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Implement http signatures support for the API (#17565)

Fixes #12338

This allows use to talk to the API with our ssh certificate (and/or ssh-agent) without needing to fetch an API key or tokens.
It will just automatically work when users have added their ssh principal in gitea.

This needs client code in tea
Update: also support normal pubkeys

ref: https://tools.ietf.org/html/draft-cavage-http-signatures

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: zeripath <art27@cantab.net>
Signed-off-by: Andrew Thornton <art27@cantab.net>
This commit is contained in:
Wim 2022-06-05 09:16:14 +02:00 committed by GitHub
parent 48be5e77e5
commit e528e2b435
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
11 changed files with 365 additions and 1 deletions

1
go.mod
View file

@ -29,6 +29,7 @@ require (
github.com/go-chi/chi/v5 v5.0.7
github.com/go-chi/cors v1.2.1
github.com/go-enry/go-enry/v2 v2.8.2
github.com/go-fed/httpsig v1.1.0
github.com/go-git/go-billy/v5 v5.3.1
github.com/go-git/go-git/v5 v5.4.3-0.20210630082519-b4368b2a2ca4
github.com/go-ldap/ldap/v3 v3.4.3

2
go.sum
View file

@ -468,6 +468,8 @@ github.com/go-enry/go-enry/v2 v2.8.2 h1:uiGmC+3K8sVd/6DOe2AOJEOihJdqda83nPyJNtMR
github.com/go-enry/go-enry/v2 v2.8.2/go.mod h1:GVzIiAytiS5uT/QiuakK7TF1u4xDab87Y8V5EJRpsIQ=
github.com/go-enry/go-oniguruma v1.2.1 h1:k8aAMuJfMrqm/56SG2lV9Cfti6tC4x8673aHCcBk+eo=
github.com/go-enry/go-oniguruma v1.2.1/go.mod h1:bWDhYP+S6xZQgiRL7wlTScFYBe023B6ilRZbCAD5Hf4=
github.com/go-fed/httpsig v1.1.0 h1:9M+hb0jkEICD8/cAiNqEB66R87tTINszBRTjwjQzWcI=
github.com/go-fed/httpsig v1.1.0/go.mod h1:RCMrTZvN1bJYtofsG4rd5NaO5obxQ5xBkdiS7xsT7bM=
github.com/go-git/gcfg v1.5.0 h1:Q5ViNfGF8zFgyJWPqYwA7qGFoMTEiBmdlkcfRmpIMa4=
github.com/go-git/gcfg v1.5.0/go.mod h1:5m20vg6GwYabIxaOonVkTdrILxQMpEShl1xiMF4ua+E=
github.com/go-git/go-billy/v5 v5.2.0/go.mod h1:pmpqyWchKfYfrkb/UVH4otLvyi/5gJlGI4Hb3ZqZ3W0=

View file

@ -0,0 +1,137 @@
// 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 integrations
import (
"encoding/base64"
"fmt"
"net/http"
"net/url"
"testing"
api "code.gitea.io/gitea/modules/structs"
"github.com/go-fed/httpsig"
"golang.org/x/crypto/ssh"
)
const (
httpsigPrivateKey = `-----BEGIN OPENSSH PRIVATE KEY-----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-----END OPENSSH PRIVATE KEY-----`
httpsigCertificate = `ssh-rsa-cert-v01@openssh.com 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`
)
func TestHTTPSigPubKey(t *testing.T) {
// Add our public key to user1
defer prepareTestEnv(t)()
session := loginUser(t, "user1")
token := url.QueryEscape(getTokenForLoggedInUser(t, session))
keysURL := fmt.Sprintf("/api/v1/user/keys?token=%s", token)
keyType := "ssh-rsa"
keyContent := "AAAAB3NzaC1yc2EAAAADAQABAAABAQCqOZB5vkRvXFXups1/0StDRdG8plbNSwsWEnNnP4Bvurxa0+z3W9B8GLKnDiLw5MbpbMNyBlpXw13GfuIeciy10DWTz0xUbiy3J3KabCaT36asIw2y7k6Z0jL0UBnrVENwq5/lUbZYqSZ4rRU744wkhh8TULpzM14npQCZwg6aEbG+MwjzddQ72fR+3BPBrKn5dTmmu8rH99O+U+Nuto81Tg7PA+NUupcHOmhdiEGq49plgVFXK98Vks5tiybL4GuzFyWgyX73Dg/QBMn2eMHt1EMv5Gs3i6GFhKKGo4rjDi9qI6PX5oDR4LTNe6cR8td8YhVD8WFZwLLl/vaYyIqd"
rawKeyBody := api.CreateKeyOption{
Title: "test-key",
Key: keyType + " " + keyContent,
}
req := NewRequestWithJSON(t, "POST", keysURL, rawKeyBody)
session.MakeRequest(t, req, http.StatusCreated)
// parse our private key and create the httpsig request
sshSigner, _ := ssh.ParsePrivateKey([]byte(httpsigPrivateKey))
keyID := ssh.FingerprintSHA256(sshSigner.PublicKey())
// create the request
req = NewRequest(t, "GET", "/api/v1/admin/users")
signer, _, err := httpsig.NewSSHSigner(sshSigner, httpsig.DigestSha512, []string{httpsig.RequestTarget, "(created)", "(expires)"}, httpsig.Signature, 10)
if err != nil {
t.Fatal(err)
}
// sign the request
err = signer.SignRequest(keyID, req, nil)
if err != nil {
t.Fatal(err)
}
// make the request
MakeRequest(t, req, http.StatusOK)
}
func TestHTTPSigCert(t *testing.T) {
// Add our public key to user1
defer prepareTestEnv(t)()
session := loginUser(t, "user1")
csrf := GetCSRF(t, session, "/user/settings/keys")
req := NewRequestWithValues(t, "POST", "/user/settings/keys", map[string]string{
"_csrf": csrf,
"content": "user1",
"title": "principal",
"type": "principal",
})
session.MakeRequest(t, req, http.StatusSeeOther)
pkcert, _, _, _, err := ssh.ParseAuthorizedKey([]byte(httpsigCertificate))
if err != nil {
t.Fatal(err)
}
// parse our private key and create the httpsig request
sshSigner, _ := ssh.ParsePrivateKey([]byte(httpsigPrivateKey))
keyID := "gitea"
// create our certificate signer using the ssh signer and our certificate
certSigner, err := ssh.NewCertSigner(pkcert.(*ssh.Certificate), sshSigner)
if err != nil {
t.Fatal(err)
}
// create the request
req = NewRequest(t, "GET", "/api/v1/admin/users")
// add our cert to the request
certString := base64.RawStdEncoding.EncodeToString(pkcert.(*ssh.Certificate).Marshal())
req.Header.Add("x-ssh-certificate", certString)
signer, _, err := httpsig.NewSSHSigner(certSigner, httpsig.DigestSha512, []string{httpsig.RequestTarget, "(created)", "(expires)", "x-ssh-certificate"}, httpsig.Signature, 10)
if err != nil {
t.Fatal(err)
}
// sign the request
err = signer.SignRequest(keyID, req, nil)
if err != nil {
t.Fatal(err)
}
// make the request
MakeRequest(t, req, http.StatusOK)
}

View file

@ -49,6 +49,7 @@ OFFLINE_MODE = false
LFS_JWT_SECRET = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
APP_DATA_PATH = integrations/gitea-integration-mssql/data
BUILTIN_SSH_SERVER_USER = git
SSH_TRUSTED_USER_CA_KEYS = ssh-rsa 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
[attachment]
PATH = integrations/gitea-integration-mssql/data/attachments

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@ -51,6 +51,7 @@ OFFLINE_MODE = false
LFS_START_SERVER = true
LFS_JWT_SECRET = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
SSH_TRUSTED_USER_CA_KEYS = ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQCb4DC1dMFnJ6pXWo7GMxTchtzmJHYzfN6sZ9FAPFR4ijMLfGki+olvOMO5Fql1/yGnGfbELQa1S6y4shSvj/5K+zUFScmEXYf3Gcr87RqilLkyk16RS+cHNB1u87xTHbETaa3nyCJeGQRpd4IQ4NKob745mwDZ7jQBH8AZEng50Oh8y8fi8skBBBzaYp1ilgvzG740L7uex6fHV62myq0SXeCa+oJUjq326FU8y+Vsa32H8A3e7tOgXZPdt2TVNltx2S9H2WO8RMi7LfaSwARNfy1zu+bfR50r6ef8Yx5YKCMz4wWb1SHU1GS800mjOjlInLQORYRNMlSwR1+vLlVDciOqFapDSbj+YOVOawR0R1aqlSKpZkt33DuOBPx9qe6CVnIi7Z+Px/KqM+OLCzlLY/RS+LbxQpDWcfTVRiP+S5qRTcE3M3UioN/e0BE/1+MpX90IGpvVkA63ILYbKEa4bM3ASL7ChTCr6xN5XT+GpVJveFKK1cfNx9ExHI4rzYE=
[lfs]
MINIO_BASE_PATH = lfs/

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@ -49,6 +49,7 @@ OFFLINE_MODE = false
LFS_JWT_SECRET = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
APP_DATA_PATH = integrations/gitea-integration-mysql8/data
BUILTIN_SSH_SERVER_USER = git
SSH_TRUSTED_USER_CA_KEYS = ssh-rsa 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
[attachment]
PATH = integrations/gitea-integration-mysql8/data/attachments

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@ -50,6 +50,7 @@ OFFLINE_MODE = false
LFS_JWT_SECRET = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
APP_DATA_PATH = integrations/gitea-integration-pgsql/data
BUILTIN_SSH_SERVER_USER = git
SSH_TRUSTED_USER_CA_KEYS = ssh-rsa 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
[attachment]
PATH = integrations/gitea-integration-pgsql/data/attachments

View file

@ -46,6 +46,7 @@ LFS_JWT_SECRET = Tv_MjmZuHqpIY6GFl12ebgkRAMt4RlWt0v4EHKSXO0w
APP_DATA_PATH = integrations/gitea-integration-sqlite/data
ENABLE_GZIP = true
BUILTIN_SSH_SERVER_USER = git
SSH_TRUSTED_USER_CA_KEYS = ssh-rsa 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
[attachment]
PATH = integrations/gitea-integration-sqlite/data/attachments

View file

@ -188,8 +188,9 @@ func publicKeyHandler(ctx ssh.Context, key ssh.PublicKey) bool {
c := &gossh.CertChecker{
IsUserAuthority: func(auth gossh.PublicKey) bool {
marshaled := auth.Marshal()
for _, k := range setting.SSH.TrustedUserCAKeysParsed {
if bytes.Equal(auth.Marshal(), k.Marshal()) {
if bytes.Equal(marshaled, k.Marshal()) {
return true
}
}

View file

@ -592,6 +592,7 @@ func bind(obj interface{}) http.HandlerFunc {
func buildAuthGroup() *auth.Group {
group := auth.NewGroup(
&auth.OAuth2{},
&auth.HTTPSign{},
&auth.Basic{}, // FIXME: this should be removed once we don't allow basic auth in API
)
if setting.Service.EnableReverseProxyAuth {

217
services/auth/httpsign.go Normal file
View file

@ -0,0 +1,217 @@
// Copyright 2021 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 auth
import (
"bytes"
"encoding/base64"
"errors"
"fmt"
"net/http"
"strings"
asymkey_model "code.gitea.io/gitea/models/asymkey"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
"github.com/go-fed/httpsig"
"golang.org/x/crypto/ssh"
)
// Ensure the struct implements the interface.
var (
_ Method = &HTTPSign{}
_ Named = &HTTPSign{}
)
// HTTPSign implements the Auth interface and authenticates requests (API requests
// only) by looking for http signature data in the "Signature" header.
// more information can be found on https://github.com/go-fed/httpsig
type HTTPSign struct{}
// Name represents the name of auth method
func (h *HTTPSign) Name() string {
return "httpsign"
}
// Verify extracts and validates HTTPsign from the Signature header of the request and returns
// the corresponding user object on successful validation.
// Returns nil if header is empty or validation fails.
func (h *HTTPSign) Verify(req *http.Request, w http.ResponseWriter, store DataStore, sess SessionStore) *user_model.User {
sigHead := req.Header.Get("Signature")
if len(sigHead) == 0 {
return nil
}
var (
publicKey *asymkey_model.PublicKey
err error
)
if len(req.Header.Get("X-Ssh-Certificate")) != 0 {
// Handle Signature signed by SSH certificates
if len(setting.SSH.TrustedUserCAKeys) == 0 {
return nil
}
publicKey, err = VerifyCert(req)
if err != nil {
log.Debug("VerifyCert on request from %s: failed: %v", req.RemoteAddr, err)
log.Warn("Failed authentication attempt from %s", req.RemoteAddr)
return nil
}
} else {
// Handle Signature signed by Public Key
publicKey, err = VerifyPubKey(req)
if err != nil {
log.Debug("VerifyPubKey on request from %s: failed: %v", req.RemoteAddr, err)
log.Warn("Failed authentication attempt from %s", req.RemoteAddr)
return nil
}
}
u, err := user_model.GetUserByID(publicKey.OwnerID)
if err != nil {
log.Error("GetUserByID: %v", err)
return nil
}
store.GetData()["IsApiToken"] = true
log.Trace("HTTP Sign: Logged in user %-v", u)
return u
}
func VerifyPubKey(r *http.Request) (*asymkey_model.PublicKey, error) {
verifier, err := httpsig.NewVerifier(r)
if err != nil {
return nil, fmt.Errorf("httpsig.NewVerifier failed: %s", err)
}
keyID := verifier.KeyId()
publicKeys, err := asymkey_model.SearchPublicKey(0, keyID)
if err != nil {
return nil, err
}
if len(publicKeys) == 0 {
return nil, fmt.Errorf("no public key found for keyid %s", keyID)
}
sshPublicKey, _, _, _, err := ssh.ParseAuthorizedKey([]byte(publicKeys[0].Content))
if err != nil {
return nil, err
}
if err := doVerify(verifier, []ssh.PublicKey{sshPublicKey}); err != nil {
return nil, err
}
return publicKeys[0], nil
}
// VerifyCert verifies the validity of the ssh certificate and returns the publickey of the signer
// We verify that the certificate is signed with the correct CA
// We verify that the http request is signed with the private key (of the public key mentioned in the certificate)
func VerifyCert(r *http.Request) (*asymkey_model.PublicKey, error) {
// Get our certificate from the header
bcert, err := base64.RawStdEncoding.DecodeString(r.Header.Get("x-ssh-certificate"))
if err != nil {
return nil, err
}
pk, err := ssh.ParsePublicKey(bcert)
if err != nil {
return nil, err
}
// Check if it's really a ssh certificate
cert, ok := pk.(*ssh.Certificate)
if !ok {
return nil, fmt.Errorf("no certificate found")
}
c := &ssh.CertChecker{
IsUserAuthority: func(auth ssh.PublicKey) bool {
marshaled := auth.Marshal()
for _, k := range setting.SSH.TrustedUserCAKeysParsed {
if bytes.Equal(marshaled, k.Marshal()) {
return true
}
}
return false
},
}
// check the CA of the cert
if !c.IsUserAuthority(cert.SignatureKey) {
return nil, fmt.Errorf("CA check failed")
}
// Create a verifier
verifier, err := httpsig.NewVerifier(r)
if err != nil {
return nil, fmt.Errorf("httpsig.NewVerifier failed: %s", err)
}
// now verify that this request was signed with the private key that matches the certificate public key
if err := doVerify(verifier, []ssh.PublicKey{cert.Key}); err != nil {
return nil, err
}
// Now for each of the certificate valid principals
for _, principal := range cert.ValidPrincipals {
// Look in the db for the public key
publicKey, err := asymkey_model.SearchPublicKeyByContentExact(r.Context(), principal)
if asymkey_model.IsErrKeyNotExist(err) {
// No public key matches this principal - try the next principal
continue
} else if err != nil {
// this error will be a db error therefore we can't solve this and we should abort
log.Error("SearchPublicKeyByContentExact: %v", err)
return nil, err
}
// Validate the cert for this principal
if err := c.CheckCert(principal, cert); err != nil {
// however, because principal is a member of ValidPrincipals - if this fails then the certificate itself is invalid
return nil, err
}
// OK we have a public key for a principal matching a valid certificate whose key has signed this request.
return publicKey, nil
}
// No public key matching a principal in the certificate is registered in gitea
return nil, fmt.Errorf("no valid principal found")
}
// doVerify iterates across the provided public keys attempting the verify the current request against each key in turn
func doVerify(verifier httpsig.Verifier, sshPublicKeys []ssh.PublicKey) error {
for _, publicKey := range sshPublicKeys {
cryptoPubkey := publicKey.(ssh.CryptoPublicKey).CryptoPublicKey()
var algos []httpsig.Algorithm
switch {
case strings.HasPrefix(publicKey.Type(), "ssh-ed25519"):
algos = []httpsig.Algorithm{httpsig.ED25519}
case strings.HasPrefix(publicKey.Type(), "ssh-rsa"):
algos = []httpsig.Algorithm{httpsig.RSA_SHA1, httpsig.RSA_SHA256, httpsig.RSA_SHA512}
}
for _, algo := range algos {
if err := verifier.Verify(cryptoPubkey, algo); err == nil {
return nil
}
}
}
return errors.New("verification failed")
}