registry/internal/api/handlers/v0/auth/dns.go
Radoslav Dimitrov 1a7cd97099
Introduce v0.1 version of the API (#658)
<!-- Provide a brief summary of your changes -->

## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->
The following PR adds a new v0.1 API version. 

The goal is to mark v0.1 as a "freeze" point while keeping v0 as the
moving target for new features so integrators can start building on top
of something stable(r).

Details:
* This change is quite simple - we re-register the same handlers twice,
once as `v0` and once as `v0.1`
* Going forward, we'll keep v0.1 frozen while we add changes either on
top of both (non-breaking) or we'll have to branch if breaking changes
are necessary
* We all acknowledge this is not exactly best-practice, but it gives us
a way to gather feedback and allow clients to start integrating with the
API without breaking them (**note** this implies a follow up PR that
would branch the handlers used in v0.1).
* For integrators/clients: please provide your feedback - what works
well, what doesn't so we can take this into account going towards GA.

## How Has This Been Tested?
<!-- Have you tested this in a real application? Which scenarios were
tested? -->

## Breaking Changes
<!-- Will users need to update their code or configurations? -->
No, this just adds a new API version alongside the existing one.

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [ ] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [ ] My code follows the repository's style guidelines
- [ ] New and existing tests pass locally
- [ ] I have added appropriate error handling
- [ ] I have added or updated documentation as needed

## Additional context
<!-- Add any other context, implementation notes, or design decisions
-->
Fixes: #649

Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>
2025-10-14 11:04:48 +03:00

92 lines
3.1 KiB
Go

package auth
import (
"context"
"fmt"
"net"
"net/http"
"github.com/danielgtaylor/huma/v2"
v0 "github.com/modelcontextprotocol/registry/internal/api/handlers/v0"
"github.com/modelcontextprotocol/registry/internal/auth"
"github.com/modelcontextprotocol/registry/internal/config"
)
// DNSTokenExchangeInput represents the input for DNS-based authentication
type DNSTokenExchangeInput struct {
Body SignatureTokenExchangeInput
}
// DNSResolver defines the interface for DNS resolution
type DNSResolver interface {
LookupTXT(ctx context.Context, name string) ([]string, error)
}
// DefaultDNSResolver uses Go's standard DNS resolution
type DefaultDNSResolver struct{}
// LookupTXT performs DNS TXT record lookup
func (r *DefaultDNSResolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
return (&net.Resolver{}).LookupTXT(ctx, name)
}
// DNSAuthHandler handles DNS-based authentication
type DNSAuthHandler struct {
CoreAuthHandler
resolver DNSResolver
}
// NewDNSAuthHandler creates a new DNS authentication handler
func NewDNSAuthHandler(cfg *config.Config) *DNSAuthHandler {
return &DNSAuthHandler{
CoreAuthHandler: *NewCoreAuthHandler(cfg),
resolver: &DefaultDNSResolver{},
}
}
// SetResolver sets a custom DNS resolver (used for testing)
func (h *DNSAuthHandler) SetResolver(resolver DNSResolver) {
h.resolver = resolver
}
// RegisterDNSEndpoint registers the DNS authentication endpoint
func RegisterDNSEndpoint(api huma.API, pathPrefix string, cfg *config.Config) {
handler := NewDNSAuthHandler(cfg)
// DNS authentication endpoint
huma.Register(api, huma.Operation{
OperationID: "exchange-dns-token" + pathPrefix,
Method: http.MethodPost,
Path: pathPrefix + "/auth/dns",
Summary: "Exchange DNS signature for Registry JWT",
Description: "Authenticate using DNS TXT record public key and signed timestamp",
Tags: []string{"auth"},
}, func(ctx context.Context, input *DNSTokenExchangeInput) (*v0.Response[auth.TokenResponse], error) {
response, err := handler.ExchangeToken(ctx, input.Body.Domain, input.Body.Timestamp, input.Body.SignedTimestamp)
if err != nil {
return nil, huma.Error401Unauthorized("DNS authentication failed", err)
}
return &v0.Response[auth.TokenResponse]{
Body: *response,
}, nil
})
}
// ExchangeToken exchanges DNS signature for a Registry JWT token
func (h *DNSAuthHandler) ExchangeToken(ctx context.Context, domain, timestamp, signedTimestamp string) (*auth.TokenResponse, error) {
keyFetcher := func(ctx context.Context, domain string) ([]string, error) {
// Lookup DNS TXT records
// DNS implies a hierarchy where subdomains are treated as part of the parent domain,
// therefore we grant permissions for all subdomains (e.g., com.example.*)
// This is in line with other DNS-based authentication methods e.g. ACME DNS-01 challenges
txtRecords, err := h.resolver.LookupTXT(ctx, domain)
if err != nil {
return nil, fmt.Errorf("failed to lookup DNS TXT records: %w", err)
}
return txtRecords, nil
}
allowSubdomains := true
return h.CoreAuthHandler.ExchangeToken(ctx, domain, timestamp, signedTimestamp, keyFetcher, allowSubdomains, auth.MethodDNS)
}