From: Nikola Jokic <jokicnikola07@gmail.com>
Date: Fri, 2 Dec 2022 16:42:48 +0000 (+0100)
Subject: debug/buildinfo: check pointer size on buildinfo.Read
X-Git-Tag: go1.20rc2~1^2~39
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c6ad9dc9b523b710afa07d7c5bcb6fe9d21c308c;p=gostls13.git

debug/buildinfo: check pointer size on buildinfo.Read

Previous implementation has a check on pointer size but only if ptrSize
is 4. but it does not check on ptrSize 8 causing the panic on read for
some inputs.

The explicit check for pointer size 8 is added and error is returned if
ptrSize is not 4 and not 8.

Fixes #57002

Change-Id: Id51de72bdef4da9955d086bfc2a5d735678ee2ac
Reviewed-on: https://go-review.googlesource.com/c/go/+/454616
Auto-Submit: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>
---

diff --git a/src/debug/buildinfo/buildinfo.go b/src/debug/buildinfo/buildinfo.go
index 255e6d3d50..8bc5753a2d 100644
--- a/src/debug/buildinfo/buildinfo.go
+++ b/src/debug/buildinfo/buildinfo.go
@@ -192,8 +192,10 @@ func readRawBuildInfo(r io.ReaderAt) (vers, mod string, err error) {
 		var readPtr func([]byte) uint64
 		if ptrSize == 4 {
 			readPtr = func(b []byte) uint64 { return uint64(bo.Uint32(b)) }
-		} else {
+		} else if ptrSize == 8 {
 			readPtr = bo.Uint64
+		} else {
+			return "", "", errNotGoExe
 		}
 		vers = readString(x, ptrSize, readPtr, readPtr(data[16:]))
 		mod = readString(x, ptrSize, readPtr, readPtr(data[16+ptrSize:]))
diff --git a/src/debug/buildinfo/buildinfo_test.go b/src/debug/buildinfo/buildinfo_test.go
index ae04b4cb1d..290e3705bc 100644
--- a/src/debug/buildinfo/buildinfo_test.go
+++ b/src/debug/buildinfo/buildinfo_test.go
@@ -248,6 +248,18 @@ func TestReadFile(t *testing.T) {
 	}
 }
 
+// FuzzIssue57002 is a regression test for golang.org/issue/57002.
+//
+// The cause of issue 57002 is when pointerSize is not being checked,
+// the read can panic with slice bounds out of range
+func FuzzIssue57002(f *testing.F) {
+	// input from issue
+	f.Add([]byte{0x4d, 0x5a, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x50, 0x45, 0x0, 0x0, 0x0, 0x0, 0x5, 0x0, 0x20, 0x20, 0x20, 0x20, 0x0, 0x0, 0x0, 0x0, 0x20, 0x3f, 0x0, 0x20, 0x0, 0x0, 0x20, 0x20, 0x20, 0x20, 0x20, 0xff, 0x20, 0x20, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xb, 0x20, 0x20, 0x20, 0xfc, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x9, 0x0, 0x0, 0x0, 0x20, 0x0, 0x0, 0x0, 0x20, 0x20, 0x20, 0x20, 0x20, 0xef, 0x20, 0xff, 0xbf, 0xff, 0xff, 0xff, 0xff, 0xff, 0xf, 0x0, 0x2, 0x0, 0x20, 0x0, 0x0, 0x9, 0x0, 0x4, 0x0, 0x20, 0xf6, 0x0, 0xd3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x20, 0x1, 0x0, 0x0, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0xa, 0x20, 0xa, 0x20, 0x20, 0x20, 0xff, 0x20, 0x20, 0xff, 0x20, 0x47, 0x6f, 0x20, 0x62, 0x75, 0x69, 0x6c, 0x64, 0x69, 0x6e, 0x66, 0x3a, 0xde, 0xb5, 0xdf, 0xff, 0xff, 0xff, 0xff, 0xff, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x6, 0x7f, 0x7f, 0x7f, 0x20, 0xf4, 0xb2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0xb, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x20, 0x20, 0x0, 0x0, 0x0, 0x0, 0x5, 0x0, 0x20, 0x20, 0x20, 0x20, 0x0, 0x0, 0x0, 0x0, 0x20, 0x3f, 0x27, 0x20, 0x0, 0xd, 0x0, 0xa, 0x20, 0x20, 0x20, 0x20, 0x20, 0xff, 0x20, 0x20, 0xff, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x0, 0x20, 0x20, 0x0, 0x0, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x5c, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20})
+	f.Fuzz(func(t *testing.T, input []byte) {
+		buildinfo.Read(bytes.NewReader(input))
+	})
+}
+
 // TestIssue54968 is a regression test for golang.org/issue/54968.
 //
 // The cause of issue 54968 is when the first buildInfoMagic is invalid, it