fix: Guard buffer peek size

Author: layou233

common/buf/buffer.go

@@ -205,6 +205,9 @@ func (b *Buffer) Read(data []byte) (n int, err error) {
 }
 
 func (b *Buffer) Peek(n int) (bytes []byte, err error) {
+	if n < 0 {
+		return nil, ErrNegativeRead
+	}
 	if b.start+n > b.end {
 		return nil, io.ErrShortBuffer
 	}

common/buf/errors.go

@@ -0,0 +1,5 @@
+package buf
+
+import "errors"
+
+var ErrNegativeRead = errors.New("read with negative size")

common/buf/readv_posix.go

@@ -2,6 +2,7 @@ package bufio
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"net"
 
@@ -57,6 +58,9 @@ func (c *CachedConn) Read(p []byte) (n int, err error) {
 }
 
 func (c *CachedConn) Peek(n int) ([]byte, error) {
+	if n < 0 {
+		return nil, fmt.Errorf("peek %d bytes: %w", n, buf.ErrNegativeRead)
+	}
 	if c.cache == nil {
 		// see above
 		c.cache = buf.NewSize(4096)