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prevent corrupted spdy stream after hijacking connection #43922

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Apr 28, 2017
Merged

prevent corrupted spdy stream after hijacking connection #43922

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33 changes: 31 additions & 2 deletions staging/src/k8s.io/apimachinery/pkg/util/httpstream/spdy/upgrade.go
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Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,13 @@ limitations under the License.
package spdy

import (
"bufio"
"fmt"
"io"
"net"
"net/http"
"strings"
"sync/atomic"

"k8s.io/apimachinery/pkg/util/httpstream"
"k8s.io/apimachinery/pkg/util/runtime"
Expand All @@ -32,6 +36,30 @@ const HeaderSpdy31 = "SPDY/3.1"
type responseUpgrader struct {
}

// connWrapper is used to wrap a hijacked connection and its bufio.Reader. All
// calls will be handled directly by the underlying net.Conn with the exception
// of Read and Close calls, which will consider data in the bufio.Reader. This
// ensures that data already inside the used bufio.Reader instance is also
// read.
type connWrapper struct {
net.Conn
closed int32
bufReader *bufio.Reader
}

func (w *connWrapper) Read(b []byte) (n int, err error) {
if atomic.LoadInt32(&w.closed) == 1 {
return 0, io.EOF
}
return w.bufReader.Read(b)
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@dsnet if we make it past the closed check on line 51, and before this line is executed, Close() executes and closes the net.Conn, what will happen when we next execute w.bufReader.Read(b) - will it EOF?

}

func (w *connWrapper) Close() error {
err := w.Conn.Close()
atomic.StoreInt32(&w.closed, 1)
return err
}

// NewResponseUpgrader returns a new httpstream.ResponseUpgrader that is
// capable of upgrading HTTP responses using SPDY/3.1 via the
// spdystream package.
Expand Down Expand Up @@ -62,13 +90,14 @@ func (u responseUpgrader) UpgradeResponse(w http.ResponseWriter, req *http.Reque
w.Header().Add(httpstream.HeaderUpgrade, HeaderSpdy31)
w.WriteHeader(http.StatusSwitchingProtocols)

conn, _, err := hijacker.Hijack()
conn, bufrw, err := hijacker.Hijack()
if err != nil {
runtime.HandleError(fmt.Errorf("unable to upgrade: error hijacking response: %v", err))
return nil
}

spdyConn, err := NewServerConnection(conn, newStreamHandler)
connWithBuf := &connWrapper{Conn: conn, bufReader: bufrw.Reader}
spdyConn, err := NewServerConnection(connWithBuf, newStreamHandler)
if err != nil {
runtime.HandleError(fmt.Errorf("unable to upgrade: error creating SPDY server connection: %v", err))
return nil
Expand Down