From ec4741e374beeb085579ba896fdee2cd6f0f8848 Mon Sep 17 00:00:00 2001
From: Rasmus Dahlberg <rasmus.dahlberg@kau.se>
Date: Wed, 21 Oct 2020 18:18:43 +0200
Subject: added start on addEntry code path

If the POSTed StItem can be parsed without errors it is handed over to
the Trillian back-end.
---
 handler.go | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 type.go    | 23 ++++++++++++++++++++
 2 files changed, 91 insertions(+), 3 deletions(-)

diff --git a/handler.go b/handler.go
index 90dbc27..7b986c1 100644
--- a/handler.go
+++ b/handler.go
@@ -4,9 +4,13 @@ import (
 	"context"
 	"fmt"
 
+	"encoding/json"
+	"io/ioutil"
 	"net/http"
 
 	"github.com/golang/glog"
+	"github.com/google/certificate-transparency-go/tls"
+	"github.com/google/trillian"
 )
 
 // appHandler implements the http.Handler interface, and contains a reference
@@ -31,7 +35,7 @@ func (a appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	statusCode, err := a.handler(ctx, a.instance, w, r)
 	if err != nil {
-		glog.Warningf("handler error %s: %v", a.instance.prefix+a.endpoint, err)
+		glog.Warningf("handler error %s/%s: %v", a.instance.prefix, a.endpoint, err)
 		a.sendHTTPError(w, statusCode, err)
 	}
 }
@@ -41,10 +45,71 @@ func (a appHandler) sendHTTPError(w http.ResponseWriter, statusCode int, err err
 	http.Error(w, http.StatusText(statusCode), statusCode)
 }
 
-// addEntry adds an entry to the Trillian backend
 func addEntry(ctx context.Context, i *instance, w http.ResponseWriter, r *http.Request) (int, error) {
 	glog.Info("in addEntry")
-	return http.StatusOK, nil // TODO
+	var request AddEntryRequest
+	if err := unpackRequest(r, &request); err != nil {
+		return http.StatusBadRequest, err
+	}
+
+	item, err := verifyAddEntryRequest(request)
+	if err != nil {
+		return http.StatusBadRequest, err
+	}
+	glog.Infof("got item: %s", item)
+
+	serializedItem, err := tls.Marshal(*item)
+	if err != nil {
+		return http.StatusInternalServerError, fmt.Errorf("tls marshal failed: %v", err)
+	}
+	trillianRequest := trillian.QueueLeafRequest{
+		LogId: i.logID,
+		Leaf: &trillian.LogLeaf{
+			LeafValue: serializedItem,
+			//TODO: add appendix here w/ chain + signature
+		},
+	}
+
+	trillianResponse, err := i.client.QueueLeaf(ctx, &trillianRequest)
+	if err != nil {
+		return http.StatusInternalServerError, fmt.Errorf("backend QueueLeaf request failed: %v", err)
+	}
+	if trillianResponse == nil {
+		return http.StatusInternalServerError, fmt.Errorf("missing QueueLeaf response")
+	}
+	// TODO: check that we got gRPC OK as specified in Trillian's API doc
+
+	queuedLeaf := trillianResponse.QueuedLeaf
+	glog.Infof("Queued leaf: %v", queuedLeaf.Leaf.LeafValue)
+	// TODO: respond with an SDI
+
+	return http.StatusOK, nil
+}
+
+// verifyAddEntryRequest
+func verifyAddEntryRequest(r AddEntryRequest) (*StItem, error) {
+	item, err := StItemFromB64(r.Item)
+	if err != nil {
+		return nil, fmt.Errorf("failed decoding StItem: %v", err)
+	}
+	if item.Format != StFormatChecksumV1 {
+		return nil, fmt.Errorf("invalid StItem format: %s", item.Format)
+	}
+	// TODO: verify checksum length
+	// TODO: verify r.Signature and r.Certificate
+	return item, nil
+}
+
+// unpackRequest tries to unpack a json-encoded HTTP POST request into `unpack`
+func unpackRequest(r *http.Request, unpack interface{}) error {
+	body, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		return fmt.Errorf("failed reading request body: %v", err)
+	}
+	if err := json.Unmarshal(body, &unpack); err != nil {
+		return fmt.Errorf("failed parsing json body: %v", err)
+	}
+	return nil
 }
 
 // getEntries provides with a list of entries from the Trillian backend
diff --git a/type.go b/type.go
index e9b5ef2..031ae8d 100644
--- a/type.go
+++ b/type.go
@@ -55,6 +55,22 @@ func (i StItem) String() string {
 	}
 }
 
+func StItemFromB64(s string) (*StItem, error) {
+	b, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return nil, fmt.Errorf("base64 decoding failed: %v", err)
+	}
+
+	var item StItem
+	extra, err := tls.Unmarshal(b, &item)
+	if err != nil {
+		return nil, fmt.Errorf("tls unmarshal failed: %v", err)
+	} else if len(extra) > 0 {
+		return nil, fmt.Errorf("tls unmarshal found extra data: %v", extra)
+	}
+	return &item, nil
+}
+
 // ChecksumV1 associates a package name with an arbitrary checksum value
 type ChecksumV1 struct {
 	Package  []byte `tls:"minlen:0,maxlen:255"`
@@ -75,3 +91,10 @@ func NewChecksumV1(name string, checksum []byte) (StItem, error) {
 func (i ChecksumV1) String() string {
 	return fmt.Sprintf("%v %v", string(i.Package), base64.StdEncoding.EncodeToString(i.Checksum))
 }
+
+// AddEntryRequest is a collection of add-entry input parameters
+type AddEntryRequest struct {
+	Item        string `json:"item"`
+	Signature   string `json:"signature"`
+	Certificate string `json:"certificate"`
+}
-- 
cgit v1.2.3