Permission System

ForkBB uses a sophisticated permission system that combines global group permissions with per-forum overrides.

Permission Architecture

The permission system operates on two levels:

Global Group Permissions

Default permissions defined for each user group

Forum-Specific Permissions

Overrides that apply to specific forums

Group Permissions

User groups define the baseline permissions for all members.

Permission Categories

Basic Access
Posting
Editing
Search

Read and View Permissions

Groups.php:567

'g_read_board' => [
    'type'    => 'radio',
    'value'   => $group->g_read_board,
    'values'  => $yn,
    'caption' => 'Read board label',
    'help'    => 'Read board help',
],
'g_view_users' => [
    'type'    => 'radio',
    'value'   => $group->g_view_users,
    'values'  => $yn,
    'caption' => 'View user info label',
    'help'    => 'View user info help',
],

Read board: Access to view the forum
View users: See user profiles and information

Content Creation Permissions

Groups.php:588

'g_post_replies' => [
    'type'    => 'radio',
    'value'   => $group->g_post_replies,
    'values'  => $yn,
    'caption' => 'Post replies label',
    'help'    => 'Post replies help',
],
'g_post_topics' => [
    'type'    => 'radio',
    'value'   => $group->g_post_topics,
    'values'  => $yn,
    'caption' => 'Post topics label',
    'help'    => 'Post topics help',
],
'g_post_links' => [
    'type'    => 'radio',
    'value'   => $group->g_post_links,
    'values'  => $yn,
    'caption' => 'Post links label',
    'help'    => 'Post links help',
],

Post replies: Reply to existing topics
Post topics: Create new topics
Post links: Include links in posts

Content Modification Permissions

Groups.php:604

'g_edit_posts' => [
    'type'    => 'radio',
    'value'   => $group->g_edit_posts,
    'values'  => $yn,
    'caption' => 'Edit posts label',
    'help'    => 'Edit posts help',
],
'g_delete_posts' => [
    'type'    => 'radio',
    'value'   => $group->g_delete_posts,
    'values'  => $yn,
    'caption' => 'Delete posts label',
    'help'    => 'Delete posts help',
],
'g_delete_topics' => [
    'type'    => 'radio',
    'value'   => $group->g_delete_topics,
    'values'  => $yn,
    'caption' => 'Delete topics label',
    'help'    => 'Delete topics help',
],

Edit posts: Modify own posts
Delete posts: Remove own posts
Delete topics: Remove own topics

Search Permissions

Groups.php:662

'g_search' => [
    'type'    => 'radio',
    'value'   => $group->g_search,
    'values'  => $yn,
    'caption' => 'User search label',
    'help'    => 'User search help',
],
'g_search_users' => [
    'type'    => 'radio',
    'value'   => $group->g_search_users,
    'values'  => $yn,
    'caption' => 'User list search label',
    'help'    => 'User list search help',
],

Search: Use search functionality
Search users: Search user lists

Moderator Permissions

Moderator permissions require the group’s g_moderator flag to be enabled.

Groups.php:511

'g_moderator' => [
    'type'    => 'radio',
    'value'   => $group->g_moderator,
    'values'  => $yn,
    'caption' => 'Mod privileges label',
    'help'    => 'Mod privileges help',
],

Available Moderator Powers

Edit Profiles

Groups.php:518

'g_mod_edit_users' => [
    'type'    => 'radio',
    'value'   => $group->g_mod_edit_users,
    'values'  => $yn,
    'caption' => 'Edit profile label',
    'help'    => 'Edit profile help',
],

Rename Users

Groups.php:525

'g_mod_rename_users' => [
    'type'    => 'radio',
    'value'   => $group->g_mod_rename_users,
    'values'  => $yn,
    'caption' => 'Rename users label',
    'help'    => 'Rename users help',
],

Change Passwords

Groups.php:532

'g_mod_change_passwords' => [
    'type'    => 'radio',
    'value'   => $group->g_mod_change_passwords,
    'values'  => $yn,
    'caption' => 'Change passwords label',
    'help'    => 'Change passwords help',
],

Promote Users

Groups.php:539

'g_mod_promote_users' => [
    'type'    => 'radio',
    'value'   => $group->g_mod_promote_users,
    'values'  => $yn,
    'caption' => 'Mod promote users label',
    'help'    => 'Mod promote users help',
],

Ban Users

Groups.php:546

'g_mod_ban_users' => [
    'type'    => 'radio',
    'value'   => $group->g_mod_ban_users,
    'values'  => $yn,
    'caption' => 'Ban users label',
    'help'    => 'Ban users help',
],

If g_moderator is set to 0, all moderator permissions are automatically disabled.

Groups.php:371

if (
    isset($data['g_moderator'])
    && 0 === $data['g_moderator']
) {
    $data['g_mod_edit_users']       = 0;
    $data['g_mod_rename_users']     = 0;
    $data['g_mod_change_passwords'] = 0;
    $data['g_mod_promote_users']    = 0;
    $data['g_mod_ban_users']        = 0;
}

Pre-moderation

Groups.php:574

'g_premoderation' => [
    'type'    => 'radio',
    'value'   => $group->g_premoderation,
    'values'  => $yn,
    'caption' => 'Use pre-moderation label',
    'help'    => 'Use pre-moderation help',
],

Pre-moderation is automatically disabled for moderators:

Groups.php:382

if (
    isset($data['g_moderator'])
    && 1 === $data['g_moderator']
) {
    $data['g_premoderation'] = 0;
}

Forum Permissions

Forum-specific permissions override global group settings.

Permission Model

Perm.php:26

public function get(Forum $forum): array
{
    $vars = [
        ':fid' => $forum->id > 0 ? $forum->id : 0,
        ':adm' => FORK_GROUP_ADMIN,
    ];
    $query = 'SELECT g.g_id, fp.read_forum, fp.post_replies, fp.post_topics
        FROM ::groups AS g
        LEFT JOIN ::forum_perms AS fp ON (g.g_id=fp.group_id AND fp.forum_id=?i:fid)
        WHERE g.g_id!=?i:adm
        ORDER BY g.g_id';
    
    $perms  = $this->c->DB->query($query, $vars)->fetchAll(PDO::FETCH_UNIQUE);
    $result = [];
    
    foreach ($perms as $gid => $perm) {
        $group  = $this->c->groups->get($gid);
        $group->g_read_forum = $group->g_read_board;
        
        foreach ($perm as $field => $value) {
            $group->{'fp_' . $field}  = $value;
            $group->{'set_' . $field} = (1 === $group->{'g_' . $field} && 0 !== $value) || 1 === $value;
            $group->{'def_' . $field} = 1 === $group->{'g_' . $field};
            $group->{'dis_' . $field} = 0 === $group->g_read_board || ('read_forum' !== $field && $forum->redirect_url);
        }
        
        $result[$gid] = $group;
    }
    
    return $result;
}

Forum Permission Types

Read Forum

Allow group members to view forum contents

Post Replies

Allow group members to reply to topics

Post Topics

Allow group members to create new topics

Permission States

Each permission can have multiple states:

Default (def_*)

Inherits from the global group permission

Perm.php:50

$group->{'def_' . $field} = 1 === $group->{'g_' . $field};

Set (set_*)

The effective permission value (combining global and override)

Perm.php:49

$group->{'set_' . $field} = (1 === $group->{'g_' . $field} && 0 !== $value) || 1 === $value;

Disabled (dis_*)

Permission is disabled (e.g., group can’t read board or forum is redirect)

Perm.php:51

$group->{'dis_' . $field} = 0 === $group->g_read_board 
    || ('read_forum' !== $field && $forum->redirect_url);

Forum Permission (fp_*)

The actual override value stored in the database

Perm.php:48

$group->{'fp_' . $field}  = $value;

Updating Forum Permissions

Perm.php:65

public function update(Forum $forum, array $perms): void
{
    if ($forum->id < 1) {
        throw new RuntimeException('The forum does not have ID');
    }
    
    foreach ($this->get($forum) as $id => $group) {
        if (0 === $group->g_read_board) {
            continue;
        }
        
        $row     = [];
        $modDef  = false;
        $modPerm = false;
        
        foreach ($this->fields as $field) {
            if ($group->{'dis_' . $field}) {
                $row[$field] = $group->{'set_' . $field} ? 1 : 0;
                $modDef      = $row[$field] !== $group->{'g_' . $field} ? true : $modDef;
            } else {
                $row[$field] = empty($perms[$id][$field]) ? 0 : 1;
                $modDef      = $row[$field] !== $group->{'g_' . $field} ? true : $modDef;
                $modPerm     = $row[$field] !== (int) $group->{'set_' . $field} ? true : $modPerm;
            }
        }
        
        if ($modDef || $modPerm) {
            // Delete existing permission
            $vars = [':gid' => $id, ':fid' => $forum->id];
            $query = 'DELETE FROM ::forum_perms
                WHERE group_id=?i:gid AND forum_id=?i:fid';
            $this->c->DB->exec($query, $vars);
        }
        
        if ($modDef) {
            // Insert new permission override
            $vars   = \array_values($row);
            $vars[] = $id;
            $vars[] = $forum->id;
            $list   = \array_keys($row);
            $list[] = 'group_id';
            $list[] = 'forum_id';
            $list2  = \array_fill(0, \count($list), '?i');
            
            $list   = \implode(', ', $list);
            $list2  = \implode(', ', $list2);
            $query  = "INSERT INTO ::forum_perms ({$list}) VALUES ({$list2})";
            
            $this->c->DB->exec($query, $vars);
        }
    }
}

Resetting Permissions

Revert forum permissions to group defaults:

Perm.php:129

public function reset(Forum $forum): void
{
    if ($forum->id < 1) {
        throw new RuntimeException('The forum does not have ID');
    }
    
    $vars = [':fid' => $forum->id];
    $query = 'DELETE FROM ::forum_perms WHERE forum_id=?i:fid';
    
    $this->c->DB->exec($query, $vars);
}

This removes all forum-specific permission overrides:

Forums.php:411

if ($v->reset) {
    $message = 'Perms reverted redirect';
    $this->c->groups->Perm->reset($forum);
}

Copying Permissions

When creating a new group, permissions are copied from the base group:

Perm.php:167

public function copy(Group $from, Group $to): void
{
    if ($from->g_id < 1 || $to->g_id < 1) {
        throw new RuntimeException('The group does not have ID');
    }
    
    $this->delete($to);
    
    $vars = [':old' => $from->g_id, ':new' => $to->g_id];
    $query = 'INSERT INTO ::forum_perms (group_id, forum_id, read_forum, post_replies, post_topics)
        SELECT ?i:new, forum_id, read_forum, post_replies, post_topics
        FROM ::forum_perms
        WHERE group_id=?i:old';
    
    $this->c->DB->exec($query, $vars);
}

Used when creating groups:

Groups.php:409

if (null === $group->g_id) {
    $message = 'Group added redirect';
    $this->c->groups->insert($group);
    $this->c->groups->Perm->copy($baseGroup, $group);
}

Special Groups

Administrator Group

The administrator group (FORK_GROUP_ADMIN) is excluded from forum permission management:

Perm.php:30

':adm' => FORK_GROUP_ADMIN,

WHERE g.g_id!=?i:adm

Administrators always have full access to all forums.

Guest Group

Guests have limited permission options. Some features are automatically disabled:

Groups.php:277

if ($group->groupGuest) {
    $v->addRules([
        'a_guest_set.show_smilies' => 'required|integer|in:0,1',
        'a_guest_set.show_sig'     => 'required|integer|in:0,1',
        'a_guest_set.show_avatars' => 'required|integer|in:0,1',
        'a_guest_set.show_img'     => 'required|integer|in:0,1',
        'a_guest_set.show_img_sig' => 'required|integer|in:0,1',
    ]);
}

Moderator Group

Moderators cannot be in groups used as default user group:

Groups.php:263

if (
    ! $group->groupGuest
    && ! $group->groupMember
    && $group->g_id !== $this->c->config->i_default_user_group
) {
    $v->addRules([
        'g_moderator'            => 'required|integer|in:0,1',
        'g_mod_edit_users'       => 'required|integer|in:0,1',
        // ... other moderator permissions
    ]);
}

Permission Hierarchy

The permission system follows this hierarchy:

Flood Control

Flood control limits are defined per group to prevent spam:

Groups.php:737

'g_post_flood' => [
    'type'    => 'number',
    'min'     => '0',
    'max'     => '32767',
    'value'   => $group->g_post_flood,
    'caption' => 'Post flood label',
    'help'    => 'Post flood help',
],
'g_search_flood' => [
    'type'    => 'number',
    'min'     => '0',
    'max'     => '32767',
    'value'   => $group->g_search_flood,
    'caption' => 'Search flood label',
    'help'    => 'Search flood help',
],

Additional flood controls for non-guests:

Groups.php:763

'g_email_flood' => [
    'type'    => 'number',
    'min'     => '0',
    'max'     => '32767',
    'value'   => $group->g_email_flood,
    'caption' => 'E-mail flood label',
    'help'    => 'E-mail flood help',
],
'g_report_flood' => [
    'type'    => 'number',
    'min'     => '0',
    'max'     => '32767',
    'value'   => $group->g_report_flood,
    'caption' => 'Report flood label',
    'help'    => 'Report flood help',
],

Best Practices

Permission Management Tips:

Start Restrictive: Begin with minimal permissions and add as needed
Test Thoroughly: Verify permissions work as expected before going live
Document Changes: Keep notes about custom forum permissions
Regular Audits: Review permissions periodically
Group Planning: Design your group structure before assigning permissions
Forum Defaults: Use forum-specific permissions sparingly - prefer group-level settings

Permission Conflicts

Conflict Resolution Rules:

If a group can’t read the board, all other permissions are disabled
Forum-specific permissions override group permissions
Disabled fields (redirect forums) ignore overrides
Moderators bypass pre-moderation automatically
Administrators always have full access

Next Steps

User Groups

Learn about user group management

Forum Management

Configure forums and permissions

Group Model

Understand the Group model API

Security

Review security best practices

​Permission Architecture

​Group Permissions

​Permission Categories

​Moderator Permissions

​Available Moderator Powers

Edit Profiles

Rename Users

Change Passwords

Promote Users

Ban Users

​Pre-moderation

​Forum Permissions

​Permission Model

​Forum Permission Types

​Permission States

​Updating Forum Permissions

​Resetting Permissions

​Copying Permissions

​Special Groups

​Administrator Group

​Guest Group

​Moderator Group

​Permission Hierarchy

​Flood Control

​Best Practices

​Permission Conflicts

​Next Steps

User Groups

Forum Management

Group Model

Security

Permission Architecture

Group Permissions

Permission Categories

Moderator Permissions

Available Moderator Powers

Pre-moderation

Forum Permissions

Permission Model

Forum Permission Types

Permission States

Updating Forum Permissions

Resetting Permissions

Copying Permissions

Special Groups

Administrator Group

Guest Group

Moderator Group

Permission Hierarchy

Flood Control

Best Practices

Permission Conflicts

Next Steps