safehttp

README

SafeHTTP Client

SafeHTTP provides users with a standard http client with sensible defaults that can be used to make http requests to untrusted URLs. This is useful, for instance, for dispatching outbound webhook requests with URLs that are provided by customers. SafeHTTP Client inspects the final ip address, instead of simply the provided URL, protecting you against the threat of SSRF even if the attacker uses a DNS record that looks harmless, but that points to localhost or other forbidden addresses.

Much of the code was adapted from Andrew Ayer's public domain code.

Installing

go get github.com/AlchemyTelcoSolutions/safehttp

Usage

// create client
client := safehttp.NewClient(c.opts)
// set forbidden endpoint
req, err := http.NewRequest("POST", "http://localhost:5000", nil)
if err != nil {
    // crash and burn
}
// do actual request, should get a safehttp error
res, err := client.Do(req)
if err != nil {
    // safehttp won't let the call to actually happen
}

Documentation

Index

• Variables
• func NewClient(opts Options) *http.Client
• type Options
• type SafeHTTPError
  • func (err *SafeHTTPError) Error() string
  • func (err *SafeHTTPError) Unwrap() error

Variables

var (
	BadNetworkTypeErrCode     uint = 1
	BadHostPortPairErrCode    uint = 2
	BadIPAddressErrCode       uint = 3
	NotPublicIPAddressErrCode uint = 4
)

Functions

func NewClient

func NewClient(opts Options) *http.Client

NewClient returns a pointer to an http.Client with some sensible defaults, plus a custon dialer control that checks the receiving IP address against a forbidden-list, and checks the network type against an allow-list. Both lists have sensible defaults that can be added to by means of the Options struct

Types

type Options

type Options struct {
	AllowedNetworkTypes []string
	ForbiddenIPs        []string
}

Options is a struct that can be passed into NewClient to override the default allow-list of network types and the default forbidden-list of ip addresses

type SafeHTTPError

type SafeHTTPError struct {
	Err     error
	Text    string
	ErrCode uint
	// contains filtered or unexported fields
}

SafeHTTPError is the error type returned by the SafeHTTPClient when an attempt is made to use a forbidden network type or IP address

func (*SafeHTTPError) Error

func (err *SafeHTTPError) Error() string

func (*SafeHTTPError) Unwrap

func (err *SafeHTTPError) Unwrap() error