Re: setuid/setgid ruby scripts

Hi,

At Tue, 3 Jun 2003 10:29:16 +0900,
Wesley J Landaker wrote:
> So, I made a "better" version that was just:
> #include <unistd.h>
> int main(int argc, char *argv[]) {
>   const char *script = "/absolute/path/to/ruby/script.rb"
>   execv(script, argv);
> }
> And then setuid the result.

A perl script creates such wrappers can be found in Camel book.

> Anyway, I was just wondering if anyone has ever needed to make a ruby 
> script setuid or setgid before--and if so, how did you go about doing 
> it? 

I had, but suid/sgid security issue has not been discussed
about enough yet.


Index: Makefile.in
===================================================================
RCS file: /cvs/ruby/src/ruby/Makefile.in,v
retrieving revision 1.44
diff -u -2 -p -r1.44 Makefile.in
--- Makefile.in	21 May 2003 11:51:55 -0000	1.44
+++ Makefile.in	3 Jun 2003 02:27:18 -0000
@@ -36,7 +36,9 @@ MAINLIBS = @MAINLIBS@
 
 RUBY_INSTALL_NAME=@RUBY_INSTALL_NAME@
+SRUBY_INSTALL_NAME=@SRUBY_INSTALL_NAME@
 RUBY_SO_NAME=@RUBY_SO_NAME@
 EXEEXT = @EXEEXT@
 PROGRAM=$(RUBY_INSTALL_NAME)$(EXEEXT)
+SPROGRAM=$(SRUBY_INSTALL_NAME)$(EXEEXT)
 RUBY = $(RUBY_INSTALL_NAME)
 MINIRUBY = @MINIRUBY@
@@ -119,4 +121,8 @@ $(PROGRAM):     $(LIBRUBY) $(MAINOBJ) $(
 		$(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(MAINLIBS) $(MAINOBJ) $(EXTOBJS) $(LIBRUBYARG) $(LIBS) -o $@
 
+$(SPROGRAM):	$(LIBRUBY) $(MAINOBJ) $(EXTOBJS) suid.@OBJEXT@
+		@rm -f $@
+		$(PURIFY) $(CC) $(LDFLAGS) $(XLDFLAGS) $(OUTFLAG)$@ $(MAINLIBS) $(MAINOBJ) $(EXTOBJS) suid.@OBJEXT@ $(LIBRUBYARG) $(LIBS)
+
 $(LIBRUBY_A):	$(OBJS) dmyext.@OBJEXT@
 		@AR@ rcu $@ $(OBJS) dmyext.@OBJEXT@
@@ -360,2 +366,3 @@ variable.@OBJEXT@: variable.c ruby.h con
 version.@OBJEXT@: version.c ruby.h config.h defines.h intern.h missing.h \
   version.h
+suid.@OBJEXT@: suid.c missing.h ruby.h rubyio.h
Index: configure.in
===================================================================
RCS file: /cvs/ruby/src/ruby/configure.in,v
retrieving revision 1.173
diff -u -2 -p -r1.173 configure.in
--- configure.in	1 Jun 2003 12:58:56 -0000	1.173
+++ configure.in	1 Jun 2003 16:16:56 -0000
@@ -379,5 +379,5 @@ AC_CHECK_FUNCS(fmod killpg wait4 waitpid
 	      getpgrp setpgrp getpgid setpgid getgroups getpriority getrlimit\
 	      dlopen sigprocmask sigaction _setjmp setsid telldir seekdir fchmod\
-	      mktime timegm cosh sinh tanh)
+	      mktime timegm cosh sinh tanh group_member)
 AC_STRUCT_TIMEZONE
 AC_CACHE_CHECK(for struct tm.tm_gmtoff, rb_cv_member_struct_tm_tm_gmtoff,
@@ -993,4 +993,25 @@ esac
 AC_SUBST(setup)
 
+case $target_os in
+cygwin*|mswin*|mingw*|djgpp*|os2_emx*|human*);;
+*)
+  AC_CACHE_CHECK([for setuid/setgid supported],
+    rb_cv_setugid,
+    [AC_TRY_CPP([
+#include <sys/stat.h>
+#ifndef S_ISUID
+#ifndef S_ISGID
+#error setuid/setgid not supported
+#endif
+#endif
+    ],
+    rb_cv_setugid=yes,
+    rb_cv_setugid=no)])
+  if test "$rb_cv_setugid" = yes; then
+    AC_LIBOBJ([suiddmy])
+  fi
+  ;;
+esac
+
 if test "$prefix" = NONE; then
   prefix=$ac_default_prefix
@@ -1213,4 +1234,5 @@ AC_SUBST(LIBRUBY_LDSHARED)
 AC_SUBST(LIBRUBY_DLDFLAGS)
 AC_SUBST(RUBY_INSTALL_NAME)
+AC_SUBST(SRUBY_INSTALL_NAME)
 AC_SUBST(rubyw_install_name)
 AC_SUBST(RUBYW_INSTALL_NAME)
@@ -1245,4 +1267,5 @@ test "$program_suffix" != NONE &&
 
 RUBY_INSTALL_NAME="${ri_prefix}ruby${ri_suffix}"
+SRUBY_INSTALL_NAME="${ri_prefix}suidruby${ri_suffix}"
 case "$target_os" in
   cygwin*|mingw*)
Index: file.c
===================================================================
RCS file: /cvs/ruby/src/ruby/file.c,v
retrieving revision 1.146
diff -u -2 -p -r1.146 file.c
--- file.c	19 May 2003 05:41:07 -0000	1.146
+++ file.c	19 May 2003 06:06:56 -0000
@@ -425,5 +425,6 @@ rb_file_lstat(obj)
 }
 
-static int
+#ifndef HAVE_GROUP_MEMBER
+int
 group_member(gid)
     GETGROUPS_T gid;
@@ -454,4 +455,5 @@ group_member(gid)
     return Qfalse;
 }
+#endif
 
 #ifndef S_IXUGO
Index: ruby.c
===================================================================
RCS file: /cvs/ruby/src/ruby/ruby.c,v
retrieving revision 1.77
diff -u -2 -p -r1.77 ruby.c
--- ruby.c	22 Apr 2003 11:58:08 -0000	1.77
+++ ruby.c	22 Apr 2003 15:40:17 -0000
@@ -25,4 +25,5 @@
 #include <stdio.h>
 #include <sys/types.h>
+#include <sys/stat.h>
 #include <ctype.h>
 
@@ -793,4 +794,8 @@ load_file(fname, script)
 		rb_io_binmode(f);
 	}
+#elif defined S_ISUID || defined S_ISGID
+	if (script) {
+	    ruby_check_loadable(f);
+	}
 #endif
     }
Index: suid.c
===================================================================
RCS file: suid.c
diff -N suid.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ suid.c	3 Oct 2001 01:55:06 -0000
@@ -0,0 +1,150 @@
+/**********************************************************************
+
+  suid.c -
+
+  $Author$
+  $Date$
+  created at: Wed Aug 29 13:45:03 JST 2001
+
+  This file is covered under the Ruby's license (see the file
+  COPYING).
+
+**********************************************************************/
+
+#include "ruby.h"
+#include "rubyio.h"
+#include <errno.h>
+#include <sys/stat.h>
+
+#if !defined S_ISUID && !defined S_ISGID
+#error "setuid/setgid not supported"
+#endif
+
+void
+ruby_check_loadable(f)
+    VALUE f;
+{
+    OpenFile *fptr;
+    struct stat st;
+    int setid = 0;
+    int uid, euid, gid, egid;
+#ifdef HAVE_SETRESUID
+    int suid;
+#endif
+#ifdef HAVE_SETRESGID
+    int sgid;
+#endif
+
+    rb_check_type(f, T_FILE);
+    GetOpenFile(f, fptr);
+    if (fstat(fileno(fptr->f), &st) == -1) {
+	rb_sys_fail(fptr->path);
+    }
+
+#ifdef HAVE_SETRESUID
+    getresuid(&uid, &euid, &suid);
+#else
+    uid = (int)getuid();
+    euid = (int)geteuid();
+#endif
+#ifdef HAVE_SETRESGID
+    getresgid(&gid, &egid, &sgid);
+#else
+    gid = (int)getgid();
+    egid = (int)getegid();
+#endif
+
+    if (uid != 0) {
+	if ((
+#if defined S_IRUSR || defined S_IXUSR
+	    (st.st_uid == uid) ?
+	    !(st.st_mode & (0
+#ifdef S_IRUSR
+			    |S_IRUSR
+#endif
+#ifdef S_IXUSR
+			    |S_IXUSR
+#endif
+		)) :
+#endif
+#if defined S_IRGRP || defined S_IXGRP
+	    group_member(st.st_gid) ?
+	    !(st.st_mode & (0
+#ifdef S_IRGRP
+			    |S_IRGRP
+#endif
+#ifdef S_IXGRP
+			    |S_IXGRP
+#endif
+		)) :
+#endif
+#if defined S_IROTH || defined S_IXOTH
+	    !(st.st_mode & (0
+#ifdef S_IROTH
+			    |S_IROTH
+#endif
+#ifdef S_IXOTH
+			    |S_IXOTH
+#endif
+		))
+#else
+	    0
+#endif
+	    )
+#if defined S_ISUID && defined S_IWGRP
+	    || !(~st.st_mode & (S_ISUID|S_IWGRP))
+#endif
+#if defined S_ISUID && defined S_IWOTH
+	    || !(~st.st_mode & (S_ISUID|S_IWOTH))
+#endif
+#if defined S_ISGID && defined S_IWOTH
+	    || !(~st.st_mode & (S_ISGID|S_IWOTH))
+#endif
+	    ) {
+	    errno = EACCES;
+	    rb_load_fail(fptr->path);
+	}
+    }
+
+#ifdef S_ISGID
+    if (st.st_mode & S_ISGID) {
+# if defined HAVE_SETEGID
+	setegid(st.st_gid);
+# elif defined HAVE_SETREGID
+	setregid(-1, st.st_gid);
+# else
+	setgid(st.st_gid);
+# endif
+	setid = 1;
+    }
+    else
+#endif
+#if defined HAVE_SETRESGID && defined HAVE_SETEGID
+	setegid(sgid);
+#else
+	setgid(gid);
+#endif
+
+#ifdef S_ISUID
+    if (st.st_mode & S_ISUID) {
+# if defined HAVE_SETEUID
+	seteuid(st.st_uid);
+# elif defined HAVE_SETREUID
+	setreuid(-1, st.st_uid);
+# else
+	setuid(st.st_uid);
+# endif
+	setid = 1;
+    }
+    else
+#endif
+#if defined HAVE_SETRESUID && defined HAVE_SETEUID
+	seteuid(suid);
+#else
+	setuid(uid);
+#endif
+
+    if (!setid) {
+	rb_loaderror("not setuid/setgid -- %s", fptr->path);
+    }
+}
Index: suiddmy.c
===================================================================
RCS file: suiddmy.c
diff -N suiddmy.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ suiddmy.c	6 Sep 2001 10:25:58 -0000
@@ -0,0 +1,4 @@
+void
+ruby_check_loadable()
+{
+}


-- 
Nobu Nakada