mirror of https://github.com/hashicorp/consul
138 lines
4.8 KiB
Go
138 lines
4.8 KiB
Go
package agent
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import (
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"context"
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"fmt"
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"github.com/hashicorp/consul/acl"
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"github.com/hashicorp/consul/agent/cache"
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cachetype "github.com/hashicorp/consul/agent/cache-types"
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"github.com/hashicorp/consul/agent/connect"
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"github.com/hashicorp/consul/agent/structs"
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)
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// TODO(rb/intentions): this should move back into the agent endpoint since
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// there is no ext_authz implementation anymore.
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//
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// ConnectAuthorize implements the core authorization logic for Connect. It's in
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// a separate agent method here because we need to re-use this both in our own
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// HTTP API authz endpoint and in the gRPX xDS/ext_authz API for envoy.
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//
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// NOTE: This treats any L7 intentions as DENY.
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//
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// The ACL token and the auth request are provided and the auth decision (true
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// means authorized) and reason string are returned.
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//
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// If the request input is invalid the error returned will be a BadRequestError,
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// if the token doesn't grant necessary access then an acl.ErrPermissionDenied
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// error is returned, otherwise error indicates an unexpected server failure. If
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// access is denied, no error is returned but the first return value is false.
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func (a *Agent) ConnectAuthorize(token string,
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req *structs.ConnectAuthorizeRequest) (allowed bool, reason string, m *cache.ResultMeta, err error) {
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// Helper to make the error cases read better without resorting to named
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// returns which get messy and prone to mistakes in a method this long.
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returnErr := func(err error) (bool, string, *cache.ResultMeta, error) {
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return false, "", nil, err
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}
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if req == nil {
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return returnErr(BadRequestError{"Invalid request"})
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}
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// We need to have a target to check intentions
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if req.Target == "" {
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return returnErr(BadRequestError{"Target service must be specified"})
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}
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// Parse the certificate URI from the client ID
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uri, err := connect.ParseCertURIFromString(req.ClientCertURI)
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if err != nil {
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return returnErr(BadRequestError{"ClientCertURI not a valid Connect identifier"})
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}
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uriService, ok := uri.(*connect.SpiffeIDService)
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if !ok {
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return returnErr(BadRequestError{"ClientCertURI not a valid Service identifier"})
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}
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// We need to verify service:write permissions for the given token.
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// We do this manually here since the RPC request below only verifies
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// service:read.
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var authzContext acl.AuthorizerContext
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authz, err := a.resolveTokenAndDefaultMeta(token, &req.EnterpriseMeta, &authzContext)
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if err != nil {
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return returnErr(err)
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}
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if authz != nil && authz.ServiceWrite(req.Target, &authzContext) != acl.Allow {
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return returnErr(acl.ErrPermissionDenied)
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}
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// Note that we DON'T explicitly validate the trust-domain matches ours. See
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// the PR for this change for details.
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// TODO(banks): Implement revocation list checking here.
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// Get the intentions for this target service.
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args := &structs.IntentionQueryRequest{
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Datacenter: a.config.Datacenter,
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Match: &structs.IntentionQueryMatch{
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Type: structs.IntentionMatchDestination,
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Entries: []structs.IntentionMatchEntry{
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{
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Namespace: req.TargetNamespace(),
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Name: req.Target,
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},
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},
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},
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QueryOptions: structs.QueryOptions{Token: token},
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}
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raw, meta, err := a.cache.Get(context.TODO(), cachetype.IntentionMatchName, args)
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if err != nil {
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return returnErr(err)
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}
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reply, ok := raw.(*structs.IndexedIntentionMatches)
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if !ok {
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return returnErr(fmt.Errorf("internal error: response type not correct"))
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}
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if len(reply.Matches) != 1 {
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return returnErr(fmt.Errorf("Internal error loading matches"))
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}
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// Figure out which source matches this request.
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var ixnMatch *structs.Intention
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for _, ixn := range reply.Matches[0] {
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// We match on the intention source because the uriService is the source of the connection to authorize.
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if _, ok := connect.AuthorizeIntentionTarget(uriService.Service, uriService.Namespace, ixn, structs.IntentionMatchSource); ok {
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ixnMatch = ixn
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break
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}
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}
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if ixnMatch != nil {
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if len(ixnMatch.Permissions) == 0 {
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// This is an L4 intention.
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reason = fmt.Sprintf("Matched L4 intention: %s", ixnMatch.String())
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auth := ixnMatch.Action == structs.IntentionActionAllow
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return auth, reason, &meta, nil
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}
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// This is an L7 intention, so DENY.
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reason = fmt.Sprintf("Matched L7 intention: %s", ixnMatch.String())
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return false, reason, &meta, nil
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}
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// No match, we need to determine the default behavior. We do this by
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// fetching the default intention behavior from the resolved authorizer. The
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// default behavior if ACLs are disabled is to allow connections to mimic the
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// behavior of Consul itself: everything is allowed if ACLs are disabled.
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if authz == nil {
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// ACLs not enabled at all, the default is allow all.
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return true, "ACLs disabled, access is allowed by default", &meta, nil
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}
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reason = "Default behavior configured by ACLs"
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return authz.IntentionDefaultAllow(nil) == acl.Allow, reason, &meta, nil
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}
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