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[minor] allow setting the header IP depth #24

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Merged
joecorall merged 2 commits into from
Feb 24, 2025
Merged

[minor] allow setting the header IP depth #24

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c4dbb18
[minor] allow setting the header IP depth
joecorall Feb 24, 2025
b333106
bump version
joecorall Feb 24, 2025
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3 changes: 2 additions & 1 deletion README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -71,7 +71,7 @@ services:
--providers.docker=true
--providers.docker.network=default
--experimental.plugins.captcha-protect.modulename=github.com/libops/captcha-protect
--experimental.plugins.captcha-protect.version=v1.2.1
--experimental.plugins.captcha-protect.version=v1.3.0
volumes:
- /var/run/docker.sock:/var/run/docker.sock:z
- /CHANGEME/TO/A/HOST/PATH/FOR/STATE/FILE:/tmp/state.json:rw
Expand Down Expand Up @@ -100,6 +100,7 @@ services:
| `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. |
Expand Down
25 changes: 24 additions & 1 deletion main.go
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Expand Up @@ -30,6 +30,7 @@ type Config struct {
IPv4SubnetMask int `json:"ipv4subnetMask"`
IPv6SubnetMask int `json:"ipv6subnetMask"`
IPForwardedHeader string `json:"ipForwardedHeader"`
IPDepth int `json:"ipDepth"`
ProtectParameters string `json:"protectParameters"`
ProtectRoutes []string `json:"protectRoutes"`
ProtectFileExtensions []string `json:"protectFileExtensions"`
Expand Down Expand Up @@ -81,6 +82,7 @@ func CreateConfig() *Config {
},
GoodBots: []string{},
ExemptIPs: []string{
"127.0.0.0/8",
"10.0.0.0/8",
"172.16.0.0/12",
"192.168.0.0/16",
Expand All @@ -90,6 +92,7 @@ func CreateConfig() *Config {
ChallengeTmpl: "challenge.tmpl.html",
EnableStatsPage: "false",
LogLevel: "INFO",
IPDepth: 0,
}
}

Expand Down Expand Up @@ -392,8 +395,28 @@ func (bc *CaptchaProtect) getClientIP(req *http.Request) (string, string) {
ip := req.Header.Get(bc.config.IPForwardedHeader)
if bc.config.IPForwardedHeader != "" && ip != "" {
components := strings.Split(ip, ",")
ip = strings.TrimSpace(components[0])
ips := []string{}
for _, _ip := range components {
i := strings.TrimSpace(_ip)
if !IsIpExcluded(i, bc.exemptIps) {
ips = append(ips, i)
}
}
if len(ips) == 0 {
log.Error("No non-empty IPs in header. Defaulting to 0", "ipDepth", bc.config.IPDepth, bc.config.IPForwardedHeader, ip)
ip = req.RemoteAddr
} else {
len := len(ips) - bc.config.IPDepth
if len < 1 {
log.Error("Bad value for ipDepth for given header. Defaulting to 0", "ipDepth", bc.config.IPDepth, bc.config.IPForwardedHeader, ip)
len = 1
}
ip = ips[len-1]
}
} else {
if bc.config.IPForwardedHeader != "" {
log.Error("Received a blank header value. Defaulting to real IP")
}
ip = req.RemoteAddr
}
if strings.Contains(ip, ":") {
Expand Down
153 changes: 138 additions & 15 deletions main_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,10 @@ package captcha_protect

import (
"errors"
"log/slog"
"net"
"net/http/httptest"
"os"
"strings"
"testing"
)
Expand Down Expand Up @@ -201,15 +204,6 @@ func TestParseIp(t *testing.T) {
}

func TestIsIpExcluded(t *testing.T) {
// Helper function to parse CIDR blocks
parseCIDR := func(cidr string) *net.IPNet {
_, block, err := net.ParseCIDR(cidr)
if err != nil {
t.Fatalf("Failed to parse CIDR %s: %v", cidr, err)
}
return block
}

tests := []struct {
name string
clientIP string
Expand All @@ -219,37 +213,37 @@ func TestIsIpExcluded(t *testing.T) {
{
name: "IP in exempt subnet",
clientIP: "192.168.1.5",
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24")},
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24", t)},
expected: true,
},
{
name: "IP not in exempt subnet",
clientIP: "192.168.2.5",
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24")},
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24", t)},
expected: false,
},
{
name: "Multiple exempt subnets, matching one",
clientIP: "10.0.0.15",
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24"), parseCIDR("10.0.0.0/16")},
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24", t), parseCIDR("10.0.0.0/16", t)},
expected: true,
},
{
name: "IPv6 address in exempt range",
clientIP: "2001:db8::1",
exemptIps: []*net.IPNet{parseCIDR("2001:db8::/32")},
exemptIps: []*net.IPNet{parseCIDR("2001:db8::/32", t)},
expected: true,
},
{
name: "IPv6 address not in exempt range",
clientIP: "2001:db9::1",
exemptIps: []*net.IPNet{parseCIDR("2001:db8::/32")},
exemptIps: []*net.IPNet{parseCIDR("2001:db8::/32", t)},
expected: false,
},
{
name: "Invalid IP address",
clientIP: "invalid-ip",
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24")},
exemptIps: []*net.IPNet{parseCIDR("192.168.1.0/24", t)},
expected: false,
},
{
Expand Down Expand Up @@ -358,3 +352,132 @@ func TestRouteIsProtected(t *testing.T) {
})
}
}

func TestGetClientIP(t *testing.T) {
tests := []struct {
name string
config Config
exemptIps []*net.IPNet
headerValue string
remoteAddr string
expectedIP string
}{
{
name: "Header with multiple IPs, no exclusion, IPDepth 0 picks last IP",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 0,
},
exemptIps: []*net.IPNet{},
headerValue: "1.1.1.1, 2.2.2.2",
remoteAddr: "3.3.3.3:1234",
expectedIP: "2.2.2.2",
},
{
name: "Header with multiple IPs and one excluded, IPDepth 0 picks non-excluded last",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 0,
},
exemptIps: []*net.IPNet{parseCIDR("2.2.2.2/32", t)},
headerValue: "1.1.1.1, 3.3.3.3, 2.2.2.2",
remoteAddr: "3.3.3.3:1234",
expectedIP: "3.3.3.3",
},
{
name: "Header with multiple IPs, IPDepth 1 picks second-to-last non-exempt IP",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 1,
},
exemptIps: []*net.IPNet{},
headerValue: "1.1.1.1, 2.2.2.2, 3.3.3.3, 127.0.0.1, 192.168.0.1",
remoteAddr: "3.3.3.3:1234",
expectedIP: "2.2.2.2",
},
{
name: "Header with multiple IPs, IPDepth 1 picks second-to-last IP",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 1,
},
exemptIps: []*net.IPNet{},
headerValue: "1.1.1.1, 2.2.2.2, 3.3.3.3",
remoteAddr: "3.3.3.3:1234",
expectedIP: "2.2.2.2",
},
{
name: "Header with just exempt IPs header falls back to RemoteAddr with port stripped",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 0,
},
exemptIps: []*net.IPNet{parseCIDR("2.2.0.0/16", t)},
headerValue: "127.0.0.1, 192.168.1.1, 172.16.1.2, 2.2.3.4",
remoteAddr: "4.4.4.4:5678",
expectedIP: "4.4.4.4",
},
{
name: "Blank header falls back to RemoteAddr with port stripped",
config: Config{
IPForwardedHeader: "X-Forwarded-For",
IPDepth: 0,
},
exemptIps: []*net.IPNet{},
headerValue: "",
remoteAddr: "4.4.4.4:5678",
expectedIP: "4.4.4.4",
},
{
name: "Header not set in config, use RemoteAddr",
config: Config{
IPDepth: 0,
IPForwardedHeader: "",
},
exemptIps: []*net.IPNet{},
headerValue: "shouldBeIgnored",
remoteAddr: "5.5.5.5:4321",
expectedIP: "5.5.5.5",
},
}
handler := slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
Level: slog.LevelDebug,
})
log = slog.New(handler)
for _, tc := range tests {

t.Run(tc.name, func(t *testing.T) {
// Create a dummy request
req := httptest.NewRequest("GET", "http://example.com", nil)
req.Header.Set("X-Forwarded-For", tc.headerValue)

req.RemoteAddr = tc.remoteAddr

c := CreateConfig()
c.IPForwardedHeader = tc.config.IPForwardedHeader
c.IPDepth = tc.config.IPDepth
exemptIps := tc.exemptIps
for _, ip := range c.ExemptIPs {
_, r := ParseIp(ip, 16, 64)
exemptIps = append(exemptIps, parseCIDR(r, t))
}
bc := &CaptchaProtect{
config: c,
exemptIps: exemptIps,
}

ip, _ := bc.getClientIP(req)
if ip != tc.expectedIP {
t.Errorf("expected ip %s, got %s", tc.expectedIP, ip)
}
})
}
}

func parseCIDR(cidr string, t *testing.T) *net.IPNet {
_, block, err := net.ParseCIDR(cidr)
if err != nil {
t.Fatalf("Failed to parse CIDR %s: %v", cidr, err)
}
return block
}