Compress data for transfer

cmd/witnessctl/api.go

@@ -18,12 +18,13 @@
 package main
 
 import (
+	"compress/gzip"
 	"errors"
 	"fmt"
+	"io"
 	"log"
 	"net"
 	"os"
-	"strings"
 	"time"
 
 	"github.com/cheggaaa/pb/v3"
@@ -80,24 +81,52 @@ func (d Device) hab() error {
 }
 
 func (d Device) getLogMessages(cmd byte) (string, error) {
-	b := strings.Builder{}
-	req := &api.LogMessagesRequest{}
-	rsp := &api.LogMessagesResponse{More: true}
-	for rsp.More {
-		rb, _ := proto.Marshal(req)
-		buf, err := d.u2f.Command(cmd, rb)
-		if err != nil {
-			return "", err
+	r, w := io.Pipe()
+	defer r.Close()
+
+	errC := make(chan error, 1)
+	// Kick off a goroutine to fetch chunks of log and pipe it into the
+	// decompressor.
+	go func() {
+		// Signal that there's no more compressed data.
+		defer w.Close()
+		defer close(errC)
+
+		req := &api.LogMessagesRequest{}
+		rsp := &api.LogMessagesResponse{More: true}
+		for rsp.More {
+			rb, _ := proto.Marshal(req)
+			buf, err := d.u2f.Command(cmd, rb)
+			if err != nil {
+				errC <- err
+				return
+			}
+			if err := proto.Unmarshal(buf, rsp); err != nil {
+				errC <- err
+				return
+			}
+			w.Write(rsp.GetPayload())
+			req.Continue = true
+
+			// Don't overload the HID endpoint
+			time.Sleep(10 * time.Millisecond)
 		}
-		if err := proto.Unmarshal(buf, rsp); err != nil {
-			return "", err
-		}
-		b.Write(rsp.GetPayload())
-		req.Continue = true
-		time.Sleep(10 * time.Millisecond)
+	}()
+
+	gz, err := gzip.NewReader(r)
+	if err != nil {
+		log.Printf("Failed to create gzip reader: %v", err)
+		return "", err
+	}
+	gz.Close()
+
+	// Grab the decompressed logs, and return
+	s, err := io.ReadAll(gz)
+	if err != nil {
+		return "", err
 	}
 
-	return b.String(), nil
+	return string(s), <-errC
 }
 
 func (d Device) consoleLogs() (string, error) {

trusted_os/ctl.go

@@ -15,6 +15,8 @@
 package main
 
 import (
+	"bytes"
+	"compress/gzip"
 	"crypto/sha256"
 	"encoding/hex"
 	"errors"
@@ -168,9 +170,19 @@ func (ctl *controlInterface) handleLogsRequest(r []byte, l func() []byte) (res [
 	if !req.Continue {
 		log.Printf("Grabbing log messages...")
 		logs := l()
-		log.Printf("Found %d bytes of log messages to send", len(logs))
-		ctl.logBuffer = make([]byte, len(logs))
-		copy(ctl.logBuffer, logs)
+		ll := len(logs)
+		b := &bytes.Buffer{}
+		gz := gzip.NewWriter(b)
+		if _, err := gz.Write(logs); err != nil {
+			log.Printf("Failed to gzip logs: %v", err)
+		}
+		if err := gz.Close(); err != nil {
+			log.Printf("Failed to close gzip writer: %v", err)
+
+		}
+		logs = nil
+		ctl.logBuffer = b.Bytes()
+		log.Printf("Compressed %d bytes of log messages to %d send", ll, len(ctl.logBuffer))
 	}
 	ret := &api.LogMessagesResponse{}
 	if l := len(ctl.logBuffer); l > maxChunkSize {