Egress TLS 流量中的 SNI 监控及策略

 阅读大约需要 6 分钟

在使用通配符主机配置 Egress 流量示例中描述了为 *.wikipedia.org 这样的域名启用 Egress 流量 TLS 支持的方法。本示例中将演示的是如何为 Egress TLS 流量配置 SNI 监控并应用策略。

开始之前

  • 按照安装指南中的说明安装 Istio。

  • 启动 sleep 示例，以获取发送请求的测试源。

    如果您启用了 自动 sidecar 注入，请执行

    Zip
    $ kubectl apply -f @samples/sleep/sleep.yaml@

    否则，在部署 sleep 应用程序前，您必须手动注入 sidecar：

    Zip
    $ kubectl apply -f <(istioctl kube-inject -f @samples/sleep/sleep.yaml@)

    您可以使用任何安装了 curl 的 pod 作为测试源。

  • 为了发送请求，您需要创建 SOURCE_POD 环境变量来存储源 pod 的名称：

    $ export SOURCE_POD=$(kubectl get pod -l app=sleep -o jsonpath={.items..metadata.name})

SNI 监控和访问策略

通过配置，让 Egress 流量流入 Egress 网关之后，就可以对其实施安全的监控和策略管理了。在本节中，会为 *.wikipedia.org 定义一个 LogEntry 以及访问策略。

  1. 创建 logentry、rules 和 handlers：

    $ kubectl apply -f - <<EOF
# Egress 访问的日志定义
apiVersion: "config.istio.io/v1alpha2"
kind: logentry
metadata:
  name: egress-access
  namespace: istio-system
spec:
  severity: '"info"'
  timestamp: context.time | timestamp("2017-01-01T00:00:00Z")
  variables:
    connectionEvent: connection.event | ""
    source: source.labels["app"] | "unknown"
    sourceNamespace: source.namespace | "unknown"
    sourceWorkload: source.workload.name | ""
    sourcePrincipal: source.principal | "unknown"
    requestedServerName: connection.requested_server_name | "unknown"
    destinationApp: destination.labels["app"] | ""
  monitored_resource_type: '"UNSPECIFIED"'
---
# 用于访问日志记录的 Handler
apiVersion: "config.istio.io/v1alpha2"
kind: stdio
metadata:
  name: egress-access-logger
  namespace: istio-system
spec:
  severity_levels:
    info: 0 # output log level as info
  outputAsJson: true
---
# 处理对 *.wikipedia.org 访问的 Rule
apiVersion: "config.istio.io/v1alpha2"
kind: rule
metadata:
  name: handle-wikipedia-access
  namespace: istio-system
spec:
  match: source.labels["app"] == "istio-egressgateway-with-sni-proxy" && destination.labels["app"] == "" && connection.event == "open"
  actions:
  - handler: egress-access-logger.stdio
    instances:
      - egress-access.logentry
EOF

  2. 向 https://en.wikipedia.org 和 https://de.wikipedia.org 发起 HTTPS 访问：

    $ kubectl exec -it $SOURCE_POD -c sleep -- sh -c 'curl -s https://en.wikipedia.org/wiki/Main_Page | grep -o "<title>.*</title>"; curl -s https://de.wikipedia.org/wiki/Wikipedia:Hauptseite | grep -o "<title>.*</title>"'
<title>Wikipedia, the free encyclopedia</title>
<title>Wikipedia – Die freie Enzyklopädie</title>

  3. 检查 Mixer 日志。如果 Istio 部署在 istio-system 命名空间，可以用如下命令：

    $ kubectl -n istio-system logs -l istio-mixer-type=telemetry -c mixer | grep 'egress-access.logentry.istio-system'

  4. 定义一条策略，允许访问主机名符合 *.wikipedia.org 规则的主机，但是排除英文版：

    $ cat <<EOF | kubectl create -f -
apiVersion: "config.istio.io/v1alpha2"
kind: listchecker
metadata:
  name: wikipedia-checker
  namespace: istio-system
spec:
  overrides: ["en.wikipedia.org"]  # 用静态列表作为黑名单
  blacklist: true
---
apiVersion: "config.istio.io/v1alpha2"
kind: listentry
metadata:
  name: requested-server-name
  namespace: istio-system
spec:
  value: connection.requested_server_name
---
# 检查对 *.wikipedia.org 的访问
apiVersion: "config.istio.io/v1alpha2"
kind: rule
metadata:
  name: check-wikipedia-access
  namespace: istio-system
spec:
  match: source.labels["app"] == "istio-egressgateway-with-sni-proxy" && destination.labels["app"] == ""
  actions:
  - handler: wikipedia-checker.listchecker
    instances:
      - requested-server-name.listentry
EOF

  5. 向黑名单中的英文版 Wikipedia：

    $ kubectl exec -it $SOURCE_POD -c sleep -- sh -c 'curl -v https://en.wikipedia.org/wiki/Main_Page'
...
curl: (35) Unknown SSL protocol error in connection to en.wikipedia.org:443
command terminated with exit code 35

    对英文版 Wikipedia 的访问会被策略拒绝。

  6. 向其它 Wikipedia 站点发送 HTTPS 请求，例如 https://es.wikipedia.org 或 https://de.wikipedia.org：

    $ kubectl exec -it $SOURCE_POD -c sleep -- sh -c 'curl -s https://es.wikipedia.org/wiki/Wikipedia:Portada | grep -o "<title>.*</title>"; curl -s https://de.wikipedia.org/wiki/Wikipedia:Hauptseite | grep -o "<title>.*</title>"'
<title>Wikipedia, la enciclopedia libre</title>
<title>Wikipedia – Die freie Enzyklopädie</title>

    和我们计划的一样，其它语言的 Wikipedia 站点是可以访问的。

清理监控和策略定义

$ kubectl delete rule handle-wikipedia-access check-wikipedia-access -n istio-system
$ kubectl delete logentry egress-access -n istio-system
$ kubectl delete stdio egress-access-logger -n istio-system
$ kubectl delete listentry requested-server-name -n istio-system
$ kubectl delete listchecker wikipedia-checker -n istio-system

监控 SNI 和源身份，并据此作出访问控制

因为已经在 Sidecar 之间、Sidecar 和 Egress 网关之间启用了双向 TLS，所以就有办法对访问外部的应用的服务身份进行监控和策略控制了。在 Kubernetes 上运行的 Istio，其身份是建立在 Service Accounts 基础之上的。这一节中将会部署两个 sleep 容器，sleep-us 和 sleep-canada，各自用不同的 Service account 运行。然后定义一个策略，允许 sleep-us 的身份访问英文和西班牙文版本的维基百科，而 sleep-canada 身份的应用可以访问英文和法文版。

  1. 部署两个 sleep 容器，sleep-us 和 sleep-canada，各自使用各自的同名 Service account 运行：

    ZipZip
    $ sed 's/: sleep/: sleep-us/g' @samples/sleep/sleep.yaml@ | kubectl apply -f -
$ sed 's/: sleep/: sleep-canada/g' @samples/sleep/sleep.yaml@ | kubectl apply -f -
serviceaccount "sleep-us" created
service "sleep-us" created
deployment "sleep-us" created
serviceaccount "sleep-canada" created
service "sleep-canada" created
deployment "sleep-canada" created

  2. 创建 logentry、rules 和 handlers：

    $ kubectl apply -f - <<EOF
# Egress 访问的日志定义
apiVersion: "config.istio.io/v1alpha2"
kind: logentry
metadata:
  name: egress-access
  namespace: istio-system
spec:
  severity: '"info"'
  timestamp: context.time | timestamp("2017-01-01T00:00:00Z")
  variables:
    connectionEvent: connection.event | ""
    source: source.labels["app"] | "unknown"
    sourceNamespace: source.namespace | "unknown"
    sourceWorkload: source.workload.name | ""
    sourcePrincipal: source.principal | "unknown"
    requestedServerName: connection.requested_server_name | "unknown"
    destinationApp: destination.labels["app"] | ""
  monitored_resource_type: '"UNSPECIFIED"'
---
# Egress 访问日志的 Handler
apiVersion: "config.istio.io/v1alpha2"
kind: stdio
metadata:
  name: egress-access-logger
  namespace: istio-system
spec:
  severity_levels:
    info: 0 # output log level as info
  outputAsJson: true
---
# 访问 *.wikipedia.org 时应用的 Rule
apiVersion: "config.istio.io/v1alpha2"
kind: rule
metadata:
  name: handle-wikipedia-access
  namespace: istio-system
spec:
  match: source.labels["app"] == "istio-egressgateway-with-sni-proxy" && destination.labels["app"] == "" && connection.event == "open"
  actions:
  - handler: egress-access-logger.stdio
    instances:
      - egress-access.logentry
EOF

  3. 从 sleep-us 向英文、德文、西班牙文和法文版本的维基百科分别发送 HTTPS 请求：

    $ kubectl exec -it $(kubectl get pod -l app=sleep-us -o jsonpath='{.items[0].metadata.name}') -c sleep-us -- sh -c 'curl -s https://en.wikipedia.org/wiki/Main_Page | grep -o "<title>.*</title>"; curl -s https://de.wikipedia.org/wiki/Wikipedia:Hauptseite | grep -o "<title>.*</title>"; curl -s https://es.wikipedia.org/wiki/Wikipedia:Portada | grep -o "<title>.*</title>"; curl -s https://fr.wikipedia.org/wiki/Wikip%C3%A9dia:Accueil_principal | grep -o "<title>.*</title>"'
<title>Wikipedia, the free encyclopedia</title>
<title>Wikipedia – Die freie Enzyklopädie</title>
<title>Wikipedia, la enciclopedia libre</title>
<title>Wikipédia, l'encyclopédie libre</title>

  4. 查看 Mixer 日志。如果 Istio 部署在 istio-system 命名空间，可以使用如下命令：

    $ kubectl -n istio-system logs -l istio-mixer-type=telemetry -c mixer | grep 'egress-access.logentry.istio-system'
{"level":"info","time":"2019-01-10T17:33:55.559093Z","instance":"egress-access.logentry.istio-system","connectionEvent":"open","destinationApp":"","requestedServerName":"en.wikipedia.org","source":"istio-egressgateway-with-sni-proxy","sourceNamespace":"default","sourcePrincipal":"cluster.local/ns/default/sa/sleep-us","sourceWorkload":"istio-egressgateway-with-sni-proxy"}
{"level":"info","time":"2019-01-10T17:33:56.166227Z","instance":"egress-access.logentry.istio-system","connectionEvent":"open","destinationApp":"","requestedServerName":"de.wikipedia.org","source":"istio-egressgateway-with-sni-proxy","sourceNamespace":"default","sourcePrincipal":"cluster.local/ns/default/sa/sleep-us","sourceWorkload":"istio-egressgateway-with-sni-proxy"}
{"level":"info","time":"2019-01-10T17:33:56.779842Z","instance":"egress-access.logentry.istio-system","connectionEvent":"open","destinationApp":"","requestedServerName":"es.wikipedia.org","source":"istio-egressgateway-with-sni-proxy","sourceNamespace":"default","sourcePrincipal":"cluster.local/ns/default/sa/sleep-us","sourceWorkload":"istio-egressgateway-with-sni-proxy"}
{"level":"info","time":"2019-01-10T17:33:57.413908Z","instance":"egress-access.logentry.istio-system","connectionEvent":"open","destinationApp":"","requestedServerName":"fr.wikipedia.org","source":"istio-egressgateway-with-sni-proxy","sourceNamespace":"default","sourcePrincipal":"cluster.local/ns/default/sa/sleep-us","sourceWorkload":"istio-egressgateway-with-sni-proxy"}

    注意 requestedServerName 属性，以及 sourcePrincipal，应取值为 cluster.local/ns/default/sa/sleep-us。

  5. 定义一条策略，允许 sleep-us Service account 访问英文和西班牙版本的维基百科；而 sleep-canada 则可以访问英文和法文版本的维基百科。对其它语言的访问会被拦截。

    $ cat <<EOF | kubectl create -f -
apiVersion: "config.istio.io/v1alpha2"
kind: listentry
metadata:
  name: requested-server-name
  namespace: istio-system
spec:
  value: connection.requested_server_name
---
apiVersion: "config.istio.io/v1alpha2"
kind: listchecker
metadata:
  name: us-wikipedia-checker
  namespace: istio-system
spec:
  overrides: ["en.wikipedia.org", "es.wikipedia.org"]
  blacklist: false
---
# 访问 *.wikipedia.org 时应用的 Rule
apiVersion: "config.istio.io/v1alpha2"
kind: rule
metadata:
  name: check-us-wikipedia-access
  namespace: istio-system
spec:
  match: source.labels["app"] == "istio-egressgateway-with-sni-proxy" && destination.labels["app"] == "" && source.principal == "cluster.local/ns/default/sa/sleep-us"
  actions:
  - handler: us-wikipedia-checker.listchecker
    instances:
      - requested-server-name.listentry
---
apiVersion: "config.istio.io/v1alpha2"
kind: listchecker
metadata:
  name: canada-wikipedia-checker
  namespace: istio-system
spec:
  overrides: ["en.wikipedia.org", "fr.wikipedia.org"]
  blacklist: false
---
#  访问 *.wikipedia.org 时应用的 Rule
apiVersion: "config.istio.io/v1alpha2"
kind: rule
metadata:
  name: check-canada-wikipedia-access
  namespace: istio-system
spec:
  match: source.labels["app"] == "istio-egressgateway-with-sni-proxy" && destination.labels["app"] == "" && source.principal == "cluster.local/ns/default/sa/sleep-canada"
  actions:
  - handler: canada-wikipedia-checker.listchecker
    instances:
      - requested-server-name.listentry
EOF

  6. 从 sleep-us 发送 HTTPS 流量到英文、德文、西班牙文和法文版本的维基百科：

    $ kubectl exec -it $(kubectl get pod -l app=sleep-us -o jsonpath='{.items[0].metadata.name}') -c sleep-us -- sh -c 'curl -s https://en.wikipedia.org/wiki/Main_Page | grep -o "<title>.*</title>"; curl -s https://de.wikipedia.org/wiki/Wikipedia:Hauptseite | grep -o "<title>.*</title>"; curl -s https://es.wikipedia.org/wiki/Wikipedia:Portada | grep -o "<title>.*</title>"; curl -s https://fr.wikipedia.org/wiki/Wikip%C3%A9dia:Accueil_principal | grep -o "<title>.*</title>";:'
<title>Wikipedia, the free encyclopedia</title>
<title>Wikipedia, la enciclopedia libre</title>

    会看到 sleep-us 身份允许访问英文和西班牙版本。

    $ kubectl delete pod -n istio-system -l istio-mixer-type=policy

  7. 从 sleep-canada 发送 HTTPS 流量到英文、德文、西班牙文和法文版本的维基百科：

    $ kubectl exec -it $(kubectl get pod -l app=sleep-canada -o jsonpath='{.items[0].metadata.name}') -c sleep-canada -- sh -c 'curl -s https://en.wikipedia.org/wiki/Main_Page | grep -o "<title>.*</title>"; curl -s https://de.wikipedia.org/wiki/Wikipedia:Hauptseite | grep -o "<title>.*</title>"; curl -s https://es.wikipedia.org/wiki/Wikipedia:Portada | grep -o "<title>.*</title>"; curl -s https://fr.wikipedia.org/wiki/Wikip%C3%A9dia:Accueil_principal | grep -o "<title>.*</title>";:'
<title>Wikipedia, the free encyclopedia</title>
<title>Wikipédia, l'encyclopédie libre</title>

    会看到 sleep-us 身份允许访问英文和法文版本。

清理基于 SNI 和源身份的监控和访问策略对象

$ kubectl delete serviceaccount sleep-us sleep-canada
$ kubectl delete service sleep-us sleep-canada
$ kubectl delete deployment sleep-us sleep-canada
$ kubectl delete rule handle-wikipedia-access check-us-wikipedia-access check-canada-wikipedia-access -n istio-system
$ kubectl delete logentry egress-access -n istio-system
$ kubectl delete stdio egress-access-logger -n istio-system
$ kubectl delete listentry requested-server-name -n istio-system
$ kubectl delete listchecker us-wikipedia-checker canada-wikipedia-checker -n istio-system

清理

  1. 执行 使用通配符主机配置 Egress 流量例子中的清理任意域名的通配符配置步骤。

  2. 停止 sleep 服务：