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[minor] allow challenge to be done on the same page that trips the rate limit #31

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joecorall merged 2 commits into from
Mar 10, 2025
Merged

[minor] allow challenge to be done on the same page that trips the rate limit #31

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61451b4
allow challenge to be done on the same page that trips the rate limit
joecorall Mar 10, 2025
b61e071
lint
joecorall Mar 10, 2025
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46 changes: 23 additions & 23 deletions README.md
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Expand Up @@ -89,29 +89,29 @@ services:
```
### Config options

| **Parameter** | **Type (Required)** | **Default** | **Description** |
|-------------------------|-------------------------|-------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `protectRoutes` | `[]string` (required) | `""` | Comma-separated list of route prefixes to protect. e.g., `"/"` protects the entire site (including file/js/css downloads, which you likely don't want). `"/browse"` protects its subtree. |
| `excludeRoutes` | `[]string` | `""` | Comma-separated list of route prefixes to **never** protect. e.g., `protectRoutes: "/"` protects the entire site. `excludeRoutes: "/ajax"` would never challenge any route starting with `/ajax` |
| `captchaProvider` | `string` (required) | `""` | The captcha type to use. Supported values: `turnstile`, `hcaptcha`, and `recaptcha`. |
| `siteKey` | `string` (required) | `""` | The captcha site key. |
| `secretKey` | `string` (required) | `""` | The captcha secret key. |
| `rateLimit` | `uint` | `20` | Maximum requests allowed from a subnet before a challenge is triggered. |
| `window` | `int` | `86400` | Duration (in seconds) for monitoring requests per subnet. |
| `ipv4subnetMask` | `int` | `16` | CIDR subnet mask to group IPv4 addresses for rate limiting. |
| `ipv6subnetMask` | `int` | `64` | CIDR subnet mask to group IPv6 addresses for rate limiting. |
| `ipForwardedHeader` | `string` | `""` | Header to check for the original client IP if Traefik is behind a load balancer. |
| `ipDepth` | `int` | `0` | How deep past the last non-exempt IP to fetch the real IP from `ipForwardedHeader`. Default 0 returns the last IP in the forward header |
| `goodBots` | `[]string` (encouraged) | *see below* | List of second-level domains for bots that are never challenged or rate-limited. |
| `protectParameters` | `string` | `"false"` | Forces rate limiting even for good bots if URL parameters are present. Useful for protecting faceted search pages. |
| `protectFileExtensions` | `[]string` | `""` | Comma-separated file extensions to protect. By default, your protected routes only protect html files. This is to prevent files like CSS/JS/img from tripping the rate limit. |
| `protectHttpMethods` | `[]string` | `"GET,HEAD"` | Comma-separated list of HTTP methods to protect against |
| `exemptIps` | `[]string` | `privateIPs` | CIDR-formatted IPs that should never be challenged. Private IP ranges are always exempt. |
| `challengeURL` | `string` | `"/challenge"` | URL where challenges are served. This will override existing routes if there is a conflict. |
| `challengeTmpl` | `string` | `"./challenge.tmpl.html"`| Path to the Go HTML template for the captcha challenge page. |
| `enableStatsPage` | `string` | `"false"` | Allows `exemptIps` to access `/captcha-protect/stats` to monitor the rate limiter. |
| `logLevel` | `string` | `"INFO"` | Log level for the middleware. Options: `ERROR`, `WARNING`, `INFO`, or `DEBUG`. |
| `persistentStateFile` | `string` | `""` | File path to persist rate limiter state across Traefik restarts. In Docker, mount this file from the host. |
| **Parameter** | **Type (Required)** | **Default** | **Description** |
|-------------------------|-------------------------|--------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| `protectRoutes` | `[]string` (required) | `""` | Comma-separated list of route prefixes to protect. e.g., `"/"` protects the entire site (including file/js/css downloads, which you likely don't want). `"/browse"` protects its subtree. |
| `excludeRoutes` | `[]string` | `""` | Comma-separated list of route prefixes to **never** protect. e.g., `protectRoutes: "/"` protects the entire site. `excludeRoutes: "/ajax"` would never challenge any route starting with `/ajax` |
| `captchaProvider` | `string` (required) | `""` | The captcha type to use. Supported values: `turnstile`, `hcaptcha`, and `recaptcha`. |
| `siteKey` | `string` (required) | `""` | The captcha site key. |
| `secretKey` | `string` (required) | `""` | The captcha secret key. |
| `rateLimit` | `uint` | `20` | Maximum requests allowed from a subnet before a challenge is triggered. |
| `window` | `int` | `86400` | Duration (in seconds) for monitoring requests per subnet. |
| `ipv4subnetMask` | `int` | `16` | CIDR subnet mask to group IPv4 addresses for rate limiting. |
| `ipv6subnetMask` | `int` | `64` | CIDR subnet mask to group IPv6 addresses for rate limiting. |
| `ipForwardedHeader` | `string` | `""` | Header to check for the original client IP if Traefik is behind a load balancer. |
| `ipDepth` | `int` | `0` | How deep past the last non-exempt IP to fetch the real IP from `ipForwardedHeader`. Default 0 returns the last IP in the forward header |
| `goodBots` | `[]string` (encouraged) | *see below* | List of second-level domains for bots that are never challenged or rate-limited. |
| `protectParameters` | `string` | `"false"` | Forces rate limiting even for good bots if URL parameters are present. Useful for protecting faceted search pages. |
| `protectFileExtensions` | `[]string` | `""` | Comma-separated file extensions to protect. By default, your protected routes only protect html files. This is to prevent files like CSS/JS/img from tripping the rate limit. |
| `protectHttpMethods` | `[]string` | `"GET,HEAD"` | Comma-separated list of HTTP methods to protect against |
| `exemptIps` | `[]string` | `privateIPs` | CIDR-formatted IPs that should never be challenged. Private IP ranges are always exempt. |
| `challengeURL` | `string` | `"/challenge"` | URL where challenges are served. This will override existing routes if there is a conflict. Setting to blank will have the challenge presented on the same page that tripped the rate limit. |
| `challengeTmpl` | `string` | `"./challenge.tmpl.html"`| Path to the Go HTML template for the captcha challenge page. |
| `enableStatsPage` | `string` | `"false"` | Allows `exemptIps` to access `/captcha-protect/stats` to monitor the rate limiter. |
| `logLevel` | `string` | `"INFO"` | Log level for the middleware. Options: `ERROR`, `WARNING`, `INFO`, or `DEBUG`. |
| `persistentStateFile` | `string` | `""` | File path to persist rate limiter state across Traefik restarts. In Docker, mount this file from the host. |


### Good Bots
Expand Down
60 changes: 49 additions & 11 deletions main.go
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Original file line number Diff line number Diff line change
Expand Up @@ -103,6 +103,10 @@ func CreateConfig() *Config {
}

func New(ctx context.Context, next http.Handler, config *Config, name string) (http.Handler, error) {
return NewCaptchaProtect(ctx, next, config, name)
}

func NewCaptchaProtect(ctx context.Context, next http.Handler, config *Config, name string) (*CaptchaProtect, error) {
var logLevel slog.LevelVar
logLevel.Set(slog.LevelInfo)
handler := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
Expand All @@ -123,6 +127,10 @@ func New(ctx context.Context, next http.Handler, config *Config, name string) (h
return nil, fmt.Errorf("you must protect at least one route with the protectRoutes config value. / will cover your entire site")
}

if config.ChallengeURL == "/" {
return nil, fmt.Errorf("your challenge URL can not be the entire site. Default is `/challenge`. A blank value will have challenges presented on the visit that trips the rate limit")
}

if len(config.ProtectHttpMethods) == 0 {
config.ProtectHttpMethods = []string{
"GET",
Expand Down Expand Up @@ -220,10 +228,26 @@ func New(ctx context.Context, next http.Handler, config *Config, name string) (h

func (bc *CaptchaProtect) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
clientIP, ipRange := bc.getClientIP(req)
challengeOnPage := bc.ChallengeOnPage()
if challengeOnPage && req.Method == http.MethodPost {
response := req.FormValue(bc.captchaConfig.key + "-response")
if response == "" {
if !strInSlice(req.Method, bc.config.ProtectHttpMethods) {
bc.next.ServeHTTP(rw, req)
return
}
} else {
statusCode := bc.verifyChallengePage(rw, req, clientIP)
log.Info("Captcha challenge", "clientIP", clientIP, "method", req.Method, "path", req.URL.Path, "status", statusCode, "useragent", req.UserAgent())
return
}
}

if req.URL.Path == bc.config.ChallengeURL {
if req.Method == http.MethodGet {
log.Info("Captcha challenge", "clientIP", clientIP, "method", req.Method, "path", req.URL.Path, "useragent", req.UserAgent())
bc.serveChallengePage(rw, req)
destination := req.URL.Query().Get("destination")
log.Info("Captcha challenge", "clientIP", clientIP, "method", req.Method, "path", req.URL.Path, "destination", destination, "useragent", req.UserAgent())
bc.serveChallengePage(rw, destination)
} else if req.Method == http.MethodPost {
statusCode := bc.verifyChallengePage(rw, req, clientIP)
log.Info("Captcha challenge", "clientIP", clientIP, "method", req.Method, "path", req.URL.Path, "status", statusCode, "useragent", req.UserAgent())
Expand All @@ -243,30 +267,40 @@ func (bc *CaptchaProtect) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
}
bc.registerRequest(ipRange)

if bc.trippedRateLimit(ipRange) {
encodedURI := url.QueryEscape(req.RequestURI)
url := fmt.Sprintf("%s?destination=%s", bc.config.ChallengeURL, encodedURI)
http.Redirect(rw, req, url, http.StatusFound)
} else {
if !bc.trippedRateLimit(ipRange) {
bc.next.ServeHTTP(rw, req)
return
}

if bc.ChallengeOnPage() {
log.Info("Captcha challenge", "clientIP", clientIP, "method", req.Method, "path", req.URL.Path, "useragent", req.UserAgent())
bc.serveChallengePage(rw, req.URL.Path)
return
}
encodedURI := url.QueryEscape(req.RequestURI)
url := fmt.Sprintf("%s?destination=%s", bc.config.ChallengeURL, encodedURI)
http.Redirect(rw, req, url, http.StatusFound)
}

func (bc *CaptchaProtect) serveChallengePage(rw http.ResponseWriter, req *http.Request) {
func (bc *CaptchaProtect) serveChallengePage(rw http.ResponseWriter, destination string) {
d := map[string]string{
"SiteKey": bc.config.SiteKey,
"FrontendJS": bc.captchaConfig.js,
"FrontendKey": bc.captchaConfig.key,
"ChallengeURL": bc.config.ChallengeURL,
"Destination": req.URL.Query().Get("destination"),
"Destination": destination,
}
status := http.StatusOK
if bc.ChallengeOnPage() {
status = http.StatusTooManyRequests
}
rw.WriteHeader(status)

err := bc.tmpl.Execute(rw, d)
if err != nil {
log.Error("Unable to execute go template", "tmpl", bc.config.ChallengeTmpl, "err", err)
http.Error(rw, "Internal error", http.StatusInternalServerError)
return
}
rw.WriteHeader(http.StatusOK)
}

func (bc *CaptchaProtect) verifyChallengePage(rw http.ResponseWriter, req *http.Request, ip string) int {
Expand Down Expand Up @@ -700,3 +734,7 @@ func strInSlice(s string, sl []string) bool {
}
return false
}

func (bc *CaptchaProtect) ChallengeOnPage() bool {
return bc.config.ChallengeURL == ""
}
61 changes: 61 additions & 0 deletions main_test.go
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Original file line number Diff line number Diff line change
@@ -1,11 +1,14 @@
package captcha_protect

import (
"context"
"errors"
"log/slog"
"net"
"net/http"
"net/http/httptest"
"os"
"strings"
"testing"
)

Expand Down Expand Up @@ -529,3 +532,61 @@ func parseCIDR(cidr string, t *testing.T) *net.IPNet {
}
return block
}

func TestServeHTTP(t *testing.T) {
next := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
rw.WriteHeader(http.StatusOK)
_, err := rw.Write([]byte("next"))
if err != nil {
slog.Error("problems", "err", err)
os.Exit(1)
}
})
config := CreateConfig()
tests := []struct {
name string
rateLimit uint
expectedStatus uint
challengePage string
expectedBody string
}{
{
name: "Redirect to 302",
rateLimit: 0,
challengePage: "/challenge",
expectedStatus: http.StatusFound,
expectedBody: "/challenge?destination=%2Fsomepath",
},
{
name: "429 on same page",
rateLimit: 0,
challengePage: "",
expectedStatus: http.StatusTooManyRequests,
expectedBody: "One moment while we verify your network connection",
},
}
for _, tc := range tests {
t.Run(tc.name, func(t *testing.T) {
config.RateLimit = tc.rateLimit
config.CaptchaProvider = "turnstile"
config.ProtectRoutes = []string{"/"}
config.ChallengeURL = tc.challengePage
config.ExemptIPs = []string{}
cp, err := NewCaptchaProtect(context.Background(), next, config, "captcha-protect")
if err != nil {
t.Errorf("unexpected error %v", err)
}
req := httptest.NewRequest(http.MethodGet, "http://example.com/somepath", nil)
req.RequestURI = "/somepath"
rr := httptest.NewRecorder()
cp.ServeHTTP(rr, req)
if rr.Code != int(tc.expectedStatus) {
t.Errorf("expected %d got %d", tc.expectedStatus, rr.Code)
}
body := rr.Body.String()
if !strings.Contains(body, tc.expectedBody) {
t.Errorf("expected %s got %s", tc.expectedBody, body)
}
})
}
}
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