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
|
// Copyright 2022 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package activitypub
import (
"crypto"
"crypto/x509"
"encoding/pem"
"fmt"
"net/http"
"net/url"
"code.gitea.io/gitea/modules/activitypub"
gitea_context "code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/setting"
ap "github.com/go-ap/activitypub"
"github.com/go-fed/httpsig"
)
func getPublicKeyFromResponse(b []byte, keyID *url.URL) (p crypto.PublicKey, err error) {
person := ap.PersonNew(ap.IRI(keyID.String()))
err = person.UnmarshalJSON(b)
if err != nil {
err = fmt.Errorf("ActivityStreams type cannot be converted to one known to have publicKey property: %v", err)
return
}
pubKey := person.PublicKey
if pubKey.ID.String() != keyID.String() {
err = fmt.Errorf("cannot find publicKey with id: %s in %s", keyID, string(b))
return
}
pubKeyPem := pubKey.PublicKeyPem
block, _ := pem.Decode([]byte(pubKeyPem))
if block == nil || block.Type != "PUBLIC KEY" {
err = fmt.Errorf("could not decode publicKeyPem to PUBLIC KEY pem block type")
return
}
p, err = x509.ParsePKIXPublicKey(block.Bytes)
return
}
func verifyHTTPSignatures(ctx *gitea_context.APIContext) (authenticated bool, err error) {
r := ctx.Req
// 1. Figure out what key we need to verify
v, err := httpsig.NewVerifier(r)
if err != nil {
return
}
ID := v.KeyId()
idIRI, err := url.Parse(ID)
if err != nil {
return
}
// 2. Fetch the public key of the other actor
b, err := activitypub.Fetch(idIRI)
if err != nil {
return
}
pubKey, err := getPublicKeyFromResponse(b, idIRI)
if err != nil {
return
}
// 3. Verify the other actor's key
algo := httpsig.Algorithm(setting.Federation.Algorithms[0])
authenticated = v.Verify(pubKey, algo) == nil
return
}
// ReqHTTPSignature function
func ReqHTTPSignature() func(ctx *gitea_context.APIContext) {
return func(ctx *gitea_context.APIContext) {
if authenticated, err := verifyHTTPSignatures(ctx); err != nil {
ctx.Error(http.StatusInternalServerError, "verifyHttpSignatures", err)
} else if !authenticated {
ctx.Error(http.StatusForbidden, "reqSignature", "request signature verification failed")
}
}
}
|
