prevent user enumeration attacks

diff --git a/PVE/API2/AccessControl.pm b/PVE/API2/AccessControl.pm
index 1679ed45eb4c0d6ff81682eb967fbce3c5521cfd..8daf10cf5f9763750af85cb70b7126d259bde296 100644 (file)
--- a/PVE/API2/AccessControl.pm
+++ b/PVE/API2/AccessControl.pm
@@ -2,6 +2,7 @@ package PVE::API2::AccessControl;
 
 use strict;
 use warnings;
 
 use strict;
 use warnings;

+use Time::HiRes qw(usleep gettimeofday tv_interval);

 
 use PVE::Exception qw(raise raise_perm_exc);
 use PVE::SafeSyslog;
 
 use PVE::Exception qw(raise raise_perm_exc);
 use PVE::SafeSyslog;


@@ -265,6 +266,8 @@ __PACKAGE__->register_method ({
 
        my $res;
 
 
        my $res;
 

+       my $starttime = [gettimeofday];
+

        eval {
            # test if user exists and is enabled
            $rpcenv->check_user_enabled($username);
        eval {
            # test if user exists and is enabled
            $rpcenv->check_user_enabled($username);


@@ -279,7 +282,13 @@ __PACKAGE__->register_method ({
        if (my $err = $@) {
            my $clientip = $rpcenv->get_client_ip() || '';
            syslog('err', "authentication failure; rhost=$clientip user=$username msg=$err");
        if (my $err = $@) {
            my $clientip = $rpcenv->get_client_ip() || '';
            syslog('err', "authentication failure; rhost=$clientip user=$username msg=$err");

-           die $err;
+           # do not return any info to prevent user enumeration attacks
+           # always try to delay exactly 3 seconds to prevent timing attacks
+           my $elapsed;
+           while (($elapsed = tv_interval($starttime)) < 3) {
+               usleep(int((3 - $elapsed)*1000000));
+           }
+           die "authentication failure\n"; 

        }
 
        $res->{cap} = &$compute_api_permission($rpcenv, $username);
        }
 
        $res->{cap} = &$compute_api_permission($rpcenv, $username);

diff --git a/PVE/AccessControl.pm b/PVE/AccessControl.pm
index ab5e52e1ff95db0127d56d604fe7b626823fd438..236efacff2946726f0fbea1a0fbe13e78a716d3c 100644 (file)
--- a/PVE/AccessControl.pm
+++ b/PVE/AccessControl.pm
@@ -306,6 +306,7 @@ sub check_user_enabled {
 }
 
 # password should be utf8 encoded
 }
 
 # password should be utf8 encoded

+# Note: some pluging delay/sleep if auth fails

 sub authenticate_user {
     my ($username, $password) = @_;
 
 sub authenticate_user {
     my ($username, $password) = @_;
 


@@ -317,32 +318,19 @@ sub authenticate_user {
 
     my $usercfg = cfs_read_file('user.cfg');
 
 
     my $usercfg = cfs_read_file('user.cfg');
 

-    eval { check_user_enabled($usercfg, $username); };
-    if (my $err = $@) {
-       sleep(2);
-       die $err;
-    }
+    check_user_enabled($usercfg, $username);

 
     my $ctime = time();
     my $expire = $usercfg->{users}->{$username}->{expire};
 
 
     my $ctime = time();
     my $expire = $usercfg->{users}->{$username}->{expire};
 

-    if ($expire && ($expire < $ctime)) {
-       sleep(2);
-       die "account expired\n"
-    }
+    die "account expired\n" if $expire && ($expire < $ctime);

 
     my $domain_cfg = cfs_read_file('domains.cfg');
 
 
     my $domain_cfg = cfs_read_file('domains.cfg');
 

-    eval {
-       my $cfg = $domain_cfg->{ids}->{$realm};
-       die "auth domain '$realm' does not exists\n" if !$cfg;
-       my $plugin = PVE::Auth::Plugin->lookup($cfg->{type});
-       $plugin->authenticate_user($cfg, $realm, $ruid, $password);
-    };
-    if (my $err = $@) {
-       sleep(2); # timeout after failed auth
-       die $err;
-    }
+    my $cfg = $domain_cfg->{ids}->{$realm};
+    die "auth domain '$realm' does not exists\n" if !$cfg;
+    my $plugin = PVE::Auth::Plugin->lookup($cfg->{type});
+    $plugin->authenticate_user($cfg, $realm, $ruid, $password);

 
     return $username;
 }
 
     return $username;
 }