From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Mon, 15 May 2023 10:58:06 -0700
Subject: [PATCH] Synchronize PaperPermissionManager

Since multiple regions can exist, there are concurrent accesses
in this class. To prevent deadlock, the monitor is not held
when recalculating permissions, as Permissable holds its own
lock.

This fixes CMEs originating from this class.

diff --git a/src/main/java/io/papermc/paper/plugin/manager/PaperPermissionManager.java b/src/main/java/io/papermc/paper/plugin/manager/PaperPermissionManager.java
index 92a69677f21b2c1c035119d8e5a6af63fa19b801..6a239a3da5676cd781057d1b4af68aa97de27881 100644
--- a/src/main/java/io/papermc/paper/plugin/manager/PaperPermissionManager.java
+++ b/src/main/java/io/papermc/paper/plugin/manager/PaperPermissionManager.java
@@ -32,7 +32,9 @@ abstract class PaperPermissionManager implements PermissionManager {
     @Override
     @Nullable
     public Permission getPermission(@NotNull String name) {
+        synchronized (this) { // Folia - synchronized
         return this.permissions().get(name.toLowerCase(java.util.Locale.ENGLISH));
+        } // Folia - synchronized
     }
 
     @Override
@@ -52,12 +54,24 @@ abstract class PaperPermissionManager implements PermissionManager {
     private void addPermission(@NotNull Permission perm, boolean dirty) {
         String name = perm.getName().toLowerCase(java.util.Locale.ENGLISH);
 
+        Boolean recalc; // Folia - synchronized
+        synchronized (this) { // Folia - synchronized
         if (this.permissions().containsKey(name)) {
             throw new IllegalArgumentException("The permission " + name + " is already defined!");
         }
 
         this.permissions().put(name, perm);
-        this.calculatePermissionDefault(perm, dirty);
+        recalc = this.calculatePermissionDefault(perm, dirty);
+        } // Folia - synchronized
+        // Folia start - synchronize this class - we hold a lock now, prevent deadlock by moving this out
+        if (recalc != null) {
+            if (recalc.booleanValue()) {
+                this.dirtyPermissibles(true);
+            } else {
+                this.dirtyPermissibles(false);
+            }
+        }
+        // Folia end - synchronize this class - we hold a lock now, prevent deadlock by moving this out
     }
 
     @Override
@@ -80,42 +94,58 @@ abstract class PaperPermissionManager implements PermissionManager {
 
     @Override
     public void recalculatePermissionDefaults(@NotNull Permission perm) {
+        Boolean recalc = null; // Folia - synchronized
+        synchronized (this) { // Folia - synchronized
         // we need a null check here because some plugins for some unknown reason pass null into this?
         if (perm != null && this.permissions().containsKey(perm.getName().toLowerCase(Locale.ENGLISH))) {
             this.defaultPerms().get(true).remove(perm);
             this.defaultPerms().get(false).remove(perm);
 
-            this.calculatePermissionDefault(perm, true);
+            recalc = this.calculatePermissionDefault(perm, true); // Folia - synchronized
+        }
+        } // Folia - synchronized
+        // Folia start - synchronize this class - we hold a lock now, prevent deadlock by moving this out
+        if (recalc != null) {
+            if (recalc.booleanValue()) {
+                this.dirtyPermissibles(true);
+            } else {
+                this.dirtyPermissibles(false);
+            }
         }
+        // Folia end - synchronize this class - we hold a lock now, prevent deadlock by moving this out
     }
 
-    private void calculatePermissionDefault(@NotNull Permission perm, boolean dirty) {
+    private Boolean calculatePermissionDefault(@NotNull Permission perm, boolean dirty) { // Folia - synchronize this class
         if ((perm.getDefault() == PermissionDefault.OP) || (perm.getDefault() == PermissionDefault.TRUE)) {
             this.defaultPerms().get(true).add(perm);
             if (dirty) {
-                this.dirtyPermissibles(true);
+                return Boolean.TRUE; // Folia - synchronize this class - we hold a lock now, prevent deadlock by moving this out
             }
         }
         if ((perm.getDefault() == PermissionDefault.NOT_OP) || (perm.getDefault() == PermissionDefault.TRUE)) {
             this.defaultPerms().get(false).add(perm);
             if (dirty) {
-                this.dirtyPermissibles(false);
+                return Boolean.FALSE; // Folia - synchronize this class - we hold a lock now, prevent deadlock by moving this out
             }
         }
+        return null; // Folia - synchronize this class
     }
 
 
     @Override
     public void subscribeToPermission(@NotNull String permission, @NotNull Permissible permissible) {
+        synchronized (this) { // Folia - synchronized
         String name = permission.toLowerCase(java.util.Locale.ENGLISH);
         Map<Permissible, Boolean> map = this.permSubs().computeIfAbsent(name, k -> new WeakHashMap<>());
 
         map.put(permissible, true);
+        } // Folia - synchronized
     }
 
     @Override
     public void unsubscribeFromPermission(@NotNull String permission, @NotNull Permissible permissible) {
         String name = permission.toLowerCase(java.util.Locale.ENGLISH);
+        synchronized (this) { // Folia - synchronized
         Map<Permissible, Boolean> map = this.permSubs().get(name);
 
         if (map != null) {
@@ -125,11 +155,13 @@ abstract class PaperPermissionManager implements PermissionManager {
                 this.permSubs().remove(name);
             }
         }
+        } // Folia - synchronized
     }
 
     @Override
     @NotNull
     public Set<Permissible> getPermissionSubscriptions(@NotNull String permission) {
+        synchronized (this) { // Folia - synchronized
         String name = permission.toLowerCase(java.util.Locale.ENGLISH);
         Map<Permissible, Boolean> map = this.permSubs().get(name);
 
@@ -138,17 +170,21 @@ abstract class PaperPermissionManager implements PermissionManager {
         } else {
             return ImmutableSet.copyOf(map.keySet());
         }
+        } // Folia - synchronized
     }
 
     @Override
     public void subscribeToDefaultPerms(boolean op, @NotNull Permissible permissible) {
+        synchronized (this) { // Folia - synchronized
         Map<Permissible, Boolean> map = this.defSubs().computeIfAbsent(op, k -> new WeakHashMap<>());
 
         map.put(permissible, true);
+        } // Folia - synchronized
     }
 
     @Override
     public void unsubscribeFromDefaultPerms(boolean op, @NotNull Permissible permissible) {
+        synchronized (this) { // Folia - synchronized
         Map<Permissible, Boolean> map = this.defSubs().get(op);
 
         if (map != null) {
@@ -158,11 +194,13 @@ abstract class PaperPermissionManager implements PermissionManager {
                 this.defSubs().remove(op);
             }
         }
+        } // Folia - synchronized
     }
 
     @Override
     @NotNull
     public Set<Permissible> getDefaultPermSubscriptions(boolean op) {
+        synchronized (this) { // Folia - synchronized
         Map<Permissible, Boolean> map = this.defSubs().get(op);
 
         if (map == null) {
@@ -170,19 +208,24 @@ abstract class PaperPermissionManager implements PermissionManager {
         } else {
             return ImmutableSet.copyOf(map.keySet());
         }
+        } // Folia - synchronized
     }
 
     @Override
     @NotNull
     public Set<Permission> getPermissions() {
+        synchronized (this) { // Folia - synchronized
         return new HashSet<>(this.permissions().values());
+        } // Folia - synchronized
     }
 
     @Override
     public void clearPermissions() {
+        synchronized (this) { // Folia - synchronized
         this.permissions().clear();
         this.defaultPerms().get(true).clear();
         this.defaultPerms().get(false).clear();
+        } // Folia - synchronized
     }