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89d51d5f29
Because this exploit has been widely known for years and has not been fixed by Mojang, we decided that it was worth allowing people to toggle it on/off due to how easy it is to make it configurable. It should be noted that this decision does not promise all future exploits will be configurable.
53 lines
2.1 KiB
Diff
53 lines
2.1 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: astei <andrew@steinborn.me>
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Date: Sat, 28 Oct 2023 19:46:21 -0400
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Subject: [PATCH] Optimize VarInts
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https://github.com/PaperMC/Paper/pull/6957#issuecomment-985250854
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diff --git a/src/main/java/net/minecraft/network/VarInt.java b/src/main/java/net/minecraft/network/VarInt.java
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index 18d5a22ad3ef4cb279475531dbc2c65e07c69929..3f362eb42587b333e27b9cf25588a9cfcb8a56e7 100644
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--- a/src/main/java/net/minecraft/network/VarInt.java
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+++ b/src/main/java/net/minecraft/network/VarInt.java
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@@ -9,6 +9,18 @@ public class VarInt {
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private static final int DATA_BITS_PER_BYTE = 7;
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public static int getByteSize(int i) {
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+ // Paper start - Optimize VarInts
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+ return VARINT_EXACT_BYTE_LENGTHS[Integer.numberOfLeadingZeros(i)];
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+ }
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+ private static final int[] VARINT_EXACT_BYTE_LENGTHS = new int[33];
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+ static {
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+ for (int i = 0; i <= 32; ++i) {
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+ VARINT_EXACT_BYTE_LENGTHS[i] = (int) Math.ceil((31d - (i - 1)) / 7d);
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+ }
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+ VARINT_EXACT_BYTE_LENGTHS[32] = 1; // Special case for the number 0.
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+ }
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+ public static int getByteSizeOld(int i) {
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+ //Paper end - Optimize VarInts
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for(int j = 1; j < 5; ++j) {
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if ((i & -1 << j * 7) == 0) {
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return j;
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@@ -39,6 +51,21 @@ public class VarInt {
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}
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public static ByteBuf write(ByteBuf buf, int i) {
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+ // Paper start - Optimize VarInts
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+ // Peel the one and two byte count cases explicitly as they are the most common VarInt sizes
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+ // that the proxy will write, to improve inlining.
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+ if ((i & (0xFFFFFFFF << 7)) == 0) {
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+ buf.writeByte(i);
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+ } else if ((i & (0xFFFFFFFF << 14)) == 0) {
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+ int w = (i & 0x7F | 0x80) << 8 | (i >>> 7);
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+ buf.writeShort(w);
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+ } else {
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+ writeOld(buf, i);
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+ }
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+ return buf;
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+ }
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+ public static ByteBuf writeOld(ByteBuf buf, int i) {
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+ // Paper end - Optimize VarInts
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while((i & -128) != 0) {
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buf.writeByte(i & 127 | 128);
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i >>>= 7;
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