Handle non existent kms key correctly (#14329)

- in PutBucketEncryption API
- admin APIs for  `mc admin KMS key [create|info]`
- PutObject API when invalid KMS key is specified

cmd/bucket-encryption-handlers.go

@@ -20,12 +20,15 @@ package cmd
 import (
 	"encoding/base64"
 	"encoding/xml"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
 
 	"github.com/gorilla/mux"
+	"github.com/minio/kes"
 	"github.com/minio/madmin-go"
+	"github.com/minio/minio/internal/kms"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/bucket/policy"
 )
@@ -84,6 +87,19 @@ func (api objectAPIHandlers) PutBucketEncryptionHandler(w http.ResponseWriter, r
 		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrKMSNotConfigured), r.URL)
 		return
 	}
+	kmsKey := encConfig.KeyID()
+	if kmsKey != "" {
+		kmsContext := kms.Context{"MinIO admin API": "ServerInfoHandler"} // Context for a test key operation
+		_, err := GlobalKMS.GenerateKey(kmsKey, kmsContext)
+		if err != nil {
+			if errors.Is(err, kes.ErrKeyNotFound) {
+				writeErrorResponse(ctx, w, toAPIError(ctx, errKMSKeyNotFound), r.URL)
+				return
+			}
+			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
+			return
+		}
+	}
 
 	configData, err := xml.Marshal(encConfig)
 	if err != nil {