From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Aikar Date: Fri, 16 Nov 2018 23:08:50 -0500 Subject: [PATCH] Book Size Limits Puts some limits on the size of books. diff --git a/src/main/java/net/minecraft/network/protocol/game/ServerboundEditBookPacket.java b/src/main/java/net/minecraft/network/protocol/game/ServerboundEditBookPacket.java index ed61767a64cdce37dc7c226ebd0d693a60de24a9..f634a830a2b58a419e84f969bd53eeae4f4513bb 100644 --- a/src/main/java/net/minecraft/network/protocol/game/ServerboundEditBookPacket.java +++ b/src/main/java/net/minecraft/network/protocol/game/ServerboundEditBookPacket.java @@ -16,9 +16,9 @@ public record ServerboundEditBookPacket(int slot, List pages, Optional STREAM_CODEC = StreamCodec.composite( ByteBufCodecs.VAR_INT, ServerboundEditBookPacket::slot, - ByteBufCodecs.stringUtf8(8192).apply(ByteBufCodecs.list(200)), + ByteBufCodecs.stringUtf8(net.minecraft.world.item.component.WritableBookContent.PAGE_EDIT_LENGTH).apply(ByteBufCodecs.list(net.minecraft.world.item.component.WritableBookContent.MAX_PAGES)), // Paper - limit books ServerboundEditBookPacket::pages, - ByteBufCodecs.stringUtf8(128).apply(ByteBufCodecs::optional), + ByteBufCodecs.stringUtf8(net.minecraft.world.item.component.WrittenBookContent.TITLE_MAX_LENGTH).apply(ByteBufCodecs::optional), // Paper - limit books ServerboundEditBookPacket::title, ServerboundEditBookPacket::new ); diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java index e880b41e1824f986d04a0a32cc735d77f25cf987..987bb9caa952a09615b0a819fc682b354be2b07c 100644 --- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java +++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java @@ -1040,6 +1040,43 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl @Override public void handleEditBook(ServerboundEditBookPacket packet) { + // Paper start - Book size limits + if (!this.cserver.isPrimaryThread()) { + final List pageList = packet.pages(); + long byteTotal = 0; + final int maxBookPageSize = io.papermc.paper.configuration.GlobalConfiguration.get().itemValidation.bookSize.pageMax; + final double multiplier = Math.clamp(io.papermc.paper.configuration.GlobalConfiguration.get().itemValidation.bookSize.totalMultiplier, 0.3D, 1D); + long byteAllowed = maxBookPageSize; + for (final String page : pageList) { + final int byteLength = page.getBytes(java.nio.charset.StandardCharsets.UTF_8).length; + byteTotal += byteLength; + final int length = page.length(); + int multiByteCharacters = 0; + if (byteLength != length) { + // Count the number of multi byte characters + for (final char c : page.toCharArray()) { + if (c > 127) { + multiByteCharacters++; + } + } + } + + // Allow pages with fewer characters to consume less of the allowed byte quota + byteAllowed += maxBookPageSize * Math.clamp((double) length / 255D, 0.1D, 1) * multiplier; + + if (multiByteCharacters > 1) { + // Penalize multibyte characters + byteAllowed -= multiByteCharacters; + } + } + + if (byteTotal > byteAllowed) { + ServerGamePacketListenerImpl.LOGGER.warn("{} tried to send a book too large. Book size: {} - Allowed: {} - Pages: {}", this.player.getScoreboardName(), byteTotal, byteAllowed, pageList.size()); + this.disconnect(Component.literal("Book too large!")); + return; + } + } + // Paper end - Book size limits // CraftBukkit start if (this.lastBookTick + 20 > MinecraftServer.currentTick) { this.disconnect("Book edited too quickly!");