gentoo-overlay/net-vpn/i2p/files/i2p-0.9.47-DataHelper-decompress-fix-length-check.patch

# from https://trac.i2p2.de/ticket/2770
From ceb0749e0d5c3c496b4a91bc3a9d3b5e296fc456 Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Wed, 2 Sep 2020 15:57:04 +0000
Subject: [PATCH] Util: Fix decompression of compressed zero bytes (ticket
 #2770)

---
 core/java/src/net/i2p/data/DataHelper.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/core/java/src/net/i2p/data/DataHelper.java b/core/java/src/net/i2p/data/DataHelper.java
index aaa47797c3..39f766e6fa 100644
--- a/core/java/src/net/i2p/data/DataHelper.java
+++ b/core/java/src/net/i2p/data/DataHelper.java
@@ -1902,7 +1902,8 @@ public static String unescapeHTML(String escaped) {
      */
     public static byte[] decompress(byte orig[], int offset, int length) throws IOException {
         if (orig == null) return orig;
-        if (length < 23)
+        // normal overhead is 23 bytes, but a compress of zero bytes is 20 bytes
+        if (length < 20)
             throw new IOException("length");
         if (length < 65559 && orig[offset + 10] == 0x01)
             return zeroDecompress(orig, offset, length);