Move CopyObject precondition checks into GetObjectReader

in order to perform SSE-C pre-condition checks using the
last 32 bytes of encrypted ETag rather than the decrypted
ETag

cmd/disk-cache.go

@@ -254,7 +254,7 @@ func (c cacheObjects) GetObjectNInfo(ctx context.Context, bucket, object string,
 
 	cleanupBackend := func() { bkReader.Close() }
 	cleanupPipe := func() { pipeReader.Close() }
-	gr = NewGetObjectReaderFromReader(teeReader, bkReader.ObjInfo, cleanupBackend, cleanupPipe)
+	gr = NewGetObjectReaderFromReader(teeReader, bkReader.ObjInfo, opts.CheckCopyPrecondFn, cleanupBackend, cleanupPipe)
 	return gr, nil
 }
 

cmd/encryption-v1.go

@@ -915,7 +915,6 @@ func getDecryptedETag(headers http.Header, objInfo ObjectInfo, copySource bool)
 		key [32]byte
 		err error
 	)
-
 	// If ETag is contentMD5Sum return it as is.
 	if len(objInfo.ETag) == 32 {
 		return objInfo.ETag

cmd/fs-v1.go

@@ -494,7 +494,7 @@ func (fs *FSObjects) GetObjectNInfo(ctx context.Context, bucket, object string,
 	if hasSuffix(object, slashSeparator) {
 		// The lock taken above is released when
 		// objReader.Close() is called by the caller.
-		return NewGetObjectReaderFromReader(bytes.NewBuffer(nil), ObjectInfo{}, nsUnlocker), nil
+		return NewGetObjectReaderFromReader(bytes.NewBuffer(nil), ObjectInfo{}, opts.CheckCopyPrecondFn, nsUnlocker), nil
 	}
 
 	// Otherwise we get the object info
@@ -519,7 +519,7 @@ func (fs *FSObjects) GetObjectNInfo(ctx context.Context, bucket, object string,
 		rwPoolUnlocker = func() { fs.rwPool.Close(fsMetaPath) }
 	}
 
-	objReaderFn, off, length, rErr := NewGetObjectReader(rs, objInfo, nsUnlocker, rwPoolUnlocker)
+	objReaderFn, off, length, rErr := NewGetObjectReader(rs, objInfo, opts.CheckCopyPrecondFn, nsUnlocker, rwPoolUnlocker)
 	if rErr != nil {
 		return nil, rErr
 	}
@@ -547,7 +547,7 @@ func (fs *FSObjects) GetObjectNInfo(ctx context.Context, bucket, object string,
 		return nil, err
 	}
 
-	return objReaderFn(reader, h, closeFn)
+	return objReaderFn(reader, h, opts.CheckCopyPrecondFn, closeFn)
 }
 
 // GetObject - reads an object from the disk.

cmd/gateway/azure/gateway-azure.go

@@ -651,7 +651,7 @@ func (a *azureObjects) GetObjectNInfo(ctx context.Context, bucket, object string
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return minio.NewGetObjectReaderFromReader(pr, objInfo, pipeCloser), nil
+	return minio.NewGetObjectReaderFromReader(pr, objInfo, opts.CheckCopyPrecondFn, pipeCloser), nil
 }
 
 // GetObject - reads an object from azure. Supports additional

cmd/gateway/b2/gateway-b2.go

@@ -417,7 +417,7 @@ func (l *b2Objects) GetObjectNInfo(ctx context.Context, bucket, object string, r
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return minio.NewGetObjectReaderFromReader(pr, objInfo, pipeCloser), nil
+	return minio.NewGetObjectReaderFromReader(pr, objInfo, opts.CheckCopyPrecondFn, pipeCloser), nil
 }
 
 // GetObject reads an object from B2. Supports additional

cmd/gateway/gcs/gateway-gcs.go

@@ -753,7 +753,7 @@ func (l *gcsGateway) GetObjectNInfo(ctx context.Context, bucket, object string,
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return minio.NewGetObjectReaderFromReader(pr, objInfo, pipeCloser), nil
+	return minio.NewGetObjectReaderFromReader(pr, objInfo, opts.CheckCopyPrecondFn, pipeCloser), nil
 }
 
 // GetObject - reads an object from GCS. Supports additional

cmd/gateway/oss/gateway-oss.go

@@ -26,7 +26,7 @@ import (
 	"strings"
 
 	"github.com/aliyun/aliyun-oss-go-sdk/oss"
-	"github.com/dustin/go-humanize"
+	humanize "github.com/dustin/go-humanize"
 
 	"github.com/minio/cli"
 	miniogopolicy "github.com/minio/minio-go/pkg/policy"
@@ -569,7 +569,7 @@ func (l *ossObjects) GetObjectNInfo(ctx context.Context, bucket, object string,
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return minio.NewGetObjectReaderFromReader(pr, objInfo, pipeCloser), nil
+	return minio.NewGetObjectReaderFromReader(pr, objInfo, opts.CheckCopyPrecondFn, pipeCloser), nil
 }
 
 // GetObject reads an object on OSS. Supports additional

cmd/gateway/s3/gateway-s3-sse.go

@@ -313,7 +313,7 @@ func (l *s3EncObjects) GetObjectNInfo(ctx context.Context, bucket, object string
 		return l.s3Objects.GetObjectNInfo(ctx, bucket, object, rs, h, lockType, opts)
 	}
 	objInfo.UserDefined = minio.CleanMinioInternalMetadataKeys(objInfo.UserDefined)
-	fn, off, length, err := minio.NewGetObjectReader(rs, objInfo)
+	fn, off, length, err := minio.NewGetObjectReader(rs, objInfo, o.CheckCopyPrecondFn)
 	if err != nil {
 		return nil, minio.ErrorRespToObjectError(err)
 	}
@@ -329,7 +329,7 @@ func (l *s3EncObjects) GetObjectNInfo(ctx context.Context, bucket, object string
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return fn(pr, h, pipeCloser)
+	return fn(pr, h, o.CheckCopyPrecondFn, pipeCloser)
 }
 
 // GetObjectInfo reads object info and replies back ObjectInfo

cmd/gateway/s3/gateway-s3.go

@@ -400,7 +400,7 @@ func (l *s3Objects) GetObjectNInfo(ctx context.Context, bucket, object string, r
 	// Setup cleanup function to cause the above go-routine to
 	// exit in case of partial read
 	pipeCloser := func() { pr.Close() }
-	return minio.NewGetObjectReaderFromReader(pr, objInfo, pipeCloser), nil
+	return minio.NewGetObjectReaderFromReader(pr, objInfo, opts.CheckCopyPrecondFn, pipeCloser), nil
 }
 
 // GetObject reads an object from S3. Supports additional

cmd/object-api-errors.go

@@ -383,3 +383,15 @@ func isErrObjectNotFound(err error) bool {
 	_, ok := err.(ObjectNotFound)
 	return ok
 }
+
+// PreConditionFailed - Check if copy precondition failed
+type PreConditionFailed struct{}
+
+func (e PreConditionFailed) Error() string {
+	return "At least one of the pre-conditions you specified did not hold"
+}
+
+func isErrPreconditionFailed(err error) bool {
+	_, ok := err.(PreConditionFailed)
+	return ok
+}

cmd/object-api-interface.go

@@ -26,10 +26,14 @@ import (
 	"github.com/minio/minio/pkg/policy"
 )
 
+// CheckCopyPreconditionFn returns true if copy precondition check failed.
+type CheckCopyPreconditionFn func(o ObjectInfo, encETag string) bool
+
 // ObjectOptions represents object options for ObjectLayer operations
 type ObjectOptions struct {
 	ServerSideEncryption encrypt.ServerSide
 	UserDefined          map[string]string
+	CheckCopyPrecondFn   CheckCopyPreconditionFn
 }
 
 // LockType represents required locking for ObjectLayer operations

cmd/object-api-utils.go

@@ -422,30 +422,32 @@ type GetObjectReader struct {
 	pReader io.Reader
 
 	cleanUpFns []func()
+	precondFn  func(ObjectInfo, string) bool
 	once       sync.Once
 }
 
 // NewGetObjectReaderFromReader sets up a GetObjectReader with a given
 // reader. This ignores any object properties.
-func NewGetObjectReaderFromReader(r io.Reader, oi ObjectInfo, cleanupFns ...func()) *GetObjectReader {
+func NewGetObjectReaderFromReader(r io.Reader, oi ObjectInfo, pcfn CheckCopyPreconditionFn, cleanupFns ...func()) *GetObjectReader {
 	return &GetObjectReader{
 		ObjInfo:    oi,
 		pReader:    r,
 		cleanUpFns: cleanupFns,
+		precondFn:  pcfn,
 	}
 }
 
 // ObjReaderFn is a function type that takes a reader and returns
 // GetObjectReader and an error. Request headers are passed to provide
 // encryption parameters. cleanupFns allow cleanup funcs to be
 // registered for calling after usage of the reader.
-type ObjReaderFn func(inputReader io.Reader, h http.Header, cleanupFns ...func()) (r *GetObjectReader, err error)
+type ObjReaderFn func(inputReader io.Reader, h http.Header, pcfn CheckCopyPreconditionFn, cleanupFns ...func()) (r *GetObjectReader, err error)
 
 // NewGetObjectReader creates a new GetObjectReader. The cleanUpFns
 // are called on Close() in reverse order as passed here. NOTE: It is
 // assumed that clean up functions do not panic (otherwise, they may
 // not all run!).
-func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func()) (
+func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, pcfn CheckCopyPreconditionFn, cleanUpFns ...func()) (
 	fn ObjReaderFn, off, length int64, err error) {
 
 	// Call the clean-up functions immediately in case of exit
@@ -486,7 +488,7 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 		// a reader that returns the desired range of
 		// encrypted bytes. The header parameter is used to
 		// provide encryption parameters.
-		fn = func(inputReader io.Reader, h http.Header, cFns ...func()) (r *GetObjectReader, err error) {
+		fn = func(inputReader io.Reader, h http.Header, pcfn CheckCopyPreconditionFn, cFns ...func()) (r *GetObjectReader, err error) {
 			copySource := h.Get(crypto.SSECopyAlgorithm) != ""
 
 			cFns = append(cleanUpFns, cFns...)
@@ -501,9 +503,18 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 				}
 				return nil, err
 			}
-
-			// Decrypt the ETag before top layer consumes this value.
-			oi.ETag = getDecryptedETag(h, oi, copySource)
+			encETag := oi.ETag
+			oi.ETag = getDecryptedETag(h, oi, copySource) // Decrypt the ETag before top layer consumes this value.
+
+			if pcfn != nil {
+				if ok := pcfn(oi, encETag); ok {
+					// Call the cleanup funcs
+					for i := len(cFns) - 1; i >= 0; i-- {
+						cFns[i]()
+					}
+					return nil, PreConditionFailed{}
+				}
+			}
 
 			// Apply the skipLen and limit on the
 			// decrypted stream
@@ -514,6 +525,7 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 				ObjInfo:    oi,
 				pReader:    decReader,
 				cleanUpFns: cFns,
+				precondFn:  pcfn,
 			}
 			return r, nil
 		}
@@ -545,7 +557,17 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 				return nil, 0, 0, errInvalidRange
 			}
 		}
-		fn = func(inputReader io.Reader, _ http.Header, cFns ...func()) (r *GetObjectReader, err error) {
+		fn = func(inputReader io.Reader, _ http.Header, pcfn CheckCopyPreconditionFn, cFns ...func()) (r *GetObjectReader, err error) {
+			cFns = append(cleanUpFns, cFns...)
+			if pcfn != nil {
+				if ok := pcfn(oi, ""); ok {
+					// Call the cleanup funcs
+					for i := len(cFns) - 1; i >= 0; i-- {
+						cFns[i]()
+					}
+					return nil, PreConditionFailed{}
+				}
+			}
 			// Decompression reader.
 			snappyReader := snappy.NewReader(inputReader)
 			// Apply the skipLen and limit on the
@@ -557,7 +579,8 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 			r = &GetObjectReader{
 				ObjInfo:    oi,
 				pReader:    decReader,
-				cleanUpFns: append(cleanUpFns, cFns...),
+				cleanUpFns: cFns,
+				precondFn:  pcfn,
 			}
 			return r, nil
 		}
@@ -567,11 +590,22 @@ func NewGetObjectReader(rs *HTTPRangeSpec, oi ObjectInfo, cleanUpFns ...func())
 		if err != nil {
 			return nil, 0, 0, err
 		}
-		fn = func(inputReader io.Reader, _ http.Header, cFns ...func()) (r *GetObjectReader, err error) {
+		fn = func(inputReader io.Reader, _ http.Header, pcfn CheckCopyPreconditionFn, cFns ...func()) (r *GetObjectReader, err error) {
+			cFns = append(cleanUpFns, cFns...)
+			if pcfn != nil {
+				if ok := pcfn(oi, ""); ok {
+					// Call the cleanup funcs
+					for i := len(cFns) - 1; i >= 0; i-- {
+						cFns[i]()
+					}
+					return nil, PreConditionFailed{}
+				}
+			}
 			r = &GetObjectReader{
 				ObjInfo:    oi,
 				pReader:    inputReader,
-				cleanUpFns: append(cleanUpFns, cFns...),
+				cleanUpFns: cFns,
+				precondFn:  pcfn,
 			}
 			return r, nil
 		}

cmd/object-handlers-common.go

@@ -23,6 +23,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/minio/minio/cmd/crypto"
 	"github.com/minio/minio/pkg/event"
 	"github.com/minio/minio/pkg/handlers"
 )
@@ -33,8 +34,8 @@ import (
 //  x-amz-copy-source-if-unmodified-since
 //  x-amz-copy-source-if-match
 //  x-amz-copy-source-if-none-match
-func checkCopyObjectPartPreconditions(ctx context.Context, w http.ResponseWriter, r *http.Request, objInfo ObjectInfo) bool {
-	return checkCopyObjectPreconditions(ctx, w, r, objInfo)
+func checkCopyObjectPartPreconditions(ctx context.Context, w http.ResponseWriter, r *http.Request, objInfo ObjectInfo, encETag string) bool {
+	return checkCopyObjectPreconditions(ctx, w, r, objInfo, encETag)
 }
 
 // Validates the preconditions for CopyObject, returns true if CopyObject operation should not proceed.
@@ -43,7 +44,7 @@ func checkCopyObjectPartPreconditions(ctx context.Context, w http.ResponseWriter
 //  x-amz-copy-source-if-unmodified-since
 //  x-amz-copy-source-if-match
 //  x-amz-copy-source-if-none-match
-func checkCopyObjectPreconditions(ctx context.Context, w http.ResponseWriter, r *http.Request, objInfo ObjectInfo) bool {
+func checkCopyObjectPreconditions(ctx context.Context, w http.ResponseWriter, r *http.Request, objInfo ObjectInfo, encETag string) bool {
 	// Return false for methods other than GET and HEAD.
 	if r.Method != "PUT" {
 		return false
@@ -95,11 +96,13 @@ func checkCopyObjectPreconditions(ctx context.Context, w http.ResponseWriter, r
 		}
 	}
 
+	ssec := crypto.SSECopy.IsRequested(r.Header)
+
 	// x-amz-copy-source-if-match : Return the object only if its entity tag (ETag) is the
 	// same as the one specified; otherwise return a 412 (precondition failed).
 	ifMatchETagHeader := r.Header.Get("x-amz-copy-source-if-match")
 	if ifMatchETagHeader != "" {
-		if objInfo.ETag != "" && !isETagEqual(objInfo.ETag, ifMatchETagHeader) {
+		if objInfo.ETag != "" && (!isETagEqual(objInfo.ETag, ifMatchETagHeader) || (ssec && !isETagEqual(encETag[len(encETag)-32:], ifMatchETagHeader))) {
 			// If the object ETag does not match with the specified ETag.
 			writeHeaders()
 			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrPreconditionFailed), r.URL, guessIsBrowserReq(r))
@@ -111,7 +114,7 @@ func checkCopyObjectPreconditions(ctx context.Context, w http.ResponseWriter, r
 	// one specified otherwise, return a 304 (not modified).
 	ifNoneMatchETagHeader := r.Header.Get("x-amz-copy-source-if-none-match")
 	if ifNoneMatchETagHeader != "" {
-		if objInfo.ETag != "" && isETagEqual(objInfo.ETag, ifNoneMatchETagHeader) {
+		if objInfo.ETag != "" && (isETagEqual(objInfo.ETag, ifNoneMatchETagHeader) || (ssec && isETagEqual(encETag[len(encETag)-32:], ifNoneMatchETagHeader))) {
 			// If the object ETag matches with the specified ETag.
 			writeHeaders()
 			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrPreconditionFailed), r.URL, guessIsBrowserReq(r))

cmd/object-handlers.go

@@ -761,21 +761,22 @@ func (api objectAPIHandlers) CopyObjectHandler(w http.ResponseWriter, r *http.Re
 	if !cpSrcDstSame {
 		lock = readLock
 	}
-
+	checkCopyPrecondFn := func(o ObjectInfo, encETag string) bool {
+		return checkCopyObjectPreconditions(ctx, w, r, o, encETag)
+	}
+	getOpts.CheckCopyPrecondFn = checkCopyPrecondFn
 	var rs *HTTPRangeSpec
 	gr, err := getObjectNInfo(ctx, srcBucket, srcObject, rs, r.Header, lock, getOpts)
 	if err != nil {
+		if isErrPreconditionFailed(err) {
+			return
+		}
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
 		return
 	}
 	defer gr.Close()
 	srcInfo := gr.ObjInfo
 
-	// Verify before x-amz-copy-source preconditions before continuing with CopyObject.
-	if checkCopyObjectPreconditions(ctx, w, r, srcInfo) {
-		return
-	}
-
 	/// maximum Upload size for object in a single CopyObject operation.
 	if isMaxObjectSize(srcInfo.Size) {
 		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrEntityTooLarge), r.URL, guessIsBrowserReq(r))
@@ -1597,9 +1598,16 @@ func (api objectAPIHandlers) CopyObjectPartHandler(w http.ResponseWriter, r *htt
 
 		}
 	}
+	checkCopyPartPrecondFn := func(o ObjectInfo, encETag string) bool {
+		return checkCopyObjectPartPreconditions(ctx, w, r, o, encETag)
+	}
+	getOpts.CheckCopyPrecondFn = checkCopyPartPrecondFn
 
 	gr, err := getObjectNInfo(ctx, srcBucket, srcObject, rs, r.Header, readLock, getOpts)
 	if err != nil {
+		if isErrPreconditionFailed(err) {
+			return
+		}
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
 		return
 	}
@@ -1621,11 +1629,6 @@ func (api objectAPIHandlers) CopyObjectPartHandler(w http.ResponseWriter, r *htt
 		return
 	}
 
-	// Verify before x-amz-copy-source preconditions before continuing with CopyObject.
-	if checkCopyObjectPartPreconditions(ctx, w, r, srcInfo) {
-		return
-	}
-
 	// Get the object offset & length
 	startOffset, length, err := rs.GetOffsetLength(actualPartSize)
 	if err != nil {