087d8085b7<!-- Provide a brief summary of your changes --> ## Motivation and Context <!-- Why is this change needed? What problem does it solve? --> Follow up from #658 addressing the feedback from @tadasant ## 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? --> ## 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 --> Signed-off-by: Radoslav Dimitrov <radoslav@stacklok.com>
93 lines
3.2 KiB
Go
93 lines
3.2 KiB
Go
package auth
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import (
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"context"
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"fmt"
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"net"
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"net/http"
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"strings"
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"github.com/danielgtaylor/huma/v2"
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v0 "github.com/modelcontextprotocol/registry/internal/api/handlers/v0"
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"github.com/modelcontextprotocol/registry/internal/auth"
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"github.com/modelcontextprotocol/registry/internal/config"
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)
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// DNSTokenExchangeInput represents the input for DNS-based authentication
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type DNSTokenExchangeInput struct {
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Body SignatureTokenExchangeInput
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}
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// DNSResolver defines the interface for DNS resolution
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type DNSResolver interface {
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LookupTXT(ctx context.Context, name string) ([]string, error)
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}
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// DefaultDNSResolver uses Go's standard DNS resolution
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type DefaultDNSResolver struct{}
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// LookupTXT performs DNS TXT record lookup
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func (r *DefaultDNSResolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
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return (&net.Resolver{}).LookupTXT(ctx, name)
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}
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// DNSAuthHandler handles DNS-based authentication
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type DNSAuthHandler struct {
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CoreAuthHandler
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resolver DNSResolver
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}
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// NewDNSAuthHandler creates a new DNS authentication handler
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func NewDNSAuthHandler(cfg *config.Config) *DNSAuthHandler {
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return &DNSAuthHandler{
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CoreAuthHandler: *NewCoreAuthHandler(cfg),
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resolver: &DefaultDNSResolver{},
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}
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}
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// SetResolver sets a custom DNS resolver (used for testing)
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func (h *DNSAuthHandler) SetResolver(resolver DNSResolver) {
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h.resolver = resolver
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}
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// RegisterDNSEndpoint registers the DNS authentication endpoint
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func RegisterDNSEndpoint(api huma.API, pathPrefix string, cfg *config.Config) {
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handler := NewDNSAuthHandler(cfg)
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// DNS authentication endpoint
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huma.Register(api, huma.Operation{
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OperationID: "exchange-dns-token" + strings.ReplaceAll(pathPrefix, "/", "-"),
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Method: http.MethodPost,
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Path: pathPrefix + "/auth/dns",
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Summary: "Exchange DNS signature for Registry JWT",
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Description: "Authenticate using DNS TXT record public key and signed timestamp",
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Tags: []string{"auth"},
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}, func(ctx context.Context, input *DNSTokenExchangeInput) (*v0.Response[auth.TokenResponse], error) {
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response, err := handler.ExchangeToken(ctx, input.Body.Domain, input.Body.Timestamp, input.Body.SignedTimestamp)
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if err != nil {
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return nil, huma.Error401Unauthorized("DNS authentication failed", err)
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}
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return &v0.Response[auth.TokenResponse]{
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Body: *response,
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}, nil
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})
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}
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// ExchangeToken exchanges DNS signature for a Registry JWT token
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func (h *DNSAuthHandler) ExchangeToken(ctx context.Context, domain, timestamp, signedTimestamp string) (*auth.TokenResponse, error) {
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keyFetcher := func(ctx context.Context, domain string) ([]string, error) {
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// Lookup DNS TXT records
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// DNS implies a hierarchy where subdomains are treated as part of the parent domain,
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// therefore we grant permissions for all subdomains (e.g., com.example.*)
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// This is in line with other DNS-based authentication methods e.g. ACME DNS-01 challenges
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txtRecords, err := h.resolver.LookupTXT(ctx, domain)
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if err != nil {
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return nil, fmt.Errorf("failed to lookup DNS TXT records: %w", err)
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}
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return txtRecords, nil
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}
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allowSubdomains := true
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return h.CoreAuthHandler.ExchangeToken(ctx, domain, timestamp, signedTimestamp, keyFetcher, allowSubdomains, auth.MethodDNS)
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}
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