gitea source for verification 2026-05-22

routers/api/v1/activitypub/person.go

@@ -0,0 +1,106 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-ap/jsonld"
+)
+
+// Person function returns the Person actor for a user
+func Person(ctx *context.APIContext) {
+	// swagger:operation GET /activitypub/user-id/{user-id} activitypub activitypubPerson
+	// ---
+	// summary: Returns the Person actor for a user
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: user-id
+	//   in: path
+	//   description: user ID of the user
+	//   type: integer
+	//   required: true
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/ActivityPub"
+
+	// TODO: the setting.AppURL during the test doesn't follow the definition: "It always has a '/' suffix"
+	link := fmt.Sprintf("%s/api/v1/activitypub/user-id/%d", strings.TrimSuffix(setting.AppURL, "/"), ctx.ContextUser.ID)
+	person := ap.PersonNew(ap.IRI(link))
+
+	person.Name = ap.NaturalLanguageValuesNew()
+	err := person.Name.Set("en", ap.Content(ctx.ContextUser.FullName))
+	if err != nil {
+		ctx.APIErrorInternal(err)
+		return
+	}
+
+	person.PreferredUsername = ap.NaturalLanguageValuesNew()
+	err = person.PreferredUsername.Set("en", ap.Content(ctx.ContextUser.Name))
+	if err != nil {
+		ctx.APIErrorInternal(err)
+		return
+	}
+
+	person.URL = ap.IRI(ctx.ContextUser.HTMLURL(ctx))
+
+	person.Icon = ap.Image{
+		Type:      ap.ImageType,
+		MediaType: "image/png",
+		URL:       ap.IRI(ctx.ContextUser.AvatarLink(ctx)),
+	}
+
+	person.Inbox = ap.IRI(link + "/inbox")
+	person.Outbox = ap.IRI(link + "/outbox")
+
+	person.PublicKey.ID = ap.IRI(link + "#main-key")
+	person.PublicKey.Owner = ap.IRI(link)
+
+	publicKeyPem, err := activitypub.GetPublicKey(ctx, ctx.ContextUser)
+	if err != nil {
+		ctx.APIErrorInternal(err)
+		return
+	}
+	person.PublicKey.PublicKeyPem = publicKeyPem
+
+	binary, err := jsonld.WithContext(jsonld.IRI(ap.ActivityBaseURI), jsonld.IRI(ap.SecurityContextURI)).Marshal(person)
+	if err != nil {
+		ctx.APIErrorInternal(err)
+		return
+	}
+	ctx.Resp.Header().Add("Content-Type", activitypub.ActivityStreamsContentType)
+	ctx.Resp.WriteHeader(http.StatusOK)
+	if _, err = ctx.Resp.Write(binary); err != nil {
+		log.Error("write to resp err: %v", err)
+	}
+}
+
+// PersonInbox function handles the incoming data for a user inbox
+func PersonInbox(ctx *context.APIContext) {
+	// swagger:operation POST /activitypub/user-id/{user-id}/inbox activitypub activitypubPersonInbox
+	// ---
+	// summary: Send to the inbox
+	// produces:
+	// - application/json
+	// parameters:
+	// - name: user-id
+	//   in: path
+	//   description: user ID of the user
+	//   type: integer
+	//   required: true
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+
+	ctx.Status(http.StatusNoContent)
+}

routers/api/v1/activitypub/reqsignature.go

@@ -0,0 +1,98 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"crypto"
+	"crypto/x509"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/httplib"
+	"code.gitea.io/gitea/modules/setting"
+	gitea_context "code.gitea.io/gitea/services/context"
+
+	"github.com/42wim/httpsig"
+	ap "github.com/go-ap/activitypub"
+)
+
+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 {
+		return nil, fmt.Errorf("ActivityStreams type cannot be converted to one known to have publicKey property: %w", err)
+	}
+	pubKey := person.PublicKey
+	if pubKey.ID.String() != keyID.String() {
+		return nil, fmt.Errorf("cannot find publicKey with id: %s in %s", keyID, string(b))
+	}
+	pubKeyPem := pubKey.PublicKeyPem
+	block, _ := pem.Decode([]byte(pubKeyPem))
+	if block == nil || block.Type != "PUBLIC KEY" {
+		return nil, errors.New("could not decode publicKeyPem to PUBLIC KEY pem block type")
+	}
+	p, err = x509.ParsePKIXPublicKey(block.Bytes)
+	return p, err
+}
+
+func fetch(iri *url.URL) (b []byte, err error) {
+	req := httplib.NewRequest(iri.String(), http.MethodGet)
+	req.Header("Accept", activitypub.ActivityStreamsContentType)
+	req.Header("User-Agent", "Gitea/"+setting.AppVer)
+	resp, err := req.Response()
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("url IRI fetch [%s] failed with status (%d): %s", iri, resp.StatusCode, resp.Status)
+	}
+	b, err = io.ReadAll(io.LimitReader(resp.Body, setting.Federation.MaxSize))
+	return b, err
+}
+
+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 false, err
+	}
+	ID := v.KeyId()
+	idIRI, err := url.Parse(ID)
+	if err != nil {
+		return false, err
+	}
+	// 2. Fetch the public key of the other actor
+	b, err := fetch(idIRI)
+	if err != nil {
+		return false, err
+	}
+	pubKey, err := getPublicKeyFromResponse(b, idIRI)
+	if err != nil {
+		return false, err
+	}
+	// 3. Verify the other actor's key
+	algo := httpsig.Algorithm(setting.Federation.Algorithms[0])
+	authenticated = v.Verify(pubKey, algo) == nil
+	return authenticated, err
+}
+
+// ReqHTTPSignature function
+func ReqHTTPSignature() func(ctx *gitea_context.APIContext) {
+	return func(ctx *gitea_context.APIContext) {
+		if authenticated, err := verifyHTTPSignatures(ctx); err != nil {
+			ctx.APIErrorInternal(err)
+		} else if !authenticated {
+			ctx.APIError(http.StatusForbidden, "request signature verification failed")
+		}
+	}
+}