| /* 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 *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 ) |
| 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 { |
| static int onetime = 0; |
| |
| if ( !onetime ) { |
| onetime = 1; |
| fprintf ( stderr, "Using fallback suid method\n" ); |
| } |
| } |
| #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; |
| |
| 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: |
| */ |