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authorWim <wim@42.be>2022-03-12 19:41:07 +0100
committerGitHub <noreply@github.com>2022-03-12 19:41:07 +0100
commitb3be2e208cb373207d6199cac5a9fc92be073e7a (patch)
tree6de6d444737edee8f0476eea87c233fa980f0002 /vendor/github.com/labstack/echo/v4/ip.go
parentc30e90ff3f7e9ff96ac79ed4b7d90d6346216a15 (diff)
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Update dependencies and vendor (#1761)
Diffstat (limited to 'vendor/github.com/labstack/echo/v4/ip.go')
-rw-r--r--vendor/github.com/labstack/echo/v4/ip.go142
1 files changed, 134 insertions, 8 deletions
diff --git a/vendor/github.com/labstack/echo/v4/ip.go b/vendor/github.com/labstack/echo/v4/ip.go
index 39cb421f..46d464cf 100644
--- a/vendor/github.com/labstack/echo/v4/ip.go
+++ b/vendor/github.com/labstack/echo/v4/ip.go
@@ -6,6 +6,130 @@ import (
"strings"
)
+/**
+By: https://github.com/tmshn (See: https://github.com/labstack/echo/pull/1478 , https://github.com/labstack/echox/pull/134 )
+Source: https://echo.labstack.com/guide/ip-address/
+
+IP address plays fundamental role in HTTP; it's used for access control, auditing, geo-based access analysis and more.
+Echo provides handy method [`Context#RealIP()`](https://godoc.org/github.com/labstack/echo#Context) for that.
+
+However, it is not trivial to retrieve the _real_ IP address from requests especially when you put L7 proxies before the application.
+In such situation, _real_ IP needs to be relayed on HTTP layer from proxies to your app, but you must not trust HTTP headers unconditionally.
+Otherwise, you might give someone a chance of deceiving you. **A security risk!**
+
+To retrieve IP address reliably/securely, you must let your application be aware of the entire architecture of your infrastructure.
+In Echo, this can be done by configuring `Echo#IPExtractor` appropriately.
+This guides show you why and how.
+
+> Note: if you dont' set `Echo#IPExtractor` explicitly, Echo fallback to legacy behavior, which is not a good choice.
+
+Let's start from two questions to know the right direction:
+
+1. Do you put any HTTP (L7) proxy in front of the application?
+ - It includes both cloud solutions (such as AWS ALB or GCP HTTP LB) and OSS ones (such as Nginx, Envoy or Istio ingress gateway).
+2. If yes, what HTTP header do your proxies use to pass client IP to the application?
+
+## Case 1. With no proxy
+
+If you put no proxy (e.g.: directory facing to the internet), all you need to (and have to) see is IP address from network layer.
+Any HTTP header is untrustable because the clients have full control what headers to be set.
+
+In this case, use `echo.ExtractIPDirect()`.
+
+```go
+e.IPExtractor = echo.ExtractIPDirect()
+```
+
+## Case 2. With proxies using `X-Forwarded-For` header
+
+[`X-Forwared-For` (XFF)](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Forwarded-For) is the popular header
+to relay clients' IP addresses.
+At each hop on the proxies, they append the request IP address at the end of the header.
+
+Following example diagram illustrates this behavior.
+
+```text
+┌──────────┐ ┌──────────┐ ┌──────────┐ ┌──────────┐
+│ "Origin" │───────────>│ Proxy 1 │───────────>│ Proxy 2 │───────────>│ Your app │
+│ (IP: a) │ │ (IP: b) │ │ (IP: c) │ │ │
+└──────────┘ └──────────┘ └──────────┘ └──────────┘
+
+Case 1.
+XFF: "" "a" "a, b"
+ ~~~~~~
+Case 2.
+XFF: "x" "x, a" "x, a, b"
+ ~~~~~~~~~
+ ↑ What your app will see
+```
+
+In this case, use **first _untrustable_ IP reading from right**. Never use first one reading from left, as it is
+configurable by client. Here "trustable" means "you are sure the IP address belongs to your infrastructre".
+In above example, if `b` and `c` are trustable, the IP address of the client is `a` for both cases, never be `x`.
+
+In Echo, use `ExtractIPFromXFFHeader(...TrustOption)`.
+
+```go
+e.IPExtractor = echo.ExtractIPFromXFFHeader()
+```
+
+By default, it trusts internal IP addresses (loopback, link-local unicast, private-use and unique local address
+from [RFC6890](https://tools.ietf.org/html/rfc6890), [RFC4291](https://tools.ietf.org/html/rfc4291) and
+[RFC4193](https://tools.ietf.org/html/rfc4193)).
+To control this behavior, use [`TrustOption`](https://godoc.org/github.com/labstack/echo#TrustOption)s.
+
+E.g.:
+
+```go
+e.IPExtractor = echo.ExtractIPFromXFFHeader(
+ TrustLinkLocal(false),
+ TrustIPRanges(lbIPRange),
+)
+```
+
+- Ref: https://godoc.org/github.com/labstack/echo#TrustOption
+
+## Case 3. With proxies using `X-Real-IP` header
+
+`X-Real-IP` is another HTTP header to relay clients' IP addresses, but it carries only one address unlike XFF.
+
+If your proxies set this header, use `ExtractIPFromRealIPHeader(...TrustOption)`.
+
+```go
+e.IPExtractor = echo.ExtractIPFromRealIPHeader()
+```
+
+Again, it trusts internal IP addresses by default (loopback, link-local unicast, private-use and unique local address
+from [RFC6890](https://tools.ietf.org/html/rfc6890), [RFC4291](https://tools.ietf.org/html/rfc4291) and
+[RFC4193](https://tools.ietf.org/html/rfc4193)).
+To control this behavior, use [`TrustOption`](https://godoc.org/github.com/labstack/echo#TrustOption)s.
+
+- Ref: https://godoc.org/github.com/labstack/echo#TrustOption
+
+> **Never forget** to configure the outermost proxy (i.e.; at the edge of your infrastructure) **not to pass through incoming headers**.
+> Otherwise there is a chance of fraud, as it is what clients can control.
+
+## About default behavior
+
+In default behavior, Echo sees all of first XFF header, X-Real-IP header and IP from network layer.
+
+As you might already notice, after reading this article, this is not good.
+Sole reason this is default is just backward compatibility.
+
+## Private IP ranges
+
+See: https://en.wikipedia.org/wiki/Private_network
+
+Private IPv4 address ranges (RFC 1918):
+* 10.0.0.0 – 10.255.255.255 (24-bit block)
+* 172.16.0.0 – 172.31.255.255 (20-bit block)
+* 192.168.0.0 – 192.168.255.255 (16-bit block)
+
+Private IPv6 address ranges:
+* fc00::/7 address block = RFC 4193 Unique Local Addresses (ULA)
+
+*/
+
type ipChecker struct {
trustLoopback bool
trustLinkLocal bool
@@ -52,6 +176,7 @@ func newIPChecker(configs []TrustOption) *ipChecker {
return checker
}
+// Go1.16+ added `ip.IsPrivate()` but until that use this implementation
func isPrivateIPRange(ip net.IP) bool {
if ip4 := ip.To4(); ip4 != nil {
return ip4[0] == 10 ||
@@ -87,10 +212,12 @@ type IPExtractor func(*http.Request) string
// ExtractIPDirect extracts IP address using actual IP address.
// Use this if your server faces to internet directory (i.e.: uses no proxy).
func ExtractIPDirect() IPExtractor {
- return func(req *http.Request) string {
- ra, _, _ := net.SplitHostPort(req.RemoteAddr)
- return ra
- }
+ return extractIP
+}
+
+func extractIP(req *http.Request) string {
+ ra, _, _ := net.SplitHostPort(req.RemoteAddr)
+ return ra
}
// ExtractIPFromRealIPHeader extracts IP address using x-real-ip header.
@@ -98,14 +225,13 @@ func ExtractIPDirect() IPExtractor {
func ExtractIPFromRealIPHeader(options ...TrustOption) IPExtractor {
checker := newIPChecker(options)
return func(req *http.Request) string {
- directIP := ExtractIPDirect()(req)
realIP := req.Header.Get(HeaderXRealIP)
if realIP != "" {
- if ip := net.ParseIP(directIP); ip != nil && checker.trust(ip) {
+ if ip := net.ParseIP(realIP); ip != nil && checker.trust(ip) {
return realIP
}
}
- return directIP
+ return extractIP(req)
}
}
@@ -115,7 +241,7 @@ func ExtractIPFromRealIPHeader(options ...TrustOption) IPExtractor {
func ExtractIPFromXFFHeader(options ...TrustOption) IPExtractor {
checker := newIPChecker(options)
return func(req *http.Request) string {
- directIP := ExtractIPDirect()(req)
+ directIP := extractIP(req)
xffs := req.Header[HeaderXForwardedFor]
if len(xffs) == 0 {
return directIP