mirror of
https://github.com/smallstep/certificates.git
synced 2024-11-19 09:25:37 +00:00
369 lines
11 KiB
Go
369 lines
11 KiB
Go
package api
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import (
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"context"
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"crypto/rsa"
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"io/ioutil"
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"net/http"
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"net/url"
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"strings"
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"github.com/go-chi/chi"
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"github.com/pkg/errors"
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"github.com/smallstep/certificates/acme"
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"github.com/smallstep/certificates/api"
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"github.com/smallstep/certificates/authority/provisioner"
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"github.com/smallstep/certificates/logging"
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"github.com/smallstep/cli/crypto/keys"
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"github.com/smallstep/cli/jose"
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"github.com/smallstep/nosql"
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)
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type nextHTTP = func(http.ResponseWriter, *http.Request)
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func logNonce(w http.ResponseWriter, nonce string) {
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if rl, ok := w.(logging.ResponseLogger); ok {
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m := map[string]interface{}{
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"nonce": nonce,
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}
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rl.WithFields(m)
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}
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}
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// addNonce is a middleware that adds a nonce to the response header.
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func (h *Handler) addNonce(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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nonce, err := h.Auth.NewNonce()
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if err != nil {
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api.WriteError(w, err)
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return
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}
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w.Header().Set("Replay-Nonce", nonce)
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w.Header().Set("Cache-Control", "no-store")
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logNonce(w, nonce)
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next(w, r)
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}
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}
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// addDirLink is a middleware that adds a 'Link' response reader with the
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// directory index url.
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func (h *Handler) addDirLink(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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prov, err := provisionerFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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w.Header().Add("Link", link(h.Auth.GetLink(acme.DirectoryLink, acme.URLSafeProvisionerName(prov), true), "index"))
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next(w, r)
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}
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}
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// verifyContentType is a middleware that verifies that content type is
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// application/jose+json.
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func (h *Handler) verifyContentType(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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prov, err := provisionerFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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ct := r.Header.Get("Content-Type")
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var expected []string
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if strings.Contains(r.URL.Path, h.Auth.GetLink(acme.CertificateLink, acme.URLSafeProvisionerName(prov), false, "")) {
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// GET /certificate requests allow a greater range of content types.
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expected = []string{"application/jose+json", "application/pkix-cert", "application/pkcs7-mime"}
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} else {
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// By default every request should have content-type applictaion/jose+json.
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expected = []string{"application/jose+json"}
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}
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for _, e := range expected {
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if ct == e {
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next(w, r)
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return
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}
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}
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api.WriteError(w, acme.MalformedErr(errors.Errorf(
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"expected content-type to be in %s, but got %s", expected, ct)))
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}
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}
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// parseJWS is a middleware that parses a request body into a JSONWebSignature struct.
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func (h *Handler) parseJWS(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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body, err := ioutil.ReadAll(r.Body)
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if err != nil {
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api.WriteError(w, acme.ServerInternalErr(errors.Wrap(err, "failed to read request body")))
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return
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}
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jws, err := jose.ParseJWS(string(body))
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if err != nil {
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api.WriteError(w, acme.MalformedErr(errors.Wrap(err, "failed to parse JWS from request body")))
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return
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}
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ctx := context.WithValue(r.Context(), jwsContextKey, jws)
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next(w, r.WithContext(ctx))
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}
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}
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// validateJWS checks the request body for to verify that it meets ACME
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// requirements for a JWS.
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//
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// The JWS MUST NOT have multiple signatures
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// The JWS Unencoded Payload Option [RFC7797] MUST NOT be used
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// The JWS Unprotected Header [RFC7515] MUST NOT be used
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// The JWS Payload MUST NOT be detached
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// The JWS Protected Header MUST include the following fields:
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// * “alg” (Algorithm)
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// * This field MUST NOT contain “none” or a Message Authentication Code
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// (MAC) algorithm (e.g. one in which the algorithm registry description
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// mentions MAC/HMAC).
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// * “nonce” (defined in Section 6.5)
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// * “url” (defined in Section 6.4)
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// * Either “jwk” (JSON Web Key) or “kid” (Key ID) as specified below<Paste>
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func (h *Handler) validateJWS(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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jws, err := jwsFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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if len(jws.Signatures) == 0 {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("request body does not contain a signature")))
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return
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}
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if len(jws.Signatures) > 1 {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("request body contains more than one signature")))
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return
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}
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sig := jws.Signatures[0]
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uh := sig.Unprotected
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if len(uh.KeyID) > 0 ||
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uh.JSONWebKey != nil ||
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len(uh.Algorithm) > 0 ||
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len(uh.Nonce) > 0 ||
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len(uh.ExtraHeaders) > 0 {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("unprotected header must not be used")))
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return
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}
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hdr := sig.Protected
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switch hdr.Algorithm {
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case jose.RS256, jose.RS384, jose.RS512:
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if hdr.JSONWebKey != nil {
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switch k := hdr.JSONWebKey.Key.(type) {
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case *rsa.PublicKey:
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if k.Size() < keys.MinRSAKeyBytes {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("rsa "+
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"keys must be at least %d bits (%d bytes) in size",
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8*keys.MinRSAKeyBytes, keys.MinRSAKeyBytes)))
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return
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}
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default:
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api.WriteError(w, acme.MalformedErr(errors.Errorf("jws key type and algorithm do not match")))
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return
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}
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}
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case jose.ES256, jose.ES384, jose.ES512, jose.EdDSA:
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// we good
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default:
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api.WriteError(w, acme.MalformedErr(errors.Errorf("unsuitable algorithm: %s", hdr.Algorithm)))
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return
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}
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// Check the validity/freshness of the Nonce.
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if err := h.Auth.UseNonce(hdr.Nonce); err != nil {
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api.WriteError(w, err)
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return
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}
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// Check that the JWS url matches the requested url.
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jwsURL, ok := hdr.ExtraHeaders["url"].(string)
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if !ok {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("jws missing url protected header")))
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return
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}
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reqURL := &url.URL{Scheme: "https", Host: r.Host, Path: r.URL.Path}
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if jwsURL != reqURL.String() {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("url header in JWS (%s) does not match request url (%s)", jwsURL, reqURL)))
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return
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}
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if hdr.JSONWebKey != nil && len(hdr.KeyID) > 0 {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("jwk and kid are mutually exclusive")))
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return
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}
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if hdr.JSONWebKey == nil && len(hdr.KeyID) == 0 {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("either jwk or kid must be defined in jws protected header")))
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return
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}
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next(w, r)
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}
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}
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// extractJWK is a middleware that extracts the JWK from the JWS and saves it
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// in the context. Make sure to parse and validate the JWS before running this
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// middleware.
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func (h *Handler) extractJWK(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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prov, err := provisionerFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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jws, err := jwsFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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jwk := jws.Signatures[0].Protected.JSONWebKey
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if jwk == nil {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("jwk expected in protected header")))
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return
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}
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if !jwk.Valid() {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("invalid jwk in protected header")))
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return
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}
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ctx = context.WithValue(ctx, jwkContextKey, jwk)
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acc, err := h.Auth.GetAccountByKey(prov, jwk)
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switch {
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case nosql.IsErrNotFound(err):
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// For NewAccount requests ...
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break
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case err != nil:
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api.WriteError(w, err)
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return
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default:
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if !acc.IsValid() {
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api.WriteError(w, acme.UnauthorizedErr(errors.New("account is not active")))
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return
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}
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ctx = context.WithValue(ctx, accContextKey, acc)
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}
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next(w, r.WithContext(ctx))
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}
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}
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// lookupProvisioner loads the provisioner associated with the request.
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// Responsds 404 if the provisioner does not exist.
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func (h *Handler) lookupProvisioner(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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name := chi.URLParam(r, "provisionerID")
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provID, err := url.PathUnescape(name)
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if err != nil {
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api.WriteError(w, acme.ServerInternalErr(errors.Wrapf(err, "error url unescaping provisioner id '%s'", name)))
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return
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}
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p, err := h.Auth.LoadProvisionerByID("acme/" + provID)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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if p.GetType() != provisioner.TypeACME {
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api.WriteError(w, acme.AccountDoesNotExistErr(errors.New("provisioner must be of type ACME")))
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return
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}
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ctx = context.WithValue(ctx, provisionerContextKey, p)
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next(w, r.WithContext(ctx))
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}
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}
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// lookupJWK loads the JWK associated with the acme account referenced by the
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// kid parameter of the signed payload.
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// Make sure to parse and validate the JWS before running this middleware.
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func (h *Handler) lookupJWK(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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ctx := r.Context()
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prov, err := provisionerFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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jws, err := jwsFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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kidPrefix := h.Auth.GetLink(acme.AccountLink, acme.URLSafeProvisionerName(prov), true, "")
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kid := jws.Signatures[0].Protected.KeyID
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if !strings.HasPrefix(kid, kidPrefix) {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("kid does not have "+
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"required prefix; expected %s, but got %s", kidPrefix, kid)))
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return
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}
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accID := strings.TrimPrefix(kid, kidPrefix)
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acc, err := h.Auth.GetAccount(prov, accID)
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switch {
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case nosql.IsErrNotFound(err):
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api.WriteError(w, acme.AccountDoesNotExistErr(nil))
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return
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case err != nil:
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api.WriteError(w, err)
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return
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default:
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if !acc.IsValid() {
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api.WriteError(w, acme.UnauthorizedErr(errors.New("account is not active")))
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return
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}
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ctx = context.WithValue(ctx, accContextKey, acc)
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ctx = context.WithValue(ctx, jwkContextKey, acc.Key)
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next(w, r.WithContext(ctx))
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return
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}
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}
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}
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// verifyAndExtractJWSPayload extracts the JWK from the JWS and saves it in the context.
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// Make sure to parse and validate the JWS before running this middleware.
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func (h *Handler) verifyAndExtractJWSPayload(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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jws, err := jwsFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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jwk, err := jwkFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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if len(jwk.Algorithm) != 0 && jwk.Algorithm != jws.Signatures[0].Protected.Algorithm {
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api.WriteError(w, acme.MalformedErr(errors.New("verifier and signature algorithm do not match")))
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return
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}
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payload, err := jws.Verify(jwk)
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if err != nil {
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api.WriteError(w, acme.MalformedErr(errors.Wrap(err, "error verifying jws")))
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return
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}
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ctx := context.WithValue(r.Context(), payloadContextKey, &payloadInfo{
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value: payload,
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isPostAsGet: string(payload) == "",
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isEmptyJSON: string(payload) == "{}",
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})
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next(w, r.WithContext(ctx))
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}
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}
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// isPostAsGet asserts that the request is a PostAsGet (empty JWS payload).
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func (h *Handler) isPostAsGet(next nextHTTP) nextHTTP {
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return func(w http.ResponseWriter, r *http.Request) {
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payload, err := payloadFromContext(r)
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if err != nil {
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api.WriteError(w, err)
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return
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}
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if !payload.isPostAsGet {
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api.WriteError(w, acme.MalformedErr(errors.Errorf("expected POST-as-GET")))
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return
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}
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next(w, r)
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}
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}
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