Re: majordomo local exploit

From: Dale Clark (clarkat_private)
Date: Mon Jan 03 2000 - 08:38:35 PST

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      The following patch, built upon code and suggestions submitted by
    Henrik Edlund, Henrik Nordstrom, and Andrew Brown, is intended to render
    safe the config file requires, in the seven scripts which use them, in
    the Majordomo 1.94.4 home directory. It also incorporates Todd Miller's
    patch of Dec. 29.
      Basically, it replaces each "require $cf" with the following:
    
    if (not sysopen CONFIG,$cf,O_RDONLY)
    {
      die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
    }
    elsif ((stat CONFIG)[4] != $>)
    {
      die qq|Config file "$cf" not owned by effective UID.\n|;
    }
    elsif (eval(join '',<CONFIG>),$@)
    {
      die qq|Unable to eval "$cf": $@.\n|;
    }
    else
    {
      close CONFIG;
    }
    
      Use by cd'ing to Majordomo HOME, and issuing
    "patch < majorodomo-1.94.4.patch". Be sure to "chmod a-x *orig" after.
    
    Dale V. Clark                                             clarkat_private
    Systems Analyst                                             907-474-5114
    Arctic Region Supercomputing Center                         www.arsc.edu
    
    ======================== majordomo-1.94.4.patch ========================
    --- archive2.pl	Mon Jan  3 14:35:32 2000
    +++ archive2.pl.new	Mon Jan  3 14:36:16 2000
    @@ -54,10 +54,23 @@
         shift(@ARGV);
         shift(@ARGV);
     }
    -if (! -r $cf) {
    -    die("$cf not readable; stopped");
    +
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
     }
    -require "$cf";
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     # All these should be in the standard PERL library
     unshift(@INC, $homedir);
    --- bounce-remind	Mon Jan  3 14:35:32 2000
    +++ bounce-remind.new	Mon Jan  3 14:38:16 2000
    @@ -24,10 +24,23 @@
         shift(@ARGV);
         shift(@ARGV);
     }
    -if (! -r $cf) {
    -    die("$cf not readable; stopped");
    +
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
     }
    -require "$cf";
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     # Go to the home directory specified by the .cf file
     chdir("$homedir");
    --- config-test	Mon Jan  3 14:35:32 2000
    +++ config-test.new	Mon Jan  3 14:58:05 2000
    @@ -119,10 +119,21 @@
    
     $cf = $ARGV[0] || $ENV{'MAJORDOMO_CF'};
    
    -if (eval "require '$cf'") {
    -    &good("'require'd $cf okay.");
    -} else {
    -    &bad("something's wrong with $cf: $@");
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
    +}
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
     }
    
     foreach (@requires) {
    --- digest	Mon Jan  3 14:35:32 2000
    +++ digest.new	Mon Jan  3 15:07:34 2000
    @@ -315,7 +315,23 @@
     		# Read and execute the .cf file
     		$cf = $opt_c || $ENV{"MAJORDOMO_CF"} ||
     		    "/etc/majordomo.cf";
    -		require "$cf";
    +
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
    +}
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     		chdir($homedir);
    
    --- majordomo	Mon Jan  3 13:37:13 2000
    +++ majordomo.new	Mon Jan  3 14:15:29 2000
    @@ -40,11 +40,23 @@
     	die "Unknown argument $ARGV[0]\n";
         }
     }
    -if (! -r $cf) {
    -    die("$cf not readable; stopped");
    -}
    
    -require "$cf";
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
    +}
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     # Go to the home directory specified by the .cf file
     chdir("$homedir") || die "chdir to $homedir failed, $!\n";
    --- request-answer	Mon Jan  3 14:35:32 2000
    +++ request-answer.new	Mon Jan  3 15:09:02 2000
    @@ -20,10 +20,23 @@
         shift(@ARGV);
         shift(@ARGV);
     }
    -if (! -r $cf) {
    -    die("$cf not readable; stopped");
    +
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
     }
    -require "$cf";
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     chdir($homedir) || die("Can't chdir(\"$homedir\"): $!");
     unshift(@INC, $homedir);
    --- resend	Mon Jan  3 15:14:49 2000
    +++ resend.new	Mon Jan  3 15:16:01 2000
    @@ -56,7 +56,7 @@
     if ($ARGV[0] =~ /^\@/) {
         $fn = shift(@ARGV);
         $fn =~ s/^@//;
    -    open(AV, $fn) || die("open(AV, \"$fn\"): $!\nStopped");
    +    sysopen(AV, $fn, O_RDONLY) || die("sysopen(AV, \"$fn\", O_RDONLY):
    $!\nStopped");
         undef($/);	# set input field separator
         $av = <AV>;	# read whole file into string
         close(AV);
    @@ -84,11 +84,23 @@
     # Despite not having a place to send the remains of the body,
     # it would be nice to send a message to root or postmaster, at least...
     #
    -if (! -r $cf) {
    -    die("$cf not readable; stopped");
    -}
    
    -require "$cf";
    +if (not sysopen CONFIG,$cf,O_RDONLY)
    +{
    +  die sprintf qq|Unable to sysopen config file "$cf"%s.\n|,$! ? ": $!" : '';
    +}
    +elsif ((stat CONFIG)[4] != $>)
    +{
    +  die qq|Config file "$cf" not owned by effective UID.\n|;
    +}
    +elsif (eval(join '',<CONFIG>),$@)
    +{
    +  die qq|Unable to eval "$cf": $@.\n|;
    +}
    +else
    +{
    +  close CONFIG;
    +}
    
     chdir($homedir) || die("Can't chdir(\"$homedir\"): $!");
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 15:25:50 PDT