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
|
// Copyright 2021 The Sigstore Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package blob
import (
"crypto/sha256"
"crypto/sha512"
"encoding/hex"
"fmt"
"io"
"net/http"
"os"
"path/filepath"
"strings"
)
type UnrecognizedSchemeError struct {
Scheme string
}
func (e *UnrecognizedSchemeError) Error() string {
return fmt.Sprintf("loading URL: unrecognized scheme: %s", e.Scheme)
}
func LoadFileOrURL(fileRef string) ([]byte, error) {
var raw []byte
var err error
parts := strings.SplitAfterN(fileRef, "://", 2)
if len(parts) == 2 {
scheme := parts[0]
switch scheme {
case "http://":
fallthrough
case "https://":
// #nosec G107
resp, err := http.Get(fileRef)
if err != nil {
return nil, err
}
defer resp.Body.Close()
raw, err = io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
case "env://":
envVar := parts[1]
// Most of Cosign should use `env.LookupEnv` (see #2236) to restrict us to known environment variables
// (usually `$COSIGN_*`). However, in this case, `envVar` is user-provided and not one of the allow-listed
// env vars.
value, found := os.LookupEnv(envVar) //nolint:forbidigo
if !found {
return nil, fmt.Errorf("loading URL: env var $%s not found", envVar)
}
raw = []byte(value)
default:
return nil, &UnrecognizedSchemeError{Scheme: scheme}
}
} else {
raw, err = os.ReadFile(filepath.Clean(fileRef))
if err != nil {
return nil, err
}
}
return raw, nil
}
func LoadFileOrURLWithChecksum(fileRef string, checksum string) ([]byte, error) {
checksumParts := strings.Split(checksum, ":")
if len(checksumParts) >= 3 {
return nil, fmt.Errorf("wrong checksum input format, must have at most 1 colon: %s", checksum)
}
checksumAlgo := sha256.New()
checksumValue := checksumParts[len(checksumParts)-1]
if len(checksumParts) == 2 {
switch checksumParts[0] {
case "sha256": // the default set above
case "sha512":
checksumAlgo = sha512.New()
default:
return nil, fmt.Errorf("unsupported checksum algorithm: %s", checksumParts[0])
}
}
fileContent, err := LoadFileOrURL(fileRef)
if err != nil {
return nil, err
}
checksumAlgo.Write(fileContent)
computedChecksum := hex.EncodeToString(checksumAlgo.Sum(nil))
if computedChecksum != checksumValue {
return nil, fmt.Errorf("incorrect checksum for file %s: expected %s but got %s", fileRef, checksumValue, computedChecksum)
}
return fileContent, nil
}
|
