fix integer underflow (#374)

Signed-off-by: Ignacio Hagopian <[email protected]>
gballet · May 8, 2024 · 8ac0570 · 8ac0570
1 parent 077ad87
commit 8ac0570
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/core/vm/instructions.go b/core/vm/instructions.go
@@ -401,11 +401,13 @@ func touchCodeChunksRangeOnReadAndChargeGas(contractAddr []byte, startPC, size u
 		return 0
 	}
 
-	// endPC is the last PC that must be touched.
-	endPC := startPC + size - 1
-	if startPC+size > codeLen {
+	endPC := startPC + size
+	if endPC > codeLen {
 		endPC = codeLen
 	}
+	if endPC > 0 {
+		endPC -= 1 // endPC is the last bytecode that will be touched.
+	}
 
 	var statelessGasCharged uint64
 	for chunkNumber := startPC / 31; chunkNumber <= endPC/31; chunkNumber++ {