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>

Changes

11 changed files (+365/-1)

• go.mod
  • @@ -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
• go.sum
  • @@ -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=
• integrations/api_httpsig_test.go (new)
  • @@ -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----- + b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAABFwAAAAdzc2gtcn + NhAAAAAwEAAQAAAQEAqjmQeb5Eb1xV7qbNf9ErQ0XRvKZWzUsLFhJzZz+Ab7q8WtPs91vQ + fBiypw4i8OTG6WzDcgZaV8Ndxn7iHnIstdA1k89MVG4stydymmwmk9+mrCMNsu5OmdIy9F + AZ61RDcKuf5VG2WKkmeK0VO+OMJIYfE1C6czNeJ6UAmcIOmhGxvjMI83XUO9n0ftwTwayp + +XU5prvKx/fTvlPjbraPNU4OzwPjVLqXBzpoXYhBquPaZYFRVyvfFZLObYsmy+BrsxcloM + l+9w4P0ATJ9njB7dRDL+RrN4uhhYSihqOK4w4vaiOj1+aA0eC0zXunEfLXfGIVQ/FhWcCy + 5f72mMiKnQAAA9AxSmzFMUpsxQAAAAdzc2gtcnNhAAABAQCqOZB5vkRvXFXups1/0StDRd + G8plbNSwsWEnNnP4Bvurxa0+z3W9B8GLKnDiLw5MbpbMNyBlpXw13GfuIeciy10DWTz0xU + biy3J3KabCaT36asIw2y7k6Z0jL0UBnrVENwq5/lUbZYqSZ4rRU744wkhh8TULpzM14npQ + CZwg6aEbG+MwjzddQ72fR+3BPBrKn5dTmmu8rH99O+U+Nuto81Tg7PA+NUupcHOmhdiEGq + 49plgVFXK98Vks5tiybL4GuzFyWgyX73Dg/QBMn2eMHt1EMv5Gs3i6GFhKKGo4rjDi9qI6 + PX5oDR4LTNe6cR8td8YhVD8WFZwLLl/vaYyIqdAAAAAwEAAQAAAQBz+nyBNi2SYir6SxPA + flcnoq5gBkUl4ndPNosCUbXEakpi5/mQHzJRGtK+F1efIYCVEdGoIsPy/90onNKbQ9dKmO + 2oI5kx/U7iCzJ+HCm8nqkEp21x+AP9scWdx+Wg/OxmG8j5iU7f4X+gwOyyvTqCuA78Lgia + 7Oi9wiJCoIEqXr6dRYGJzfASwKA2dj995HzATexleLSD5fQCmZTF+Vh5OQ5WmE+c53JdZS + T3Plie/P/smgSWBtf1fWr6JL2+EBsqQsIK1Jo7r/7rxsz+ILoVfnneNQY4QSa9W+t6ZAI+ + caSA0Guv7vC92ewjlMVlwKa3XaEjMJb5sFlg1r6TYMwBAAAAgQDQwXvgSXNaSHIeH53/Ab + t4BlNibtxK8vY8CZFloAKXkjrivKSlDAmQCM0twXOweX2ScPjE+XlSMV4AUsv/J6XHGHci + W3+PGIBfc/fQRBpiyhzkoXYDVrlkSKHffCnAqTUQlYkhr0s7NkZpEeqPE0doAUs4dK3Iqb + zdtz8e5BPXZwAAAIEA4U/JskIu5Oge8Is2OLOhlol0EJGw5JGodpFyhbMC+QYK9nYqy7wI + a6mZ2EfOjjwIZD/+wYyulw6cRve4zXwgzUEXLIKp8/H3sYvJK2UMeP7y68sQFqGxbm6Rnh + tyBBSaJQnOXVOFf9gqZGCyO/J0Illg3AXTuC8KS/cxwasC38EAAACBAMFo/6XQoR6E3ynj + VBaz2SilWqQBixUyvcNz8LY73IIDCecoccRMFSEKhWtvlJijxvFbF9M8g9oKAVPuub4V5r + CGmwVPEd5yt4C2iyV0PhLp1PA2/i42FpCSnHaz/EXSz6ncTZcOMMuDqUbgUUpQg4VSUDl9 + fhTNAzWwZoQ91aHdAAAAFHUwMDIyMTQ2QGljdHMtcC1ueC03AQIDBAUG + -----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) + }
• integrations/mssql.ini.tmpl
  • @@ -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
• integrations/mysql.ini.tmpl
  • @@ -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/
• integrations/mysql8.ini.tmpl
  • @@ -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
• integrations/pgsql.ini.tmpl
  • @@ -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
• integrations/sqlite.ini.tmpl
  • @@ -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
• modules/ssh/ssh.go
  • @@ -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 } }
• routers/api/v1/api.go
  • @@ -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 {
• services/auth/httpsign.go (new)
  • @@ -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") + }