From 0e7e9353749e1245e063d79b2e7e20c3ad0a74bb Mon Sep 17 00:00:00 2001
From: Sasha Koshka <sashakoshka@tebibyte.media>
Date: Sun, 18 May 2025 17:59:05 -0400
Subject: [PATCH] tape: Make table decoding more robust

---
 tape/table.go | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tape/table.go b/tape/table.go
index 28f0ea2..349aa79 100644
--- a/tape/table.go
+++ b/tape/table.go
@@ -11,15 +11,19 @@ type TablePullFunc func() (tag uint16, value []byte, n int, err error)
 func DecodeTable(data []byte) TablePullFunc {
 	n := 0
 	return func() (tag uint16, value []byte, n_ int, err error) {
+		if n >= len(data) { return 0, nil, n, ErrWrongBufferLength }
 		tag, nn, err := DecodeI16[uint16](data[n:])
-		if err != nil { return tag, value, n, err }
+		if err != nil { return 0, nil, n, err }
 		n += nn
 
+		if n >= len(data) { return 0, nil, n, ErrWrongBufferLength }
 		length, nn, err := DecodeGBEU[uint64](data[n:])
-		if err != nil { return tag, value, n, err }
+		if err != nil { return 0, nil, n, err }
 		n += nn
 
-		value = data[n:n + int(length)]
+		end := n + int(length)
+		if end > len(data) { return 0, nil, n, ErrWrongBufferLength }
+		value = data[n:end]
 		n += int(length)
 		return tag, value, n, err
 	}