Adding upstream version 9.0.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

5 files changed, 702 insertions, 0 deletions

diff --git a/modules/httplib/request.go b/modules/httplib/request.go
new file mode 100644
index 0000000..880d7ad
--- /dev/null
+++ b/modules/httplib/request.go
@@ -0,0 +1,206 @@
+// Copyright 2013 The Beego Authors. All rights reserved.
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+var defaultSetting = Settings{"GiteaServer", 60 * time.Second, 60 * time.Second, nil, nil}
+
+// newRequest returns *Request with specific method
+func newRequest(url, method string) *Request {
+	var resp http.Response
+	req := http.Request{
+		Method:     method,
+		Header:     make(http.Header),
+		Proto:      "HTTP/1.1",
+		ProtoMajor: 1,
+		ProtoMinor: 1,
+	}
+	return &Request{url, &req, map[string]string{}, defaultSetting, &resp, nil}
+}
+
+// NewRequest returns *Request with specific method
+func NewRequest(url, method string) *Request {
+	return newRequest(url, method)
+}
+
+// Settings is the default settings for http client
+type Settings struct {
+	UserAgent        string
+	ConnectTimeout   time.Duration
+	ReadWriteTimeout time.Duration
+	TLSClientConfig  *tls.Config
+	Transport        http.RoundTripper
+}
+
+// Request provides more useful methods for requesting one url than http.Request.
+type Request struct {
+	url     string
+	req     *http.Request
+	params  map[string]string
+	setting Settings
+	resp    *http.Response
+	body    []byte
+}
+
+// SetContext sets the request's Context
+func (r *Request) SetContext(ctx context.Context) *Request {
+	r.req = r.req.WithContext(ctx)
+	return r
+}
+
+// SetTimeout sets connect time out and read-write time out for BeegoRequest.
+func (r *Request) SetTimeout(connectTimeout, readWriteTimeout time.Duration) *Request {
+	r.setting.ConnectTimeout = connectTimeout
+	r.setting.ReadWriteTimeout = readWriteTimeout
+	return r
+}
+
+func (r *Request) SetReadWriteTimeout(readWriteTimeout time.Duration) *Request {
+	r.setting.ReadWriteTimeout = readWriteTimeout
+	return r
+}
+
+// SetTLSClientConfig sets tls connection configurations if visiting https url.
+func (r *Request) SetTLSClientConfig(config *tls.Config) *Request {
+	r.setting.TLSClientConfig = config
+	return r
+}
+
+// Header add header item string in request.
+func (r *Request) Header(key, value string) *Request {
+	r.req.Header.Set(key, value)
+	return r
+}
+
+// SetTransport sets transport to
+func (r *Request) SetTransport(transport http.RoundTripper) *Request {
+	r.setting.Transport = transport
+	return r
+}
+
+// Param adds query param in to request.
+// params build query string as ?key1=value1&key2=value2...
+func (r *Request) Param(key, value string) *Request {
+	r.params[key] = value
+	return r
+}
+
+// Body adds request raw body.
+// it supports string and []byte.
+func (r *Request) Body(data any) *Request {
+	switch t := data.(type) {
+	case string:
+		bf := bytes.NewBufferString(t)
+		r.req.Body = io.NopCloser(bf)
+		r.req.ContentLength = int64(len(t))
+	case []byte:
+		bf := bytes.NewBuffer(t)
+		r.req.Body = io.NopCloser(bf)
+		r.req.ContentLength = int64(len(t))
+	}
+	return r
+}
+
+func (r *Request) getResponse() (*http.Response, error) {
+	if r.resp.StatusCode != 0 {
+		return r.resp, nil
+	}
+
+	var paramBody string
+	if len(r.params) > 0 {
+		var buf bytes.Buffer
+		for k, v := range r.params {
+			buf.WriteString(url.QueryEscape(k))
+			buf.WriteByte('=')
+			buf.WriteString(url.QueryEscape(v))
+			buf.WriteByte('&')
+		}
+		paramBody = buf.String()
+		paramBody = paramBody[0 : len(paramBody)-1]
+	}
+
+	if r.req.Method == "GET" && len(paramBody) > 0 {
+		if strings.Contains(r.url, "?") {
+			r.url += "&" + paramBody
+		} else {
+			r.url = r.url + "?" + paramBody
+		}
+	} else if r.req.Method == "POST" && r.req.Body == nil && len(paramBody) > 0 {
+		r.Header("Content-Type", "application/x-www-form-urlencoded")
+		r.Body(paramBody)
+	}
+
+	var err error
+	r.req.URL, err = url.Parse(r.url)
+	if err != nil {
+		return nil, err
+	}
+
+	trans := r.setting.Transport
+	if trans == nil {
+		// create default transport
+		trans = &http.Transport{
+			TLSClientConfig: r.setting.TLSClientConfig,
+			Proxy:           http.ProxyFromEnvironment,
+			DialContext:     TimeoutDialer(r.setting.ConnectTimeout),
+		}
+	} else if t, ok := trans.(*http.Transport); ok {
+		if t.TLSClientConfig == nil {
+			t.TLSClientConfig = r.setting.TLSClientConfig
+		}
+		if t.DialContext == nil {
+			t.DialContext = TimeoutDialer(r.setting.ConnectTimeout)
+		}
+	}
+
+	client := &http.Client{
+		Transport: trans,
+		Timeout:   r.setting.ReadWriteTimeout,
+	}
+
+	if len(r.setting.UserAgent) > 0 && len(r.req.Header.Get("User-Agent")) == 0 {
+		r.req.Header.Set("User-Agent", r.setting.UserAgent)
+	}
+
+	resp, err := client.Do(r.req)
+	if err != nil {
+		return nil, err
+	}
+	r.resp = resp
+	return resp, nil
+}
+
+// Response executes request client gets response manually.
+func (r *Request) Response() (*http.Response, error) {
+	return r.getResponse()
+}
+
+// TimeoutDialer returns functions of connection dialer with timeout settings for http.Transport Dial field.
+func TimeoutDialer(cTimeout time.Duration) func(ctx context.Context, net, addr string) (c net.Conn, err error) {
+	return func(ctx context.Context, netw, addr string) (net.Conn, error) {
+		d := net.Dialer{Timeout: cTimeout}
+		conn, err := d.DialContext(ctx, netw, addr)
+		if err != nil {
+			return nil, err
+		}
+		return conn, nil
+	}
+}
+
+func (r *Request) GoString() string {
+	return fmt.Sprintf("%s %s", r.req.Method, r.url)
+}
diff --git a/modules/httplib/serve.go b/modules/httplib/serve.go
new file mode 100644
index 0000000..2e3e6a7
--- /dev/null
+++ b/modules/httplib/serve.go
@@ -0,0 +1,237 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
+	charsetModule "code.gitea.io/gitea/modules/charset"
+	"code.gitea.io/gitea/modules/container"
+	"code.gitea.io/gitea/modules/httpcache"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/typesniffer"
+	"code.gitea.io/gitea/modules/util"
+
+	"github.com/klauspost/compress/gzhttp"
+)
+
+type ServeHeaderOptions struct {
+	ContentType        string // defaults to "application/octet-stream"
+	ContentTypeCharset string
+	ContentLength      *int64
+	Disposition        string // defaults to "attachment"
+	Filename           string
+	CacheDuration      time.Duration // defaults to 5 minutes
+	LastModified       time.Time
+}
+
+// ServeSetHeaders sets necessary content serve headers
+func ServeSetHeaders(w http.ResponseWriter, opts *ServeHeaderOptions) {
+	header := w.Header()
+
+	skipCompressionExts := container.SetOf(".gz", ".bz2", ".zip", ".xz", ".zst", ".deb", ".apk", ".jar", ".png", ".jpg", ".webp")
+	if skipCompressionExts.Contains(strings.ToLower(path.Ext(opts.Filename))) {
+		w.Header().Add(gzhttp.HeaderNoCompression, "1")
+	}
+
+	contentType := typesniffer.ApplicationOctetStream
+	if opts.ContentType != "" {
+		if opts.ContentTypeCharset != "" {
+			contentType = opts.ContentType + "; charset=" + strings.ToLower(opts.ContentTypeCharset)
+		} else {
+			contentType = opts.ContentType
+		}
+	}
+	header.Set("Content-Type", contentType)
+	header.Set("X-Content-Type-Options", "nosniff")
+
+	if opts.ContentLength != nil {
+		header.Set("Content-Length", strconv.FormatInt(*opts.ContentLength, 10))
+	}
+
+	if opts.Filename != "" {
+		disposition := opts.Disposition
+		if disposition == "" {
+			disposition = "attachment"
+		}
+
+		backslashEscapedName := strings.ReplaceAll(strings.ReplaceAll(opts.Filename, `\`, `\\`), `"`, `\"`) // \ -> \\, " -> \"
+		header.Set("Content-Disposition", fmt.Sprintf(`%s; filename="%s"; filename*=UTF-8''%s`, disposition, backslashEscapedName, url.PathEscape(opts.Filename)))
+		header.Set("Access-Control-Expose-Headers", "Content-Disposition")
+	}
+
+	duration := opts.CacheDuration
+	if duration == 0 {
+		duration = 5 * time.Minute
+	}
+	httpcache.SetCacheControlInHeader(header, duration)
+
+	if !opts.LastModified.IsZero() {
+		// http.TimeFormat required a UTC time, refer to https://pkg.go.dev/net/http#TimeFormat
+		header.Set("Last-Modified", opts.LastModified.UTC().Format(http.TimeFormat))
+	}
+}
+
+// ServeData download file from io.Reader
+func setServeHeadersByFile(r *http.Request, w http.ResponseWriter, filePath string, mineBuf []byte) {
+	// do not set "Content-Length", because the length could only be set by callers, and it needs to support range requests
+	opts := &ServeHeaderOptions{
+		Filename: path.Base(filePath),
+	}
+
+	sniffedType := typesniffer.DetectContentType(mineBuf)
+
+	// the "render" parameter came from year 2016: 638dd24c, it doesn't have clear meaning, so I think it could be removed later
+	isPlain := sniffedType.IsText() || r.FormValue("render") != ""
+
+	if setting.MimeTypeMap.Enabled {
+		fileExtension := strings.ToLower(filepath.Ext(filePath))
+		opts.ContentType = setting.MimeTypeMap.Map[fileExtension]
+	}
+
+	if opts.ContentType == "" {
+		if sniffedType.IsBrowsableBinaryType() {
+			opts.ContentType = sniffedType.GetMimeType()
+		} else if isPlain {
+			opts.ContentType = "text/plain"
+		} else {
+			opts.ContentType = typesniffer.ApplicationOctetStream
+		}
+	}
+
+	if isPlain {
+		charset, err := charsetModule.DetectEncoding(mineBuf)
+		if err != nil {
+			log.Error("Detect raw file %s charset failed: %v, using by default utf-8", filePath, err)
+			charset = "utf-8"
+		}
+		opts.ContentTypeCharset = strings.ToLower(charset)
+	}
+
+	isSVG := sniffedType.IsSvgImage()
+
+	// serve types that can present a security risk with CSP
+	if isSVG {
+		w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'; sandbox")
+	} else if sniffedType.IsPDF() {
+		// no sandbox attribute for pdf as it breaks rendering in at least safari. this
+		// should generally be safe as scripts inside PDF can not escape the PDF document
+		// see https://bugs.chromium.org/p/chromium/issues/detail?id=413851 for more discussion
+		w.Header().Set("Content-Security-Policy", "default-src 'none'; style-src 'unsafe-inline'")
+	}
+
+	opts.Disposition = "inline"
+	if isSVG && !setting.UI.SVG.Enabled {
+		opts.Disposition = "attachment"
+	}
+
+	ServeSetHeaders(w, opts)
+}
+
+const mimeDetectionBufferLen = 1024
+
+func ServeContentByReader(r *http.Request, w http.ResponseWriter, filePath string, size int64, reader io.Reader) {
+	buf := make([]byte, mimeDetectionBufferLen)
+	n, err := util.ReadAtMost(reader, buf)
+	if err != nil {
+		http.Error(w, "serve content: unable to pre-read", http.StatusRequestedRangeNotSatisfiable)
+		return
+	}
+	if n >= 0 {
+		buf = buf[:n]
+	}
+	setServeHeadersByFile(r, w, filePath, buf)
+
+	// reset the reader to the beginning
+	reader = io.MultiReader(bytes.NewReader(buf), reader)
+
+	rangeHeader := r.Header.Get("Range")
+
+	// if no size or no supported range, serve as 200 (complete response)
+	if size <= 0 || !strings.HasPrefix(rangeHeader, "bytes=") {
+		if size >= 0 {
+			w.Header().Set("Content-Length", strconv.FormatInt(size, 10))
+		}
+		_, _ = io.Copy(w, reader) // just like http.ServeContent, not necessary to handle the error
+		return
+	}
+
+	// do our best to support the minimal "Range" request (no support for multiple range: "Range: bytes=0-50, 100-150")
+	//
+	// GET /...
+	// Range: bytes=0-1023
+	//
+	// HTTP/1.1 206 Partial Content
+	// Content-Range: bytes 0-1023/146515
+	// Content-Length: 1024
+
+	_, rangeParts, _ := strings.Cut(rangeHeader, "=")
+	rangeBytesStart, rangeBytesEnd, found := strings.Cut(rangeParts, "-")
+	start, err := strconv.ParseInt(rangeBytesStart, 10, 64)
+	if start < 0 || start >= size {
+		err = errors.New("invalid start range")
+	}
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusRequestedRangeNotSatisfiable)
+		return
+	}
+	end, err := strconv.ParseInt(rangeBytesEnd, 10, 64)
+	if rangeBytesEnd == "" && found {
+		err = nil
+		end = size - 1
+	}
+	if end >= size {
+		end = size - 1
+	}
+	if end < start {
+		err = errors.New("invalid end range")
+	}
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+
+	partialLength := end - start + 1
+	w.Header().Set("Content-Range", fmt.Sprintf("bytes %d-%d/%d", start, end, size))
+	w.Header().Set("Content-Length", strconv.FormatInt(partialLength, 10))
+	if _, err = io.CopyN(io.Discard, reader, start); err != nil {
+		http.Error(w, "serve content: unable to skip", http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusPartialContent)
+	_, _ = io.CopyN(w, reader, partialLength) // just like http.ServeContent, not necessary to handle the error
+}
+
+func ServeContentByReadSeeker(r *http.Request, w http.ResponseWriter, filePath string, modTime *time.Time, reader io.ReadSeeker) {
+	buf := make([]byte, mimeDetectionBufferLen)
+	n, err := util.ReadAtMost(reader, buf)
+	if err != nil {
+		http.Error(w, "serve content: unable to read", http.StatusInternalServerError)
+		return
+	}
+	if _, err = reader.Seek(0, io.SeekStart); err != nil {
+		http.Error(w, "serve content: unable to seek", http.StatusInternalServerError)
+		return
+	}
+	if n >= 0 {
+		buf = buf[:n]
+	}
+	setServeHeadersByFile(r, w, filePath, buf)
+	if modTime == nil {
+		modTime = &time.Time{}
+	}
+	http.ServeContent(w, r, path.Base(filePath), *modTime, reader)
+}
diff --git a/modules/httplib/serve_test.go b/modules/httplib/serve_test.go
new file mode 100644
index 0000000..fe609e1
--- /dev/null
+++ b/modules/httplib/serve_test.go
@@ -0,0 +1,109 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestServeContentByReader(t *testing.T) {
+	data := "0123456789abcdef"
+
+	test := func(t *testing.T, expectedStatusCode int, expectedContent string) {
+		_, rangeStr, _ := strings.Cut(t.Name(), "_range_")
+		r := &http.Request{Header: http.Header{}, Form: url.Values{}}
+		if rangeStr != "" {
+			r.Header.Set("Range", fmt.Sprintf("bytes=%s", rangeStr))
+		}
+		reader := strings.NewReader(data)
+		w := httptest.NewRecorder()
+		ServeContentByReader(r, w, "test", int64(len(data)), reader)
+		assert.Equal(t, expectedStatusCode, w.Code)
+		if expectedStatusCode == http.StatusPartialContent || expectedStatusCode == http.StatusOK {
+			assert.Equal(t, fmt.Sprint(len(expectedContent)), w.Header().Get("Content-Length"))
+			assert.Equal(t, expectedContent, w.Body.String())
+		}
+	}
+
+	t.Run("_range_", func(t *testing.T) {
+		test(t, http.StatusOK, data)
+	})
+	t.Run("_range_0-", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data)
+	})
+	t.Run("_range_0-15", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data)
+	})
+	t.Run("_range_1-", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:])
+	})
+	t.Run("_range_1-3", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:3+1])
+	})
+	t.Run("_range_16-", func(t *testing.T) {
+		test(t, http.StatusRequestedRangeNotSatisfiable, "")
+	})
+	t.Run("_range_1-99999", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:])
+	})
+}
+
+func TestServeContentByReadSeeker(t *testing.T) {
+	data := "0123456789abcdef"
+	tmpFile := t.TempDir() + "/test"
+	err := os.WriteFile(tmpFile, []byte(data), 0o644)
+	require.NoError(t, err)
+
+	test := func(t *testing.T, expectedStatusCode int, expectedContent string) {
+		_, rangeStr, _ := strings.Cut(t.Name(), "_range_")
+		r := &http.Request{Header: http.Header{}, Form: url.Values{}}
+		if rangeStr != "" {
+			r.Header.Set("Range", fmt.Sprintf("bytes=%s", rangeStr))
+		}
+
+		seekReader, err := os.OpenFile(tmpFile, os.O_RDONLY, 0o644)
+		require.NoError(t, err)
+
+		defer seekReader.Close()
+
+		w := httptest.NewRecorder()
+		ServeContentByReadSeeker(r, w, "test", nil, seekReader)
+		assert.Equal(t, expectedStatusCode, w.Code)
+		if expectedStatusCode == http.StatusPartialContent || expectedStatusCode == http.StatusOK {
+			assert.Equal(t, fmt.Sprint(len(expectedContent)), w.Header().Get("Content-Length"))
+			assert.Equal(t, expectedContent, w.Body.String())
+		}
+	}
+
+	t.Run("_range_", func(t *testing.T) {
+		test(t, http.StatusOK, data)
+	})
+	t.Run("_range_0-", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data)
+	})
+	t.Run("_range_0-15", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data)
+	})
+	t.Run("_range_1-", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:])
+	})
+	t.Run("_range_1-3", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:3+1])
+	})
+	t.Run("_range_16-", func(t *testing.T) {
+		test(t, http.StatusRequestedRangeNotSatisfiable, "")
+	})
+	t.Run("_range_1-99999", func(t *testing.T) {
+		test(t, http.StatusPartialContent, data[1:])
+	})
+}
diff --git a/modules/httplib/url.go b/modules/httplib/url.go
new file mode 100644
index 0000000..14b9589
--- /dev/null
+++ b/modules/httplib/url.go
@@ -0,0 +1,27 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"net/url"
+	"strings"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+// IsRiskyRedirectURL returns true if the URL is considered risky for redirects
+func IsRiskyRedirectURL(s string) bool {
+	// Unfortunately browsers consider a redirect Location with preceding "//", "\\", "/\" and "\/" as meaning redirect to "http(s)://REST_OF_PATH"
+	// Therefore we should ignore these redirect locations to prevent open redirects
+	if len(s) > 1 && (s[0] == '/' || s[0] == '\\') && (s[1] == '/' || s[1] == '\\') {
+		return true
+	}
+
+	u, err := url.Parse(s)
+	if err != nil || ((u.Scheme != "" || u.Host != "") && !strings.HasPrefix(strings.ToLower(s), strings.ToLower(setting.AppURL))) {
+		return true
+	}
+
+	return false
+}
diff --git a/modules/httplib/url_test.go b/modules/httplib/url_test.go
new file mode 100644
index 0000000..2842edd
--- /dev/null
+++ b/modules/httplib/url_test.go
@@ -0,0 +1,123 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package httplib
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIsRiskyRedirectURL(t *testing.T) {
+	defer test.MockVariableValue(&setting.AppURL, "http://localhost:3000/sub/")()
+	defer test.MockVariableValue(&setting.AppSubURL, "/sub")()
+
+	tests := []struct {
+		input string
+		want  bool
+	}{
+		{"", false},
+		{"foo", false},
+		{"./", false},
+		{"?key=val", false},
+		{"/sub/", false},
+		{"http://localhost:3000/sub/", false},
+		{"/sub/foo", false},
+		{"http://localhost:3000/sub/foo", false},
+		{"http://localhost:3000/sub/test?param=false", false},
+		// FIXME: should probably be true (would requires resolving references using setting.appURL.ResolveReference(u))
+		{"/sub/../", false},
+		{"http://localhost:3000/sub/../", false},
+		{"/sUb/", false},
+		{"http://localhost:3000/sUb/foo", false},
+		{"/sub", false},
+		{"/foo?k=%20#abc", false},
+		{"/", false},
+		{"a/", false},
+		{"test?param=false", false},
+		{"/hey/hey/hey#3244", false},
+
+		{"//", true},
+		{"\\\\", true},
+		{"/\\", true},
+		{"\\/", true},
+		{"mail:a@b.com", true},
+		{"https://test.com", true},
+		{"http://localhost:3000/foo", true},
+		{"http://localhost:3000/sub", true},
+		{"http://localhost:3000/sub?key=val", true},
+		{"https://example.com/", true},
+		{"//example.com", true},
+		{"http://example.com", true},
+		{"http://localhost:3000/test?param=false", true},
+		{"//localhost:3000/test?param=false", true},
+		{"://missing protocol scheme", true},
+		// FIXME: should probably be false
+		{"//localhost:3000/sub/test?param=false", true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			assert.Equal(t, tt.want, IsRiskyRedirectURL(tt.input))
+		})
+	}
+}
+
+func TestIsRiskyRedirectURLWithoutSubURL(t *testing.T) {
+	defer test.MockVariableValue(&setting.AppURL, "https://next.forgejo.org/")()
+	defer test.MockVariableValue(&setting.AppSubURL, "")()
+
+	tests := []struct {
+		input string
+		want  bool
+	}{
+		{"", false},
+		{"foo", false},
+		{"./", false},
+		{"?key=val", false},
+		{"/sub/", false},
+		{"https://next.forgejo.org/sub/", false},
+		{"/sub/foo", false},
+		{"https://next.forgejo.org/sub/foo", false},
+		{"https://next.forgejo.org/sub/test?param=false", false},
+		{"https://next.forgejo.org/sub/../", false},
+		{"/sub/../", false},
+		{"/sUb/", false},
+		{"https://next.forgejo.org/sUb/foo", false},
+		{"/sub", false},
+		{"/foo?k=%20#abc", false},
+		{"/", false},
+		{"a/", false},
+		{"test?param=false", false},
+		{"/hey/hey/hey#3244", false},
+		{"https://next.forgejo.org/test?param=false", false},
+		{"https://next.forgejo.org/foo", false},
+		{"https://next.forgejo.org/sub", false},
+		{"https://next.forgejo.org/sub?key=val", false},
+
+		{"//", true},
+		{"\\\\", true},
+		{"/\\", true},
+		{"\\/", true},
+		{"mail:a@b.com", true},
+		{"https://test.com", true},
+		{"https://example.com/", true},
+		{"//example.com", true},
+		{"http://example.com", true},
+		{"://missing protocol scheme", true},
+		{"https://forgejo.org", true},
+		{"https://example.org?url=https://next.forgejo.org", true},
+		// FIXME: should probably be false
+		{"https://next.forgejo.org", true},
+		{"//next.forgejo.org/test?param=false", true},
+		{"//next.forgejo.org/sub/test?param=false", true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.input, func(t *testing.T) {
+			assert.Equal(t, tt.want, IsRiskyRedirectURL(tt.input))
+		})
+	}
+}