From 748a806adc5a325e63ca6883b2aa9bf15da90513 Mon Sep 17 00:00:00 2001
From: T <t@tjp.lol>
Date: Thu, 3 Apr 2025 10:00:40 -0600
Subject: Harden Gopher parsing and recover server goroutines

Reject oversized or malformed Gopher selectors as parse errors instead of panicking. Keep search requests bounded, and wrap shared server goroutines with panic logging so one bad connection cannot take down the process.
---
 internal/server_test.go | 66 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 internal/server_test.go

(limited to 'internal/server_test.go')

diff --git a/internal/server_test.go b/internal/server_test.go
new file mode 100644
index 0000000..62d8681
--- /dev/null
+++ b/internal/server_test.go
@@ -0,0 +1,66 @@
+package internal_test
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"tildegit.org/tjp/sliderule/internal"
+)
+
+type captureLogger struct {
+	mu   sync.Mutex
+	logs []string
+}
+
+func (cl *captureLogger) Log(keyvals ...any) error {
+	cl.mu.Lock()
+	defer cl.mu.Unlock()
+
+	for _, val := range keyvals {
+		cl.logs = append(cl.logs, fmt.Sprint(val))
+	}
+	return nil
+}
+
+func (cl *captureLogger) String() string {
+	cl.mu.Lock()
+	defer cl.mu.Unlock()
+
+	return strings.Join(cl.logs, " ")
+}
+
+func TestServerRecoversConnectionPanic(t *testing.T) {
+	var logs captureLogger
+	server, err := internal.NewServer(
+		context.Background(),
+		"localhost",
+		"tcp",
+		"127.0.0.1:0",
+		&logs,
+		func(net.Conn) { panic("boom") },
+	)
+	require.Nil(t, err)
+
+	done := make(chan error, 1)
+	go func() { done <- server.Serve() }()
+
+	conn, err := net.Dial(server.Network(), server.Address())
+	require.Nil(t, err)
+	_ = conn.Close()
+
+	require.Eventually(t, func() bool {
+		return strings.Contains(logs.String(), "panic in server goroutine")
+	}, time.Second, 10*time.Millisecond)
+
+	server.Close()
+	assert.Nil(t, <-done)
+	assert.Contains(t, logs.String(), "boom")
+}
-- 
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