From a5b230b81d0d23bf3f0681235de6bb90d6a956d0 Mon Sep 17 00:00:00 2001
From: aarzilli <alessandro.arzilli@gmail.com>
Date: Tue, 12 Sep 2017 12:40:19 +0200
Subject: [PATCH] pkg/dwarf/frame: fix parsing of zero length entries

Some linkers will sometimes insert a zero length entry between the last
FDE of a CIE and the next CIE.
---
 pkg/dwarf/frame/parser.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/pkg/dwarf/frame/parser.go b/pkg/dwarf/frame/parser.go
index 9afa5a2f..4fe84f6b 100644
--- a/pkg/dwarf/frame/parser.go
+++ b/pkg/dwarf/frame/parser.go
@@ -45,11 +45,18 @@ func cieEntry(data []byte) bool {
 }
 
 func parselength(ctx *parseContext) parsefunc {
-	var data = ctx.buf.Next(8)
+	binary.Read(ctx.buf, binary.LittleEndian, &ctx.length)
 
-	ctx.length = binary.LittleEndian.Uint32(data[:4]) - 4 // take off the length of the CIE id / CIE pointer.
+	if ctx.length == 0 {
+		// ZERO terminator
+		return parselength
+	}
 
-	if cieEntry(data[4:]) {
+	var data = ctx.buf.Next(4)
+
+	ctx.length -= 4 // take off the length of the CIE id / CIE pointer.
+
+	if cieEntry(data) {
 		ctx.common = &CommonInformationEntry{Length: ctx.length}
 		return parseCIE
 	}