diff --git a/cmd/anubis/main.go b/cmd/anubis/main.go index faf76a8..92fe1a2 100644 --- a/cmd/anubis/main.go +++ b/cmd/anubis/main.go @@ -68,6 +68,7 @@ var ( extractResources = flag.String("extract-resources", "", "if set, extract the static resources to the specified folder") webmasterEmail = flag.String("webmaster-email", "", "if set, displays webmaster's email on the reject page for appeals") versionFlag = flag.Bool("version", false, "print Anubis version") + xffStripPrivate = flag.Bool("xff-strip-private", true, "if set, strip private addresses from X-Forwarded-For") ) func keyFromHex(value string) (ed25519.PrivateKey, error) { @@ -336,7 +337,7 @@ func main() { h = s h = internal.RemoteXRealIP(*useRemoteAddress, *bindNetwork, h) h = internal.XForwardedForToXRealIP(h) - h = internal.XForwardedForUpdate(h) + h = internal.XForwardedForUpdate(*xffStripPrivate, h) srv := http.Server{Handler: h, ErrorLog: internal.GetFilteredHTTPLogger()} listener, listenerUrl := setupListener(*bindNetwork, *bind) diff --git a/docs/docs/CHANGELOG.md b/docs/docs/CHANGELOG.md index 3278abe..ec0e119 100644 --- a/docs/docs/CHANGELOG.md +++ b/docs/docs/CHANGELOG.md @@ -14,6 +14,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0 development +- Add `--xff-strip-private` flag/envvar to toggle skipping X-Forwarded-For private addresses or not - Refactor challenge presentation logic to use a challenge registry - Allow challenge implementations to register HTTP routes - Implement a no-JS challenge method: [`metarefresh`](./admin/configuration/challenges/metarefresh.mdx) ([#95](https://github.com/TecharoHQ/anubis/issues/95)) diff --git a/docs/docs/admin/installation.mdx b/docs/docs/admin/installation.mdx index 5db3b8a..5992739 100644 --- a/docs/docs/admin/installation.mdx +++ b/docs/docs/admin/installation.mdx @@ -49,29 +49,30 @@ For more detailed information on installing Anubis with native packages, please Anubis uses these environment variables for configuration: -| Environment Variable | Default value | Explanation | -| :----------------------------- | :---------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -| `BASE_PREFIX` | unset | If set, adds a global prefix to all Anubis endpoints. For example, setting this to `/myapp` would make Anubis accessible at `/myapp/` instead of `/`. This is useful when running Anubis behind a reverse proxy that routes based on path prefixes. | -| `BIND` | `:8923` | The network address that Anubis listens on. For `unix`, set this to a path: `/run/anubis/instance.sock` | -| `BIND_NETWORK` | `tcp` | The address family that Anubis listens on. Accepts `tcp`, `unix` and anything Go's [`net.Listen`](https://pkg.go.dev/net#Listen) supports. | -| `COOKIE_DOMAIN` | unset | The domain the Anubis challenge pass cookie should be set to. This should be set to the domain you bought from your registrar (EG: `techaro.lol` if your webapp is running on `anubis.techaro.lol`). See this [stackoverflow explanation of cookies](https://stackoverflow.com/a/1063760) for more information.

Note that unlike `REDIRECT_DOMAINS`, you should never include a port number in this variable. | -| `COOKIE_EXPIRATION_TIME` | `168h` | The amount of time the authorization cookie is valid for. | -| `COOKIE_PARTITIONED` | `false` | If set to `true`, enables the [partitioned (CHIPS) flag](https://developers.google.com/privacy-sandbox/cookies/chips), meaning that Anubis inside an iframe has a different set of cookies than the domain hosting the iframe. | -| `DIFFICULTY` | `4` | The difficulty of the challenge, or the number of leading zeroes that must be in successful responses. | -| `ED25519_PRIVATE_KEY_HEX` | unset | The hex-encoded ed25519 private key used to sign Anubis responses. If this is not set, Anubis will generate one for you. This should be exactly 64 characters long. See below for details. | -| `ED25519_PRIVATE_KEY_HEX_FILE` | unset | Path to a file containing the hex-encoded ed25519 private key. Only one of this or its sister option may be set. | -| `METRICS_BIND` | `:9090` | The network address that Anubis serves Prometheus metrics on. See `BIND` for more information. | -| `METRICS_BIND_NETWORK` | `tcp` | The address family that the Anubis metrics server listens on. See `BIND_NETWORK` for more information. | -| `OG_EXPIRY_TIME` | `24h` | The expiration time for the Open Graph tag cache. | -| `OG_PASSTHROUGH` | `false` | If set to `true`, Anubis will enable Open Graph tag passthrough. | -| `OG_CACHE_CONSIDER_HOST` | `false` | If set to `true`, Anubis will consider the host in the Open Graph tag cache key. | -| `POLICY_FNAME` | unset | The file containing [bot policy configuration](./policies.mdx). See the bot policy documentation for more details. If unset, the default bot policy configuration is used. | +| Environment Variable | Default value | Explanation | +| :----------------------------- | :---------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | +| `BASE_PREFIX` | unset | If set, adds a global prefix to all Anubis endpoints. For example, setting this to `/myapp` would make Anubis accessible at `/myapp/` instead of `/`. This is useful when running Anubis behind a reverse proxy that routes based on path prefixes. | +| `BIND` | `:8923` | The network address that Anubis listens on. For `unix`, set this to a path: `/run/anubis/instance.sock` | +| `BIND_NETWORK` | `tcp` | The address family that Anubis listens on. Accepts `tcp`, `unix` and anything Go's [`net.Listen`](https://pkg.go.dev/net#Listen) supports. | +| `COOKIE_DOMAIN` | unset | The domain the Anubis challenge pass cookie should be set to. This should be set to the domain you bought from your registrar (EG: `techaro.lol` if your webapp is running on `anubis.techaro.lol`). See this [stackoverflow explanation of cookies](https://stackoverflow.com/a/1063760) for more information.

Note that unlike `REDIRECT_DOMAINS`, you should never include a port number in this variable. | +| `COOKIE_EXPIRATION_TIME` | `168h` | The amount of time the authorization cookie is valid for. | +| `COOKIE_PARTITIONED` | `false` | If set to `true`, enables the [partitioned (CHIPS) flag](https://developers.google.com/privacy-sandbox/cookies/chips), meaning that Anubis inside an iframe has a different set of cookies than the domain hosting the iframe. | +| `DIFFICULTY` | `4` | The difficulty of the challenge, or the number of leading zeroes that must be in successful responses. | +| `ED25519_PRIVATE_KEY_HEX` | unset | The hex-encoded ed25519 private key used to sign Anubis responses. If this is not set, Anubis will generate one for you. This should be exactly 64 characters long. See below for details. | +| `ED25519_PRIVATE_KEY_HEX_FILE` | unset | Path to a file containing the hex-encoded ed25519 private key. Only one of this or its sister option may be set. | +| `METRICS_BIND` | `:9090` | The network address that Anubis serves Prometheus metrics on. See `BIND` for more information. | +| `METRICS_BIND_NETWORK` | `tcp` | The address family that the Anubis metrics server listens on. See `BIND_NETWORK` for more information. | +| `OG_EXPIRY_TIME` | `24h` | The expiration time for the Open Graph tag cache. | +| `OG_PASSTHROUGH` | `false` | If set to `true`, Anubis will enable Open Graph tag passthrough. | +| `OG_CACHE_CONSIDER_HOST` | `false` | If set to `true`, Anubis will consider the host in the Open Graph tag cache key. | +| `POLICY_FNAME` | unset | The file containing [bot policy configuration](./policies.mdx). See the bot policy documentation for more details. If unset, the default bot policy configuration is used. | | `REDIRECT_DOMAINS` | unset | If set, restrict the domains that Anubis can redirect to when passing a challenge.

If this is unset, Anubis may redirect to any domain which could cause security issues in the unlikely case that an attacker passes a challenge for your browser and then tricks you into clicking a link to your domain.

Note that if you are hosting Anubis on a non-standard port (`https://example:com:8443`, `http://www.example.net:8080`, etc.), you must also include the port number here. | -| `SERVE_ROBOTS_TXT` | `false` | If set `true`, Anubis will serve a default `robots.txt` file that disallows all known AI scrapers by name and then additionally disallows every scraper. This is useful if facts and circumstances make it difficult to change the underlying service to serve such a `robots.txt` file. | -| `SOCKET_MODE` | `0770` | _Only used when at least one of the `*_BIND_NETWORK` variables are set to `unix`._ The socket mode (permissions) for Unix domain sockets. | -| `TARGET` | `http://localhost:3923` | The URL of the service that Anubis should forward valid requests to. Supports Unix domain sockets, set this to a URI like so: `unix:///path/to/socket.sock`. | -| `USE_REMOTE_ADDRESS` | unset | If set to `true`, Anubis will take the client's IP from the network socket. For production deployments, it is expected that a reverse proxy is used in front of Anubis, which pass the IP using headers, instead. | -| `WEBMASTER_EMAIL` | unset | If set, shows a contact email address when rendering error pages. This email address will be how users can get in contact with administrators. | +| `SERVE_ROBOTS_TXT` | `false` | If set `true`, Anubis will serve a default `robots.txt` file that disallows all known AI scrapers by name and then additionally disallows every scraper. This is useful if facts and circumstances make it difficult to change the underlying service to serve such a `robots.txt` file. | +| `SOCKET_MODE` | `0770` | _Only used when at least one of the `*_BIND_NETWORK` variables are set to `unix`._ The socket mode (permissions) for Unix domain sockets. | +| `TARGET` | `http://localhost:3923` | The URL of the service that Anubis should forward valid requests to. Supports Unix domain sockets, set this to a URI like so: `unix:///path/to/socket.sock`. | +| `USE_REMOTE_ADDRESS` | unset | If set to `true`, Anubis will take the client's IP from the network socket. For production deployments, it is expected that a reverse proxy is used in front of Anubis, which pass the IP using headers, instead. | +| `WEBMASTER_EMAIL` | unset | If set, shows a contact email address when rendering error pages. This email address will be how users can get in contact with administrators. | +| `XFF_STRIP_PRIVATE` | `true` | If set, strip private addresses from `X-Forwarded-For` headers. To unset this, you must set `XFF_STRIP_PRIVATE=false` or `--xff-strip-private=false`. |
Advanced configuration settings diff --git a/internal/headers.go b/internal/headers.go index 2596a02..87bca47 100644 --- a/internal/headers.go +++ b/internal/headers.go @@ -81,12 +81,12 @@ func XForwardedForToXRealIP(next http.Handler) http.Handler { // XForwardedForUpdate sets or updates the X-Forwarded-For header, adding // the known remote address to an existing chain if present -func XForwardedForUpdate(next http.Handler) http.Handler { +func XForwardedForUpdate(stripPrivate bool, next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { defer next.ServeHTTP(w, r) pref := XFFComputePreferences{ - StripPrivate: true, + StripPrivate: stripPrivate, StripLoopback: true, StripCGNAT: true, Flatten: true, diff --git a/internal/xff_test.go b/internal/xff_test.go index 8eeea8e..e99af82 100644 --- a/internal/xff_test.go +++ b/internal/xff_test.go @@ -23,7 +23,7 @@ func TestXForwardedForUpdateIgnoreUnix(t *testing.T) { w := httptest.NewRecorder() - XForwardedForUpdate(h).ServeHTTP(w, r) + XForwardedForUpdate(true, h).ServeHTTP(w, r) if r.RemoteAddr != remoteAddr { t.Errorf("wanted remoteAddr to be %s, got: %s", r.RemoteAddr, remoteAddr) @@ -43,7 +43,7 @@ func TestXForwardedForUpdateAddToChain(t *testing.T) { w.WriteHeader(http.StatusOK) }) - srv := httptest.NewServer(XForwardedForUpdate(h)) + srv := httptest.NewServer(XForwardedForUpdate(true, h)) r, err := http.NewRequest(http.MethodGet, srv.URL, nil) if err != nil { @@ -81,6 +81,15 @@ func TestComputeXFFHeader(t *testing.T) { }, result: "1.1.1.1,127.0.0.1", }, + { + name: "StripPrivate", + remoteAddr: "127.0.0.1:80", + origXFFHeader: "1.1.1.1,10.0.0.1", + pref: XFFComputePreferences{ + StripPrivate: false, + }, + result: "1.1.1.1,10.0.0.1,127.0.0.1", + }, { name: "StripLoopback", remoteAddr: "127.0.0.1:80",