vendor: update golang.org/x/net/dns/dnsmessage from upstream

Updates to x/net git rev 24dd378 for CL 100055

Fixes #10622
Updates #16218

Change-Id: I99e26da7b908b36585a0379d9381030c01819b54
Reviewed-on: https://go-review.googlesource.com/101278
Run-TryBot: Ian Gudger <igudger@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

diff --git a/src/vendor/golang_org/x/net/dns/dnsmessage/message.go b/src/vendor/golang_org/x/net/dns/dnsmessage/message.go
index 0ab4aab20235870d1a7ed29633b940e06030774f..d8d3b0342925137eaf77fe6b6a6118983f6d6caf 100644 (file)
--- a/src/vendor/golang_org/x/net/dns/dnsmessage/message.go
+++ b/src/vendor/golang_org/x/net/dns/dnsmessage/message.go
@@ -91,6 +91,7 @@ var (
        errTooManyAdditionals = errors.New("too many Additionals to pack (>65535)")
        errNonCanonicalName   = errors.New("name is not in canonical format (it must end with a .)")
        errStringTooLong      = errors.New("character string exceeds maximum length (255)")
+       errCompressedSRV      = errors.New("compressed name in SRV resource data")
 )
 
 // Internal constants.
@@ -1610,6 +1611,10 @@ func (n *Name) pack(msg []byte, compression map[string]int, compressionOff int)
 
 // unpack unpacks a domain name.
 func (n *Name) unpack(msg []byte, off int) (int, error) {
+       return n.unpackCompressed(msg, off, true /* allowCompression */)
+}
+
+func (n *Name) unpackCompressed(msg []byte, off int, allowCompression bool) (int, error) {
        // currOff is the current working offset.
        currOff := off
 
@@ -1645,6 +1650,9 @@ Loop:
                        name = append(name, '.')
                        currOff = endOff
                case 0xC0: // Pointer
+                       if !allowCompression {
+                               return off, errCompressedSRV
+                       }
                        if currOff >= len(msg) {
                                return off, errInvalidPtr
                        }
@@ -2044,7 +2052,7 @@ func unpackSRVResource(msg []byte, off int) (SRVResource, error) {
                return SRVResource{}, &nestedError{"Port", err}
        }
        var target Name
-       if _, err := target.unpack(msg, off); err != nil {
+       if _, err := target.unpackCompressed(msg, off, false /* allowCompression */); err != nil {
                return SRVResource{}, &nestedError{"Target", err}
        }
        return SRVResource{priority, weight, port, target}, nil

diff --git a/src/vendor/golang_org/x/net/dns/dnsmessage/message_test.go b/src/vendor/golang_org/x/net/dns/dnsmessage/message_test.go
index c143d7e791c9c754f611eefb130de413d5248e4a..052897f3cf55d95bdcf033d1ce895230eed71807 100644 (file)
--- a/src/vendor/golang_org/x/net/dns/dnsmessage/message_test.go
+++ b/src/vendor/golang_org/x/net/dns/dnsmessage/message_test.go
@@ -158,6 +158,28 @@ func TestNamePackUnpack(t *testing.T) {
        }
 }
 
+func TestIncompressibleName(t *testing.T) {
+       name := mustNewName("example.com.")
+       compression := map[string]int{}
+       buf, err := name.pack(make([]byte, 0, 100), compression, 0)
+       if err != nil {
+               t.Fatal("First packing failed:", err)
+       }
+       buf, err = name.pack(buf, compression, 0)
+       if err != nil {
+               t.Fatal("Second packing failed:", err)
+       }
+       var n1 Name
+       off, err := n1.unpackCompressed(buf, 0, false /* allowCompression */)
+       if err != nil {
+               t.Fatal("Unpacking incompressible name without pointers failed:", err)
+       }
+       var n2 Name
+       if _, err := n2.unpackCompressed(buf, off, false /* allowCompression */); err != errCompressedSRV {
+               t.Errorf("Unpacking compressed incompressible name with pointers: got err = %v, want = %v", err, errCompressedSRV)
+       }
+}
+
 func checkErrorPrefix(err error, prefix string) bool {
        e, ok := err.(*nestedError)
        return ok && e.s == prefix