[#1157] object: Make APE checker use Bearer-token's APE overrides

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

pkg/services/object/ape/checker.go

@@ -2,13 +2,17 @@ package ape
 
 import (
 	"context"
+	"crypto/ecdsa"
 	"errors"
 	"fmt"
 
 	objectV2 "git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/object"
+	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/ape/router"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/container"
 	frostfsidcore "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/frostfsid"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/core/netmap"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/ape"
+	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/bearer"
 	cid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/container/id"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/user"
@@ -23,16 +27,18 @@ type checkerImpl struct {
 	headerProvider  HeaderProvider
 	frostFSIDClient frostfsidcore.SubjectProvider
 	nm              netmap.Source
+	st              netmap.State
 	cnrSource       container.Source
 	nodePK          []byte
 }
 
-func NewChecker(chainRouter policyengine.ChainRouter, headerProvider HeaderProvider, frostFSIDClient frostfsidcore.SubjectProvider, nm netmap.Source, cnrSource container.Source, nodePK []byte) Checker {
+func NewChecker(chainRouter policyengine.ChainRouter, headerProvider HeaderProvider, frostFSIDClient frostfsidcore.SubjectProvider, nm netmap.Source, st netmap.State, cnrSource container.Source, nodePK []byte) Checker {
 	return &checkerImpl{
 		chainRouter:     chainRouter,
 		headerProvider:  headerProvider,
 		frostFSIDClient: frostFSIDClient,
 		nm:              nm,
+		st:              st,
 		cnrSource:       cnrSource,
 		nodePK:          nodePK,
 	}
@@ -67,9 +73,69 @@ type Prm struct {
 
 	// If true, object headers will not retrieved from storage engine.
 	WithoutHeaderRequest bool
+
+	// The request's bearer token. It is used in order to check APE overrides with the token.
+	BearerToken *bearer.Token
 }
 
-var errMissingOID = errors.New("object ID is not set")
+var (
+	errMissingOID               = errors.New("object ID is not set")
+	errInvalidTargetType        = errors.New("bearer token defines non-container target override")
+	errBearerExpired            = errors.New("bearer token has expired")
+	errBearerInvalidSignature   = errors.New("bearer token has invalid signature")
+	errBearerInvalidContainerID = errors.New("bearer token was created for another container")
+	errBearerNotSignedByOwner   = errors.New("bearer token is not signed by the container owner")
+	errBearerInvalidOwner       = errors.New("bearer token owner differs from the request sender")
+)
+
+// isValidBearer checks whether bearer token was correctly signed by authorized
+// entity. This method might be defined on whole ACL service because it will
+// require fetching current epoch to check lifetime.
+func isValidBearer(token *bearer.Token, ownerCnr user.ID, containerID cid.ID, publicKey *keys.PublicKey, st netmap.State) error {
+	if token == nil {
+		return nil
+	}
+
+	// 1. First check token lifetime. Simplest verification.
+	if token.InvalidAt(st.CurrentEpoch()) {
+		return errBearerExpired
+	}
+
+	// 2. Then check if bearer token is signed correctly.
+	if !token.VerifySignature() {
+		return errBearerInvalidSignature
+	}
+
+	// 3. Then check if container is either empty or equal to the container in the request.
+	apeOverride := token.APEOverride()
+	if apeOverride.Target.TargetType != ape.TargetTypeContainer {
+		return errInvalidTargetType
+	}
+
+	var targetCnr cid.ID
+	err := targetCnr.DecodeString(apeOverride.Target.Name)
+	if err != nil {
+		return fmt.Errorf("invalid cid format: %s", apeOverride.Target.Name)
+	}
+	if !containerID.Equals(targetCnr) {
+		return errBearerInvalidContainerID
+	}
+
+	// 4. Then check if container owner signed this token.
+	if !bearer.ResolveIssuer(*token).Equals(ownerCnr) {
+		return errBearerNotSignedByOwner
+	}
+
+	// 5. Then check if request sender has rights to use this token.
+	var usrSender user.ID
+	user.IDFromKey(&usrSender, (ecdsa.PublicKey)(*publicKey))
+
+	if !token.AssertUser(usrSender) {
+		return errBearerInvalidOwner
+	}
+
+	return nil
+}
 
 // CheckAPE checks if a request or a response is permitted creating an ape request and passing
 // it to chain router.
@@ -99,6 +165,26 @@ func (c *checkerImpl) CheckAPE(ctx context.Context, prm Prm) error {
 		return err
 	}
 
+	if prm.BearerToken != nil && !prm.BearerToken.Impersonate() {
+		if err := isValidBearer(prm.BearerToken, prm.ContainerOwner, prm.Container, pub, c.st); err != nil {
+			return fmt.Errorf("bearer token validation error: %w", err)
+		}
+		btRouter, err := router.SingleUseRouterWithBearerTokenChains([]bearer.APEOverride{prm.BearerToken.APEOverride()})
+		if err != nil {
+			return err
+		}
+		status, found, err := btRouter.IsAllowed(apechain.Ingress, policyengine.NewRequestTargetWithContainer(prm.Container.EncodeToString()), r)
+		if err != nil {
+			return err
+		}
+		if found && status == apechain.Allow {
+			return nil
+		}
+		if status != apechain.NoRuleFound {
+			return fmt.Errorf("bearer token: method %s: %s", prm.Method, status)
+		}
+	}
+
 	rt := policyengine.NewRequestTargetExtended(prm.Namespace, prm.Container.EncodeToString(), fmt.Sprintf("%s:%s", prm.Namespace, pub.Address()), nil)
 	status, ruleFound, err := c.chainRouter.IsAllowed(apechain.Ingress, rt, r)
 	if err != nil {