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busybox/applets/applets.c
Glenn L McGrath 6ead3abd55 Save a few bytes in show_usage
2002-11-28 08:33:04 +00:00

423 lines
10 KiB
C
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/* 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 int parse_config_file ( void );
static int config_ok;
#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 *usage_string = usage_messages;
int i;
for (i = applet_using - applets; i > 0; ) {
if (!*usage_string++) {
--i;
}
}
if(*usage_string == '\b') {
fprintf(stderr, "%s\n\nNo help available.\n\n", full_version);
} else {
fprintf(stderr, "%s\n\nUsage: %s %s\n\n", 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 )
config_ok = 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
if ( config_ok ) {
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 );
}
return;
}
else {
#ifndef CONFIG_FEATURE_SUID_CONFIG_QUIET
static int onetime = 0;
if ( !onetime ) {
onetime = 1;
fprintf ( stderr, "Using fallback suid method\n" );
}
#endif
}
#endif
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 );
}
}
#ifdef CONFIG_FEATURE_SUID_CONFIG
#define parse_error(x) { err=x; goto pe_label; }
int parse_config_file ( void )
{
struct stat st;
char *err = 0;
FILE *f = 0;
int lc = 0;
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 */
f = fopen ( CONFIG_FILE, "r" );
if ( f ) {
char buffer [256];
int section = 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 ( "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 ( "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 ( "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 ( "invalid group mode" );
}
switch ( *p ) {
case 't':
case 'x': sct-> m_mode |= S_IXOTH; break;
case 'T':
case '-': break;
default : parse_error ( "invalid other mode" );
}
while ( isspace ( *++p )) { } /* skip whitespace */
if ( isdigit ( *p )) {
sct-> m_uid = strtol ( p, &p, 10 );
if ( *p++ != '.' )
parse_error ( "parsing <uid>.<gid>" );
}
else {
struct passwd *pwd;
char *p2 = strchr ( p, '.' );
if ( !p2 )
parse_error ( "parsing <uid>.<gid>" );
*p2 = 0;
pwd = getpwnam ( p );
if ( !pwd )
parse_error ( "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 ( "invalid group name" );
sct-> m_gid = grp-> gr_gid;
}
}
break;
}
default: /* unknown - skip */
break;
}
}
else
parse_error ( "keyword not within section" );
}
fclose ( f );
return 1;
}
}
}
return 0; /* no config file or not readable (not an error) */
pe_label:
fprintf ( stderr, "Parse error in %s, line %d: %s\n", CONFIG_FILE, lc, err );
if ( f )
fclose ( f );
return 0;
}
#endif
#endif
/* END CODE */
/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/
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