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lib/protocol: Add some consistency checks on incoming index updates (fixes #4053)

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With this change we will throw a protocol error on some kinds of
malformed index entries.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4064
This commit is contained in:
Jakob Borg
2017-03-27 07:21:08 +00:00
committed by Audrius Butkevicius
parent 1ad547fb65
commit b75b4190c8
2 changed files with 85 additions and 4 deletions
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35
lib/protocol/protocol.go
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@@ -57,6 +57,9 @@ var (
errUnknownMessage = errors.New("unknown message")
errInvalidFilename = errors.New("filename is invalid")
errUncleanFilename = errors.New("filename not in canonical format")
errDeletedHasBlocks = errors.New("deleted file with non-empty block list")
errDirectoryHasBlocks = errors.New("directory with non-empty block list")
errFileHasNoBlocks = errors.New("file with empty block list")
)
type Model interface {
@@ -308,7 +311,7 @@ func (c *rawConnection) readerLoop() (err error) {
if state != stateReady {
return fmt.Errorf("protocol error: index message in state %d", state)
}
if err := checkFilenames(msg.Files); err != nil {
if err := checkIndexConsistency(msg.Files); err != nil {
return fmt.Errorf("protocol error: index: %v", err)
}
c.handleIndex(*msg)
@@ -319,7 +322,7 @@ func (c *rawConnection) readerLoop() (err error) {
if state != stateReady {
return fmt.Errorf("protocol error: index update message in state %d", state)
}
if err := checkFilenames(msg.Files); err != nil {
if err := checkIndexConsistency(msg.Files); err != nil {
return fmt.Errorf("protocol error: index update: %v", err)
}
c.handleIndexUpdate(*msg)
@@ -466,15 +469,39 @@ func (c *rawConnection) handleIndexUpdate(im IndexUpdate) {
c.receiver.IndexUpdate(c.id, im.Folder, im.Files)
}
func checkFilenames(fs []FileInfo) error {
// checkIndexConsistency verifies a number of invariants on FileInfos received in
// index messages.
func checkIndexConsistency(fs []FileInfo) error {
for _, f := range fs {
if err := checkFilename(f.Name); err != nil {
if err := checkFileInfoConsistency(f); err != nil {
return fmt.Errorf("%q: %v", f.Name, err)
}
}
return nil
}
// checkFileInfoConsistency verifies a number of invariants on the given FileInfo
func checkFileInfoConsistency(f FileInfo) error {
if err := checkFilename(f.Name); err != nil {
return err
}
switch {
case f.Deleted && len(f.Blocks) != 0:
// Deleted files should have no blocks
return errDeletedHasBlocks
case f.Type == FileInfoTypeDirectory && len(f.Blocks) != 0:
// Directories should have no blocks
return errDirectoryHasBlocks
case !f.Deleted && f.Type == FileInfoTypeFile && len(f.Blocks) == 0:
// Non-deleted files should have at least one block
return errFileHasNoBlocks
}
return nil
}
// checkFilename verifies that the given filename is valid according to the
// spec on what's allowed over the wire. A filename failing this test is
// grounds for disconnecting the device.