diff options
Diffstat (limited to 'applets')
-rw-r--r-- | applets/applets.c | 287 |
1 files changed, 287 insertions, 0 deletions
diff --git a/applets/applets.c b/applets/applets.c index f3e56a9..2ab4405 100644 --- a/applets/applets.c +++ b/applets/applets.c @@ -25,6 +25,7 @@ * */ +#include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> @@ -40,6 +41,42 @@ 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; @@ -80,6 +117,11 @@ 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) { @@ -96,6 +138,10 @@ void run_applet_by_name(const char *name, int argc, char **argv) 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] */ @@ -106,6 +152,247 @@ void run_applet_by_name(const char *name, int argc, char **argv) } +#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: |