1 files changed, 203 insertions, 0 deletions
diff --git a/workhorse/internal/upload/rewrite.go b/workhorse/internal/upload/rewrite.go
new file mode 100644
index 00000000000..e51604c6ed9
--- /dev/null
+++ b/workhorse/internal/upload/rewrite.go
@@ -0,0 +1,203 @@
+package upload
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"strings"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"gitlab.com/gitlab-org/labkit/log"
+
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/api"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/filestore"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/lsif_transformer/parser"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/upload/exif"
+)
+
+// ErrInjectedClientParam means that the client sent a parameter that overrides one of our own fields
+var ErrInjectedClientParam = errors.New("injected client parameter")
+
+var (
+	multipartUploadRequests = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+
+			Name: "gitlab_workhorse_multipart_upload_requests",
+			Help: "How many multipart upload requests have been processed by gitlab-workhorse. Partitioned by type.",
+		},
+		[]string{"type"},
+	)
+
+	multipartFileUploadBytes = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitlab_workhorse_multipart_upload_bytes",
+			Help: "How many disk bytes of multipart file parts have been successfully written by gitlab-workhorse. Partitioned by type.",
+		},
+		[]string{"type"},
+	)
+
+	multipartFiles = promauto.NewCounterVec(
+		prometheus.CounterOpts{
+			Name: "gitlab_workhorse_multipart_upload_files",
+			Help: "How many multipart file parts have been processed by gitlab-workhorse. Partitioned by type.",
+		},
+		[]string{"type"},
+	)
+)
+
+type rewriter struct {
+	writer          *multipart.Writer
+	preauth         *api.Response
+	filter          MultipartFormProcessor
+	finalizedFields map[string]bool
+}
+
+func rewriteFormFilesFromMultipart(r *http.Request, writer *multipart.Writer, preauth *api.Response, filter MultipartFormProcessor, opts *filestore.SaveFileOpts) error {
+	// Create multipart reader
+	reader, err := r.MultipartReader()
+	if err != nil {
+		if err == http.ErrNotMultipart {
+			// We want to be able to recognize http.ErrNotMultipart elsewhere so no fmt.Errorf
+			return http.ErrNotMultipart
+		}
+		return fmt.Errorf("get multipart reader: %v", err)
+	}
+
+	multipartUploadRequests.WithLabelValues(filter.Name()).Inc()
+
+	rew := &rewriter{
+		writer:          writer,
+		preauth:         preauth,
+		filter:          filter,
+		finalizedFields: make(map[string]bool),
+	}
+
+	for {
+		p, err := reader.NextPart()
+		if err != nil {
+			if err == io.EOF {
+				break
+			}
+			return err
+		}
+
+		name := p.FormName()
+		if name == "" {
+			continue
+		}
+
+		if rew.finalizedFields[name] {
+			return ErrInjectedClientParam
+		}
+
+		if p.FileName() != "" {
+			err = rew.handleFilePart(r.Context(), name, p, opts)
+		} else {
+			err = rew.copyPart(r.Context(), name, p)
+		}
+
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (rew *rewriter) handleFilePart(ctx context.Context, name string, p *multipart.Part, opts *filestore.SaveFileOpts) error {
+	multipartFiles.WithLabelValues(rew.filter.Name()).Inc()
+
+	filename := p.FileName()
+
+	if strings.Contains(filename, "/") || filename == "." || filename == ".." {
+		return fmt.Errorf("illegal filename: %q", filename)
+	}
+
+	opts.TempFilePrefix = filename
+
+	var inputReader io.ReadCloser
+	var err error
+	switch {
+	case exif.IsExifFile(filename):
+		inputReader, err = handleExifUpload(ctx, p, filename)
+		if err != nil {
+			return err
+		}
+	case rew.preauth.ProcessLsif:
+		inputReader, err = handleLsifUpload(ctx, p, opts.LocalTempPath, filename, rew.preauth)
+		if err != nil {
+			return err
+		}
+	default:
+		inputReader = ioutil.NopCloser(p)
+	}
+
+	defer inputReader.Close()
+
+	fh, err := filestore.SaveFileFromReader(ctx, inputReader, -1, opts)
+	if err != nil {
+		switch err {
+		case filestore.ErrEntityTooLarge, exif.ErrRemovingExif:
+			return err
+		default:
+			return fmt.Errorf("persisting multipart file: %v", err)
+		}
+	}
+
+	fields, err := fh.GitLabFinalizeFields(name)
+	if err != nil {
+		return fmt.Errorf("failed to finalize fields: %v", err)
+	}
+
+	for key, value := range fields {
+		rew.writer.WriteField(key, value)
+		rew.finalizedFields[key] = true
+	}
+
+	multipartFileUploadBytes.WithLabelValues(rew.filter.Name()).Add(float64(fh.Size))
+
+	return rew.filter.ProcessFile(ctx, name, fh, rew.writer)
+}
+
+func handleExifUpload(ctx context.Context, r io.Reader, filename string) (io.ReadCloser, error) {
+	log.WithContextFields(ctx, log.Fields{
+		"filename": filename,
+	}).Print("running exiftool to remove any metadata")
+
+	cleaner, err := exif.NewCleaner(ctx, r)
+	if err != nil {
+		return nil, err
+	}
+
+	return cleaner, nil
+}
+
+func handleLsifUpload(ctx context.Context, reader io.Reader, tempPath, filename string, preauth *api.Response) (io.ReadCloser, error) {
+	parserConfig := parser.Config{
+		TempPath: tempPath,
+	}
+
+	return parser.NewParser(ctx, reader, parserConfig)
+}
+
+func (rew *rewriter) copyPart(ctx context.Context, name string, p *multipart.Part) error {
+	np, err := rew.writer.CreatePart(p.Header)
+	if err != nil {
+		return fmt.Errorf("create multipart field: %v", err)
+	}
+
+	if _, err := io.Copy(np, p); err != nil {
+		return fmt.Errorf("duplicate multipart field: %v", err)
+	}
+
+	if err := rew.filter.ProcessField(ctx, name, rew.writer); err != nil {
+		return fmt.Errorf("process multipart field: %v", err)
+	}
+
+	return nil
+}