BB_suid_config {
	struct BB_applet *m_applet;

	uid_t m_uid;
	gid_t m_gid;
	mode_t m_mode;

	struct BB_suid_config *m_next;
	};

	static struct BB_suid_config *suid_config;

	#endif // CONFIG_FEATURE_SUID_CONFIG

	#endif // CONFIG_FEATURE_SUID



	extern void show_usage(void)
	{
	const char *format_string;
	const char *usage_string = usage_messages;
	int i;

	for (i = applet_using - applets; i > 0; ) {
	if (!*usage_string++) {
	--i;
	}
	}
	format_string = "%s\n\nUsage: %s %s\n\n";
	if(*usage_string == 0)
	format_string = "%s\n\nNo help available.\n\n";
	fprintf(stderr, format_string,
	full_version, applet_using->name, usage_string);
	exit(EXIT_FAILURE);
	}

	static int applet_name_compare(const void x, const void y)
	{
	const char *name = x;
	const struct BB_applet *applet = y;

	return strcmp(name, applet->name);
	}

	extern const size_t NUM_APPLETS;

	struct BB_applet find_applet_by_name(const char name)
	{
	return bsearch(name, applets, NUM_APPLETS, sizeof(struct BB_applet),
	applet_name_compare);
	}

	void run_applet_by_name(const char name, int argc, char *argv)
	{
	static int recurse_level = 0;
	extern int been_there_done_that; /* From busybox.c */

	#ifdef CONFIG_FEATURE_SUID_CONFIG
	if ( recurse_level == 0 )
	parse_config_file ( );
	#endif

	recurse_level++;
	/* Do a binary search to find the applet entry given the name. */
	if ((applet_using = find_applet_by_name(name)) != NULL) {
	applet_name = applet_using->name;
	if (argv[1] && strcmp(argv[1], "--help") == 0) {
	if (strcmp(applet_using->name, "busybox")==0) {
	if(argv[2])
	applet_using = find_applet_by_name(argv[2]);
	else
	applet_using = NULL;
	}
	if(applet_using)
	show_usage();
	been_there_done_that=1;
	busybox_main(0, NULL);
	}
	#ifdef CONFIG_FEATURE_SUID
	check_suid ( applet_using );
	#endif

	exit((*(applet_using->main)) (argc, argv));
	}
	/* Just in case they have renamed busybox - Check argv[1] */
	if (recurse_level == 1) {
	run_applet_by_name("busybox", argc, argv);
	}
	recurse_level--;
	}


	#ifdef CONFIG_FEATURE_SUID

	#ifdef CONFIG_FEATURE_SUID_CONFIG

	// check if u is member of group g
	static int ingroup ( uid_t u, gid_t g )
	{
	struct group *grp = getgrgid ( g );

	if ( grp ) {
	char **mem;

	for ( mem = grp-> gr_mem; *mem; mem++ ) {
	struct passwd pwd = getpwnam ( mem );

	if ( pwd && ( pwd-> pw_uid == u ))
	return 1;
	}
	}
	return 0;
	}

	#endif


	void check_suid ( struct BB_applet *applet )
	{
	uid_t ruid = getuid ( ); // real [ug]id
	uid_t rgid = getgid ( );

	#ifdef CONFIG_FEATURE_SUID_CONFIG
	struct BB_suid_config *sct;

	for ( sct = suid_config; sct; sct = sct-> m_next ) {
	if ( sct-> m_applet == applet )
	break;
	}
	if ( sct ) {
	mode_t m = sct-> m_mode;

	if ( sct-> m_uid == ruid ) // same uid
	m >>= 6;
	else if (( sct-> m_gid == rgid ) \|\| ingroup ( ruid, sct-> m_gid )) // same group / in group
	m >>= 3;

	if (!( m & S_IXOTH )) // is x bit not set ?
	error_msg_and_die ( "You have no permission to run this applet!" );

	if (( sct-> m_mode & ( S_ISGID \| S_IXGRP )) == ( S_ISGID \| S_IXGRP )) { // both have to be set for sgid
	if ( setegid ( sct-> m_gid ))
	error_msg_and_die ( "BusyBox binary has insufficient rights to set proper GID for applet!" );
	}
	else
	setgid ( rgid ); // no sgid -> drop

	if ( sct-> m_mode & S_ISUID ) {
	if ( seteuid ( sct-> m_uid ))
	error_msg_and_die ( "BusyBox binary has insufficient rights to set proper UID for applet!" );
	}
	else
	setuid ( ruid ); // no suid -> drop
	}
	else { // default: drop all priviledges
	setgid ( rgid );
	setuid ( ruid );
	}
	#else

	if ( applet-> need_suid == _BB_SUID_ALWAYS ) {
	if ( geteuid ( ) != 0 )
	error_msg_and_die ( "This applet requires root priviledges!" );
	}
	else if ( applet-> need_suid == _BB_SUID_NEVER ) {
	setgid ( rgid ); // drop all priviledges
	setuid ( ruid );
	}
	#endif
	}

	#ifdef CONFIG_FEATURE_SUID_CONFIG

	void parse_error ( int line, const char *err )
	{
	char msg [512];
	snprintf ( msg, sizeof( msg ) - 1, "Parse error in %s, line %d: %s", CONFIG_FILE, line, err );

	error_msg_and_die ( msg );
	}


	void parse_config_file ( void )
	{
	struct stat st;

	suid_config = 0;

	// is there a config file ?
	if ( stat ( CONFIG_FILE, &st ) == 0 ) {
	// is it owned by root with no write perm. for group and others ?
	if ( S_ISREG( st. st_mode ) && ( st. st_uid == 0 ) && (!( st. st_mode & ( S_IWGRP \| S_IWOTH )))) {
	// that's ok .. then try to open it
	FILE *f = fopen ( CONFIG_FILE, "r" );

	if ( f ) {
	char buffer [4096];
	int section = 0;
	int lc = 0;

	while ( fgets ( buffer, sizeof( buffer ) - 1, f )) {
	char c = buffer [0];
	char *p;

	lc++;

	p = strchr ( buffer, '#' );
	if ( p )
	*p = 0;
	p = buffer + xstrlen ( buffer );
	while (( p > buffer ) && isspace ( *--p ))
	*p = 0;

	if ( p == buffer )
	continue;

	if ( c == '[' ) {
	p = strchr ( buffer, ']' );

	if ( !p \|\| ( p == ( buffer + 1 ))) // no matching ] or empty []
	parse_error ( lc, "malformed section header" );

	*p = 0;

	if ( strcasecmp ( buffer + 1, "SUID" ) == 0 )
	section = 1;
	else
	section = -1; // unknown section - just skip
	}
	else if ( section ) {
	switch ( section ) {
	case 1: { // SUID
	int l;
	struct BB_applet *applet;

	p = strchr ( buffer, '=' ); // <key>[::space::]=[::space::]<value>

	if ( !p \|\| ( p == ( buffer + 1 ))) // no = or key is empty
	parse_error ( lc, "malformed keyword" );

	l = p - buffer;
	while ( isspace ( buffer [--l] )) { } // skip whitespace

	buffer [l+1] = 0;

	if (( applet = find_applet_by_name ( buffer ))) {
	struct BB_suid_config *sct = xmalloc ( sizeof( struct BB_suid_config ));

	sct-> m_applet = applet;
	sct-> m_next = suid_config;
	suid_config = sct;

	while ( isspace ( *++p )) { } // skip whitespace

	sct-> m_mode = 0;

	switch ( *p++ ) {
	case 'S': sct-> m_mode \|= S_ISUID; break;
	case 's': sct-> m_mode \|= S_ISUID; // no break
	case 'x': sct-> m_mode \|= S_IXUSR; break;
	case '-': break;
	default : parse_error ( lc, "invalid user mode" );
	}

	switch ( *p++ ) {
	case 's': sct-> m_mode \|= S_ISGID; // no break
	case 'x': sct-> m_mode \|= S_IXGRP; break;
	case 'S': break;
	case '-': break;
	default : parse_error ( lc, "invalid group mode" );
	}

	switch ( *p ) {
	case 't':
	case 'x': sct-> m_mode \|= S_IXOTH; break;
	case 'T':
	case '-': break;
	default : parse_error ( lc, "invalid other mode" );
	}

	while ( isspace ( *++p )) { } // skip whitespace

	if ( isdigit ( *p )) {
	sct-> m_uid = strtol ( p, &p, 10 );
	if ( *p++ != '.' )
	parse_error ( lc, "parsing <uid>.<gid>" );
	}
	else {
	struct passwd *pwd;
	char *p2 = strchr ( p, '.' );

	if ( !p2 )
	parse_error ( lc, "parsing <uid>.<gid>" );

	*p2 = 0;
	pwd = getpwnam ( p );

	if ( !pwd )
	parse_error ( lc, "invalid user name" );

	sct-> m_uid = pwd-> pw_uid;
	p = p2 + 1;
	}
	if ( isdigit ( *p ))
	sct-> m_gid = strtol ( p, &p, 10 );
	else {
	struct group *grp = getgrnam ( p );

	if ( !grp )
	parse_error ( lc, "invalid group name" );

	sct-> m_gid = grp-> gr_gid;
	}
	}
	break;
	}
	default: // unknown - skip
	break;
	}
	}
	else
	parse_error ( lc, "keyword not within section" );
	}
	fclose ( f );
	}
	}
	}
	}

	#endif

	#endif

	/* END CODE */
	/*
	Local Variables:
	c-file-style: "linux"
	c-basic-offset: 4
	tab-width: 4
	End:
	*/