add basic ip centric access control on routes

docs/content/cfg/_index.md

@@ -24,14 +24,16 @@ Add a route for a service `svc` for the `src` (e.g. `/path` or `:port`) to a `ds
 
 `route add <svc> <src> <dst>[ weight <w>][ tags "<t1>,<t2>,..."][ opts "k1=v1 k2=v2 ..."]`
 
-Option               | Description
--------------------- | -----------
-`strip=/path`        | Forward `/path/to/file` as `/to/file`
-`proto=tcp`          | Upstream service is TCP, `dst` must be `:port`
-`proto=https`        | Upstream service is HTTPS
-`tlsskipverify=true` | Disable TLS cert validation for HTTPS upstream
-`host=name`          | Set the `Host` header to `name`. If `name == 'dst'` then the `Host` header will be set to the registered upstream host name
-`register=name`      | Register fabio as new service `name`. Useful for registering hostnames for host specific routes.
+Option                                     | Description
+------------------------------------------ | -----------
+`allow=ip:10.0.0.0/8,ip:192.168.0.0/24`    | Restrict access to source addresses within the `10.0.0.0/8` or `192.168.0.0/24` CIDR mask.  All other requests will be denied.
+`deny=ip:10.0.0.0/8,ip:1.2.3.4/32`         | Deny requests that source from the `10.0.0.0/8` CIDR mask or `1.2.3.4`.  All other requests will be allowed.
+`strip=/path`                              | Forward `/path/to/file` as `/to/file`
+`proto=tcp`                                | Upstream service is TCP, `dst` must be `:port`
+`proto=https`                              | Upstream service is HTTPS
+`tlsskipverify=true`                       | Disable TLS cert validation for HTTPS upstream
+`host=name`                                | Set the `Host` header to `name`. If `name == 'dst'` then the `Host` header will be set to the registered upstream host name
+`register=name`                            | Register fabio as new service `name`. Useful for registering hostnames for host specific routes.
 
 ##### Example
 

docs/content/feature/_index.md

@@ -6,6 +6,7 @@ weight: 200
 The following list provides a list of features supported by fabio. 
 
  * [Access Logging](/feature/access-logging/) - customizable access logs
+ * [Access Control](/feature/access-control/) - route specific access control
  * [Certificate Stores](/feature/certificate-stores/) - dynamic certificate stores like file system, HTTP server, [Consul](https://consul.io/) and [Vault](https://vaultproject.io/)
  * [Compression](/feature/compression/) - GZIP compression for HTTP responses
  * [Docker Support](/feature/docker/) - Official Docker image, Registrator and Docker Compose example

docs/content/feature/access-control.md

@@ -0,0 +1,31 @@
+---
+title: "Access Control"
+since: "1.5.8"
+---
+
+fabio supports basic ip centric access control per route.  You may
+specify one of `allow` or `deny` options per route to control access.
+Currently only source ip control is available.
+
+<!--more-->
+
+To allow access to a route from clients within the `192.168.1.0/24`
+and `10.0.0.0/8` subnet you would add the following option:
+
+```
+allow=ip:192.168.1.0/24,ip:10.0.0.0/8
+```
+
+With this specified only clients sourced from those two subnets will
+be allowed.  All other requests to that route will be denied.
+
+
+Inversely, to only deny a specific set of clients you can use the
+following option syntax:
+
+```
+deny=ip:1.2.3.4/32,100.123.0.0/16
+```
+
+With this configuration access will be denied to any clients with
+the `1.2.3.4` address or coming from the `100.123.0.0/16` network.

proxy/http_proxy.go

@@ -84,6 +84,11 @@ func (p *HTTPProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if t.AccessDeniedHTTP(r) {
+		http.Error(w, "access denied", http.StatusForbidden)
+		return
+	}
+
 	// build the request url since r.URL will get modified
 	// by the reverse proxy and contains only the RequestURI anyway
 	requestURL := &url.URL{

proxy/tcp/sni_proxy.go

@@ -78,6 +78,11 @@ func (p *SNIProxy) ServeTCP(in net.Conn) error {
 	}
 	addr := t.URL.Host
 
+	if t.AccessDeniedTCP(in) {
+		log.Print("[INFO] route rules denied access to ", t.URL.String())
+		return nil
+	}
+
 	out, err := net.DialTimeout("tcp", addr, p.DialTimeout)
 	if err != nil {
 		log.Print("[WARN] tcp+sni: cannot connect to upstream ", addr)

proxy/tcp/tcp_proxy.go

@@ -48,6 +48,11 @@ func (p *Proxy) ServeTCP(in net.Conn) error {
 	}
 	addr := t.URL.Host
 
+	if t.AccessDeniedTCP(in) {
+		log.Print("[INFO] route rules denied access to ", t.URL.String())
+		return nil
+	}
+
 	out, err := net.DialTimeout("tcp", addr, p.DialTimeout)
 	if err != nil {
 		log.Print("[WARN] tcp: cannot connect to upstream ", addr)

route/access_rules.go

@@ -0,0 +1,127 @@
+package route
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"net"
+	"net/http"
+	"strings"
+)
+
+const (
+	ipAllowTag = "allow:ip"
+	ipDenyTag  = "deny:ip"
+)
+
+// AccessDeniedHTTP checks rules on the target for HTTP proxy routes.
+func (t *Target) AccessDeniedHTTP(r *http.Request) bool {
+	host, _, err := net.SplitHostPort(r.RemoteAddr)
+
+	if err != nil {
+		log.Printf("[ERROR] Failed to get host from RemoteAddr %s: %s",
+			r.RemoteAddr, err.Error())
+		return false
+	}
+
+	// prefer xff header if set
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" && xff != host {
+		host = xff
+	}
+
+	// currently only one function - more may be added in the future
+	return t.denyByIP(net.ParseIP(host))
+}
+
+// AccessDeniedTCP checks rules on the target for TCP proxy routes.
+func (t *Target) AccessDeniedTCP(c net.Conn) bool {
+	// currently only one function - more may be added in the future
+	return t.denyByIP(net.ParseIP(c.RemoteAddr().String()))
+}
+
+func (t *Target) denyByIP(ip net.IP) bool {
+	if ip == nil || t.accessRules == nil {
+		return false
+	}
+
+	// check allow (whitelist) first if it exists
+	if _, ok := t.accessRules[ipAllowTag]; ok {
+		var block *net.IPNet
+		for _, x := range t.accessRules[ipAllowTag] {
+			if block, ok = x.(*net.IPNet); !ok {
+				log.Print("[ERROR] failed to assert ip block while checking allow rule for ", t.Service)
+				continue
+			}
+			if block.Contains(ip) {
+				// specific allow matched - allow this request
+				return false
+			}
+		}
+		// we checked all the blocks - deny this request
+		return true
+	}
+
+	// still going - check deny (blacklist) if it exists
+	if _, ok := t.accessRules[ipDenyTag]; ok {
+		var block *net.IPNet
+		for _, x := range t.accessRules[ipDenyTag] {
+			if block, ok = x.(*net.IPNet); !ok {
+				log.Print("[INFO] failed to assert ip block while checking deny rule for ", t.Service)
+				continue
+			}
+			if block.Contains(ip) {
+				// specific deny matched - deny this request
+				return true
+			}
+		}
+	}
+
+	// default - do not deny
+	return false
+}
+
+func (t *Target) parseAccessRule(allowDeny string) error {
+	var accessTag string
+	var temps []string
+
+	// init rules if needed
+	if t.accessRules == nil {
+		t.accessRules = make(map[string][]interface{})
+	}
+
+	// loop over rule elements
+	for _, c := range strings.Split(t.Opts[allowDeny], ",") {
+		if temps = strings.SplitN(c, ":", 2); len(temps) != 2 {
+			return fmt.Errorf("invalid access item, expected <type>:<data>, got %s", temps)
+		}
+		accessTag = allowDeny + ":" + strings.ToLower(temps[0])
+		switch accessTag {
+		case ipAllowTag, ipDenyTag:
+			_, net, err := net.ParseCIDR(strings.TrimSpace(temps[1]))
+			if err != nil {
+				return fmt.Errorf("failed to parse CIDR %s with error: %s",
+					c, err.Error())
+			}
+			// add element to rule map
+			t.accessRules[accessTag] = append(t.accessRules[accessTag], net)
+		default:
+			return fmt.Errorf("unknown access item type: %s", temps[0])
+		}
+	}
+	return nil
+}
+
+func (t *Target) processAccessRules() error {
+	if t.Opts["allow"] != "" && t.Opts["deny"] != "" {
+		return errors.New("specifying allow and deny on the same route is not supported")
+	}
+
+	for _, allowDeny := range []string{"allow", "deny"} {
+		if t.Opts[allowDeny] != "" {
+			if err := t.parseAccessRule(allowDeny); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

route/access_rules_test.go

@@ -0,0 +1,107 @@
+package route
+
+import (
+	"net"
+	"testing"
+)
+
+func TestAccessRules_parseAccessRule(t *testing.T) {
+	tests := []struct {
+		desc      string
+		allowDeny string
+		fail      bool
+	}{
+		{
+			desc:      "parseAccessRuleGood",
+			allowDeny: "ip:10.0.0.0/8,ip:192.168.0.0/24,ip:1.2.3.4/32",
+		},
+		{
+			desc:      "parseAccessRuleBadType",
+			allowDeny: "x:10.0.0.0/8",
+			fail:      true,
+		},
+		{
+			desc:      "parseAccessRuleIncompleteIP",
+			allowDeny: "ip:10/8",
+			fail:      true,
+		},
+		{
+			desc:      "parseAccessRuleBadCIDR",
+			allowDeny: "ip:10.0.0.0/255",
+			fail:      true,
+		},
+	}
+
+	for i, tt := range tests {
+		tt := tt // capture loop var
+
+		t.Run(tt.desc, func(t *testing.T) {
+			for _, ad := range []string{"allow", "deny"} {
+				tgt := &Target{Opts: map[string]string{ad: tt.allowDeny}}
+				err := tgt.parseAccessRule(ad)
+				if err != nil && !tt.fail {
+					t.Errorf("%d: %s\nfailed: %s", i, tt.desc, err.Error())
+					return
+				}
+			}
+		})
+	}
+}
+
+func TestAccessRules_denyByIP(t *testing.T) {
+	tests := []struct {
+		desc   string
+		target *Target
+		remote net.IP
+		denied bool
+	}{
+		{
+			desc: "denyByIPAllowAllowed",
+			target: &Target{
+				Opts: map[string]string{"allow": "ip:10.0.0.0/8,ip:192.168.0.0/24"},
+			},
+			remote: net.ParseIP("10.10.0.1"),
+			denied: false,
+		},
+		{
+			desc: "denyByIPAllowDenied",
+			target: &Target{
+				Opts: map[string]string{"allow": "ip:10.0.0.0/8,ip:192.168.0.0/24"},
+			},
+			remote: net.ParseIP("1.2.3.4"),
+			denied: true,
+		},
+		{
+			desc: "denyByIPDenyDenied",
+			target: &Target{
+				Opts: map[string]string{"deny": "ip:10.0.0.0/8,ip:192.168.0.0/24"},
+			},
+			remote: net.ParseIP("10.10.0.1"),
+			denied: true,
+		},
+		{
+			desc: "denyByIPDenyAllow",
+			target: &Target{
+				Opts: map[string]string{"deny": "ip:10.0.0.0/8,ip:192.168.0.0/24"},
+			},
+			remote: net.ParseIP("1.2.3.4"),
+			denied: false,
+		},
+	}
+
+	for i, tt := range tests {
+		tt := tt // capture loop var
+
+		t.Run(tt.desc, func(t *testing.T) {
+			if err := tt.target.processAccessRules(); err != nil {
+				t.Errorf("%d: %s - failed to process access rules: %s",
+					i, tt.desc, err.Error())
+			}
+			if deny := tt.target.denyByIP(tt.remote); deny != tt.denied {
+				t.Errorf("%d: %s\ngot denied: %t\nwant denied: %t\n",
+					i, tt.desc, deny, tt.denied)
+				return
+			}
+		})
+	}
+}

route/route.go

@@ -65,6 +65,7 @@ func (r *Route) addTarget(service string, targetURL *url.URL, fixedWeight float6
 		Timer:       ServiceRegistry.GetTimer(name),
 		TimerName:   name,
 	}
+
 	if opts != nil {
 		t.StripPath = opts["strip"]
 		t.TLSSkipVerify = opts["tlsskipverify"] == "true"
@@ -79,6 +80,11 @@ func (r *Route) addTarget(service string, targetURL *url.URL, fixedWeight float6
 				log.Printf("[ERROR] redirect status code should be in 3xx range. Got: %s", opts["redirect"])
 			}
 		}
+
+		if err = t.processAccessRules(); err != nil {
+			log.Printf("[ERROR] failed to process access rules: %s",
+				err.Error())
+		}
 	}
 
 	r.Targets = append(r.Targets, t)

route/target.go

@@ -50,6 +50,9 @@ type Target struct {
 
 	// TimerName is the name of the timer in the metrics registry
 	TimerName string
+
+	// accessRules is map of access information for the target.
+	accessRules map[string][]interface{}
 }
 
 func (t *Target) GetRedirectURL(requestURL *url.URL) *url.URL {