Retrieve remote file size without the Content-Size header (#1537)

* Get downloaded file size regardless of the Content-Size header

Signed-off-by: Florian Le Minoux <darkgallium+git@deuxfleurs.fr>

* fixing lint issues

* Don't exhaust memory for large files, don't limit more than necessary

* Don't use errors.Wrap in download.go

Co-authored-by: Neil Alexander <neilalexander@users.noreply.github.com>
This commit is contained in:
darkgallium 2021-02-17 14:54:53 +01:00 committed by GitHub
parent 2386e0c7af
commit da797c7998
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 62 additions and 29 deletions

View File

@ -109,7 +109,7 @@ func RemoveDir(dir types.Path, logger *log.Entry) {
// WriteTempFile writes to a new temporary file. // WriteTempFile writes to a new temporary file.
// The file is deleted if there was an error while writing. // The file is deleted if there was an error while writing.
func WriteTempFile( func WriteTempFile(
ctx context.Context, reqReader io.Reader, maxFileSizeBytes config.FileSizeBytes, absBasePath config.Path, ctx context.Context, reqReader io.Reader, absBasePath config.Path,
) (hash types.Base64Hash, size types.FileSizeBytes, path types.Path, err error) { ) (hash types.Base64Hash, size types.FileSizeBytes, path types.Path, err error) {
size = -1 size = -1
logger := util.GetLogger(ctx) logger := util.GetLogger(ctx)
@ -124,18 +124,11 @@ func WriteTempFile(
} }
}() }()
// If the max_file_size_bytes configuration option is set to a positive
// number then limit the upload to that size. Otherwise, just read the
// whole file.
limitedReader := reqReader
if maxFileSizeBytes > 0 {
limitedReader = io.LimitReader(reqReader, int64(maxFileSizeBytes))
}
// Hash the file data. The hash will be returned. The hash is useful as a // Hash the file data. The hash will be returned. The hash is useful as a
// method of deduplicating files to save storage, as well as a way to conduct // method of deduplicating files to save storage, as well as a way to conduct
// integrity checks on the file data in the repository. // integrity checks on the file data in the repository.
hasher := sha256.New() hasher := sha256.New()
teeReader := io.TeeReader(limitedReader, hasher) teeReader := io.TeeReader(reqReader, hasher)
bytesWritten, err := io.Copy(tmpFileWriter, teeReader) bytesWritten, err := io.Copy(tmpFileWriter, teeReader)
if err != nil && err != io.EOF { if err != nil && err != io.EOF {
RemoveDir(tmpDir, logger) RemoveDir(tmpDir, logger)

View File

@ -19,6 +19,7 @@ import (
"encoding/json" "encoding/json"
"fmt" "fmt"
"io" "io"
"io/ioutil"
"mime" "mime"
"net/http" "net/http"
"net/url" "net/url"
@ -214,7 +215,7 @@ func (r *downloadRequest) doDownload(
ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin, ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin,
) )
if err != nil { if err != nil {
return nil, errors.Wrap(err, "error querying the database") return nil, fmt.Errorf("db.GetMediaMetadata: %w", err)
} }
if mediaMetadata == nil { if mediaMetadata == nil {
if r.MediaMetadata.Origin == cfg.Matrix.ServerName { if r.MediaMetadata.Origin == cfg.Matrix.ServerName {
@ -253,16 +254,16 @@ func (r *downloadRequest) respondFromLocalFile(
) (*types.MediaMetadata, error) { ) (*types.MediaMetadata, error) {
filePath, err := fileutils.GetPathFromBase64Hash(r.MediaMetadata.Base64Hash, absBasePath) filePath, err := fileutils.GetPathFromBase64Hash(r.MediaMetadata.Base64Hash, absBasePath)
if err != nil { if err != nil {
return nil, errors.Wrap(err, "failed to get file path from metadata") return nil, fmt.Errorf("fileutils.GetPathFromBase64Hash: %w", err)
} }
file, err := os.Open(filePath) file, err := os.Open(filePath)
defer file.Close() // nolint: errcheck, staticcheck, megacheck defer file.Close() // nolint: errcheck, staticcheck, megacheck
if err != nil { if err != nil {
return nil, errors.Wrap(err, "failed to open file") return nil, fmt.Errorf("os.Open: %w", err)
} }
stat, err := file.Stat() stat, err := file.Stat()
if err != nil { if err != nil {
return nil, errors.Wrap(err, "failed to stat file") return nil, fmt.Errorf("file.Stat: %w", err)
} }
if r.MediaMetadata.FileSizeBytes > 0 && int64(r.MediaMetadata.FileSizeBytes) != stat.Size() { if r.MediaMetadata.FileSizeBytes > 0 && int64(r.MediaMetadata.FileSizeBytes) != stat.Size() {
@ -324,7 +325,7 @@ func (r *downloadRequest) respondFromLocalFile(
w.Header().Set("Content-Security-Policy", contentSecurityPolicy) w.Header().Set("Content-Security-Policy", contentSecurityPolicy)
if _, err := io.Copy(w, responseFile); err != nil { if _, err := io.Copy(w, responseFile); err != nil {
return nil, errors.Wrap(err, "failed to copy from cache") return nil, fmt.Errorf("io.Copy: %w", err)
} }
return responseMetadata, nil return responseMetadata, nil
} }
@ -421,7 +422,7 @@ func (r *downloadRequest) getThumbnailFile(
ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin, ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin,
) )
if err != nil { if err != nil {
return nil, nil, errors.Wrap(err, "error looking up thumbnails") return nil, nil, fmt.Errorf("db.GetThumbnails: %w", err)
} }
// If we get a thumbnailSize, a pre-generated thumbnail would be best but it is not yet generated. // If we get a thumbnailSize, a pre-generated thumbnail would be best but it is not yet generated.
@ -459,12 +460,12 @@ func (r *downloadRequest) getThumbnailFile(
thumbFile, err := os.Open(string(thumbPath)) thumbFile, err := os.Open(string(thumbPath))
if err != nil { if err != nil {
thumbFile.Close() // nolint: errcheck thumbFile.Close() // nolint: errcheck
return nil, nil, errors.Wrap(err, "failed to open file") return nil, nil, fmt.Errorf("os.Open: %w", err)
} }
thumbStat, err := thumbFile.Stat() thumbStat, err := thumbFile.Stat()
if err != nil { if err != nil {
thumbFile.Close() // nolint: errcheck thumbFile.Close() // nolint: errcheck
return nil, nil, errors.Wrap(err, "failed to stat file") return nil, nil, fmt.Errorf("thumbFile.Stat: %w", err)
} }
if types.FileSizeBytes(thumbStat.Size()) != thumbnail.MediaMetadata.FileSizeBytes { if types.FileSizeBytes(thumbStat.Size()) != thumbnail.MediaMetadata.FileSizeBytes {
thumbFile.Close() // nolint: errcheck thumbFile.Close() // nolint: errcheck
@ -491,7 +492,7 @@ func (r *downloadRequest) generateThumbnail(
activeThumbnailGeneration, maxThumbnailGenerators, db, r.Logger, activeThumbnailGeneration, maxThumbnailGenerators, db, r.Logger,
) )
if err != nil { if err != nil {
return nil, errors.Wrap(err, "error creating thumbnail") return nil, fmt.Errorf("thumbnailer.GenerateThumbnail: %w", err)
} }
if busy { if busy {
return nil, nil return nil, nil
@ -502,7 +503,7 @@ func (r *downloadRequest) generateThumbnail(
thumbnailSize.Width, thumbnailSize.Height, thumbnailSize.ResizeMethod, thumbnailSize.Width, thumbnailSize.Height, thumbnailSize.ResizeMethod,
) )
if err != nil { if err != nil {
return nil, errors.Wrap(err, "error looking up thumbnail") return nil, fmt.Errorf("db.GetThumbnail: %w", err)
} }
return thumbnail, nil return thumbnail, nil
} }
@ -543,7 +544,7 @@ func (r *downloadRequest) getRemoteFile(
ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin, ctx, r.MediaMetadata.MediaID, r.MediaMetadata.Origin,
) )
if err != nil { if err != nil {
return errors.Wrap(err, "error querying the database.") return fmt.Errorf("db.GetMediaMetadata: %w", err)
} }
if mediaMetadata == nil { if mediaMetadata == nil {
@ -555,7 +556,7 @@ func (r *downloadRequest) getRemoteFile(
cfg.MaxThumbnailGenerators, cfg.MaxThumbnailGenerators,
) )
if err != nil { if err != nil {
return errors.Wrap(err, "error querying the database.") return fmt.Errorf("r.fetchRemoteFileAndStoreMetadata: %w", err)
} }
} else { } else {
// If we have a record, we can respond from the local file // If we have a record, we can respond from the local file
@ -673,6 +674,43 @@ func (r *downloadRequest) fetchRemoteFileAndStoreMetadata(
return nil return nil
} }
func (r *downloadRequest) GetContentLengthAndReader(contentLengthHeader string, body *io.ReadCloser, maxFileSizeBytes config.FileSizeBytes) (int64, io.Reader, error) {
reader := *body
var contentLength int64
if contentLengthHeader != "" {
// A Content-Length header is provided. Let's try to parse it.
parsedLength, parseErr := strconv.ParseInt(contentLengthHeader, 10, 64)
if parseErr != nil {
r.Logger.WithError(parseErr).Warn("Failed to parse content length")
return 0, nil, fmt.Errorf("strconv.ParseInt: %w", parseErr)
}
if parsedLength > int64(maxFileSizeBytes) {
return 0, nil, fmt.Errorf(
"remote file size (%d bytes) exceeds locally configured max media size (%d bytes)",
parsedLength, maxFileSizeBytes,
)
}
// We successfully parsed the Content-Length, so we'll return a limited
// reader that restricts us to reading only up to this size.
reader = ioutil.NopCloser(io.LimitReader(*body, parsedLength))
contentLength = parsedLength
} else {
// Content-Length header is missing. If we have a maximum file size
// configured then we'll just make sure that the reader is limited to
// that size. We'll return a zero content length, but that's OK, since
// ultimately it will get rewritten later when the temp file is written
// to disk.
if maxFileSizeBytes > 0 {
reader = ioutil.NopCloser(io.LimitReader(*body, int64(maxFileSizeBytes)))
}
contentLength = 0
}
return contentLength, reader, nil
}
func (r *downloadRequest) fetchRemoteFile( func (r *downloadRequest) fetchRemoteFile(
ctx context.Context, ctx context.Context,
client *gomatrixserverlib.Client, client *gomatrixserverlib.Client,
@ -692,16 +730,18 @@ func (r *downloadRequest) fetchRemoteFile(
} }
defer resp.Body.Close() // nolint: errcheck defer resp.Body.Close() // nolint: errcheck
// get metadata from request and set metadata on response // The reader returned here will be limited either by the Content-Length
contentLength, err := strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 64) // and/or the configured maximum media size.
if err != nil { contentLength, reader, parseErr := r.GetContentLengthAndReader(resp.Header.Get("Content-Length"), &resp.Body, maxFileSizeBytes)
r.Logger.WithError(err).Warn("Failed to parse content length") if parseErr != nil {
return "", false, errors.Wrap(err, "invalid response from remote server") return "", false, parseErr
} }
if contentLength > int64(maxFileSizeBytes) { if contentLength > int64(maxFileSizeBytes) {
// TODO: Bubble up this as a 413 // TODO: Bubble up this as a 413
return "", false, fmt.Errorf("remote file is too large (%v > %v bytes)", contentLength, maxFileSizeBytes) return "", false, fmt.Errorf("remote file is too large (%v > %v bytes)", contentLength, maxFileSizeBytes)
} }
r.MediaMetadata.FileSizeBytes = types.FileSizeBytes(contentLength) r.MediaMetadata.FileSizeBytes = types.FileSizeBytes(contentLength)
r.MediaMetadata.ContentType = types.ContentType(resp.Header.Get("Content-Type")) r.MediaMetadata.ContentType = types.ContentType(resp.Header.Get("Content-Type"))
@ -728,7 +768,7 @@ func (r *downloadRequest) fetchRemoteFile(
// method of deduplicating files to save storage, as well as a way to conduct // method of deduplicating files to save storage, as well as a way to conduct
// integrity checks on the file data in the repository. // integrity checks on the file data in the repository.
// Data is truncated to maxFileSizeBytes. Content-Length was reported as 0 < Content-Length <= maxFileSizeBytes so this is OK. // Data is truncated to maxFileSizeBytes. Content-Length was reported as 0 < Content-Length <= maxFileSizeBytes so this is OK.
hash, bytesWritten, tmpDir, err := fileutils.WriteTempFile(ctx, resp.Body, maxFileSizeBytes, absBasePath) hash, bytesWritten, tmpDir, err := fileutils.WriteTempFile(ctx, reader, absBasePath)
if err != nil { if err != nil {
r.Logger.WithError(err).WithFields(log.Fields{ r.Logger.WithError(err).WithFields(log.Fields{
"MaxFileSizeBytes": maxFileSizeBytes, "MaxFileSizeBytes": maxFileSizeBytes,
@ -747,7 +787,7 @@ func (r *downloadRequest) fetchRemoteFile(
// The database is the source of truth so we need to have moved the file first // The database is the source of truth so we need to have moved the file first
finalPath, duplicate, err := fileutils.MoveFileWithHashCheck(tmpDir, r.MediaMetadata, absBasePath, r.Logger) finalPath, duplicate, err := fileutils.MoveFileWithHashCheck(tmpDir, r.MediaMetadata, absBasePath, r.Logger)
if err != nil { if err != nil {
return "", false, errors.Wrap(err, "failed to move file") return "", false, fmt.Errorf("fileutils.MoveFileWithHashCheck: %w", err)
} }
if duplicate { if duplicate {
r.Logger.WithField("dst", finalPath).Info("File was stored previously - discarding duplicate") r.Logger.WithField("dst", finalPath).Info("File was stored previously - discarding duplicate")

View File

@ -147,7 +147,7 @@ func (r *uploadRequest) doUpload(
// r.storeFileAndMetadata(ctx, tmpDir, ...) // r.storeFileAndMetadata(ctx, tmpDir, ...)
// before you return from doUpload else we will leak a temp file. We could make this nicer with a `WithTransaction` style of // before you return from doUpload else we will leak a temp file. We could make this nicer with a `WithTransaction` style of
// nested function to guarantee either storage or cleanup. // nested function to guarantee either storage or cleanup.
hash, bytesWritten, tmpDir, err := fileutils.WriteTempFile(ctx, reqReader, *cfg.MaxFileSizeBytes, cfg.AbsBasePath) hash, bytesWritten, tmpDir, err := fileutils.WriteTempFile(ctx, reqReader, cfg.AbsBasePath)
if err != nil { if err != nil {
r.Logger.WithError(err).WithFields(log.Fields{ r.Logger.WithError(err).WithFields(log.Fields{
"MaxFileSizeBytes": *cfg.MaxFileSizeBytes, "MaxFileSizeBytes": *cfg.MaxFileSizeBytes,