[#32] Add request sender classifier

ACL has to classify request senders by roles:
- owner of the container,
- request from container or inner ring node,
- any other request.

According to this roles ACL checker use different
bits of basic ACL to grant or deny access.

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/services/object/acl/basic.go

@@ -3,44 +3,59 @@ package acl
 import (
 	"context"
 
+	"github.com/nspcc-dev/neofs-api-go/v2/acl"
+	"github.com/nspcc-dev/neofs-api-go/v2/container"
 	"github.com/nspcc-dev/neofs-api-go/v2/object"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+	"github.com/pkg/errors"
 )
 
 type (
 	// ContainerGetter accesses NeoFS container storage.
-	ContainerGetter interface{}
+	ContainerGetter interface {
+		Get(*refs.ContainerID) (*container.Container, error)
+	}
+
+	Classifier interface {
+		Classify(RequestV2, *refs.ContainerID) acl.Role
+	}
 
 	// BasicChecker checks basic ACL rules.
 	BasicChecker struct {
-		containers ContainerGetter
+		sender SenderClassifier
 		next   object.Service
 	}
 
 	putStreamBasicChecker struct {
-		containers ContainerGetter
+		sender SenderClassifier
 		next   object.PutObjectStreamer
 	}
 
 	getStreamBasicChecker struct {
-		containers ContainerGetter
+		sender SenderClassifier
 		next   object.GetObjectStreamer
 	}
 
 	searchStreamBasicChecker struct {
-		containers ContainerGetter
+		sender SenderClassifier
 		next   object.SearchObjectStreamer
 	}
 
 	getRangeStreamBasicChecker struct {
-		containers ContainerGetter
+		sender SenderClassifier
 		next   object.GetRangeObjectStreamer
 	}
 )
 
+var (
+	ErrMalformedRequest = errors.New("malformed request")
+	ErrUnknownRole      = errors.New("can't classify request sender")
+)
+
 // NewBasicChecker is a constructor for basic ACL checker of object requests.
-func NewBasicChecker(cnr ContainerGetter, next object.Service) BasicChecker {
+func NewBasicChecker(c SenderClassifier, next object.Service) BasicChecker {
 	return BasicChecker{
-		containers: cnr,
+		sender: c,
 		next:   next,
 	}
 }
@@ -49,9 +64,22 @@ func (b BasicChecker) Get(
 	ctx context.Context,
 	request *object.GetRequest) (object.GetObjectStreamer, error) {
 
+	// get container address and do not panic at malformed request
+	var addr *refs.Address
+	if body := request.GetBody(); body == nil {
+		return nil, ErrMalformedRequest
+	} else {
+		addr = body.GetAddress()
+	}
+
+	role := b.sender.Classify(request, addr.GetContainerID())
+	if role == acl.RoleUnknown {
+		return nil, ErrUnknownRole
+	}
+
 	stream, err := b.next.Get(ctx, request)
 	return getStreamBasicChecker{
-		containers: b.containers,
+		sender: b.sender,
 		next:   stream,
 	}, err
 }
@@ -60,7 +88,7 @@ func (b BasicChecker) Put(ctx context.Context) (object.PutObjectStreamer, error)
 	streamer, err := b.next.Put(ctx)
 
 	return putStreamBasicChecker{
-		containers: b.containers,
+		sender: b.sender,
 		next:   streamer,
 	}, err
 }
@@ -78,7 +106,7 @@ func (b BasicChecker) Search(
 
 	stream, err := b.next.Search(ctx, request)
 	return searchStreamBasicChecker{
-		containers: b.containers,
+		sender: b.sender,
 		next:   stream,
 	}, err
 }
@@ -96,7 +124,7 @@ func (b BasicChecker) GetRange(
 
 	stream, err := b.next.GetRange(ctx, request)
 	return getRangeStreamBasicChecker{
-		containers: b.containers,
+		sender: b.sender,
 		next:   stream,
 	}, err
 }

pkg/services/object/acl/classifier.go

@@ -0,0 +1,216 @@
+package acl
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+
+	"github.com/nspcc-dev/neofs-api-go/pkg/netmap"
+	sdk "github.com/nspcc-dev/neofs-api-go/pkg/owner"
+	"github.com/nspcc-dev/neofs-api-go/v2/acl"
+	"github.com/nspcc-dev/neofs-api-go/v2/container"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+	"github.com/nspcc-dev/neofs-api-go/v2/session"
+	crypto "github.com/nspcc-dev/neofs-crypto"
+	"github.com/pkg/errors"
+)
+
+type (
+	// ContainerFetcher accesses NeoFS container storage.
+	// fixme: use core.container interface implementation
+	ContainerFetcher interface {
+		Fetch(*refs.ContainerID) (*container.Container, error)
+	}
+
+	// fixme: use core.netmap interface implementation
+	NetmapFetcher interface {
+		Current() (netmap.Netmap, error)
+		Previous(int) (netmap.Netmap, error)
+	}
+
+	InnerRingFetcher interface {
+		InnerRingKeys() ([][]byte, error)
+	}
+
+	RequestV2 interface {
+		GetMetaHeader() *session.RequestMetaHeader
+		GetVerificationHeader() *session.RequestVerificationHeader
+	}
+
+	SenderClassifier struct {
+		containers ContainerFetcher
+		innerRing  InnerRingFetcher
+		netmap     NetmapFetcher
+	}
+)
+
+// fixme: update classifier constructor
+func NewSenderClassifier() SenderClassifier {
+	return SenderClassifier{}
+}
+
+func (c SenderClassifier) Classify(req RequestV2, cid *refs.ContainerID) acl.Role {
+	if cid == nil || req == nil {
+		// log there
+		return acl.RoleUnknown
+	}
+
+	ownerID, ownerKey, err := requestOwner(req)
+	if err != nil || ownerID == nil || ownerKey == nil {
+		// log there
+		return acl.RoleUnknown
+	}
+
+	// todo: get owner from neofs.id if present
+
+	// fetch actual container
+	cnr, err := c.containers.Fetch(cid)
+	if err != nil || cnr.GetOwnerID() == nil {
+		// log there
+		return acl.RoleUnknown
+	}
+
+	// if request owner is the same as container owner, return RoleUser
+	if bytes.Equal(cnr.GetOwnerID().GetValue(), cid.GetValue()) {
+		return acl.RoleUser
+	}
+
+	ownerKeyInBytes := crypto.MarshalPublicKey(ownerKey)
+
+	isInnerRingNode, err := c.isInnerRingKey(ownerKeyInBytes)
+	if err != nil {
+		// log there
+		return acl.RoleUnknown
+	} else if isInnerRingNode {
+		return acl.RoleSystem
+	}
+
+	isContainerNode, err := c.isContainerKey(ownerKeyInBytes, cid.GetValue(), cnr)
+	if err != nil {
+		// log there
+		return acl.RoleUnknown
+	} else if isContainerNode {
+		return acl.RoleSystem
+	}
+
+	// if none of above, return RoleOthers
+	return acl.RoleOthers
+}
+
+func requestOwner(req RequestV2) (*refs.OwnerID, *ecdsa.PublicKey, error) {
+	var (
+		meta   = req.GetMetaHeader()
+		verify = req.GetVerificationHeader()
+	)
+
+	if meta == nil || verify == nil {
+		return nil, nil, errors.Wrap(ErrMalformedRequest, "nil at meta or verify header")
+	}
+
+	// if session token is presented, use it as truth source
+	if token := meta.GetSessionToken(); token != nil {
+		body := token.GetBody()
+		if body == nil {
+			return nil, nil, errors.Wrap(ErrMalformedRequest, "nil at session token body")
+		}
+
+		signature := token.GetSignature()
+		if signature == nil {
+			return nil, nil, errors.Wrap(ErrMalformedRequest, "nil at signature")
+		}
+
+		return body.GetOwnerID(), crypto.UnmarshalPublicKey(signature.GetKey()), nil
+	}
+
+	// otherwise get original body signature
+	bodySignature := originalBodySignature(verify)
+	if bodySignature == nil {
+		return nil, nil, errors.Wrap(ErrMalformedRequest, "nil at body signature")
+	}
+
+	key := crypto.UnmarshalPublicKey(bodySignature.GetKey())
+	neo3wallet, err := sdk.NEO3WalletFromPublicKey(key)
+	if err != nil {
+		return nil, nil, errors.Wrap(err, "can't create neo3 wallet")
+	}
+
+	// form owner from public key
+	owner := new(refs.OwnerID)
+	owner.SetValue(neo3wallet.Bytes())
+
+	return owner, key, nil
+}
+
+func originalBodySignature(v *session.RequestVerificationHeader) *refs.Signature {
+	if v == nil {
+		return nil
+	}
+
+	for v.GetOrigin() != nil {
+		v = v.GetOrigin()
+	}
+
+	return v.GetBodySignature()
+}
+
+func (c SenderClassifier) isInnerRingKey(owner []byte) (bool, error) {
+	innerRingKeys, err := c.innerRing.InnerRingKeys()
+	if err != nil {
+		return false, err
+	}
+
+	// if request owner key in the inner ring list, return RoleSystem
+	for i := range innerRingKeys {
+		if bytes.Equal(innerRingKeys[i], owner) {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}
+
+func (c SenderClassifier) isContainerKey(
+	owner, cid []byte,
+	cnr *container.Container) (bool, error) {
+
+	// first check current netmap
+	nm, err := c.netmap.Current()
+	if err != nil {
+		return false, err
+	}
+
+	in, err := lookupKeyInContainer(nm, owner, cid, cnr)
+	if err != nil {
+		return false, err
+	} else if in {
+		return true, nil
+	}
+
+	// then check previous netmap, this can happen in-between epoch change
+	// when node migrates data from last epoch container
+	nm, err = c.netmap.Previous(1)
+	if err != nil {
+		return false, err
+	}
+
+	return lookupKeyInContainer(nm, owner, cid, cnr)
+}
+
+func lookupKeyInContainer(
+	nm netmap.Netmap,
+	owner, cid []byte,
+	cnr *container.Container) (bool, error) {
+
+	cnrNodes, err := nm.GetContainerNodes(cnr.GetPlacementPolicy(), cid)
+	if err != nil {
+		return false, err
+	}
+
+	flatCnrNodes := cnrNodes.Flatten() // we need single array to iterate on
+	for i := range flatCnrNodes {
+		if bytes.Equal(flatCnrNodes[i].InfoV2.GetPublicKey(), owner) {
+			return true, nil
+		}
+	}
+
+	return false, nil
+}