Validate audio configuration values

fix.txt

@@ -182,20 +182,20 @@ Priority 2: protocol and data correctness
     is 2x/4x/6x too high. Calculate bits per frame divided by the actual
     Config.AudioInterval, or set the bitrate once when configuration changes.
 
-23. AudioInterval accepts invalid values
+[x] 23. AudioInterval accepts invalid values
     File: gumble/gumble/config.go
     AudioFrameSize truncates arbitrary intervals to a count of 10 ms frames,
     while the ticker still uses the original interval. Validate and reject
     values other than 10/20/40/60 ms (and validate AudioDataBytes/Buffers).
 
-24. Legacy/custom varint has a MinInt64 recursion failure
+[x] 24. Legacy/custom varint has a MinInt64 recursion failure
     File: gumble/gumble/varint/write.go
     Encoding math.MinInt64 evaluates -value to the same negative number and
     recursively encodes forever until panic. Handle MinInt64 explicitly or
     encode negatives using an unsigned magnitude without overflow. Validate
     output buffer capacity in the exported encoder too.
 
-25. Mumble version layout documentation is wrong
+[x] 25. Mumble version layout documentation is wrong
     File: gumble/gumble/version.go
     The comment says major uses bits 0-15, but SemanticVersion and ClientVersion
     use bits 16-31. Correct the documentation and add known version tests.

gumble/gumble/client.go

@@ -110,6 +110,9 @@ func Dial(config *Config) (*Client, error) {
 // min(time.Now() + dialer.Timeout, dialer.Deadline), or if the server rejects
 // the client.
 func DialWithDialer(dialer *net.Dialer, config *Config, tlsConfig *tls.Config) (*Client, error) {
+	if err := config.Validate(); err != nil {
+		return nil, err
+	}
 	start := time.Now()
 
 	conn, err := tls.DialWithDialer(dialer, "tcp", config.Address, tlsConfig)

gumble/gumble/config.go

@@ -1,6 +1,7 @@
 package gumble
 
 import (
+	"fmt"
 	"time"
 )
 
@@ -43,6 +44,22 @@ func NewConfig() *Config {
 	}
 }
 
+// Validate checks values that are used by the audio ticker and encoder.
+func (c *Config) Validate() error {
+	switch c.AudioInterval {
+	case 10 * time.Millisecond, 20 * time.Millisecond, 40 * time.Millisecond, 60 * time.Millisecond:
+	default:
+		return fmt.Errorf("gumble: AudioInterval must be 10ms, 20ms, 40ms, or 60ms")
+	}
+	if c.AudioDataBytes <= 0 {
+		return fmt.Errorf("gumble: AudioDataBytes must be positive")
+	}
+	if c.Buffers <= 0 {
+		return fmt.Errorf("gumble: Buffers must be positive")
+	}
+	return nil
+}
+
 // Attach is an alias of c.Listeners.Attach.
 func (c *Config) Attach(l EventListener) Detacher {
 	return c.Listeners.Attach(l)

gumble/gumble/config_regression_test.go

@@ -0,0 +1,20 @@
+package gumble
+
+import (
+	"testing"
+	"time"
+)
+
+// Regression: arbitrary intervals were truncated to 10 ms frames while the
+// ticker kept the original duration, producing malformed audio timing.
+func TestConfigValidateRejectsUnsupportedAudioInterval(t *testing.T) {
+	config := NewConfig()
+	config.AudioInterval = 15 * time.Millisecond
+	if err := config.Validate(); err == nil {
+		t.Fatal("invalid audio interval was accepted")
+	}
+	config.AudioInterval = 60 * time.Millisecond
+	if err := config.Validate(); err != nil {
+		t.Fatalf("valid audio interval rejected: %v", err)
+	}
+}