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-rw-r--r--applets/applets.c287
1 files changed, 287 insertions, 0 deletions
diff --git a/applets/applets.c b/applets/applets.c
index f3e56a9f3..2ab44059a 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:
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 16:22:01 +0000