cloudflared-mirror/cmd/cloudflared/access/validation.go

76 lines
2.2 KiB
Go

package access
import (
"errors"
"fmt"
"net"
"net/http"
"net/url"
"strings"
"golang.org/x/net/http/httpguts"
)
// parseRequestHeaders will take user-provided header values as strings "Content-Type: application/json" and create
// a http.Header object.
func parseRequestHeaders(values []string) http.Header {
headers := make(http.Header)
for _, valuePair := range values {
header, value, found := strings.Cut(valuePair, ":")
if found {
headers.Add(strings.TrimSpace(header), strings.TrimSpace(value))
}
}
return headers
}
// bracketBareIPv6 wraps bare IPv6 addresses in a URL with square brackets.
// Go 1.26 tightened net/url parsing to strictly require RFC 3986 bracket syntax
// for IPv6 addresses in URLs. Before Go 1.26, bare forms like "http://::1" were
// accepted; now they are rejected. This function detects bare IPv6 in the host
// portion and brackets it so that url.ParseRequestURI can parse it correctly.
func bracketBareIPv6(input string) string {
prefix := input[:strings.Index(input, "://")+3]
rest := input[len(prefix):]
host := rest
if i := strings.IndexAny(rest, "/?#"); i >= 0 {
host = rest[:i]
}
if net.ParseIP(host) != nil && strings.Contains(host, ":") {
return prefix + "[" + host + "]" + rest[len(host):]
}
return input
}
// parseHostname will attempt to convert a user provided URL string into a string with some light error checking on
// certain expectations from the URL.
// Will convert all HTTP URLs to HTTPS
func parseURL(input string) (*url.URL, error) {
if input == "" {
return nil, errors.New("no input provided")
}
if !strings.HasPrefix(input, "https://") && !strings.HasPrefix(input, "http://") {
input = fmt.Sprintf("https://%s", input)
}
input = bracketBareIPv6(input)
url, err := url.ParseRequestURI(input)
if err != nil {
return nil, fmt.Errorf("failed to parse as URL: %w", err)
}
if url.Scheme != "https" {
url.Scheme = "https"
}
if url.Host == "" {
return nil, errors.New("failed to parse Host")
}
host, err := httpguts.PunycodeHostPort(url.Host)
if err != nil || host == "" {
return nil, err
}
if !httpguts.ValidHostHeader(host) {
return nil, errors.New("invalid Host provided")
}
url.Host = host
return url, nil
}