| 1 | // Copyright 2019 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | // authtest is a diagnostic tool for implementations of the GOAUTH protocol |
| 6 | // described in https://golang.org/issue/26232. |
| 7 | // |
| 8 | // It accepts a single URL as an argument, and executes the GOAUTH protocol to |
| 9 | // fetch and display the headers for that URL. |
| 10 | // |
| 11 | // CAUTION: authtest logs the GOAUTH responses, which may include user |
| 12 | // credentials, to stderr. Do not post its output unless you are certain that |
| 13 | // all of the credentials involved are fake! |
| 14 | package main |
| 15 | |
| 16 | import ( |
| 17 | "bufio" |
| 18 | "bytes" |
| 19 | "flag" |
| 20 | "fmt" |
| 21 | exec "golang.org/x/sys/execabs" |
| 22 | "io" |
| 23 | "log" |
| 24 | "net/http" |
| 25 | "net/textproto" |
| 26 | "net/url" |
| 27 | "os" |
| 28 | "path/filepath" |
| 29 | "strings" |
| 30 | ) |
| 31 | |
| 32 | var v = flag.Bool("v", false, "if true, log GOAUTH responses to stderr") |
| 33 | |
| 34 | func main() { |
| 35 | log.SetFlags(log.LstdFlags | log.Lshortfile) |
| 36 | flag.Parse() |
| 37 | args := flag.Args() |
| 38 | if len(args) != 1 { |
| 39 | log.Fatalf("usage: [GOAUTH=CMD...] %s URL", filepath.Base(os.Args[0])) |
| 40 | } |
| 41 | |
| 42 | resp := try(args[0], nil) |
| 43 | if resp.StatusCode == http.StatusOK { |
| 44 | return |
| 45 | } |
| 46 | |
| 47 | resp = try(args[0], resp) |
| 48 | if resp.StatusCode != http.StatusOK { |
| 49 | os.Exit(1) |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | func try(url string, prev *http.Response) *http.Response { |
| 54 | req := new(http.Request) |
| 55 | if prev != nil { |
| 56 | *req = *prev.Request |
| 57 | } else { |
| 58 | var err error |
| 59 | req, err = http.NewRequest("HEAD", os.Args[1], nil) |
| 60 | if err != nil { |
| 61 | log.Fatal(err) |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | goauth: |
| 66 | for _, argList := range strings.Split(os.Getenv("GOAUTH"), ";") { |
| 67 | // TODO(golang.org/issue/26849): If we escape quoted strings in GOFLAGS, use |
| 68 | // the same quoting here. |
| 69 | args := strings.Split(argList, " ") |
| 70 | if len(args) == 0 || args[0] == "" { |
| 71 | log.Fatalf("invalid or empty command in GOAUTH") |
| 72 | } |
| 73 | |
| 74 | creds, err := getCreds(args, prev) |
| 75 | if err != nil { |
| 76 | log.Fatal(err) |
| 77 | } |
| 78 | for _, c := range creds { |
| 79 | if c.Apply(req) { |
| 80 | fmt.Fprintf(os.Stderr, "# request to %s\n", req.URL) |
| 81 | fmt.Fprintf(os.Stderr, "%s %s %s\n", req.Method, req.URL, req.Proto) |
| 82 | req.Header.Write(os.Stderr) |
| 83 | fmt.Fprintln(os.Stderr) |
| 84 | break goauth |
| 85 | } |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | resp, err := http.DefaultClient.Do(req) |
| 90 | if err != nil { |
| 91 | log.Fatal(err) |
| 92 | } |
| 93 | defer resp.Body.Close() |
| 94 | |
| 95 | if resp.StatusCode != http.StatusOK && resp.StatusCode < 400 || resp.StatusCode > 500 { |
| 96 | log.Fatalf("unexpected status: %v", resp.Status) |
| 97 | } |
| 98 | |
| 99 | fmt.Fprintf(os.Stderr, "# response from %s\n", resp.Request.URL) |
| 100 | formatHead(os.Stderr, resp) |
| 101 | return resp |
| 102 | } |
| 103 | |
| 104 | func formatHead(out io.Writer, resp *http.Response) { |
| 105 | fmt.Fprintf(out, "%s %s\n", resp.Proto, resp.Status) |
| 106 | if err := resp.Header.Write(out); err != nil { |
| 107 | log.Fatal(err) |
| 108 | } |
| 109 | fmt.Fprintln(out) |
| 110 | } |
| 111 | |
| 112 | type Cred struct { |
| 113 | URLPrefixes []*url.URL |
| 114 | Header http.Header |
| 115 | } |
| 116 | |
| 117 | func (c Cred) Apply(req *http.Request) bool { |
| 118 | if req.URL == nil { |
| 119 | return false |
| 120 | } |
| 121 | ok := false |
| 122 | for _, prefix := range c.URLPrefixes { |
| 123 | if prefix.Host == req.URL.Host && |
| 124 | (req.URL.Path == prefix.Path || |
| 125 | (strings.HasPrefix(req.URL.Path, prefix.Path) && |
| 126 | (strings.HasSuffix(prefix.Path, "/") || |
| 127 | req.URL.Path[len(prefix.Path)] == '/'))) { |
| 128 | ok = true |
| 129 | break |
| 130 | } |
| 131 | } |
| 132 | if !ok { |
| 133 | return false |
| 134 | } |
| 135 | |
| 136 | for k, vs := range c.Header { |
| 137 | req.Header.Del(k) |
| 138 | for _, v := range vs { |
| 139 | req.Header.Add(k, v) |
| 140 | } |
| 141 | } |
| 142 | return true |
| 143 | } |
| 144 | |
| 145 | func (c Cred) String() string { |
| 146 | var buf strings.Builder |
| 147 | for _, u := range c.URLPrefixes { |
| 148 | fmt.Fprintln(&buf, u) |
| 149 | } |
| 150 | buf.WriteString("\n") |
| 151 | c.Header.Write(&buf) |
| 152 | buf.WriteString("\n") |
| 153 | return buf.String() |
| 154 | } |
| 155 | |
| 156 | func getCreds(args []string, resp *http.Response) ([]Cred, error) { |
| 157 | cmd := exec.Command(args[0], args[1:]...) |
| 158 | cmd.Stderr = os.Stderr |
| 159 | |
| 160 | if resp != nil { |
| 161 | u := *resp.Request.URL |
| 162 | u.RawQuery = "" |
| 163 | cmd.Args = append(cmd.Args, u.String()) |
| 164 | } |
| 165 | |
| 166 | var head strings.Builder |
| 167 | if resp != nil { |
| 168 | formatHead(&head, resp) |
| 169 | } |
| 170 | cmd.Stdin = strings.NewReader(head.String()) |
| 171 | |
| 172 | fmt.Fprintf(os.Stderr, "# %s\n", strings.Join(cmd.Args, " ")) |
| 173 | out, err := cmd.Output() |
| 174 | if err != nil { |
| 175 | return nil, fmt.Errorf("%s: %v", strings.Join(cmd.Args, " "), err) |
| 176 | } |
| 177 | os.Stderr.Write(out) |
| 178 | os.Stderr.WriteString("\n") |
| 179 | |
| 180 | var creds []Cred |
| 181 | r := textproto.NewReader(bufio.NewReader(bytes.NewReader(out))) |
| 182 | line := 0 |
| 183 | readLoop: |
| 184 | for { |
| 185 | var prefixes []*url.URL |
| 186 | for { |
| 187 | prefix, err := r.ReadLine() |
| 188 | if err == io.EOF { |
| 189 | if len(prefixes) > 0 { |
| 190 | return nil, fmt.Errorf("line %d: %v", line, io.ErrUnexpectedEOF) |
| 191 | } |
| 192 | break readLoop |
| 193 | } |
| 194 | line++ |
| 195 | |
| 196 | if prefix == "" { |
| 197 | if len(prefixes) == 0 { |
| 198 | return nil, fmt.Errorf("line %d: unexpected newline", line) |
| 199 | } |
| 200 | break |
| 201 | } |
| 202 | u, err := url.Parse(prefix) |
| 203 | if err != nil { |
| 204 | return nil, fmt.Errorf("line %d: malformed URL: %v", line, err) |
| 205 | } |
| 206 | if u.Scheme != "https" { |
| 207 | return nil, fmt.Errorf("line %d: non-HTTPS URL %q", line, prefix) |
| 208 | } |
| 209 | if len(u.RawQuery) > 0 { |
| 210 | return nil, fmt.Errorf("line %d: unexpected query string in URL %q", line, prefix) |
| 211 | } |
| 212 | if len(u.Fragment) > 0 { |
| 213 | return nil, fmt.Errorf("line %d: unexpected fragment in URL %q", line, prefix) |
| 214 | } |
| 215 | prefixes = append(prefixes, u) |
| 216 | } |
| 217 | |
| 218 | header, err := r.ReadMIMEHeader() |
| 219 | if err != nil { |
| 220 | return nil, fmt.Errorf("headers at line %d: %v", line, err) |
| 221 | } |
| 222 | if len(header) > 0 { |
| 223 | creds = append(creds, Cred{ |
| 224 | URLPrefixes: prefixes, |
| 225 | Header: http.Header(header), |
| 226 | }) |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | return creds, nil |
| 231 | } |
| 232 |
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