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PaperMC/patches/server/0937-Improve-tag-parser-handling.patch
Bjarne Koll ad9c58e103
Only expose velocity relative tp flags to API (#11532) 
Since 1.21.2, vanilla split relative teleportation flags into position
and delta/velocity flags into separate enum entries.
This highlighted a design flaw in the paper api addition for teleport
flags, which just simply mirrored internals while also only being able
to apply the delta/velocity part of a flag, given the teleport target is
always absolute in the API.

This patch proposes to simply no longer expose the non-velocity related
flags to the API, instead marking the entire Relative enum as being
purely velocity related, as non-velocity related flags are not useful to
callers. This was done over simply exposing all internal flags, as
another vanilla change to the internal enum would result in the same
breakage.

The newly proposed API *only* promises that the passed flags prevent the
loss of velocity in the specific axis/context, which should be
independent enough of vanillas specific implementation of this feature.
2024-10-31 17:25:52 +01:00

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Raw Blame History

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <nassim@njahnke.dev>
Date: Mon, 5 Feb 2024 11:54:04 +0100
Subject: [PATCH] Improve tag parser handling
diff --git a/src/main/java/com/mojang/brigadier/CommandDispatcher.java b/src/main/java/com/mojang/brigadier/CommandDispatcher.java
index 92848b64a78fce7a92e1657c2da6fc5ee53eea44..4b4f812eb13d5f03bcf3f8724d8aa8dbbc724e8b 100644
--- a/src/main/java/com/mojang/brigadier/CommandDispatcher.java
+++ b/src/main/java/com/mojang/brigadier/CommandDispatcher.java
@@ -304,9 +304,15 @@ public class CommandDispatcher<S> {
}
final CommandContextBuilder<S> context = contextSoFar.copy();
final StringReader reader = new StringReader(originalReader);
+ boolean stop = false; // Paper - Handle non-recoverable exceptions
try {
try {
child.parse(reader, context);
+ // Paper start - Handle non-recoverable exceptions
+ } catch (final io.papermc.paper.brigadier.TagParseCommandSyntaxException e) {
+ stop = true;
+ throw e;
+ // Paper end - Handle non-recoverable exceptions
} catch (final RuntimeException ex) {
throw CommandSyntaxException.BUILT_IN_EXCEPTIONS.dispatcherParseException().createWithContext(reader, ex.getMessage());
}
@@ -321,6 +327,7 @@ public class CommandDispatcher<S> {
}
errors.put(child, ex);
reader.setCursor(cursor);
+ if (stop) return new ParseResults<>(contextSoFar, originalReader, errors); // Paper - Handle non-recoverable exceptions
continue;
}
diff --git a/src/main/java/io/papermc/paper/brigadier/TagParseCommandSyntaxException.java b/src/main/java/io/papermc/paper/brigadier/TagParseCommandSyntaxException.java
new file mode 100644
index 0000000000000000000000000000000000000000..a375ad4ba9db990b24a2b9ff366fcba66b753815
--- /dev/null
+++ b/src/main/java/io/papermc/paper/brigadier/TagParseCommandSyntaxException.java
@@ -0,0 +1,15 @@
+package io.papermc.paper.brigadier;
+
+import com.mojang.brigadier.LiteralMessage;
+import com.mojang.brigadier.exceptions.CommandSyntaxException;
+import com.mojang.brigadier.exceptions.SimpleCommandExceptionType;
+import net.minecraft.network.chat.Component;
+
+public final class TagParseCommandSyntaxException extends CommandSyntaxException {
+
+ private static final SimpleCommandExceptionType EXCEPTION_TYPE = new SimpleCommandExceptionType(new LiteralMessage("Error parsing NBT"));
+
+ public TagParseCommandSyntaxException(final String message) {
+ super(EXCEPTION_TYPE, Component.literal(message));
+ }
+}
diff --git a/src/main/java/net/minecraft/commands/arguments/selector/SelectorPattern.java b/src/main/java/net/minecraft/commands/arguments/selector/SelectorPattern.java
index 82ecd9c034a2ee5040b6a66233070ce1cb4e48d2..50e66b10ec3943b9068e546763087161395f673a 100644
--- a/src/main/java/net/minecraft/commands/arguments/selector/SelectorPattern.java
+++ b/src/main/java/net/minecraft/commands/arguments/selector/SelectorPattern.java
@@ -13,7 +13,7 @@ public record SelectorPattern(String pattern, EntitySelector resolved) {
EntitySelectorParser entitySelectorParser = new EntitySelectorParser(new StringReader(selector), true);
return DataResult.success(new SelectorPattern(selector, entitySelectorParser.parse()));
} catch (CommandSyntaxException var2) {
- return DataResult.error(() -> "Invalid selector component: " + selector + ": " + var2.getMessage());
+ return DataResult.error(() -> "Invalid selector component"); // Paper - limit selector error message
}
}
diff --git a/src/main/java/net/minecraft/nbt/TagParser.java b/src/main/java/net/minecraft/nbt/TagParser.java
index da101bca71f4710812621b98f0a0d8cab180346a..3cd112584accb8e8f050ac99738eed11c902e60e 100644
--- a/src/main/java/net/minecraft/nbt/TagParser.java
+++ b/src/main/java/net/minecraft/nbt/TagParser.java
@@ -49,6 +49,7 @@ public class TagParser {
}, CompoundTag::toString);
public static final Codec<CompoundTag> LENIENT_CODEC = Codec.withAlternative(AS_CODEC, CompoundTag.CODEC);
private final StringReader reader;
+ private int depth; // Paper
public static CompoundTag parseTag(String string) throws CommandSyntaxException {
return new TagParser(new StringReader(string)).readSingleStruct();
@@ -159,6 +160,7 @@ public class TagParser {
public CompoundTag readStruct() throws CommandSyntaxException {
this.expect('{');
+ this.increaseDepth(); // Paper
CompoundTag compoundTag = new CompoundTag();
this.reader.skipWhitespace();
@@ -182,6 +184,7 @@ public class TagParser {
}
this.expect('}');
+ this.depth--; // Paper
return compoundTag;
}
@@ -191,6 +194,7 @@ public class TagParser {
if (!this.reader.canRead()) {
throw ERROR_EXPECTED_VALUE.createWithContext(this.reader);
} else {
+ this.increaseDepth(); // Paper
ListTag listTag = new ListTag();
TagType<?> tagType = null;
@@ -216,6 +220,7 @@ public class TagParser {
}
this.expect(']');
+ this.depth--; // Paper
return listTag;
}
}
@@ -288,4 +293,11 @@ public class TagParser {
this.reader.skipWhitespace();
this.reader.expect(c);
}
+
+ private void increaseDepth() throws CommandSyntaxException {
+ this.depth++;
+ if (this.depth > 512) {
+ throw new io.papermc.paper.brigadier.TagParseCommandSyntaxException("NBT tag is too complex, depth > 512");
+ }
+ }
}
diff --git a/src/main/java/net/minecraft/network/chat/ComponentUtils.java b/src/main/java/net/minecraft/network/chat/ComponentUtils.java
index 3365aed2b67ae0e4dd0410f5190ba474f146139b..8b776434a733b91129b089d702b2583b727bf3d2 100644
--- a/src/main/java/net/minecraft/network/chat/ComponentUtils.java
+++ b/src/main/java/net/minecraft/network/chat/ComponentUtils.java
@@ -33,10 +33,30 @@ public class ComponentUtils {
}
}
+ @io.papermc.paper.annotation.DoNotUse // Paper - validate separators - right now this method is only used for separator evaluation. Error on build if this changes to re-evaluate.
public static Optional<MutableComponent> updateForEntity(@Nullable CommandSourceStack source, Optional<Component> text, @Nullable Entity sender, int depth) throws CommandSyntaxException {
return text.isPresent() ? Optional.of(updateForEntity(source, text.get(), sender, depth)) : Optional.empty();
}
+ // Paper start - validate separator
+ public static Optional<MutableComponent> updateSeparatorForEntity(@Nullable CommandSourceStack source, Optional<Component> text, @Nullable Entity sender, int depth) throws CommandSyntaxException {
+ if (text.isEmpty() || !isValidSelector(text.get())) return Optional.empty();
+ return Optional.of(updateForEntity(source, text.get(), sender, depth));
+ }
+ public static boolean isValidSelector(final Component component) {
+ final ComponentContents contents = component.getContents();
+
+ if (contents instanceof net.minecraft.network.chat.contents.NbtContents || contents instanceof net.minecraft.network.chat.contents.SelectorContents) return false;
+ if (contents instanceof final net.minecraft.network.chat.contents.TranslatableContents translatableContents) {
+ for (final Object arg : translatableContents.getArgs()) {
+ if (arg instanceof final Component argumentAsComponent && !isValidSelector(argumentAsComponent)) return false;
+ }
+ }
+
+ return true;
+ }
+ // Paper end - validate separator
+
public static MutableComponent updateForEntity(@Nullable CommandSourceStack source, Component text, @Nullable Entity sender, int depth) throws CommandSyntaxException {
if (depth > 100) {
return text.copy();
diff --git a/src/main/java/net/minecraft/network/chat/contents/NbtContents.java b/src/main/java/net/minecraft/network/chat/contents/NbtContents.java
index df26c39a2bb20e2021b50211dce905483a77f4e6..5634122dac8afeecab0cde623e9868d8e865e02a 100644
--- a/src/main/java/net/minecraft/network/chat/contents/NbtContents.java
+++ b/src/main/java/net/minecraft/network/chat/contents/NbtContents.java
@@ -120,7 +120,7 @@ public class NbtContents implements ComponentContents {
}).map(Tag::getAsString);
if (this.interpreting) {
Component component = DataFixUtils.orElse(
- ComponentUtils.updateForEntity(source, this.separator, sender, depth), ComponentUtils.DEFAULT_NO_STYLE_SEPARATOR
+ ComponentUtils.updateSeparatorForEntity(source, this.separator, sender, depth), ComponentUtils.DEFAULT_NO_STYLE_SEPARATOR // Paper - validate separator
);
return stream.flatMap(text -> {
try {
@@ -132,7 +132,7 @@ public class NbtContents implements ComponentContents {
}
}).reduce((accumulator, current) -> accumulator.append(component).append(current)).orElseGet(Component::empty);
} else {
- return ComponentUtils.updateForEntity(source, this.separator, sender, depth)
+ return ComponentUtils.updateSeparatorForEntity(source, this.separator, sender, depth) // Paper - validate separator
.map(
text -> stream.map(Component::literal)
.reduce((accumulator, current) -> accumulator.append(text).append(current))
diff --git a/src/main/java/net/minecraft/network/chat/contents/SelectorContents.java b/src/main/java/net/minecraft/network/chat/contents/SelectorContents.java
index 5e87f5a2bbffe2eba3fc4fb0da51acee99e72fc2..4131067620f723be28a6cdb7508e14d7e2aed48b 100644
--- a/src/main/java/net/minecraft/network/chat/contents/SelectorContents.java
+++ b/src/main/java/net/minecraft/network/chat/contents/SelectorContents.java
@@ -36,7 +36,7 @@ public record SelectorContents(SelectorPattern selector, Optional<Component> sep
if (source == null) {
return Component.empty();
} else {
- Optional<? extends Component> optional = ComponentUtils.updateForEntity(source, this.separator, sender, depth);
+ Optional<? extends Component> optional = ComponentUtils.updateSeparatorForEntity(source, this.separator, sender, depth); // Paper - validate separator
return ComponentUtils.formatList(this.selector.resolved().findEntities(source), optional, Entity::getDisplayName);
}
}
diff --git a/src/main/java/net/minecraft/network/chat/contents/TranslatableContents.java b/src/main/java/net/minecraft/network/chat/contents/TranslatableContents.java
index 56e641bc5f6edc657647993ea2efbb7bb9c2f732..4aa6232bf0f72fcde32d257100bd15b1c5192aaa 100644
--- a/src/main/java/net/minecraft/network/chat/contents/TranslatableContents.java
+++ b/src/main/java/net/minecraft/network/chat/contents/TranslatableContents.java
@@ -181,6 +181,15 @@ public class TranslatableContents implements ComponentContents {
@Override
public <T> Optional<T> visit(FormattedText.ContentConsumer<T> visitor) {
+ // Paper start - Count visited parts
+ try {
+ return this.visit(new TranslatableContentConsumer<>(visitor));
+ } catch (IllegalArgumentException ignored) {
+ return visitor.accept("...");
+ }
+ }
+ private <T> Optional<T> visit(TranslatableContentConsumer<T> visitor) {
+ // Paper end - Count visited parts
this.decompose();
for (FormattedText formattedText : this.decomposedParts) {
@@ -192,6 +201,25 @@ public class TranslatableContents implements ComponentContents {
return Optional.empty();
}
+ // Paper start - Count visited parts
+ private static final class TranslatableContentConsumer<T> implements FormattedText.ContentConsumer<T> {
+ private static final IllegalArgumentException EX = new IllegalArgumentException("Too long");
+ private final FormattedText.ContentConsumer<T> visitor;
+ private int visited;
+
+ private TranslatableContentConsumer(FormattedText.ContentConsumer<T> visitor) {
+ this.visitor = visitor;
+ }
+
+ @Override
+ public Optional<T> accept(final String asString) {
+ if (visited++ > 32) {
+ throw EX;
+ }
+ return this.visitor.accept(asString);
+ }
+ }
+ // Paper end - Count visited parts
@Override
public MutableComponent resolve(@Nullable CommandSourceStack source, @Nullable Entity sender, int depth) throws CommandSyntaxException {
diff --git a/src/main/java/net/minecraft/network/protocol/game/ServerboundCommandSuggestionPacket.java b/src/main/java/net/minecraft/network/protocol/game/ServerboundCommandSuggestionPacket.java
index 898b19887ed34c87003fc63cb5905df2ba6234a5..b47eeb23055b135d5567552ba983bfbc3e1fab67 100644
--- a/src/main/java/net/minecraft/network/protocol/game/ServerboundCommandSuggestionPacket.java
+++ b/src/main/java/net/minecraft/network/protocol/game/ServerboundCommandSuggestionPacket.java
@@ -19,7 +19,7 @@ public class ServerboundCommandSuggestionPacket implements Packet<ServerGamePack
private ServerboundCommandSuggestionPacket(FriendlyByteBuf buf) {
this.id = buf.readVarInt();
- this.command = buf.readUtf(32500);
+ this.command = buf.readUtf(2048); // Paper
}
private void write(FriendlyByteBuf buf) {
diff --git a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
index bf8355d3b235ce48cbb1011142096d42246a08e2..c4ffa8519b520e0793af90e149518951d7ffb65b 100644
--- a/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerGamePacketListenerImpl.java
@@ -778,6 +778,13 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
return;
}
// Paper end - Don't suggest if tab-complete is disabled
+ // Paper start
+ final int index;
+ if (packet.getCommand().length() > 64 && ((index = packet.getCommand().indexOf(' ')) == -1 || index >= 64)) {
+ this.disconnect(Component.translatable("disconnect.spam"), org.bukkit.event.player.PlayerKickEvent.Cause.SPAM);
+ return;
+ }
+ // Paper end
// Paper start - AsyncTabCompleteEvent
TAB_COMPLETE_EXECUTOR.execute(() -> this.handleCustomCommandSuggestions0(packet));
}
@@ -830,6 +837,13 @@ public class ServerGamePacketListenerImpl extends ServerCommonPacketListenerImpl
private void sendServerSuggestions(final ServerboundCommandSuggestionPacket packet, final StringReader stringreader) {
// Paper end - AsyncTabCompleteEvent
ParseResults<CommandSourceStack> parseresults = this.server.getCommands().getDispatcher().parse(stringreader, this.player.createCommandSourceStack());
+ // Paper start - Handle non-recoverable exceptions
+ if (!parseresults.getExceptions().isEmpty()
+ && parseresults.getExceptions().values().stream().anyMatch(e -> e instanceof io.papermc.paper.brigadier.TagParseCommandSyntaxException)) {
+ this.disconnect(Component.translatable("disconnect.spam"), org.bukkit.event.player.PlayerKickEvent.Cause.SPAM);
+ return;
+ }
+ // Paper end - Handle non-recoverable exceptions
this.server.getCommands().getDispatcher().getCompletionSuggestions(parseresults).thenAccept((suggestions) -> {
// Paper start - Don't tab-complete namespaced commands if send-namespaced is false
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