1 files changed, 360 insertions, 0 deletions
diff --git a/src/cmd/go/internal/web/http.go b/src/cmd/go/internal/web/http.go
new file mode 100644
index 0000000..a3b7787
--- /dev/null
+++ b/src/cmd/go/internal/web/http.go
@@ -0,0 +1,360 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build !cmd_go_bootstrap
+
+// This code is compiled into the real 'go' binary, but it is not
+// compiled into the binary that is built during all.bash, so as
+// to avoid needing to build net (and thus use cgo) during the
+// bootstrap process.
+
+package web
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"mime"
+	"net"
+	"net/http"
+	urlpkg "net/url"
+	"os"
+	"strings"
+	"time"
+
+	"cmd/go/internal/auth"
+	"cmd/go/internal/cfg"
+	"cmd/internal/browser"
+)
+
+// impatientInsecureHTTPClient is used with GOINSECURE,
+// when we're connecting to https servers that might not be there
+// or might be using self-signed certificates.
+var impatientInsecureHTTPClient = &http.Client{
+	CheckRedirect: checkRedirect,
+	Timeout:       5 * time.Second,
+	Transport: &http.Transport{
+		Proxy: http.ProxyFromEnvironment,
+		TLSClientConfig: &tls.Config{
+			InsecureSkipVerify: true,
+		},
+	},
+}
+
+var securityPreservingDefaultClient = securityPreservingHTTPClient(http.DefaultClient)
+
+// securityPreservingDefaultClient returns a client that is like the original
+// but rejects redirects to plain-HTTP URLs if the original URL was secure.
+func securityPreservingHTTPClient(original *http.Client) *http.Client {
+	c := new(http.Client)
+	*c = *original
+	c.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+		if len(via) > 0 && via[0].URL.Scheme == "https" && req.URL.Scheme != "https" {
+			lastHop := via[len(via)-1].URL
+			return fmt.Errorf("redirected from secure URL %s to insecure URL %s", lastHop, req.URL)
+		}
+		return checkRedirect(req, via)
+	}
+	return c
+}
+
+func checkRedirect(req *http.Request, via []*http.Request) error {
+	// Go's http.DefaultClient allows 10 redirects before returning an error.
+	// Mimic that behavior here.
+	if len(via) >= 10 {
+		return errors.New("stopped after 10 redirects")
+	}
+
+	interceptRequest(req)
+	return nil
+}
+
+type Interceptor struct {
+	Scheme   string
+	FromHost string
+	ToHost   string
+	Client   *http.Client
+}
+
+func EnableTestHooks(interceptors []Interceptor) error {
+	if enableTestHooks {
+		return errors.New("web: test hooks already enabled")
+	}
+
+	for _, t := range interceptors {
+		if t.FromHost == "" {
+			panic("EnableTestHooks: missing FromHost")
+		}
+		if t.ToHost == "" {
+			panic("EnableTestHooks: missing ToHost")
+		}
+	}
+
+	testInterceptors = interceptors
+	enableTestHooks = true
+	return nil
+}
+
+func DisableTestHooks() {
+	if !enableTestHooks {
+		panic("web: test hooks not enabled")
+	}
+	enableTestHooks = false
+	testInterceptors = nil
+}
+
+var (
+	enableTestHooks  = false
+	testInterceptors []Interceptor
+)
+
+func interceptURL(u *urlpkg.URL) (*Interceptor, bool) {
+	if !enableTestHooks {
+		return nil, false
+	}
+	for i, t := range testInterceptors {
+		if u.Host == t.FromHost && (t.Scheme == "" || u.Scheme == t.Scheme) {
+			return &testInterceptors[i], true
+		}
+	}
+	return nil, false
+}
+
+func interceptRequest(req *http.Request) {
+	if t, ok := interceptURL(req.URL); ok {
+		req.Host = req.URL.Host
+		req.URL.Host = t.ToHost
+	}
+}
+
+func get(security SecurityMode, url *urlpkg.URL) (*Response, error) {
+	start := time.Now()
+
+	if url.Scheme == "file" {
+		return getFile(url)
+	}
+
+	if enableTestHooks {
+		switch url.Host {
+		case "proxy.golang.org":
+			if os.Getenv("TESTGOPROXY404") == "1" {
+				res := &Response{
+					URL:        url.Redacted(),
+					Status:     "404 testing",
+					StatusCode: 404,
+					Header:     make(map[string][]string),
+					Body:       http.NoBody,
+				}
+				if cfg.BuildX {
+					fmt.Fprintf(os.Stderr, "# get %s: %v (%.3fs)\n", url.Redacted(), res.Status, time.Since(start).Seconds())
+				}
+				return res, nil
+			}
+
+		case "localhost.localdev":
+			return nil, fmt.Errorf("no such host localhost.localdev")
+
+		default:
+			if os.Getenv("TESTGONETWORK") == "panic" {
+				if _, ok := interceptURL(url); !ok {
+					host := url.Host
+					if h, _, err := net.SplitHostPort(url.Host); err == nil && h != "" {
+						host = h
+					}
+					addr := net.ParseIP(host)
+					if addr == nil || (!addr.IsLoopback() && !addr.IsUnspecified()) {
+						panic("use of network: " + url.String())
+					}
+				}
+			}
+		}
+	}
+
+	fetch := func(url *urlpkg.URL) (*urlpkg.URL, *http.Response, error) {
+		// Note: The -v build flag does not mean "print logging information",
+		// despite its historical misuse for this in GOPATH-based go get.
+		// We print extra logging in -x mode instead, which traces what
+		// commands are executed.
+		if cfg.BuildX {
+			fmt.Fprintf(os.Stderr, "# get %s\n", url.Redacted())
+		}
+
+		req, err := http.NewRequest("GET", url.String(), nil)
+		if err != nil {
+			return nil, nil, err
+		}
+		if url.Scheme == "https" {
+			auth.AddCredentials(req)
+		}
+		t, intercepted := interceptURL(req.URL)
+		if intercepted {
+			req.Host = req.URL.Host
+			req.URL.Host = t.ToHost
+		}
+
+		var res *http.Response
+		if security == Insecure && url.Scheme == "https" { // fail earlier
+			res, err = impatientInsecureHTTPClient.Do(req)
+		} else {
+			if intercepted && t.Client != nil {
+				client := securityPreservingHTTPClient(t.Client)
+				res, err = client.Do(req)
+			} else {
+				res, err = securityPreservingDefaultClient.Do(req)
+			}
+		}
+		return url, res, err
+	}
+
+	var (
+		fetched *urlpkg.URL
+		res     *http.Response
+		err     error
+	)
+	if url.Scheme == "" || url.Scheme == "https" {
+		secure := new(urlpkg.URL)
+		*secure = *url
+		secure.Scheme = "https"
+
+		fetched, res, err = fetch(secure)
+		if err != nil {
+			if cfg.BuildX {
+				fmt.Fprintf(os.Stderr, "# get %s: %v\n", secure.Redacted(), err)
+			}
+			if security != Insecure || url.Scheme == "https" {
+				// HTTPS failed, and we can't fall back to plain HTTP.
+				// Report the error from the HTTPS attempt.
+				return nil, err
+			}
+		}
+	}
+
+	if res == nil {
+		switch url.Scheme {
+		case "http":
+			if security == SecureOnly {
+				if cfg.BuildX {
+					fmt.Fprintf(os.Stderr, "# get %s: insecure\n", url.Redacted())
+				}
+				return nil, fmt.Errorf("insecure URL: %s", url.Redacted())
+			}
+		case "":
+			if security != Insecure {
+				panic("should have returned after HTTPS failure")
+			}
+		default:
+			if cfg.BuildX {
+				fmt.Fprintf(os.Stderr, "# get %s: unsupported\n", url.Redacted())
+			}
+			return nil, fmt.Errorf("unsupported scheme: %s", url.Redacted())
+		}
+
+		insecure := new(urlpkg.URL)
+		*insecure = *url
+		insecure.Scheme = "http"
+		if insecure.User != nil && security != Insecure {
+			if cfg.BuildX {
+				fmt.Fprintf(os.Stderr, "# get %s: insecure credentials\n", insecure.Redacted())
+			}
+			return nil, fmt.Errorf("refusing to pass credentials to insecure URL: %s", insecure.Redacted())
+		}
+
+		fetched, res, err = fetch(insecure)
+		if err != nil {
+			if cfg.BuildX {
+				fmt.Fprintf(os.Stderr, "# get %s: %v\n", insecure.Redacted(), err)
+			}
+			// HTTP failed, and we already tried HTTPS if applicable.
+			// Report the error from the HTTP attempt.
+			return nil, err
+		}
+	}
+
+	// Note: accepting a non-200 OK here, so people can serve a
+	// meta import in their http 404 page.
+	if cfg.BuildX {
+		fmt.Fprintf(os.Stderr, "# get %s: %v (%.3fs)\n", fetched.Redacted(), res.Status, time.Since(start).Seconds())
+	}
+
+	r := &Response{
+		URL:        fetched.Redacted(),
+		Status:     res.Status,
+		StatusCode: res.StatusCode,
+		Header:     map[string][]string(res.Header),
+		Body:       res.Body,
+	}
+
+	if res.StatusCode != http.StatusOK {
+		contentType := res.Header.Get("Content-Type")
+		if mediaType, params, _ := mime.ParseMediaType(contentType); mediaType == "text/plain" {
+			switch charset := strings.ToLower(params["charset"]); charset {
+			case "us-ascii", "utf-8", "":
+				// Body claims to be plain text in UTF-8 or a subset thereof.
+				// Try to extract a useful error message from it.
+				r.errorDetail.r = res.Body
+				r.Body = &r.errorDetail
+			}
+		}
+	}
+
+	return r, nil
+}
+
+func getFile(u *urlpkg.URL) (*Response, error) {
+	path, err := urlToFilePath(u)
+	if err != nil {
+		return nil, err
+	}
+	f, err := os.Open(path)
+
+	if os.IsNotExist(err) {
+		return &Response{
+			URL:        u.Redacted(),
+			Status:     http.StatusText(http.StatusNotFound),
+			StatusCode: http.StatusNotFound,
+			Body:       http.NoBody,
+			fileErr:    err,
+		}, nil
+	}
+
+	if os.IsPermission(err) {
+		return &Response{
+			URL:        u.Redacted(),
+			Status:     http.StatusText(http.StatusForbidden),
+			StatusCode: http.StatusForbidden,
+			Body:       http.NoBody,
+			fileErr:    err,
+		}, nil
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &Response{
+		URL:        u.Redacted(),
+		Status:     http.StatusText(http.StatusOK),
+		StatusCode: http.StatusOK,
+		Body:       f,
+	}, nil
+}
+
+func openBrowser(url string) bool { return browser.Open(url) }
+
+func isLocalHost(u *urlpkg.URL) bool {
+	// VCSTestRepoURL itself is secure, and it may redirect requests to other
+	// ports (such as a port serving the "svn" protocol) which should also be
+	// considered secure.
+	host, _, err := net.SplitHostPort(u.Host)
+	if err != nil {
+		host = u.Host
+	}
+	if host == "localhost" {
+		return true
+	}
+	if ip := net.ParseIP(host); ip != nil && ip.IsLoopback() {
+		return true
+	}
+	return false
+}