From: Ian Lance Taylor <iant@golang.org>
Date: Thu, 19 Oct 2023 00:30:31 +0000 (-0700)
Subject: debug/elf: return error in DynString for invalid dynamic section size
X-Git-Tag: go1.22rc1~517
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=57322b3cbf1ed26c3b19c6edcd5758c794a36467;p=gostls13.git

debug/elf: return error in DynString for invalid dynamic section size

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

Fixes #63610

Change-Id: I797b4d9bdb08286ad3e3a9a6f800ee8c90cb7261
Reviewed-on: https://go-review.googlesource.com/c/go/+/536400
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Mauri de Souza Meneguzzo <mauri870@gmail.com>
---

diff --git a/src/debug/elf/file.go b/src/debug/elf/file.go
index e748716cb7..fcbe76b195 100644
--- a/src/debug/elf/file.go
+++ b/src/debug/elf/file.go
@@ -1607,6 +1607,15 @@ func (f *File) DynString(tag DynTag) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
+
+	dynSize := 8
+	if f.Class == ELFCLASS64 {
+		dynSize = 16
+	}
+	if len(d)%dynSize != 0 {
+		return nil, errors.New("length of dynamic section is not a multiple of dynamic entry size")
+	}
+
 	str, err := f.stringTable(ds.Link)
 	if err != nil {
 		return nil, err