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memos/plugin/webhook/validate.go

76 lines
2.2 KiB
Go

package webhook
import (
"net"
"net/url"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
// reservedCIDRs lists IP ranges that must never be targeted by outbound webhook requests.
// Covers loopback, RFC-1918 private, link-local (including cloud IMDS at 169.254.169.254),
// and their IPv6 equivalents.
var reservedCIDRs = []string{
"127.0.0.0/8", // IPv4 loopback
"10.0.0.0/8", // RFC-1918 class A
"172.16.0.0/12", // RFC-1918 class B
"192.168.0.0/16", // RFC-1918 class C
"169.254.0.0/16", // Link-local / cloud IMDS
"::1/128", // IPv6 loopback
"fc00::/7", // IPv6 unique local
"fe80::/10", // IPv6 link-local
}
// reservedNetworks is the parsed form of reservedCIDRs, built once at startup.
var reservedNetworks []*net.IPNet
func init() {
for _, cidr := range reservedCIDRs {
_, network, err := net.ParseCIDR(cidr)
if err != nil {
panic("webhook: invalid reserved CIDR " + cidr + ": " + err.Error())
}
reservedNetworks = append(reservedNetworks, network)
}
}
// isReservedIP reports whether ip falls within any reserved/private range.
func isReservedIP(ip net.IP) bool {
for _, network := range reservedNetworks {
if network.Contains(ip) {
return true
}
}
return false
}
// ValidateURL checks that rawURL:
// 1. Parses as a valid absolute URL.
// 2. Uses the http or https scheme.
// 3. Does not resolve to a reserved/private IP address.
//
// It returns a gRPC InvalidArgument status error so callers can return it directly.
func ValidateURL(rawURL string) error {
u, err := url.ParseRequestURI(rawURL)
if err != nil {
return status.Errorf(codes.InvalidArgument, "invalid webhook URL: %v", err)
}
if u.Scheme != "http" && u.Scheme != "https" {
return status.Errorf(codes.InvalidArgument, "webhook URL must use http or https scheme, got %q", u.Scheme)
}
ips, err := net.LookupHost(u.Hostname())
if err != nil {
return status.Errorf(codes.InvalidArgument, "webhook URL hostname could not be resolved: %v", err)
}
for _, ipStr := range ips {
ip := net.ParseIP(ipStr)
if ip != nil && isReservedIP(ip) {
return status.Errorf(codes.InvalidArgument, "webhook URL must not resolve to a reserved or private IP address")
}
}
return nil
}