dns/dnsmessage: reject names with dots inside label
Fixes golang/go#56246
Change-Id: I9c8d611d1305536a7510bf6c4a02a5e551aa657a
GitHub-Last-Rev: 8a8703a1a7bde3457682c27db3e7d63856bd0cbc
GitHub-Pull-Request: golang/net#154
Reviewed-on: https://go-review.googlesource.com/c/net/+/443215
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Mateusz Poliwczak <mpoliwczak34@gmail.com>
Auto-Submit: Roland Shoemaker <roland@golang.org>
diff --git a/dns/dnsmessage/message.go b/dns/dnsmessage/message.go
index 69c611b..1577d4a 100644
--- a/dns/dnsmessage/message.go
+++ b/dns/dnsmessage/message.go
@@ -260,6 +260,7 @@
errReserved = errors.New("segment prefix is reserved")
errTooManyPtr = errors.New("too many pointers (>10)")
errInvalidPtr = errors.New("invalid pointer")
+ errInvalidName = errors.New("invalid dns name")
errNilResouceBody = errors.New("nil resource body")
errResourceLen = errors.New("insufficient data for resource body length")
errSegTooLong = errors.New("segment length too long")
@@ -2034,6 +2035,15 @@
if endOff > len(msg) {
return off, errCalcLen
}
+
+ // Reject names containing dots.
+ // See issue golang/go#56246
+ for _, v := range msg[currOff:endOff] {
+ if v == '.' {
+ return off, errInvalidName
+ }
+ }
+
name = append(name, msg[currOff:endOff]...)
name = append(name, '.')
currOff = endOff
diff --git a/dns/dnsmessage/message_test.go b/dns/dnsmessage/message_test.go
index ef5326d..ce2716e 100644
--- a/dns/dnsmessage/message_test.go
+++ b/dns/dnsmessage/message_test.go
@@ -211,6 +211,15 @@
}
}
+func TestNameWithDotsUnpack(t *testing.T) {
+ name := []byte{3, 'w', '.', 'w', 2, 'g', 'o', 3, 'd', 'e', 'v', 0}
+ var n Name
+ _, err := n.unpack(name, 0)
+ if err != errInvalidName {
+ t.Fatalf("expected %v, got %v", errInvalidName, err)
+ }
+}
+
func TestNamePackUnpack(t *testing.T) {
const suffix = ".go.dev."
var longDNSPrefix = strings.Repeat("verylongdomainlabel.", 20)
