debug/dwarf: better stmt list attr checking in LineReader

Check for insane statement list attribute values when
constructing LineReader's for a compilation unit.

Fixes #52354.

Change-Id: Icb5298db31f6c5fe34c44e0ed4fe277a7cd676b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/400255
Run-TryBot: Than McIntosh <thanm@google.com>
Auto-Submit: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>

diff --git a/src/debug/dwarf/line.go b/src/debug/dwarf/line.go
index c4937ca7dd8636ce4580fd6560dab5aa8e2f7cd4..bb281fbdd93b71b5d4c901111829a0770e8a6859 100644 (file)
--- a/src/debug/dwarf/line.go
+++ b/src/debug/dwarf/line.go
@@ -152,7 +152,7 @@ func (d *Data) LineReader(cu *Entry) (*LineReader, error) {
                // cu has no line table.
                return nil, nil
        }
-       if off > int64(len(d.line)) {
+       if off < 0 || off > int64(len(d.line)) {
                return nil, errors.New("AttrStmtList value out of range")
        }
        // AttrCompDir is optional if all file names are absolute. Use

diff --git a/src/debug/dwarf/line_test.go b/src/debug/dwarf/line_test.go
index 9c6b6ff5b0326674ca38b59fdea3c6ad383fd973..163fc3bbb99bb6da25e08233e1247c6a54e6be13 100644 (file)
--- a/src/debug/dwarf/line_test.go
+++ b/src/debug/dwarf/line_test.go
@@ -389,3 +389,32 @@ func TestPathJoin(t *testing.T) {
                }
        }
 }
+
+func TestPathLineReaderMalformed(t *testing.T) {
+       // This test case drawn from issue #52354. What's happening
+       // here is that the stmtList attribute in the compilation
+       // unit is malformed (negative).
+       var aranges, frame, pubnames, ranges, str []byte
+       abbrev := []byte{0x10, 0x20, 0x20, 0x20, 0x21, 0x20, 0x10, 0x21, 0x61,
+               0x0, 0x0, 0xff, 0x20, 0xff, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
+               0x20, 0x20, 0x20, 0x20, 0x20, 0x20}
+       info := []byte{0x0, 0x0, 0x0, 0x9, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0,
+               0x20, 0x10, 0x10}
+       line := []byte{0x20}
+       Data0, err := New(abbrev, aranges, frame, info, line, pubnames, ranges, str)
+       if err != nil {
+               t.Fatalf("error unexpected: %v", err)
+       }
+       Reader0 := Data0.Reader()
+       Entry0, err := Reader0.Next()
+       if err != nil {
+               t.Fatalf("error unexpected: %v", err)
+       }
+       LineReader0, err := Data0.LineReader(Entry0)
+       if err == nil {
+               t.Fatalf("expected error")
+       }
+       if LineReader0 != nil {
+               t.Fatalf("expected nil line reader")
+       }
+}