From: Ian Lance Taylor <iant@golang.org>
Date: Tue, 27 Sep 2022 01:24:03 +0000 (-0700)
Subject: debug/dwarf: don't crash on invalid range/rnglist offset
X-Git-Tag: go1.20rc1~912
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c929a5b855e5d1680a70c5e1ab11a4933655d66c;p=gostls13.git

debug/dwarf: don't crash on invalid range/rnglist offset

No test case because the problem can only happen for invalid data. Let
the fuzzer find cases like this.

Fixes #53529

Change-Id: I318c87795e545fe5a006d16b4d361cd4bf5d502d
Reviewed-on: https://go-review.googlesource.com/c/go/+/434936
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
---

diff --git a/src/debug/dwarf/entry.go b/src/debug/dwarf/entry.go
index 6f80d07503..7f48ff3a04 100644
--- a/src/debug/dwarf/entry.go
+++ b/src/debug/dwarf/entry.go
@@ -13,6 +13,7 @@ package dwarf
 import (
 	"encoding/binary"
 	"errors"
+	"fmt"
 	"strconv"
 )
 
@@ -1103,6 +1104,9 @@ func (d *Data) baseAddressForEntry(e *Entry) (*Entry, uint64, error) {
 }
 
 func (d *Data) dwarf2Ranges(u *unit, base uint64, ranges int64, ret [][2]uint64) ([][2]uint64, error) {
+	if ranges > int64(len(d.ranges)) {
+		return nil, fmt.Errorf("invalid range offset %d (max %d)", ranges, len(d.ranges))
+	}
 	buf := makeBuf(d, u, "ranges", Offset(ranges), d.ranges[ranges:])
 	for len(buf.data) > 0 {
 		low := buf.addr()
@@ -1125,6 +1129,9 @@ func (d *Data) dwarf2Ranges(u *unit, base uint64, ranges int64, ret [][2]uint64)
 // dwarf5Ranges interprets a debug_rnglists sequence, see DWARFv5 section
 // 2.17.3 (page 53).
 func (d *Data) dwarf5Ranges(u *unit, cu *Entry, base uint64, ranges int64, ret [][2]uint64) ([][2]uint64, error) {
+	if ranges > int64(len(d.rngLists)) {
+		return nil, fmt.Errorf("invalid rnglist offset %d (max %d)", ranges, len(d.ranges))
+	}
 	var addrBase int64
 	if cu != nil {
 		addrBase, _ = cu.Val(AttrAddrBase).(int64)