webnet/tailscale
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tsdns: copy name when loewrcasing.

Browse Source 
The previous approach modifies name in-place in the request slice to avoid an allocation.
This is incorrect: the question section of a DNS request
must be copied verbatim, without any such modification.
Software may rely on it (we rely on other resolvers doing it it in tsdns/forwarder).

Signed-off-by: Dmytro Shynkevych <dmytro@tailscale.com>
This commit is contained in:
Dmytro Shynkevych
2020-08-20 18:54:18 -04:00
parent 1886dfdca3
commit 6c71e5b851
2 changed files with 61 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files
wgengine/tsdns/tsdns_test.go
+28 -13
View File
@@ -122,8 +122,7 @@ func TestRDNSNameToIPv4(t *testing.T) {
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
name := []byte(tt.input)
ip, ok := rdnsNameToIPv4(name)
ip, ok := rdnsNameToIPv4(tt.input)
if ok != tt.wantOK {
t.Errorf("ok = %v; want %v", ok, tt.wantOK)
} else if ok && ip != tt.wantIP {
@@ -168,8 +167,7 @@ func TestRDNSNameToIPv6(t *testing.T) {
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
name := []byte(tt.input)
ip, ok := rdnsNameToIPv6(name)
ip, ok := rdnsNameToIPv6(tt.input)
if ok != tt.wantOK {
t.Errorf("ok = %v; want %v", ok, tt.wantOK)
} else if ok && ip != tt.wantIP {
@@ -467,7 +465,7 @@ func TestConcurrentSetUpstreams(t *testing.T) {
wg.Wait()
}
var validIPv4Response = []byte{
var ipv4Response = []byte{
0x00, 0x00, // transaction id: 0
0x84, 0x00, // flags: response, authoritative, no error
0x00, 0x01, // one question
@@ -484,7 +482,7 @@ var validIPv4Response = []byte{
0x01, 0x02, 0x03, 0x04, // A: 1.2.3.4
}
var validIPv6Response = []byte{
var ipv6Response = []byte{
0x00, 0x00, // transaction id: 0
0x84, 0x00, // flags: response, authoritative, no error
0x00, 0x01, // one question
@@ -502,7 +500,24 @@ var validIPv6Response = []byte{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0xb, 0xc, 0xd, 0xe, 0xf,
}
var validPTRResponse = []byte{
var ipv4UppercaseResponse = []byte{
0x00, 0x00, // transaction id: 0
0x84, 0x00, // flags: response, authoritative, no error
0x00, 0x01, // one question
0x00, 0x01, // one answer
0x00, 0x00, 0x00, 0x00, // no authority or additional RRs
// Question:
0x05, 0x54, 0x45, 0x53, 0x54, 0x31, 0x03, 0x49, 0x50, 0x4e, 0x03, 0x44, 0x45, 0x56, 0x00, // name
0x00, 0x01, 0x00, 0x01, // type A, class IN
// Answer:
0x05, 0x54, 0x45, 0x53, 0x54, 0x31, 0x03, 0x49, 0x50, 0x4e, 0x03, 0x44, 0x45, 0x56, 0x00, // name
0x00, 0x01, 0x00, 0x01, // type A, class IN
0x00, 0x00, 0x02, 0x58, // TTL: 600
0x00, 0x04, // length: 4 bytes
0x01, 0x02, 0x03, 0x04, // A: 1.2.3.4
}
var ptrResponse = []byte{
0x00, 0x00, // transaction id: 0
0x84, 0x00, // flags: response, authoritative, no error
0x00, 0x01, // one question
@@ -548,10 +563,10 @@ func TestFull(t *testing.T) {
request []byte
response []byte
}{
{"ipv4", dnspacket("test1.ipn.dev.", dns.TypeA), validIPv4Response},
{"ipv6", dnspacket("test2.ipn.dev.", dns.TypeAAAA), validIPv6Response},
{"upper", dnspacket("TEST1.IPN.DEV.", dns.TypeA), validIPv4Response},
{"ptr", dnspacket("4.3.2.1.in-addr.arpa.", dns.TypePTR), validPTRResponse},
{"ipv4", dnspacket("test1.ipn.dev.", dns.TypeA), ipv4Response},
{"ipv6", dnspacket("test2.ipn.dev.", dns.TypeAAAA), ipv6Response},
{"upper", dnspacket("TEST1.IPN.DEV.", dns.TypeA), ipv4UppercaseResponse},
{"ptr", dnspacket("4.3.2.1.in-addr.arpa.", dns.TypePTR), ptrResponse},
{"error", dnspacket("test3.ipn.dev.", dns.TypeA), nxdomainResponse},
}
@@ -584,8 +599,8 @@ func TestAllocs(t *testing.T) {
query []byte
want int
}{
// The only alloc is the slice created by dns.NewBuilder.
{"forward", dnspacket("test1.ipn.dev.", dns.TypeA), 1},
// Name lowercasing and response slice created by dns.NewBuilder.
{"forward", dnspacket("test1.ipn.dev.", dns.TypeA), 2},
// 3 extra allocs in rdnsNameToIPv4 and one in marshalPTRRecord (dns.NewName).
{"reverse", dnspacket("4.3.2.1.in-addr.arpa.", dns.TypePTR), 5},
}