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Geoblocking v2 #15

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Geoblocking v2 #15

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4c3da40
Adjusted to v2 API
mluk-sap Aug 19, 2024
8510272
Improved error handling
mluk-sap Aug 20, 2024
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72 changes: 61 additions & 11 deletions README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -78,16 +78,66 @@ If you want to use a static list of blocked IP ranges, you can create the config
```json
[
{
"network": "1.2.3.0/24",
"policy": "BLOCK_ACCESS"
},
{
"network": "2.4.0.0/16",
"policy": "BLOCK_ACCESS"
},
{
"network": "5.6.7.128/25",
"policy": "BLOCK_ACCESS"
"id": "some-policy-list-id",
"projectID": "some-project-id",
"versionID": "some-version-id",
"policyVersion": "some-policy-version",
"entries": [
{
"target": "1.2.3.0/24",
"tags": [
{
"name": "R",
"values": [
"some-region"
]
},
{
"name": "S",
"values": [
"some-sanctions-package"
]
}
],
"policy": "BLOCK"
},
{
"target": "2.4.0.0/16",
"tags": [
{
"name": "R",
"values": [
"some-region"
]
},
{
"name": "S",
"values": [
"some-sanctions-package"
]
}
],
"policy": "BLOCK"
},
{
"target": "5.6.7.128/25",
"tags": [
{
"name": "R",
"values": [
"some-region"
]
},
{
"name": "S",
"values": [
"some-sanctions-package"
]
}
],
"policy": "BLOCK"
}
]
}
]
```
Expand Down Expand Up @@ -151,7 +201,7 @@ go run main.go
Without config file, the service will use policy.json file from current directory. You can test the service by sending a request with the `x-envoy-external-address` header set to the IP address you want to check. For example:

```bash
curl -v -H "x-envoy-external-address: 1.2.3.0"
curl -v -H "x-envoy-external-address: 1.2.3.0" localhost:8000
```

If the IP address is in the list of blocked IP ranges, the service will return a 403 Forbidden response. If the IP address is not in the list, the service will return a 200 OK response.
Expand Down
175 changes: 117 additions & 58 deletions main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,26 @@ type IpAuthConfig struct {
UsePolicyUrl bool `yaml:"usePolicyUrl"`
}

type Policy struct {
Id string
ProjectID string
VersionID string
PolicyVersion string
Type string
Entries []PolicyEntry
}

type PolicyEntry struct {
Target string
Tags []PolicyTag
Policy string
}

type PolicyTag struct {
Name string
Values []string
}

const denyBody = "denied by ip-auth"

var (
Expand All @@ -42,83 +62,131 @@ var (
type ExtAuthzServer struct {
httpServer *http.Server
// For test only
httpPort chan int
config IpAuthConfig
block []netip.Prefix
httpPort chan int
config IpAuthConfig
allowlist []netip.Prefix
blocklist []netip.Prefix
etag string
}

func (s *ExtAuthzServer) isBlocked(extIp string) bool {
func (s *ExtAuthzServer) isAllowed(extIp string) bool {
ip, err := netip.ParseAddr(extIp)
if err != nil {
log.Fatalf("Failed to parse IP: %v", err)
log.Printf("Failed to parse IP: %v", err)
return false
}
for _, p := range s.block {
// allow list takes precedence over the block list
for _, p := range s.allowlist {
if p.Contains(ip) {
return true
}
}
for _, p := range s.blocklist {
if p.Contains(ip) {
return false
}
}
// if there are no rules then allow
return true
}

func (s *ExtAuthzServer) refreshPolicies(interval int) {
if s.config.UsePolicyFile {
s.readPolicyFile(*policyFile)
err := s.readPolicyFile(*policyFile)
if err != nil {
log.Printf("Error during policy read: %v", err)
}
}
if s.config.UsePolicyUrl {
s.fetchPolicies()
err := s.fetchPolicies()
if err != nil {
log.Printf("Error during policy fetch: %v", err)
}
}
if interval > 0 {
log.Printf("Refreshing policies every %v seconds", interval)
for range time.Tick(time.Duration(interval) * time.Second) {
if s.config.UsePolicyFile {
s.readPolicyFile(*policyFile)
err := s.readPolicyFile(*policyFile)
if err != nil {
log.Printf("Error during policy read: %v", err)
}
}
if s.config.UsePolicyUrl {
s.fetchPolicies()
err := s.fetchPolicies()
if err != nil {
log.Printf("Error during policy fetch: %v", err)
}
}
}
} else {
log.Printf("Policy refresh is disabled")
}
}

func (s *ExtAuthzServer) applyPolicies(policies []Policy) {
var allowlist, blocklist []netip.Prefix
for _, policy := range policies {
log.Printf("Applying policy ID %v, version %v, project %v", policy.Id, policy.PolicyVersion, policy.ProjectID)
for _, policyEntry := range policy.Entries {
p, err := netip.ParsePrefix(policyEntry.Target)
if err != nil {
log.Printf("Failed to parse network: %v", err)
}
if policyEntry.Policy == "BLOCK" {
blocklist = append(blocklist, p)
} else if policyEntry.Policy == "ALLOW" {
allowlist = append(allowlist, p)
} else {
log.Printf("Unknown policy %v for target %v, ignoring", policyEntry.Policy, policyEntry.Target)
}
}
}
s.allowlist = allowlist
s.blocklist = blocklist
log.Printf("Number of network ranges: allowed: %v, blocked: %v", len(s.allowlist), len(s.blocklist))
}

func (s *ExtAuthzServer) fetchPolicies() {
func (s *ExtAuthzServer) fetchPolicies() error {
log.Printf("Fetching policies from %s", s.config.PolicyURL)
cfg := clientcredentials.Config{
ClientID: s.config.ClientId,
ClientSecret: s.config.ClientSecret,
TokenURL: s.config.TokenURL,
}
client := cfg.Client(context.Background())
res, err := client.Get(s.config.PolicyURL)
if err != nil {
log.Fatalf("Failed to get policies: %v", err)
}
resBody, err := io.ReadAll(res.Body)
defer res.Body.Close()
if err != nil {
log.Fatalf("Failed to read response body: %v", err)

req, _ := http.NewRequest("GET", s.config.PolicyURL, nil)
if s.etag != "" {
req.Header.Set("if-none-match", s.etag)
}
policies := []map[string]string{}
err = json.Unmarshal(resBody, &policies)
res, err := client.Do(req)
if err != nil {
log.Fatalf("Failed to parse policies: %v", err)
}
var block []netip.Prefix
return fmt.Errorf("failed to get policies: %w", err)
} else if res.StatusCode == 304 {
log.Printf("Policy with etag %v is already applied", s.etag)
return nil
} else if res.StatusCode == 200 {
etag := res.Header.Get("etag")
log.Printf("Received policy list with etag: %v", etag)

for _, policy := range policies {
if policy["policy"] == "BLOCK_ACCESS" {
p, err := netip.ParsePrefix(policy["network"])
if err != nil {
log.Fatalf("Failed to parse network: %v", err)
}
block = append(block, p)
resBody, err := io.ReadAll(res.Body)
defer res.Body.Close()
if err != nil {
return fmt.Errorf("failed to read response body: %w", err)
}
var policies []Policy
err = json.Unmarshal(resBody, &policies)
if err != nil {
return fmt.Errorf("failed to parse policies: %w", err)
} else {
s.applyPolicies(policies)
s.etag = etag
return nil
}
} else {
return fmt.Errorf("failed to get policies, status code: %v", res.StatusCode)
}
s.block = block
log.Printf("Number of blocked network ranges: %v", len(s.block))

}

// ServeHTTP implements the HTTP check request.
Expand All @@ -129,8 +197,7 @@ func (s *ExtAuthzServer) ServeHTTP(response http.ResponseWriter, request *http.R
}
extIp := request.Header.Get("x-envoy-external-address")
l := fmt.Sprintf("%s %s%s, ip: %v\n", request.Method, request.Host, request.URL, extIp)
log.Printf("External IP: %s", extIp)
if s.isBlocked(extIp) {
if s.isAllowed(extIp) {
log.Printf("[HTTP][allowed]: %s", l)
response.WriteHeader(http.StatusOK)
} else {
Expand Down Expand Up @@ -171,39 +238,31 @@ func (s *ExtAuthzServer) stop() {
log.Printf("HTTP server stopped: %v", s.httpServer.Close())
}

func NewExtAuthzServer(config IpAuthConfig, block []netip.Prefix) *ExtAuthzServer {
func NewExtAuthzServer(config IpAuthConfig, allow []netip.Prefix, block []netip.Prefix) *ExtAuthzServer {
return &ExtAuthzServer{
httpPort: make(chan int, 1),
config: config,
block: block,
httpPort: make(chan int, 1),
config: config,
allowlist: allow,
blocklist: block,
}
}

func (s *ExtAuthzServer) readPolicyFile(policyFile string) {
func (s *ExtAuthzServer) readPolicyFile(policyFile string) error {
log.Printf("Reading policies from %s", policyFile)
policies := []map[string]string{}

policiesJson, err := os.ReadFile(policyFile)
if err != nil {
panic(err)
return err
}

var policies []Policy
err = json.Unmarshal(policiesJson, &policies)
if err != nil {
panic(err)
return err
}
var block []netip.Prefix

for _, policy := range policies {
if policy["policy"] == "BLOCK_ACCESS" {
p, err := netip.ParsePrefix(policy["network"])
if err != nil {
log.Fatalf("Failed to parse network: %v", err)
}
block = append(block, p)
}
}
s.block = block
log.Printf("Number of blocked network ranges: %v", len(s.block))
s.applyPolicies(policies)
return nil
}

func readConfigFile(configFile string, config *IpAuthConfig) {
Expand All @@ -222,13 +281,13 @@ func main() {
flag.Parse()

config := IpAuthConfig{UsePolicyFile: true, UsePolicyUrl: false, PolicyUpdateInterval: 600}
var block []netip.Prefix
var allow, block []netip.Prefix

if *configFile != "" {
readConfigFile(*configFile, &config)
}

s := NewExtAuthzServer(config, block)
s := NewExtAuthzServer(config, allow, block)

go s.refreshPolicies(config.PolicyUpdateInterval)

Expand Down
22 changes: 17 additions & 5 deletions main_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,9 +9,11 @@ import (

func TestExtAuthz(t *testing.T) {
var config IpAuthConfig
prefix, _ := netip.ParsePrefix("2.57.3.0/24")
block := []netip.Prefix{prefix}
server := NewExtAuthzServer(config, block)
blockedIP, _ := netip.ParsePrefix("2.57.3.0/24")
blocklist := []netip.Prefix{blockedIP}
allowedIP, _ := netip.ParsePrefix("2.57.3.1/32")
allowlist := []netip.Prefix{allowedIP}
server := NewExtAuthzServer(config, allowlist, blocklist)

go server.run("localhost:0")

Expand All @@ -27,15 +29,25 @@ func TestExtAuthz(t *testing.T) {
want int
}{
{
name: "HTTP-allow",
name: "HTTP-allow-unknown",
ip: "10.10.0.0",
want: http.StatusOK,
},
{
name: "HTTP-deny",
name: "HTTP-deny-blocklisted",
ip: "2.57.3.5",
want: http.StatusForbidden,
},
{
name: "HTTP-deny-empty",
ip: "",
want: http.StatusForbidden,
},
{
name: "HTTP-allow-allowlisted",
ip: "2.57.3.1",
want: http.StatusOK,
},
}
for _, tc := range cases {
t.Run(tc.name, func(t *testing.T) {
Expand Down
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