zgrab2/modules/http/http_readlimit_test.go
2018-09-27 14:00:26 -04:00

348 lines
13 KiB
Go

package http
import (
"crypto/rsa"
"encoding/hex"
"fmt"
"io"
"math/big"
"net"
"strings"
"testing"
"time"
"github.com/zmap/zcrypto/tls"
"github.com/zmap/zgrab2"
)
// BEGIN Taken from handshake_server_test.go -- certs for TLS server
func fromHex(s string) []byte {
b, _ := hex.DecodeString(s)
return b
}
func bigFromString(s string) *big.Int {
ret := new(big.Int)
ret.SetString(s, 10)
return ret
}
var testRSACertificate = fromHex("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")
var testSNICertificate = fromHex("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")
var testRSAPrivateKey = &rsa.PrivateKey{
PublicKey: rsa.PublicKey{
N: bigFromString("131650079503776001033793877885499001334664249354723305978524647182322416328664556247316495448366990052837680518067798333412266673813370895702118944398081598789828837447552603077848001020611640547221687072142537202428102790818451901395596882588063427854225330436740647715202971973145151161964464812406232198521"),
E: 65537,
},
D: bigFromString("29354450337804273969007277378287027274721892607543397931919078829901848876371746653677097639302788129485893852488285045793268732234230875671682624082413996177431586734171663258657462237320300610850244186316880055243099640544518318093544057213190320837094958164973959123058337475052510833916491060913053867729"),
Primes: []*big.Int{
bigFromString("11969277782311800166562047708379380720136961987713178380670422671426759650127150688426177829077494755200794297055316163155755835813760102405344560929062149"),
bigFromString("10998999429884441391899182616418192492905073053684657075974935218461686523870125521822756579792315215543092255516093840728890783887287417039645833477273829"),
},
}
// END Taken from handshake_server_test.go -- certs for TLS server
// Get the tls.Config object for the server; adapted from handshake_server_test.go.
func getTLSConfig() *tls.Config {
testConfig := &tls.Config{
Time: func() time.Time { return time.Unix(0, 0) },
Certificates: make([]tls.Certificate, 2),
InsecureSkipVerify: true,
MinVersion: tls.VersionSSL30,
MaxVersion: tls.VersionTLS12,
}
testConfig.Certificates[0].Certificate = [][]byte{testRSACertificate}
testConfig.Certificates[0].PrivateKey = testRSAPrivateKey
testConfig.Certificates[1].Certificate = [][]byte{testSNICertificate}
testConfig.Certificates[1].PrivateKey = testRSAPrivateKey
testConfig.BuildNameToCertificate()
return testConfig
}
// Helper function to write and check for short writes
func _write(writer io.Writer, data []byte) error {
n, err := writer.Write(data)
if err == nil && len(data) != n {
err = io.ErrShortWrite
}
return err
}
// Start a local server that sends responds to any requests with a cfg.headerSize-byte set of
// headers followed by a cfg.bodySize-byte body.
// The response ends up looking like this:
// HTTP/1.0 200 OK
// Bogus-Header: XXX...
// Content-Length: <bodySize>
//
// XXXX....
func (cfg *readLimitTestConfig) runFakeHTTPServer(t *testing.T) {
endpoint := fmt.Sprintf("127.0.0.1:%d", cfg.port)
listener, err := net.Listen("tcp", endpoint)
if err != nil {
t.Fatal(err)
}
go func() {
defer listener.Close()
sock, err := listener.Accept()
if err != nil {
t.Fatal(err)
}
defer sock.Close()
if cfg.tls {
tlsSock := tls.Server(sock, getTLSConfig())
if err := tlsSock.Handshake(); err != nil {
t.Fatalf("server handshake error: %v", err)
}
sock = tlsSock
}
// don't care what the client sends, always respond with a HTTP-like response
buf := make([]byte, 1)
_, err = sock.Read(buf)
if err != nil {
// any error, including EOF, is unexpected -- the client should send something
t.Fatalf("Unexpected error reading from client: %v", err)
}
head := "HTTP/1.0 200 OK\r\nBogus-Header: X"
headSuffix := fmt.Sprintf("\r\nContent-Length: %d\r\n\r\n", cfg.bodySize)
size := cfg.headerSize - len(head) - len(headSuffix)
if size < 0 {
t.Fatalf("Header size %d too small: must be at least %d bytes", cfg.headerSize, len(head)+len(headSuffix))
}
if err := _write(sock, []byte(head)); err != nil {
t.Fatalf("write error: %v", err)
}
chunkSize := 256
sent := len(head)
chunk := []byte(strings.Repeat("X", chunkSize))
for i := 0; i < size; i += chunkSize {
if i+chunkSize > size {
chunk = []byte(strings.Repeat("X", size-i))
}
if err := _write(sock, chunk); err != nil {
t.Logf("Failed writing to client after %d bytes: %v", sent, err)
return
}
sent += len(chunk)
}
if err := _write(sock, []byte(headSuffix)); err != nil {
t.Logf("Failed writing foot to client: %v", err)
return
}
sent += len(headSuffix)
body := strings.Repeat("X", cfg.bodySize)
if err := _write(sock, []byte(body)); err != nil {
t.Logf("Failed writing body to client: %v", err)
return
}
}()
}
// Get an HTTP scanner module with the desired config
func (cfg *readLimitTestConfig) getScanner(t *testing.T) *Scanner {
var module Module
flags := module.NewFlags().(*Flags)
flags.Endpoint = "/"
flags.Method = "GET"
flags.UserAgent = "Mozilla/5.0 zgrab/0.x"
if cfg.maxBodySize&0x03ff != 0 {
t.Fatalf("%d is not a valid maxBodySize (must be a multiple of 1024)", cfg.maxBodySize)
}
flags.MaxSize = cfg.maxBodySize / 1024
flags.MaxRedirects = 0
flags.Timeout = 1 * time.Second
flags.Port = uint(cfg.port)
flags.UseHTTPS = cfg.tls
zgrab2.DefaultBytesReadLimit = cfg.maxReadSize
scanner := module.NewScanner()
scanner.Init(flags)
return scanner.(*Scanner)
}
// Configuration for a single test run
type readLimitTestConfig struct {
// if true, the client/server will use TLS. NOTE: the limits are on the *raw* connection.
tls bool
// port where the server listens.
port int
// Bodies larger than this are truncated. NOTE: this must be a multiple of 1024, since MaxSize
// is given in kilobytes.
maxBodySize int
// The maximum number of bytes to read from the (raw) socket. Beyond that data is truncated and
// EOF is returned.
maxReadSize int
// The size of the HTTP server's "header" (actually, all of the data before the body). Must be
// at least 58 (the size of the static parts of the response).
headerSize int
// The size of the HTTP body to send (the Content-Length).
bodySize int
// The status that should be returned by the scan.
expectedStatus zgrab2.ScanStatus
// If set, the error returned by the scan must contain this.
expectedError string
}
const (
readLimitTestConfigHTTPBasePort = 0x7f7f
readLimitTestConfigHTTPSBasePort = 0x7bbc
)
var readLimitTestConfigs = map[string]*readLimitTestConfig{
// The socket truncates the connection while reading the body. To the client it looks as if the
// server closed the connection prior to sending Content-Length bytes; the result is success,
// but with a truncated body.
// bodySize + headerSize > maxReadSize > headerSize
"truncate_read_body": {
tls: false,
port: readLimitTestConfigHTTPBasePort,
maxBodySize: 2048,
maxReadSize: 1024,
headerSize: 64,
bodySize: 4096,
expectedStatus: zgrab2.SCAN_SUCCESS,
},
// NOTE: There is no tls_truncate_read_body, since the truncation will almost certainly occur
// in the middle of a TLS packet -- so the response would always be "unexpected EOF"
// The HTTP library stops reading the body after reaching its internal limit. It returns success
// and the truncated body.
// maxReadSize > headerSize + bodySize > bodySize > maxBodySize
"truncate_body": {
tls: false,
port: readLimitTestConfigHTTPBasePort + 1,
maxBodySize: 2048,
maxReadSize: 8192,
headerSize: 64,
bodySize: 4096,
expectedStatus: zgrab2.SCAN_SUCCESS,
},
"tls_truncate_body": {
tls: true,
port: readLimitTestConfigHTTPSBasePort + 1,
maxBodySize: 2048,
maxReadSize: 8192,
headerSize: 64,
bodySize: 4096,
expectedStatus: zgrab2.SCAN_SUCCESS,
},
// The socket truncates the connection while reading the headers. The result isn't a valid HTTP
// response, so the library returns an unexpected EOF error.
// headerSize > maxReadSize
"truncate_read_header": {
tls: false,
port: readLimitTestConfigHTTPBasePort + 2,
maxBodySize: 1024,
maxReadSize: 2048,
headerSize: 3072,
bodySize: 8,
expectedError: "unexpected EOF",
expectedStatus: zgrab2.SCAN_UNKNOWN_ERROR,
},
"tls_truncate_read_header": {
tls: true,
port: readLimitTestConfigHTTPSBasePort + 2,
maxBodySize: 1024,
maxReadSize: 2048,
headerSize: 3072,
bodySize: 8,
expectedError: "unexpected EOF",
expectedStatus: zgrab2.SCAN_UNKNOWN_ERROR,
},
// Happy case. None of the limits are hit.
// maxReadSize >= maxBodySize > bodySize + headerSize
"happy_case": {
tls: false,
port: readLimitTestConfigHTTPBasePort + 3,
maxBodySize: 8192,
maxReadSize: 8192,
headerSize: 1024,
bodySize: 1024,
expectedStatus: zgrab2.SCAN_SUCCESS,
},
"tls_happy_case": {
tls: true,
port: readLimitTestConfigHTTPSBasePort + 3,
maxBodySize: 8192,
maxReadSize: 8192,
headerSize: 1024,
bodySize: 1024,
expectedStatus: zgrab2.SCAN_SUCCESS,
},
}
// Try to get the HTTP body from a result; otherwise return the empty string.
func getBody(result interface{}) string {
if result == nil {
return ""
}
httpResult, ok := result.(*Results)
if !ok {
return ""
}
response := httpResult.Response
if response == nil {
return ""
}
return response.BodyText
}
// Run a single test with the given configuration.
func (cfg *readLimitTestConfig) runTest(t *testing.T, testName string) {
scanner := cfg.getScanner(t)
cfg.runFakeHTTPServer(t)
target := zgrab2.ScanTarget{
IP: net.ParseIP("127.0.0.1"),
}
status, ret, err := scanner.Scan(target)
if status != cfg.expectedStatus {
t.Errorf("Wrong status: expected %s, got %s", cfg.expectedStatus, status)
}
if err != nil {
if !strings.Contains(err.Error(), cfg.expectedError) {
t.Errorf("Wrong error: expected %s, got %s", err.Error(), cfg.expectedError)
}
} else if len(cfg.expectedError) > 0 {
t.Errorf("Expected error '%s' but got none", cfg.expectedError)
}
if cfg.expectedStatus == zgrab2.SCAN_SUCCESS {
body := getBody(ret)
if body == "" {
t.Errorf("Expected success, but got no body")
} else {
if len(body) > cfg.maxBodySize || len(body) > cfg.maxReadSize {
t.Errorf("Body exceeds max size: len(body)=%d; maxBodySize=%d, maxReadSize=%d", len(body), cfg.maxBodySize, cfg.maxReadSize)
}
if !cfg.tls {
if len(body)+cfg.headerSize > cfg.maxReadSize {
t.Errorf("Body and header exceed max read size: len(body)=%d, headerSize=%d, maxReadSize=%d", len(body), cfg.headerSize, cfg.maxReadSize)
}
}
}
}
}
// TestReadLimitHTTP checks that the HTTP scanner works as expected with the default
// ReadLimitExeededAction (specifically, ReadLimnitExceededActionTruncate) defined in conn.go.
func TestReadLimitHTTP(t *testing.T) {
if zgrab2.DefaultReadLimitExceededAction != zgrab2.ReadLimitExceededActionTruncate {
t.Logf("Warning: DefaultReadLimitExceededAction is %s, not %s", zgrab2.DefaultReadLimitExceededAction, zgrab2.ReadLimitExceededActionTruncate)
}
for testName, cfg := range readLimitTestConfigs {
cfg.runTest(t, testName)
}
}