From c8afc5b4d20f244116c355ccf53d2c65d3466014 Mon Sep 17 00:00:00 2001
From: rihi <19492038+rihi@users.noreply.github.com>
Date: Sun, 31 Mar 2024 21:15:08 +0200
Subject: [PATCH] Fix LumpFile error with invalid offet/size

Fixes checks of valid offset/size and also try to gracefully handle these cases by defaulting to sensible values.
Motivated by https://github.com/ata4/bspsrc/issues/150#issuecomment-2028457654
---
 .../main/java/info/ata4/bspsrc/lib/BspFile.java |  4 ++--
 .../info/ata4/bspsrc/lib/lump/LumpFile.java     | 17 +++++++++--------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/BspFile.java b/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/BspFile.java
index d744269c..265755da 100644
--- a/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/BspFile.java
+++ b/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/BspFile.java
@@ -358,7 +358,7 @@ private void loadLumps(ByteBuffer bb) {
             }
 
             Lump l = new Lump(i, ltype);
-            l.setBuffer(ByteBufferUtils.getSlice(bb, ofs, len));
+            l.setBuffer(bb.slice(ofs, len).order(bb.order()));
             l.setOffset(ofs);
             l.setParentFile(file);
             l.setFourCC(fourCC);
@@ -600,7 +600,7 @@ && checkInvalidHeaders(in, false)
                 }
 
                 GameLump gl = new GameLump();
-                gl.setBuffer(ByteBufferUtils.getSlice(lump.getBuffer(), ofs, len));
+                gl.setBuffer(lump.getBuffer().slice(ofs, len).order(lump.getBuffer().order()));
                 gl.setOffset(ofs);
                 gl.setFourCC(fourCC);
                 gl.setFlags(flags);
diff --git a/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/lump/LumpFile.java b/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/lump/LumpFile.java
index afe9625f..53ea0d58 100644
--- a/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/lump/LumpFile.java
+++ b/bspsrc-lib/src/main/java/info/ata4/bspsrc/lib/lump/LumpFile.java
@@ -78,21 +78,22 @@ public void load(Path file, ByteOrder bo) throws IOException {
         L.trace("Lump size: {}", lumpSize);
         L.trace("Map revision: {}", mapRev);
 
-        if (lumpOffset != HEADER_SIZE) {
-            throw new LumpException("Unexpected lump offset: " + lumpOffset);
-        }
-
         if (lumpIndex < 0 || lumpIndex > BspFile.HEADER_LUMPS) {
             throw new LumpException("Invalid lump ID: " + lumpIndex);
         }
-
-        if (lumpSize < 0 || lumpOffset > bb.limit()) {
-            throw new LumpException("Invalid lump size: " + lumpOffset);
+        if (lumpOffset < 0 || lumpOffset > bb.limit()) {
+            L.warn("Invalid offset %d for lump %d, assuming %d".formatted(lumpOffset, lumpIndex, HEADER_SIZE));
+            lumpOffset = HEADER_SIZE;
+        }
+        if (lumpSize < 0 || lumpOffset + lumpSize > bb.limit()) {
+            int newLumpSize = bb.limit() - lumpOffset;
+            L.warn("Invalid size %d for lump %d, assuming %d".formatted(lumpSize, lumpIndex, newLumpSize));
+            lumpSize = newLumpSize;
         }
 
         // lump data
         lump = new Lump(lumpIndex, LumpType.get(lumpIndex, bspVersion));
-        lump.setBuffer(ByteBufferUtils.getSlice(bb, lumpOffset, lumpSize));
+        lump.setBuffer(bb.slice(lumpOffset, lumpSize).order(bb.order()));
         lump.setOffset(lumpOffset);
         lump.setParentFile(file);
     }