add forced update procedure

Author: facchinm

handlers.go

@@ -31,6 +31,53 @@ func StatusCB(status *Status) mqtt.MessageHandler {
 	}
 }
 
+type UpdatePayload struct {
+	URL       string `json:"url"`
+	Signature string `json:"signature"`
+	Token     string `json:"token"`
+}
+
+// UpdateCB handles the connector autoupdate
+// Any URL must be signed with Arduino private key
+func UpdateCB(status *Status) mqtt.MessageHandler {
+	return func(client mqtt.Client, msg mqtt.Message) {
+		var info UpdatePayload
+		err := json.Unmarshal(msg.Payload(), &info)
+		if err != nil {
+			status.Error("/update", errors.Wrapf(err, "unmarshal %s", msg.Payload()))
+			return
+		}
+		executablePath, _ := os.Executable()
+		name := filepath.Join(os.TempDir(), filepath.Base(executablePath))
+		err = downloadFile(name, info.URL, info.Token)
+		err = downloadFile(name+".sig", info.URL+".sig", info.Token)
+		if err != nil {
+			status.Error("/update", errors.Wrap(err, "no signature file "+info.URL+".sig"))
+			return
+		}
+		// check the signature
+		err = checkGPGSig(name, name+".sig")
+		if err != nil {
+			status.Error("/update", errors.Wrap(err, "wrong signature "+info.URL+".sig"))
+			return
+		}
+		// chmod it
+		err = os.Chmod(name, 0744)
+		if err != nil {
+			status.Error("/update", errors.Wrapf(err, "chmod 744 %s", name))
+			return
+		}
+		// copy it over existing binary
+		copyFileAndRemoveOriginal(name, executablePath)
+		if err != nil {
+			status.Error("/update", errors.Wrap(err, "error copying itself from "+name+" to "+executablePath))
+			return
+		}
+		// leap of faith: kill itself, systemd should respawn the process
+		os.Exit(0)
+	}
+}
+
 // UploadPayload contains the name and url of the sketch to upload on the device
 type UploadPayload struct {
 	ID    string `json:"id"`

main.go

@@ -180,6 +180,7 @@ func subscribeTopics(mqttClient mqtt.Client, id string, status *Status) {
 	mqttClient.Subscribe("$aws/things/"+id+"/status/post", 1, StatusCB(status))
 	mqttClient.Subscribe("$aws/things/"+id+"/upload/post", 1, UploadCB(status))
 	mqttClient.Subscribe("$aws/things/"+id+"/sketch/post", 1, SketchCB(status))
+	mqttClient.Subscribe("$aws/things/"+id+"/update/post", 1, UpdateCB(status))
 }
 
 func addFileToSketchDB(file os.FileInfo, status *Status) *SketchStatus {

validate.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"bytes"
+	"encoding/hex"
+	"os"
+
+	"golang.org/x/crypto/openpgp"
+)
+
+// gpg --export YOURKEYID --export-options export-minimal,no-export-attributes | hexdump /dev/stdin -v -e '/1 "%02X"'
+var publicKeyHex string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+
+func checkGPGSig(fileName string, sigFileName string) error {
+
+	// Get a Reader for the signature file
+	sigFile, err := os.Open(sigFileName)
+	if err != nil {
+		return err
+	}
+	defer sigFile.Close()
+
+	// Get a Reader for the signature file
+	file, err := os.Open(fileName)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	publicKeyBin, err := hex.DecodeString(publicKeyHex)
+	if err != nil {
+		return err
+	}
+
+	keyring, _ := openpgp.ReadKeyRing(bytes.NewReader(publicKeyBin))
+
+	_, err = openpgp.CheckDetachedSignature(keyring, file, sigFile)
+
+	return err
+}