From 1f6fcddba6da0e8d6c65283464d76ed8cb687126 Mon Sep 17 00:00:00 2001
From: Daichi Sakaue <daichi-sakaue@cybozu.co.jp>
Date: Thu, 17 Oct 2024 17:38:25 +0900
Subject: [PATCH] Return policy information from cilium-agent-proxy

Signed-off-by: Daichi Sakaue <daichi-sakaue@cybozu.co.jp>
---
 Dockerfile                           |  2 +-
 Makefile                             | 11 ++++++++++-
 cmd/cilium-agent-proxy/sub/run.go    | 21 ++++++++++++++++++++-
 e2e/testdata/cilium-agent-proxy.yaml | 10 ++++++----
 4 files changed, 37 insertions(+), 7 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 77ea4d0..bd9d8d8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -19,7 +19,7 @@ FROM ghcr.io/cybozu/ubuntu:22.04
 LABEL org.opencontainers.image.source=https://github.com/cybozu-go/network-policy-viewer
 
 WORKDIR /
+COPY bin/download/cilium /
 COPY --from=builder /work/cilium-agent-proxy /
 
-USER 10000:10000
 ENTRYPOINT ["/cilium-agent-proxy"]
diff --git a/Makefile b/Makefile
index a4d5f0e..e7137d2 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,8 @@ TOOLS_DIR := $(BIN_DIR)/download
 CACHE_DIR := $(shell pwd)/cache
 
 # Test tools
+CILIUM_IMAGE_VERSION := 1.14.14.1
+CILIUM_CLI := $(TOOLS_DIR)/cilium
 CUSTOMCHECKER := $(TOOLS_DIR)/custom-checker
 HELM := helm --repository-cache $(CACHE_DIR)/helm/repository --repository-config $(CACHE_DIR)/helm/repositories.yaml
 STATICCHECK := $(TOOLS_DIR)/staticcheck
@@ -17,7 +19,7 @@ help: ## Display this help
 	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_0-9-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 
 .PHONY: setup
-setup: $(CUSTOMCHECKER) $(STATICCHECK) ## Install necessary tools
+setup: $(CILIUM_CLI) $(CUSTOMCHECKER) $(STATICCHECK) ## Install necessary tools
 	if ! which aqua; then \
 		echo 'setup needs aqua.'; \
 		exit 1; \
@@ -26,6 +28,13 @@ setup: $(CUSTOMCHECKER) $(STATICCHECK) ## Install necessary tools
 	$(HELM) repo add cilium https://helm.cilium.io/
 	$(HELM) repo update cilium
 
+$(CILIUM_CLI):
+	mkdir -p $(TOOLS_DIR)
+	CONTAINER_ID=$$(docker run --detach --entrypoint pause ghcr.io/cybozu/cilium:$(CILIUM_IMAGE_VERSION)); \
+	docker cp $${CONTAINER_ID}:/usr/bin/cilium $(CILIUM_CLI); \
+	docker stop $${CONTAINER_ID}; \
+	docker rm $${CONTAINER_ID}
+
 $(CUSTOMCHECKER):
 	GOBIN=$(TOOLS_DIR) go install github.com/cybozu-go/golang-custom-analyzer/cmd/custom-checker@latest
 
diff --git a/cmd/cilium-agent-proxy/sub/run.go b/cmd/cilium-agent-proxy/sub/run.go
index e8d625a..397668f 100644
--- a/cmd/cilium-agent-proxy/sub/run.go
+++ b/cmd/cilium-agent-proxy/sub/run.go
@@ -69,7 +69,26 @@ func handleIdentity(w http.ResponseWriter, r *http.Request) {
 }
 
 func handlePolicy(w http.ResponseWriter, r *http.Request) {
-	fmt.Fprint(w, "error\n")
+	param := r.URL.Path[len("/policy/"):]
+	if len(param) == 0 {
+		renderError(w, r.URL.Path, "failed to read endpoint ID", http.StatusBadRequest)
+		return
+	}
+
+	// Convert to number to avoid parameter injection
+	endpoint, err := strconv.Atoi(param)
+	if err != nil {
+		renderError(w, r.URL.Path, "failed to read endpoint ID", http.StatusBadRequest)
+		return
+	}
+
+	stdout, _, err := runCommand(ciliumPath, nil, "bpf", "policy", "get", strconv.Itoa(endpoint), "-ojson")
+	if err != nil {
+		renderError(w, r.URL.Path, "failed to read BPF map", http.StatusInternalServerError)
+		return
+	}
+
+	renderJSON(w, r.URL.Path, stdout, http.StatusOK)
 }
 
 func subMain() error {
diff --git a/e2e/testdata/cilium-agent-proxy.yaml b/e2e/testdata/cilium-agent-proxy.yaml
index 76066fa..7c105aa 100644
--- a/e2e/testdata/cilium-agent-proxy.yaml
+++ b/e2e/testdata/cilium-agent-proxy.yaml
@@ -20,11 +20,13 @@ spec:
           volumeMounts:
             - name: cilium-socket
               mountPath: /var/run/cilium
-          securityContext:
-            capabilities:
-              drop:
-                - ALL
+            - name: bpf
+              mountPath: /sys/fs/bpf
       volumes:
         - name: cilium-socket
           hostPath:
             path: /var/run/cilium
+        - name: bpf
+          hostPath:
+            path: /sys/fs/bpf
+            type: DirectoryOrCreate