Merge pull request #1449 from weaveworks/1368-start-hostconfig

Override sneaky /start HostConfig params

Fixes #1368.

proxy/create_container_interceptor.go

@@ -2,16 +2,11 @@ package proxy
 
 import (
 	"errors"
-	"fmt"
-	"io/ioutil"
 	"net/http"
 	"strings"
 
 	"github.com/fsouza/go-dockerclient"
-
 	. "github.com/weaveworks/weave/common"
-	"github.com/weaveworks/weave/nameserver"
-	"github.com/weaveworks/weave/router"
 )
 
 const MaxDockerHostname = 64
@@ -55,7 +50,7 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 		if container.Config == nil {
 			container.Config = &docker.Config{}
 		}
-		i.addWeaveWaitVolume(container.HostConfig)
+		i.proxy.addWeaveWaitVolume(container.HostConfig)
 		if err := i.setWeaveWaitEntrypoint(container.Config); err != nil {
 			return err
 		}
@@ -66,8 +61,11 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 			}
 		}
 		hostname = i.proxy.hostnameMatchRegexp.ReplaceAllString(hostname, i.proxy.HostnameReplacement)
-		if err := i.setWeaveDNS(&container, hostname); err != nil {
-			return err
+		if dnsDomain := i.proxy.getDNSDomain(); dnsDomain != "" {
+			i.setHostname(&container, hostname, dnsDomain)
+			if err := i.proxy.setWeaveDNS(container.HostConfig, container.Hostname, dnsDomain); err != nil {
+				return err
+			}
 		}
 
 		return marshalRequestBody(r, container)
@@ -76,18 +74,6 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 	return nil
 }
 
-func (i *createContainerInterceptor) addWeaveWaitVolume(hostConfig *docker.HostConfig) {
-	var binds []string
-	for _, bind := range hostConfig.Binds {
-		s := strings.Split(bind, ":")
-		if len(s) >= 2 && s[1] == "/w" {
-			continue
-		}
-		binds = append(binds, bind)
-	}
-	hostConfig.Binds = append(binds, fmt.Sprintf("%s:/w:ro", i.proxy.weaveWaitVolume))
-}
-
 func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Config) error {
 	if len(container.Entrypoint) == 0 {
 		image, err := i.proxy.client.InspectImage(container.Image)
@@ -117,18 +103,7 @@ func (i *createContainerInterceptor) setWeaveWaitEntrypoint(container *docker.Co
 	return nil
 }
 
-func (i *createContainerInterceptor) setWeaveDNS(container *createContainerRequestBody, name string) error {
-	if i.proxy.WithoutDNS {
-		return nil
-	}
-
-	dnsDomain, dnsRunning := i.getDNSDomain()
-	if !(dnsRunning || i.proxy.WithDNS) {
-		return nil
-	}
-
-	container.HostConfig.DNS = append(container.HostConfig.DNS, i.proxy.dockerBridgeIP)
-
+func (i *createContainerInterceptor) setHostname(container *createContainerRequestBody, name, dnsDomain string) {
 	if container.Hostname == "" && name != "" {
 		// Strip trailing period because it's unusual to see it used on the end of a host name
 		trimmedDNSDomain := strings.TrimSuffix(dnsDomain, ".")
@@ -140,39 +115,7 @@ func (i *createContainerInterceptor) setWeaveDNS(container *createContainerReque
 		}
 	}
 
-	if len(container.HostConfig.DNSSearch) == 0 {
-		if container.Hostname == "" {
-			container.HostConfig.DNSSearch = []string{dnsDomain}
-		} else {
-			container.HostConfig.DNSSearch = []string{"."}
-		}
-	}
-
-	return nil
-}
-
-func (i *createContainerInterceptor) getDNSDomain() (domain string, running bool) {
-	domain = nameserver.DefaultDomain
-	weaveContainer, err := i.proxy.client.InspectContainer("weave")
-	if err != nil ||
-		weaveContainer.NetworkSettings == nil ||
-		weaveContainer.NetworkSettings.IPAddress == "" {
-		return
-	}
-
-	url := fmt.Sprintf("http://%s:%d/domain", weaveContainer.NetworkSettings.IPAddress, router.HTTPPort)
-	resp, err := http.Get(url)
-	if err != nil || resp.StatusCode != http.StatusOK {
-		return
-	}
-	defer resp.Body.Close()
-
-	b, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return
-	}
-
-	return string(b), true
+	return
 }
 
 func (i *createContainerInterceptor) InterceptResponse(r *http.Response) error {

proxy/proxy.go

@@ -4,6 +4,7 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
+	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -15,6 +16,8 @@ import (
 	docker "github.com/fsouza/go-dockerclient"
 	. "github.com/weaveworks/weave/common"
 	weavedocker "github.com/weaveworks/weave/common/docker"
+	"github.com/weaveworks/weave/nameserver"
+	"github.com/weaveworks/weave/router"
 )
 
 const (
@@ -365,3 +368,60 @@ func (proxy *Proxy) weaveCIDRsFromConfig(config *docker.Config, hostConfig *dock
 	}
 	return nil, nil
 }
+
+func (proxy *Proxy) addWeaveWaitVolume(hostConfig *docker.HostConfig) {
+	var binds []string
+	for _, bind := range hostConfig.Binds {
+		s := strings.Split(bind, ":")
+		if len(s) >= 2 && s[1] == "/w" {
+			continue
+		}
+		binds = append(binds, bind)
+	}
+	hostConfig.Binds = append(binds, fmt.Sprintf("%s:/w:ro", proxy.weaveWaitVolume))
+}
+
+func (proxy *Proxy) setWeaveDNS(hostConfig *docker.HostConfig, hostname, dnsDomain string) error {
+	hostConfig.DNS = append(hostConfig.DNS, proxy.dockerBridgeIP)
+
+	if len(hostConfig.DNSSearch) == 0 {
+		if hostname == "" {
+			hostConfig.DNSSearch = []string{dnsDomain}
+		} else {
+			hostConfig.DNSSearch = []string{"."}
+		}
+	}
+
+	return nil
+}
+
+func (proxy *Proxy) getDNSDomain() (domain string) {
+	if proxy.WithoutDNS {
+		return ""
+	}
+
+	if proxy.WithDNS {
+		domain = nameserver.DefaultDomain
+	}
+
+	weaveContainer, err := proxy.client.InspectContainer("weave")
+	if err != nil ||
+		weaveContainer.NetworkSettings == nil ||
+		weaveContainer.NetworkSettings.IPAddress == "" {
+		return
+	}
+
+	url := fmt.Sprintf("http://%s:%d/domain", weaveContainer.NetworkSettings.IPAddress, router.HTTPPort)
+	resp, err := http.Get(url)
+	if err != nil || resp.StatusCode != http.StatusOK {
+		return
+	}
+	defer resp.Body.Close()
+
+	b, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return
+	}
+
+	return string(b)
+}

proxy/start_container_interceptor.go

@@ -2,16 +2,44 @@ package proxy
 
 import (
 	"net/http"
+
+	"github.com/fsouza/go-dockerclient"
 )
 
 type startContainerInterceptor struct{ proxy *Proxy }
 
+type startContainerRequestBody struct {
+	HostConfig *docker.HostConfig `json:"HostConfig,omitempty" yaml:"HostConfig,omitempty"`
+}
+
 func (i *startContainerInterceptor) InterceptRequest(r *http.Request) error {
 	container, err := inspectContainerInPath(i.proxy.client, r.URL.Path)
-	if err == nil && containerShouldAttach(container) {
-		i.proxy.createWait(r, container.ID)
+	if err != nil {
+		return err
 	}
-	return err
+
+	if !containerShouldAttach(container) || r.Header.Get("Content-Type") != "application/json" {
+		i.proxy.createWait(r, container.ID)
+		return nil
+	}
+
+	hostConfig := &docker.HostConfig{}
+	if err := unmarshalRequestBody(r, &hostConfig); err != nil {
+		return err
+	}
+
+	i.proxy.addWeaveWaitVolume(hostConfig)
+	if dnsDomain := i.proxy.getDNSDomain(); dnsDomain != "" {
+		if err := i.proxy.setWeaveDNS(hostConfig, container.Config.Hostname, dnsDomain); err != nil {
+			return err
+		}
+	}
+
+	if err := marshalRequestBody(r, hostConfig); err != nil {
+		return err
+	}
+	i.proxy.createWait(r, container.ID)
+	return nil
 }
 
 func (i *startContainerInterceptor) InterceptResponse(r *http.Response) error {

test/666_abuse_of_start_test.sh

@@ -0,0 +1,21 @@
+#! /bin/bash
+
+. ./config.sh
+
+start_suite "Abuse of 'start' operation"
+
+weave_on $HOST1 launch
+docker_bridge_ip=$(weave_on $HOST1 docker-bridge-ip)
+proxy_start_container $HOST1 --name=c1
+
+# Start c2 with a sneaky HostConfig
+proxy docker_on $HOST1 create --name=c2 $SMALL_IMAGE $CHECK_ETHWE_UP
+proxy docker_api_on $HOST1 POST /containers/c2/start '{"NetworkMode": "container:c1"}'
+assert "docker_on $HOST1 inspect -f '{{.State.Running}} {{.State.ExitCode}} {{.HostConfig.Dns}}' c2" "false 0 [$docker_bridge_ip]"
+
+# Start c3 with HostConfig having empty binds and null dns/networking settings
+proxy docker_on $HOST1 create --name=c3 -v /tmp:/hosttmp $SMALL_IMAGE $CHECK_ETHWE_UP
+proxy docker_api_on $HOST1 POST /containers/c3/start '{"Binds":[],"Dns":null,"DnsSearch":null,"ExtraHosts":null,"VolumesFrom":null,"Devices":null,"NetworkMode":""}'
+assert "docker_on $HOST1 inspect -f '{{.State.Running}} {{.State.ExitCode}} {{.HostConfig.Dns}}' c3" "false 0 [$docker_bridge_ip]"
+
+end_suite

test/666_the_beast.sh

@@ -1,15 +0,0 @@
-#! /bin/bash
-
-. ./config.sh
-
-start_suite "Abuse of 'start' operation"
-
-weave_on $HOST1 launch
-
-proxy_start_container $HOST1 --name=c1
-proxy docker_on $HOST1 create --name=c2 $SMALL_IMAGE grep "^1$" /sys/class/net/ethwe/carrier
-# Now start c2 with a sneaky HostConfig
-curl -X POST -H Content-Type:application/json -d '{"HostConfig": {"NetworkMode": "container:c1"}}' http://$HOST1:12375/containers/c2/start
-assert "docker_on $HOST1 inspect -f '{{.State.Running}} {{.State.ExitCode}}' c2" "false 0"
-
-end_suite

test/config.sh

@@ -99,6 +99,16 @@ docker_on() {
     docker -H tcp://$host:$DOCKER_PORT "$@"
 }
 
+docker_api_on() {
+    host=$1
+    method=$2
+    url=$3
+    data=$4
+    shift 4
+    [ -z "$DEBUG" ] || greyly echo "Docker (API) on $host:$DOCKER_PORT: $method $url" >&2
+    echo -n "$data" | curl -s -X "$method" -H Content-Type:application/json "http://$host:$DOCKER_PORT/v1.15$url" -d @-
+}
+
 proxy() {
     DOCKER_PORT=12375 "$@"
 }