diff options
| -rw-r--r-- | src/net/dnsclient_unix_test.go | 223 | ||||
| -rw-r--r-- | src/net/lookup.go | 80 |
2 files changed, 235 insertions, 68 deletions
diff --git a/src/net/dnsclient_unix_test.go b/src/net/dnsclient_unix_test.go index f0f6e577ad..9958a133a8 100644 --- a/src/net/dnsclient_unix_test.go +++ b/src/net/dnsclient_unix_test.go @@ -1846,6 +1846,17 @@ func TestCVE202133195(t *testing.T) { Target: dnsmessage.MustNewName("<html>.golang.org."), }, }, + dnsmessage.Resource{ + Header: dnsmessage.ResourceHeader{ + Name: n, + Type: dnsmessage.TypeSRV, + Class: dnsmessage.ClassINET, + Length: 4, + }, + Body: &dnsmessage.SRVResource{ + Target: dnsmessage.MustNewName("good.golang.org."), + }, + }, ) case dnsmessage.TypeMX: r.Answers = append(r.Answers, @@ -1860,6 +1871,17 @@ func TestCVE202133195(t *testing.T) { MX: dnsmessage.MustNewName("<html>.golang.org."), }, }, + dnsmessage.Resource{ + Header: dnsmessage.ResourceHeader{ + Name: dnsmessage.MustNewName("good.golang.org."), + Type: dnsmessage.TypeMX, + Class: dnsmessage.ClassINET, + Length: 4, + }, + Body: &dnsmessage.MXResource{ + MX: dnsmessage.MustNewName("good.golang.org."), + }, + }, ) case dnsmessage.TypeNS: r.Answers = append(r.Answers, @@ -1874,6 +1896,17 @@ func TestCVE202133195(t *testing.T) { NS: dnsmessage.MustNewName("<html>.golang.org."), }, }, + dnsmessage.Resource{ + Header: dnsmessage.ResourceHeader{ + Name: dnsmessage.MustNewName("good.golang.org."), + Type: dnsmessage.TypeNS, + Class: dnsmessage.ClassINET, + Length: 4, + }, + Body: &dnsmessage.NSResource{ + NS: dnsmessage.MustNewName("good.golang.org."), + }, + }, ) case dnsmessage.TypePTR: r.Answers = append(r.Answers, @@ -1888,6 +1921,17 @@ func TestCVE202133195(t *testing.T) { PTR: dnsmessage.MustNewName("<html>.golang.org."), }, }, + dnsmessage.Resource{ + Header: dnsmessage.ResourceHeader{ + Name: dnsmessage.MustNewName("good.golang.org."), + Type: dnsmessage.TypePTR, + Class: dnsmessage.ClassINET, + Length: 4, + }, + Body: &dnsmessage.PTRResource{ + PTR: dnsmessage.MustNewName("good.golang.org."), + }, + }, ) } return r, nil @@ -1903,58 +1947,137 @@ func TestCVE202133195(t *testing.T) { defer func(orig string) { testHookHostsPath = orig }(testHookHostsPath) testHookHostsPath = "testdata/hosts" - _, err := r.LookupCNAME(context.Background(), "golang.org") - if expected := "lookup golang.org: CNAME target is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupCNAME returned unexpected error, got %q, want %q", err, expected) - } - _, err = LookupCNAME("golang.org") - if expected := "lookup golang.org: CNAME target is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupCNAME returned unexpected error, got %q, want %q", err, expected) - } - - _, _, err = r.LookupSRV(context.Background(), "target", "tcp", "golang.org") - if expected := "lookup golang.org: SRV target is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupSRV returned unexpected error, got %q, want %q", err, expected) - } - _, _, err = LookupSRV("target", "tcp", "golang.org") - if expected := "lookup golang.org: SRV target is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupSRV returned unexpected error, got %q, want %q", err, expected) - } - - _, _, err = r.LookupSRV(context.Background(), "hdr", "tcp", "golang.org") - if expected := "lookup golang.org: SRV header name is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupSRV returned unexpected error, got %q, want %q", err, expected) - } - _, _, err = LookupSRV("hdr", "tcp", "golang.org") - if expected := "lookup golang.org: SRV header name is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupSRV returned unexpected error, got %q, want %q", err, expected) - } - - _, err = r.LookupMX(context.Background(), "golang.org") - if expected := "lookup golang.org: MX target is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupMX returned unexpected error, got %q, want %q", err, expected) - } - _, err = LookupMX("golang.org") - if expected := "lookup golang.org: MX target is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupMX returned unexpected error, got %q, want %q", err, expected) - } - - _, err = r.LookupNS(context.Background(), "golang.org") - if expected := "lookup golang.org: NS target is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupNS returned unexpected error, got %q, want %q", err, expected) - } - _, err = LookupNS("golang.org") - if expected := "lookup golang.org: NS target is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupNS returned unexpected error, got %q, want %q", err, expected) + tests := []struct { + name string + f func(*testing.T) + }{ + { + name: "CNAME", + f: func(t *testing.T) { + expectedErr := &DNSError{Err: errMalformedDNSRecordsDetail, Name: "golang.org"} + _, err := r.LookupCNAME(context.Background(), "golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + _, err = LookupCNAME("golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + }, + }, + { + name: "SRV (bad record)", + f: func(t *testing.T) { + expected := []*SRV{ + { + Target: "good.golang.org.", + }, + } + expectedErr := &DNSError{Err: errMalformedDNSRecordsDetail, Name: "golang.org"} + _, records, err := r.LookupSRV(context.Background(), "target", "tcp", "golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + _, records, err = LookupSRV("target", "tcp", "golang.org") + if err.Error() != expectedErr.Error() { + t.Errorf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + }, + }, + { + name: "SRV (bad header)", + f: func(t *testing.T) { + _, _, err := r.LookupSRV(context.Background(), "hdr", "tcp", "golang.org.") + if expected := "lookup golang.org.: SRV header name is invalid"; err == nil || err.Error() != expected { + t.Errorf("Resolver.LookupSRV returned unexpected error, got %q, want %q", err, expected) + } + _, _, err = LookupSRV("hdr", "tcp", "golang.org.") + if expected := "lookup golang.org.: SRV header name is invalid"; err == nil || err.Error() != expected { + t.Errorf("LookupSRV returned unexpected error, got %q, want %q", err, expected) + } + }, + }, + { + name: "MX", + f: func(t *testing.T) { + expected := []*MX{ + { + Host: "good.golang.org.", + }, + } + expectedErr := &DNSError{Err: errMalformedDNSRecordsDetail, Name: "golang.org"} + records, err := r.LookupMX(context.Background(), "golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + records, err = LookupMX("golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + }, + }, + { + name: "NS", + f: func(t *testing.T) { + expected := []*NS{ + { + Host: "good.golang.org.", + }, + } + expectedErr := &DNSError{Err: errMalformedDNSRecordsDetail, Name: "golang.org"} + records, err := r.LookupNS(context.Background(), "golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + records, err = LookupNS("golang.org") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + }, + }, + { + name: "Addr", + f: func(t *testing.T) { + expected := []string{"good.golang.org."} + expectedErr := &DNSError{Err: errMalformedDNSRecordsDetail, Name: "192.0.2.42"} + records, err := r.LookupAddr(context.Background(), "192.0.2.42") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + records, err = LookupAddr("192.0.2.42") + if err.Error() != expectedErr.Error() { + t.Fatalf("unexpected error: %s", err) + } + if !reflect.DeepEqual(records, expected) { + t.Error("Unexpected record set") + } + }, + }, } - _, err = r.LookupAddr(context.Background(), "192.0.2.42") - if expected := "lookup 192.0.2.42: PTR target is invalid"; err == nil || err.Error() != expected { - t.Errorf("Resolver.LookupAddr returned unexpected error, got %q, want %q", err, expected) - } - _, err = LookupAddr("192.0.2.42") - if expected := "lookup 192.0.2.42: PTR target is invalid"; err == nil || err.Error() != expected { - t.Errorf("LookupAddr returned unexpected error, got %q, want %q", err, expected) + for _, tc := range tests { + t.Run(tc.name, tc.f) } } diff --git a/src/net/lookup.go b/src/net/lookup.go index 01c81dbaaf..4135122d60 100644 --- a/src/net/lookup.go +++ b/src/net/lookup.go @@ -415,7 +415,7 @@ func (r *Resolver) LookupCNAME(ctx context.Context, host string) (string, error) return "", err } if !isDomainName(cname) { - return "", &DNSError{Err: "CNAME target is invalid", Name: host} + return "", &DNSError{Err: errMalformedDNSRecordsDetail, Name: host} } return cname, nil } @@ -431,7 +431,9 @@ func (r *Resolver) LookupCNAME(ctx context.Context, host string) (string, error) // and proto are empty strings, LookupSRV looks up name directly. // // The returned service names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err error) { return DefaultResolver.LookupSRV(context.Background(), service, proto, name) } @@ -447,7 +449,9 @@ func LookupSRV(service, proto, name string) (cname string, addrs []*SRV, err err // and proto are empty strings, LookupSRV looks up name directly. // // The returned service names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) (string, []*SRV, error) { cname, addrs, err := r.lookupSRV(ctx, service, proto, name) if err != nil { @@ -456,21 +460,31 @@ func (r *Resolver) LookupSRV(ctx context.Context, service, proto, name string) ( if cname != "" && !isDomainName(cname) { return "", nil, &DNSError{Err: "SRV header name is invalid", Name: name} } + filteredAddrs := make([]*SRV, 0, len(addrs)) for _, addr := range addrs { if addr == nil { continue } if !isDomainName(addr.Target) { - return "", nil, &DNSError{Err: "SRV target is invalid", Name: name} + continue } + filteredAddrs = append(filteredAddrs, addr) + } + if len(addrs) != len(filteredAddrs) { + return cname, filteredAddrs, &DNSError{Err: errMalformedDNSRecordsDetail, Name: name} } - return cname, addrs, nil + return cname, filteredAddrs, nil } // LookupMX returns the DNS MX records for the given domain name sorted by preference. // // The returned mail server names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. +// +// LookupMX uses context.Background internally; to specify the context, use +// Resolver.LookupMX. func LookupMX(name string) ([]*MX, error) { return DefaultResolver.LookupMX(context.Background(), name) } @@ -478,12 +492,15 @@ func LookupMX(name string) ([]*MX, error) { // LookupMX returns the DNS MX records for the given domain name sorted by preference. // // The returned mail server names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. func (r *Resolver) LookupMX(ctx context.Context, name string) ([]*MX, error) { records, err := r.lookupMX(ctx, name) if err != nil { return nil, err } + filteredMX := make([]*MX, 0, len(records)) for _, mx := range records { if mx == nil { continue @@ -491,16 +508,25 @@ func (r *Resolver) LookupMX(ctx context.Context, name string) ([]*MX, error) { // Bypass the hostname validity check for targets which contain only a dot, // as this is used to represent a 'Null' MX record. if mx.Host != "." && !isDomainName(mx.Host) { - return nil, &DNSError{Err: "MX target is invalid", Name: name} + continue } + filteredMX = append(filteredMX, mx) + } + if len(records) != len(filteredMX) { + return filteredMX, &DNSError{Err: errMalformedDNSRecordsDetail, Name: name} } - return records, nil + return filteredMX, nil } // LookupNS returns the DNS NS records for the given domain name. // // The returned name server names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. +// +// LookupNS uses context.Background internally; to specify the context, use +// Resolver.LookupNS. func LookupNS(name string) ([]*NS, error) { return DefaultResolver.LookupNS(context.Background(), name) } @@ -508,21 +534,28 @@ func LookupNS(name string) ([]*NS, error) { // LookupNS returns the DNS NS records for the given domain name. // // The returned name server names are validated to be properly -// formatted presentation-format domain names. +// formatted presentation-format domain names. If the response contains +// invalid names, those records are filtered out and an error +// will be returned alongside the the remaining results, if any. func (r *Resolver) LookupNS(ctx context.Context, name string) ([]*NS, error) { records, err := r.lookupNS(ctx, name) if err != nil { return nil, err } + filteredNS := make([]*NS, 0, len(records)) for _, ns := range records { if ns == nil { continue } if !isDomainName(ns.Host) { - return nil, &DNSError{Err: "NS target is invalid", Name: name} + continue } + filteredNS = append(filteredNS, ns) + } + if len(records) != len(filteredNS) { + return filteredNS, &DNSError{Err: errMalformedDNSRecordsDetail, Name: name} } - return records, nil + return filteredNS, nil } // LookupTXT returns the DNS TXT records for the given domain name. @@ -539,7 +572,8 @@ func (r *Resolver) LookupTXT(ctx context.Context, name string) ([]string, error) // of names mapping to that address. // // The returned names are validated to be properly formatted presentation-format -// domain names. +// domain names. If the response contains invalid names, those records are filtered +// out and an error will be returned alongside the the remaining results, if any. // // When using the host C library resolver, at most one result will be // returned. To bypass the host resolver, use a custom Resolver. @@ -551,16 +585,26 @@ func LookupAddr(addr string) (names []string, err error) { // of names mapping to that address. // // The returned names are validated to be properly formatted presentation-format -// domain names. +// domain names. If the response contains invalid names, those records are filtered +// out and an error will be returned alongside the the remaining results, if any. func (r *Resolver) LookupAddr(ctx context.Context, addr string) ([]string, error) { names, err := r.lookupAddr(ctx, addr) if err != nil { return nil, err } + filteredNames := make([]string, 0, len(names)) for _, name := range names { - if !isDomainName(name) { - return nil, &DNSError{Err: "PTR target is invalid", Name: addr} + if isDomainName(name) { + filteredNames = append(filteredNames, name) } } - return names, nil + if len(names) != len(filteredNames) { + return filteredNames, &DNSError{Err: errMalformedDNSRecordsDetail, Name: addr} + } + return filteredNames, nil } + +// errMalformedDNSRecordsDetail is the DNSError detail which is returned when a Resolver.Lookup... +// method recieves DNS records which contain invalid DNS names. This may be returned alongside +// results which have had the malformed records filtered out. +var errMalformedDNSRecordsDetail = "DNS response contained records which contain invalid names" |