Add admin file inspector (#12635)

Download files from *any* bucket/path as an encrypted zip file.

The key is included in the response but can be separated so zip 
and the key doesn't have to be sent on the same channel.

Requires https://github.com/minio/pkg/pull/6

cmd/admin-handlers.go

@@ -19,6 +19,7 @@ package cmd
 
 import (
 	"context"
+	crand "crypto/rand"
 	"crypto/subtle"
 	"crypto/tls"
 	"encoding/json"
@@ -37,6 +38,7 @@ import (
 	"time"
 
 	"github.com/gorilla/mux"
+	"github.com/klauspost/compress/zip"
 	"github.com/minio/kes"
 	"github.com/minio/madmin-go"
 	"github.com/minio/minio/internal/auth"
@@ -49,6 +51,7 @@ import (
 	"github.com/minio/minio/internal/logger/message/log"
 	iampolicy "github.com/minio/pkg/iam/policy"
 	xnet "github.com/minio/pkg/net"
+	"github.com/secure-io/sio-go"
 )
 
 const (
@@ -1951,3 +1954,104 @@ func checkConnection(endpointStr string, timeout time.Duration) error {
 	defer xhttp.DrainBody(resp.Body)
 	return nil
 }
+
+// getRawDataer provides an interface for getting raw FS files.
+type getRawDataer interface {
+	GetRawData(ctx context.Context, volume, file string, fn func(r io.Reader, host string, disk string, filename string, size int64, modtime time.Time) error) error
+}
+
+// InspectDataHandler - GET /minio/admin/v3/inspect-data
+// ----------
+// Download file from all nodes in a zip format
+func (a adminAPIHandlers) InspectDataHandler(w http.ResponseWriter, r *http.Request) {
+	ctx := newContext(r, w, "InspectData")
+
+	// Validate request signature.
+	_, adminAPIErr := checkAdminRequestAuth(ctx, r, iampolicy.InspectDataAction, "")
+	if adminAPIErr != ErrNone {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(adminAPIErr), r.URL)
+		return
+	}
+	defer logger.AuditLog(ctx, w, r, mustGetClaimsFromToken(r))
+
+	o, ok := newObjectLayerFn().(getRawDataer)
+	if !ok {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrNotImplemented), r.URL)
+		return
+	}
+
+	volume := r.URL.Query().Get("volume")
+	file := r.URL.Query().Get("file")
+	if len(volume) == 0 {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidBucketName), r.URL)
+		return
+	}
+	if len(file) == 0 {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInvalidRequest), r.URL)
+		return
+	}
+
+	var key [32]byte
+	// MUST use crypto/rand
+	n, err := crand.Read(key[:])
+	if err != nil || n != len(key) {
+		logger.LogIf(ctx, err)
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInternalError), r.URL)
+		return
+	}
+	stream, err := sio.AES_256_GCM.Stream(key[:])
+	if err != nil {
+		logger.LogIf(ctx, err)
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInternalError), r.URL)
+		return
+	}
+	// Zero nonce, we only use each key once, and 32 bytes is plenty.
+	nonce := make([]byte, stream.NonceSize())
+	encw := stream.EncryptWriter(w, nonce, nil)
+
+	defer encw.Close()
+
+	// Write a version for making *incompatible* changes.
+	// The AdminClient will reject any version it does not know.
+	w.Write([]byte{1})
+
+	// Write key first (without encryption)
+	_, err = w.Write(key[:])
+	if err != nil {
+		writeErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInternalError), r.URL)
+		return
+	}
+
+	// Initialize a zip writer which will provide a zipped content
+	// of profiling data of all nodes
+	zipWriter := zip.NewWriter(encw)
+	defer zipWriter.Close()
+
+	err = o.GetRawData(ctx, volume, file, func(r io.Reader, host, disk, filename string, size int64, modtime time.Time) error {
+		// Prefix host+disk
+		filename = path.Join(host, disk, filename)
+		header, zerr := zip.FileInfoHeader(dummyFileInfo{
+			name:    filename,
+			size:    size,
+			mode:    0600,
+			modTime: modtime,
+			isDir:   false,
+			sys:     nil,
+		})
+		if zerr != nil {
+			logger.LogIf(ctx, zerr)
+			return nil
+		}
+		header.Method = zip.Deflate
+		zwriter, zerr := zipWriter.CreateHeader(header)
+		if zerr != nil {
+			logger.LogIf(ctx, zerr)
+			return nil
+		}
+		if _, err = io.Copy(zwriter, r); err != nil {
+			logger.LogIf(ctx, err)
+		}
+		return nil
+	})
+	logger.LogIf(ctx, err)
+}