From 4efa6a670c8a4c072d2b6384e408faeb4049aafa Mon Sep 17 00:00:00 2001
From: Janusz Majnert <janusz.majnert@tietoevry.com>
Date: Tue, 31 Oct 2023 15:04:46 +0100
Subject: [PATCH] Fix reading 0 bits

---
 pkg/asn1/aper/aper.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkg/asn1/aper/aper.go b/pkg/asn1/aper/aper.go
index d4cf10d..3afa864 100644
--- a/pkg/asn1/aper/aper.go
+++ b/pkg/asn1/aper/aper.go
@@ -44,6 +44,10 @@ func GetBitString(srcBytes []byte, bitsOffset uint, numBits uint) (dstBytes []by
 		err = fmt.Errorf("Get bits overflow, requireBits: %d, leftBits: %d", numBits, bitsLeft)
 		return
 	}
+	if numBits == 0 {
+		err = fmt.Errorf("Get bits called with zero numBits")
+		return
+	}
 	byteLen := (bitsOffset + numBits + 7) >> 3
 	numBitsByteLen := (numBits + 7) >> 3
 	dstBytes = make([]byte, numBitsByteLen)