1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
|
package getter
import (
"bufio"
"bytes"
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"encoding/hex"
"fmt"
"hash"
"io"
"net/url"
"os"
"path/filepath"
"strings"
urlhelper "github.com/hashicorp/go-getter/helper/url"
)
// fileChecksum helps verifying the checksum for a file.
type fileChecksum struct {
Type string
Hash hash.Hash
Value []byte
Filename string
}
// A ChecksumError is returned when a checksum differs
type ChecksumError struct {
Hash hash.Hash
Actual []byte
Expected []byte
File string
}
func (cerr *ChecksumError) Error() string {
if cerr == nil {
return "<nil>"
}
return fmt.Sprintf(
"Checksums did not match for %s.\nExpected: %s\nGot: %s\n%T",
cerr.File,
hex.EncodeToString(cerr.Expected),
hex.EncodeToString(cerr.Actual),
cerr.Hash, // ex: *sha256.digest
)
}
// checksum is a simple method to compute the checksum of a source file
// and compare it to the given expected value.
func (c *fileChecksum) checksum(source string) error {
f, err := os.Open(source)
if err != nil {
return fmt.Errorf("Failed to open file for checksum: %s", err)
}
defer f.Close()
c.Hash.Reset()
if _, err := io.Copy(c.Hash, f); err != nil {
return fmt.Errorf("Failed to hash: %s", err)
}
if actual := c.Hash.Sum(nil); !bytes.Equal(actual, c.Value) {
return &ChecksumError{
Hash: c.Hash,
Actual: actual,
Expected: c.Value,
File: source,
}
}
return nil
}
// extractChecksum will return a fileChecksum based on the 'checksum'
// parameter of u.
// ex:
// http://hashicorp.com/terraform?checksum=<checksumValue>
// http://hashicorp.com/terraform?checksum=<checksumType>:<checksumValue>
// http://hashicorp.com/terraform?checksum=file:<checksum_url>
// when checksumming from a file, extractChecksum will go get checksum_url
// in a temporary directory, parse the content of the file then delete it.
// Content of files are expected to be BSD style or GNU style.
//
// BSD-style checksum:
// MD5 (file1) = <checksum>
// MD5 (file2) = <checksum>
//
// GNU-style:
// <checksum> file1
// <checksum> *file2
//
// see parseChecksumLine for more detail on checksum file parsing
func (c *Client) extractChecksum(u *url.URL) (*fileChecksum, error) {
q := u.Query()
v := q.Get("checksum")
if v == "" {
return nil, nil
}
vs := strings.SplitN(v, ":", 2)
switch len(vs) {
case 2:
break // good
default:
// here, we try to guess the checksum from it's length
// if the type was not passed
return newChecksumFromValue(v, filepath.Base(u.EscapedPath()))
}
checksumType, checksumValue := vs[0], vs[1]
switch checksumType {
case "file":
return c.checksumFromFile(checksumValue, u)
default:
return newChecksumFromType(checksumType, checksumValue, filepath.Base(u.EscapedPath()))
}
}
func newChecksum(checksumValue, filename string) (*fileChecksum, error) {
c := &fileChecksum{
Filename: filename,
}
var err error
c.Value, err = hex.DecodeString(checksumValue)
if err != nil {
return nil, fmt.Errorf("invalid checksum: %s", err)
}
return c, nil
}
func newChecksumFromType(checksumType, checksumValue, filename string) (*fileChecksum, error) {
c, err := newChecksum(checksumValue, filename)
if err != nil {
return nil, err
}
c.Type = strings.ToLower(checksumType)
switch c.Type {
case "md5":
c.Hash = md5.New()
case "sha1":
c.Hash = sha1.New()
case "sha256":
c.Hash = sha256.New()
case "sha512":
c.Hash = sha512.New()
default:
return nil, fmt.Errorf(
"unsupported checksum type: %s", checksumType)
}
return c, nil
}
func newChecksumFromValue(checksumValue, filename string) (*fileChecksum, error) {
c, err := newChecksum(checksumValue, filename)
if err != nil {
return nil, err
}
switch len(c.Value) {
case md5.Size:
c.Hash = md5.New()
c.Type = "md5"
case sha1.Size:
c.Hash = sha1.New()
c.Type = "sha1"
case sha256.Size:
c.Hash = sha256.New()
c.Type = "sha256"
case sha512.Size:
c.Hash = sha512.New()
c.Type = "sha512"
default:
return nil, fmt.Errorf("Unknown type for checksum %s", checksumValue)
}
return c, nil
}
// checksumsFromFile will return all the fileChecksums found in file
//
// checksumsFromFile will try to guess the hashing algorithm based on content
// of checksum file
//
// checksumsFromFile will only return checksums for files that match file
// behind src
func (c *Client) checksumFromFile(checksumFile string, src *url.URL) (*fileChecksum, error) {
checksumFileURL, err := urlhelper.Parse(checksumFile)
if err != nil {
return nil, err
}
tempfile, err := tmpFile("", filepath.Base(checksumFileURL.Path))
if err != nil {
return nil, err
}
defer os.Remove(tempfile)
c2 := &Client{
Ctx: c.Ctx,
Getters: c.Getters,
Decompressors: c.Decompressors,
Detectors: c.Detectors,
Pwd: c.Pwd,
Dir: false,
Src: checksumFile,
Dst: tempfile,
ProgressListener: c.ProgressListener,
}
if err = c2.Get(); err != nil {
return nil, fmt.Errorf(
"Error downloading checksum file: %s", err)
}
filename := filepath.Base(src.Path)
absPath, err := filepath.Abs(src.Path)
if err != nil {
return nil, err
}
checksumFileDir := filepath.Dir(checksumFileURL.Path)
relpath, err := filepath.Rel(checksumFileDir, absPath)
switch {
case err == nil ||
err.Error() == "Rel: can't make "+absPath+" relative to "+checksumFileDir:
// ex: on windows C:\gopath\...\content.txt cannot be relative to \
// which is okay, may be another expected path will work.
break
default:
return nil, err
}
// possible file identifiers:
options := []string{
filename, // ubuntu-14.04.1-server-amd64.iso
"*" + filename, // *ubuntu-14.04.1-server-amd64.iso Standard checksum
"?" + filename, // ?ubuntu-14.04.1-server-amd64.iso shasum -p
relpath, // dir/ubuntu-14.04.1-server-amd64.iso
"./" + relpath, // ./dir/ubuntu-14.04.1-server-amd64.iso
absPath, // fullpath; set if local
}
f, err := os.Open(tempfile)
if err != nil {
return nil, fmt.Errorf(
"Error opening downloaded file: %s", err)
}
defer f.Close()
rd := bufio.NewReader(f)
for {
line, err := rd.ReadString('\n')
if err != nil {
if err != io.EOF {
return nil, fmt.Errorf(
"Error reading checksum file: %s", err)
}
break
}
checksum, err := parseChecksumLine(line)
if err != nil || checksum == nil {
continue
}
if checksum.Filename == "" {
// filename not sure, let's try
return checksum, nil
}
// make sure the checksum is for the right file
for _, option := range options {
if option != "" && checksum.Filename == option {
// any checksum will work so we return the first one
return checksum, nil
}
}
}
return nil, fmt.Errorf("no checksum found in: %s", checksumFile)
}
// parseChecksumLine takes a line from a checksum file and returns
// checksumType, checksumValue and filename parseChecksumLine guesses the style
// of the checksum BSD vs GNU by splitting the line and by counting the parts.
// of a line.
// for BSD type sums parseChecksumLine guesses the hashing algorithm
// by checking the length of the checksum.
func parseChecksumLine(line string) (*fileChecksum, error) {
parts := strings.Fields(line)
switch len(parts) {
case 4:
// BSD-style checksum:
// MD5 (file1) = <checksum>
// MD5 (file2) = <checksum>
if len(parts[1]) <= 2 ||
parts[1][0] != '(' || parts[1][len(parts[1])-1] != ')' {
return nil, fmt.Errorf(
"Unexpected BSD-style-checksum filename format: %s", line)
}
filename := parts[1][1 : len(parts[1])-1]
return newChecksumFromType(parts[0], parts[3], filename)
case 2:
// GNU-style:
// <checksum> file1
// <checksum> *file2
return newChecksumFromValue(parts[0], parts[1])
case 0:
return nil, nil // empty line
default:
return newChecksumFromValue(parts[0], "")
}
}
|