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Ignore invalid host header between go1.6 and old docker clients

BenchmarkWithHack-4	   50000	     37082 ns/op	  44.50
MB/s	    1920 B/op	      30 allocs/op
BenchmarkNoHack-4  	   50000	     30829 ns/op	  53.52
MB/s	       0 B/op	       0 allocs/op

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
This commit is contained in:
Antonio Murdaca 2016-04-12 17:21:20 +02:00
parent 376c15bbaa
commit 3d6f5984f5
7 changed files with 274 additions and 2 deletions

View file

@ -0,0 +1,116 @@
// +build !windows
package hack
import "net"
// MalformedHostHeaderOverride is a wrapper to be able
// to overcome the 400 Bad request coming from old docker
// clients that send an invalid Host header.
type MalformedHostHeaderOverride struct {
net.Listener
}
// MalformedHostHeaderOverrideConn wraps the underlying unix
// connection and keeps track of the first read from http.Server
// which just reads the headers.
type MalformedHostHeaderOverrideConn struct {
net.Conn
first bool
}
var closeConnHeader = []byte("\r\nConnection: close\r")
// Read reads the first *read* request from http.Server to inspect
// the Host header. If the Host starts with / then we're talking to
// an old docker client which send an invalid Host header. To not
// error out in http.Server we rewrite the first bytes of the request
// to sanitize the Host header itself.
// In case we're not dealing with old docker clients the data is just passed
// to the server w/o modification.
func (l *MalformedHostHeaderOverrideConn) Read(b []byte) (n int, err error) {
// http.Server uses a 4k buffer
if l.first && len(b) == 4096 {
// This keeps track of the first read from http.Server which just reads
// the headers
l.first = false
// The first read of the connection by http.Server is done limited to
// DefaultMaxHeaderBytes (usually 1 << 20) + 4096.
// Here we do the first read which gets us all the http headers to
// be inspected and modified below.
c, err := l.Conn.Read(b)
if err != nil {
return c, err
}
var (
start, end int
firstLineFeed = -1
buf []byte
)
for i, bb := range b[:c] {
if bb == '\n' && firstLineFeed == -1 {
firstLineFeed = i
}
if bb != '\n' {
continue
}
if b[i+1] != 'H' {
continue
}
if b[i+2] != 'o' {
continue
}
if b[i+3] != 's' {
continue
}
if b[i+4] != 't' {
continue
}
if b[i+5] != ':' {
continue
}
if b[i+6] != ' ' {
continue
}
if b[i+7] != '/' {
continue
}
// ensure clients other than the docker clients do not get this hack
if i != firstLineFeed {
return c, nil
}
start = i + 7
// now find where the value ends
for ii, bbb := range b[start:c] {
if bbb == '\n' {
end = start + ii
break
}
}
buf = make([]byte, 0, c+len(closeConnHeader)-(end-start))
// strip the value of the host header and
// inject `Connection: close` to ensure we don't reuse this connection
buf = append(buf, b[:start]...)
buf = append(buf, closeConnHeader...)
buf = append(buf, b[end:c]...)
copy(b, buf)
break
}
if len(buf) == 0 {
return c, nil
}
return len(buf), nil
}
return l.Conn.Read(b)
}
// Accept makes the listener accepts connections and wraps the connection
// in a MalformedHostHeaderOverrideConn initilizing first to true.
func (l *MalformedHostHeaderOverride) Accept() (net.Conn, error) {
c, err := l.Listener.Accept()
if err != nil {
return c, err
}
return &MalformedHostHeaderOverrideConn{c, true}, nil
}

View file

@ -0,0 +1,115 @@
// +build !windows
package hack
import (
"bytes"
"io"
"net"
"strings"
"testing"
)
func TestHeaderOverrideHack(t *testing.T) {
client, srv := net.Pipe()
tests := [][2][]byte{
{
[]byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\r\n\r\n"),
[]byte("GET /foo\nHost: \r\nConnection: close\r\nUser-Agent: Docker\r\n\r\n"),
},
{
[]byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\nFoo: Bar\r\n"),
[]byte("GET /foo\nHost: \r\nConnection: close\r\nUser-Agent: Docker\nFoo: Bar\r\n"),
},
{
[]byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\r\n\r\ntest something!"),
[]byte("GET /foo\nHost: \r\nConnection: close\r\nUser-Agent: Docker\r\n\r\ntest something!"),
},
{
[]byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\r\n\r\ntest something! " + strings.Repeat("test", 15000)),
[]byte("GET /foo\nHost: \r\nConnection: close\r\nUser-Agent: Docker\r\n\r\ntest something! " + strings.Repeat("test", 15000)),
},
{
[]byte("GET /foo\nFoo: Bar\nHost: /var/run/docker.sock\nUser-Agent: Docker\r\n\r\n"),
[]byte("GET /foo\nFoo: Bar\nHost: /var/run/docker.sock\nUser-Agent: Docker\r\n\r\n"),
},
}
l := MalformedHostHeaderOverrideConn{client, true}
read := make([]byte, 4096)
for _, pair := range tests {
go func() {
srv.Write(pair[0])
}()
n, err := l.Read(read)
if err != nil && err != io.EOF {
t.Fatalf("read: %d - %d, err: %v\n%s", n, len(pair[0]), err, string(read[:n]))
}
if !bytes.Equal(read[:n], pair[1][:n]) {
t.Fatalf("\n%s\n%s\n", read[:n], pair[1][:n])
}
l.first = true
// clean out the slice
read = read[:0]
}
srv.Close()
l.Close()
}
func BenchmarkWithHack(b *testing.B) {
client, srv := net.Pipe()
done := make(chan struct{})
req := []byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\n")
read := make([]byte, 4096)
b.SetBytes(int64(len(req) * 30))
l := MalformedHostHeaderOverrideConn{client, true}
go func() {
for {
if _, err := srv.Write(req); err != nil {
srv.Close()
break
}
l.first = true // make sure each subsequent run uses the hack parsing
}
close(done)
}()
for i := 0; i < b.N; i++ {
for i := 0; i < 30; i++ {
if n, err := l.Read(read); err != nil && err != io.EOF {
b.Fatalf("read: %d - %d, err: %v\n%s", n, len(req), err, string(read[:n]))
}
}
}
l.Close()
<-done
}
func BenchmarkNoHack(b *testing.B) {
client, srv := net.Pipe()
done := make(chan struct{})
req := []byte("GET /foo\nHost: /var/run/docker.sock\nUser-Agent: Docker\n")
read := make([]byte, 4096)
b.SetBytes(int64(len(req) * 30))
go func() {
for {
if _, err := srv.Write(req); err != nil {
srv.Close()
break
}
}
close(done)
}()
for i := 0; i < b.N; i++ {
for i := 0; i < 30; i++ {
if _, err := client.Read(read); err != nil && err != io.EOF {
b.Fatal(err)
}
}
}
client.Close()
<-done
}