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|
package proxy
import (
"bufio"
"bytes"
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/http"
"time"
"github.com/shiv/internal/events"
internalhttp "github.com/shiv/internal/http"
"github.com/shiv/internal/logger"
)
func (p *Proxy) handleConnect(w http.ResponseWriter, r *http.Request) {
defer recoverPanic("ServeHTTP " + r.URL.String())
w.WriteHeader(http.StatusOK)
if flusher, ok := w.(http.Flusher); ok {
flusher.Flush()
}
hijacker, ok := w.(http.Hijacker)
if !ok {
logger.Error("mitm: server does not support hijacking")
return
}
clientConn, _, err := hijacker.Hijack()
if err != nil {
logger.Error("mitm: hijack: %v", err)
return
}
p.trackConn(clientConn)
defer p.untrackConn(clientConn)
defer clientConn.Close()
bareHost, _, err := net.SplitHostPort(r.Host)
if err != nil {
bareHost = r.Host
}
tlsCert, err := p.certAuth.TLSCertForHost(bareHost)
if err != nil {
logger.Error("mitm: cert for %s: %v", bareHost, err)
return
}
browserTLS := tls.Server(clientConn, &tls.Config{
Certificates: []tls.Certificate{*tlsCert},
NextProtos: []string{"h2", "http/1.1"},
})
if err := browserTLS.Handshake(); err != nil {
logger.Debug("mitm: browser TLS handshake for %s: %v", bareHost, err)
return
}
defer browserTLS.Close()
logger.Debug("mitm: negotiated protocol for %s: %q", bareHost, browserTLS.ConnectionState().NegotiatedProtocol)
if browserTLS.ConnectionState().NegotiatedProtocol == "h2" {
p.handleConnectH2(browserTLS, r, bareHost)
return
}
transport := &http.Transport{
DialTLSContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
conn, err := (&net.Dialer{Timeout: 10 * time.Second}).DialContext(ctx, "tcp", addr)
if err != nil {
return nil, fmt.Errorf("mitm: dial %s: %w", addr, err)
}
tlsConn := tls.Client(conn, &tls.Config{
ServerName: bareHost,
InsecureSkipVerify: true, //nolint:gosec
})
if err := tlsConn.Handshake(); err != nil {
conn.Close()
return nil, fmt.Errorf("mitm: upstream TLS handshake for %s: %w", bareHost, err)
}
return tlsConn, nil
},
ResponseHeaderTimeout: 30 * time.Second,
}
defer transport.CloseIdleConnections()
// No client-level Timeout — a per-connection timeout would terminate the
// entire keep-alive session after the first long request. Individual
// requests are bounded by ResponseHeaderTimeout + read deadlines instead.
upstreamClient := &http.Client{
Transport: transport,
CheckRedirect: func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
},
}
browserReader := bufio.NewReader(browserTLS)
for {
req, err := http.ReadRequest(browserReader)
if err != nil {
logger.Debug("mitm: connection closed for %s: %v", bareHost, err)
return
}
start := time.Now()
reqBody, err := io.ReadAll(io.LimitReader(req.Body, maxBodySize))
if err != nil {
logger.Error("mitm: read request body for %s: %v", bareHost, err)
return
}
req.Body.Close()
req.URL.Scheme = "https"
// Preserve r.Host (with port) so non-443 HTTPS targets work correctly.
req.URL.Host = r.Host
// Detect WebSocket upgrade before intercept. WebSocket connections are
// long-lived bidirectional streams — they cannot be intercepted the same
// way as regular HTTP requests. Hand off to the WebSocket handler which
// manages the entire session and returns when the connection closes.
if isWebSocketUpgrade(req) {
p.handleWebSocketTLS(browserTLS, browserReader, req, bareHost, r.Host)
return
}
result := p.bus.EmitRequest(events.RequestEvent{Request: req, Body: reqBody})
if result.Drop {
resp := &http.Response{
Status: "403 Forbidden",
StatusCode: 403,
Proto: "HTTP/1.1",
ProtoMajor: 1,
ProtoMinor: 1,
Body: http.NoBody,
Header: make(http.Header),
ContentLength: 0,
}
if err := resp.Write(browserTLS); err != nil {
logger.Error("mitm: write 403 to browser for %s: %v", bareHost, err)
}
continue
}
interceptedReq, reqBody := result.Request, result.Body
outReq, err := http.NewRequest(interceptedReq.Method, interceptedReq.URL.String(), bytes.NewReader(reqBody))
if err != nil {
logger.Error("mitm: build upstream request for %s: %v", bareHost, err)
return
}
outReq.Header = interceptedReq.Header.Clone()
outReq.Host = internalhttp.NormalizeHost(bareHost, true)
internalhttp.StripRequestCacheHeaders(outReq.Header)
resp, err := upstreamClient.Do(outReq)
if err != nil {
// Distinguish client-cancelled requests (normal) from real upstream
// failures. Context cancellation here means the browser closed the
// connection before we could forward — log at Debug.
if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
logger.Debug("mitm: stream cancelled for %s: %v", bareHost, err)
} else {
logger.Error("mitm: upstream request for %s: %v", bareHost, err)
}
return
}
var respBuf bytes.Buffer
reader := io.TeeReader(io.LimitReader(resp.Body, maxBodySize), &respBuf)
internalhttp.StripResponseCacheHeaders(resp.Header)
resp.Body = io.NopCloser(reader)
writeErr := resp.Write(browserTLS)
_, _ = io.Copy(io.Discard, resp.Body)
resp.Body.Close()
if writeErr != nil {
logger.Debug("mitm: write response to browser for %s: %v", bareHost, writeErr)
return
}
respBody := respBuf.Bytes()
if len(respBody) >= int(maxBodySize) {
logger.Debug("mitm: response body truncated at %d bytes for %s %s",
maxBodySize, interceptedReq.Method, interceptedReq.URL)
}
elapsed := time.Since(start).Milliseconds()
logger.Info("%s %s %d %db %dms", interceptedReq.Method, interceptedReq.URL, resp.StatusCode, len(respBody), elapsed)
logBody := internalhttp.Decompress(resp.Header, respBody)
if internalhttp.IsBinary(resp.Header) {
logBody = nil
}
p.bus.EmitResponse(events.ResponseEvent{
Timestamp: start,
Host: r.Host,
Proto: "HTTP/1.1",
Method: interceptedReq.Method,
URL: interceptedReq.URL.String(),
ReqHeaders: interceptedReq.Header,
ReqBody: reqBody,
StatusCode: resp.StatusCode,
RespHeaders: resp.Header,
RespBody: logBody,
DurationMs: elapsed,
TLS: true,
})
}
}
|
