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Diffstat (limited to 'filesystem/filesystem.go')
-rw-r--r--filesystem/filesystem.go148
1 files changed, 64 insertions, 84 deletions
diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index 434826b..960c06f 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -33,7 +33,6 @@
package filesystem
import (
- "errors"
"fmt"
"io/ioutil"
"log"
@@ -42,41 +41,26 @@ import (
"strings"
"github.com/golang/protobuf/proto"
+ "github.com/pkg/errors"
"golang.org/x/sys/unix"
"fscrypt/metadata"
"fscrypt/util"
)
-// FSError is the error type returned by all Mount methods. It contains an
-// error value as well as the corresponding filesystem path. The error value
-// is generally one of the errors defined in this package or an underlying
-// error from the operating system.
-type FSError struct {
- Path string
- Err error
-}
-
-func (m FSError) Error() string {
- return fmt.Sprintf("filesystem %q: %v", m.Path, m.Err)
-}
-
// Filesystem error values
var (
- ErrBadLoad = util.SystemError("couldn't load mountpoint info")
- ErrRootNotMount = util.SystemError("reached root directory without finding a mountpoint")
- ErrInvalidMount = errors.New("invalid mountpoint provided")
- ErrNotSetup = errors.New("not setup for use with fscrypt")
+ ErrNotAMountpoint = errors.New("not a mountpoint")
ErrAlreadySetup = errors.New("already setup for use with fscrypt")
- ErrBadState = util.SystemError("metadata directory in bad state: rerun setup")
+ ErrNotSetup = errors.New("not setup for use with fscrypt")
+ ErrNoMetadata = errors.New("could not find metadata")
+ ErrLinkedProtector = errors.New("not a regular protector")
ErrInvalidMetadata = errors.New("provided metadata is invalid")
- ErrCorruptMetadata = util.SystemError("metadata is corrupt")
- ErrNoMetadata = errors.New("no metadata could be found for the provided descriptor")
- ErrLinkedProtector = errors.New("descriptor corresponds to a linked protector")
- ErrCannotLink = util.SystemError("cannot create filesystem link")
- ErrNoLink = util.SystemError("link does not point to a valid filesystem")
- ErrOldLink = util.SystemError("link points to filesystems not using fscrypt")
- ErrNoSupport = errors.New("this filesystem does not support encryption")
+ ErrFollowLink = errors.New("cannot follow filesystem link")
+ ErrLinkExpired = errors.New("no longer exists on linked filesystem")
+ ErrMakeLink = util.SystemError("cannot create filesystem link")
+ ErrGlobalMountInfo = util.SystemError("creating global mountpoint list failed")
+ ErrCorruptMetadata = util.SystemError("on-disk metadata is corrupt")
)
// Mount contains information for a specific mounted filesystem.
@@ -138,24 +122,24 @@ const (
func (m *Mount) String() string {
return fmt.Sprintf(`%s
Filsystem: %s
- Options: %v
- Device: %s`, m.Path, m.Filesystem, m.Options, m.Device)
+ Options: %v
+ Device: %s`, m.Path, m.Filesystem, m.Options, m.Device)
}
-// baseDir returns the path of the base fscrypt directory on this filesystem.
-func (m *Mount) baseDir() string {
+// BaseDir returns the path of the base fscrypt directory on this filesystem.
+func (m *Mount) BaseDir() string {
return filepath.Join(m.Path, baseDirName)
}
-// protectorDir returns the directory containing the protector metadata.
-func (m *Mount) protectorDir() string {
- return filepath.Join(m.baseDir(), protectorDirName)
+// ProtectorDir returns the directory containing the protector metadata.
+func (m *Mount) ProtectorDir() string {
+ return filepath.Join(m.BaseDir(), protectorDirName)
}
// protectorPath returns the full path to a regular protector file with the
// specified descriptor.
func (m *Mount) protectorPath(descriptor string) string {
- return filepath.Join(m.protectorDir(), descriptor)
+ return filepath.Join(m.ProtectorDir(), descriptor)
}
// linkedProtectorPath returns the full path to a linked protector file with the
@@ -164,15 +148,15 @@ func (m *Mount) linkedProtectorPath(descriptor string) string {
return m.protectorPath(descriptor) + linkFileExtension
}
-// policyDir returns the directory containing the policy metadata.
-func (m *Mount) policyDir() string {
- return filepath.Join(m.baseDir(), policyDirName)
+// PolicyDir returns the directory containing the policy metadata.
+func (m *Mount) PolicyDir() string {
+ return filepath.Join(m.BaseDir(), policyDirName)
}
// policyPath returns the full path to a regular policy file with the
// specified descriptor.
func (m *Mount) policyPath(descriptor string) string {
- return filepath.Join(m.policyDir(), descriptor)
+ return filepath.Join(m.PolicyDir(), descriptor)
}
// tempMount creates a temporary Mount under the main directory. The path for
@@ -182,28 +166,22 @@ func (m *Mount) tempMount() (*Mount, error) {
return &Mount{Path: trashDir}, err
}
-// err creates a FSErr for this filesystem with the provided error. If the
-// passed error is an OS error, the full error is logged, but only the
-// underlying error is used in the message. If the message is nil, nil is
-// returned.
+// err modifies an error to contain the path of this filesystem.
func (m *Mount) err(err error) error {
- if err == nil {
- return nil
- }
-
- return FSError{
- Path: m.Path,
- Err: util.UnderlyingError(err),
- }
+ return errors.Wrapf(err, "filesystem %s", m.Path)
}
-// CheckSetup returns an error if all the fscrypt metadata directories exist.
-// Will log any unexpected errors, or if any permissions are incorrect.
+// CheckSetup returns an error if this filesystem does not support fscrypt or
+// all the fscrypt metadata directories do not exist. Will log any unexpected
+// errors or incorrect permissions.
func (m *Mount) CheckSetup() error {
+ if err := metadata.CheckSupport(m.Path); err != nil {
+ return m.err(err)
+ }
// Run all the checks so we will always get all the warnings
- baseGood := isDirCheckPerm(m.baseDir(), basePermissions)
- policyGood := isDirCheckPerm(m.policyDir(), dirPermissions)
- protectorGood := isDirCheckPerm(m.protectorDir(), dirPermissions)
+ baseGood := isDirCheckPerm(m.BaseDir(), basePermissions)
+ policyGood := isDirCheckPerm(m.PolicyDir(), dirPermissions)
+ protectorGood := isDirCheckPerm(m.ProtectorDir(), dirPermissions)
if baseGood && policyGood && protectorGood {
return nil
@@ -220,13 +198,13 @@ func (m *Mount) makeDirectories() error {
unix.Umask(oldMask)
}()
- if err := os.Mkdir(m.baseDir(), basePermissions); err != nil {
+ if err := os.Mkdir(m.BaseDir(), basePermissions); err != nil {
return err
}
- if err := os.Mkdir(m.policyDir(), dirPermissions); err != nil {
+ if err := os.Mkdir(m.PolicyDir(), dirPermissions); err != nil {
return err
}
- return os.Mkdir(m.protectorDir(), dirPermissions)
+ return os.Mkdir(m.ProtectorDir(), dirPermissions)
}
// Setup sets up the filesystem for use with fscrypt, note that this merely
@@ -234,8 +212,13 @@ func (m *Mount) makeDirectories() error {
// the filesystem's feature flags. This operation is atomic, it either succeeds
// or no files in the baseDir are created.
func (m *Mount) Setup() error {
- if m.CheckSetup() == nil {
+ switch err := m.CheckSetup(); errors.Cause(err) {
+ case ErrNotSetup:
+ break
+ case nil:
return m.err(ErrAlreadySetup)
+ default:
+ return err
}
// We build the directories under a temp Mount and then move into place.
temp, err := m.tempMount()
@@ -248,13 +231,8 @@ func (m *Mount) Setup() error {
return m.err(err)
}
- // Move directory into place. If the base directory exists despite our
- // earlier check that we were not setup, we are in bad state.
- err = os.Rename(temp.baseDir(), m.baseDir())
- if os.IsExist(err) {
- err = ErrBadState
- }
- return m.err(err)
+ // Atomically move directory into place.
+ return m.err(os.Rename(temp.BaseDir(), m.BaseDir()))
}
// RemoveAllMetadata removes all the policy and protector metadata from the
@@ -274,7 +252,7 @@ func (m *Mount) RemoveAllMetadata() error {
defer os.RemoveAll(temp.Path)
// Move directory into temp (to be destroyed on defer)
- return m.err(os.Rename(m.baseDir(), temp.baseDir()))
+ return m.err(os.Rename(m.BaseDir(), temp.BaseDir()))
}
// writeDataAtomic writes the data to the path such that the data is either
@@ -283,8 +261,7 @@ func (m *Mount) writeDataAtomic(path string, data []byte) error {
// Write the file to a temporary file then move into place so that the
// operation will be atomic.
tempPath := filepath.Join(filepath.Dir(path), tempPrefix+filepath.Base(path))
- // We use O_SYNC so the write actually gets to stable storage.
- tempFile, err := os.OpenFile(tempPath, os.O_WRONLY|os.O_CREATE|os.O_SYNC, filePermissions)
+ tempFile, err := os.OpenFile(tempPath, os.O_WRONLY|os.O_CREATE, filePermissions)
if err != nil {
return err
}
@@ -304,8 +281,8 @@ func (m *Mount) writeDataAtomic(path string, data []byte) error {
// addMetadata writes the metadata structure to the file with the specified
// path this will overwrite any existing data. The operation is atomic.
func (m *Mount) addMetadata(path string, md metadata.Metadata) error {
- if !md.IsValid() {
- return ErrInvalidMetadata
+ if err := md.CheckValidity(); err != nil {
+ return errors.Wrap(ErrInvalidMetadata, err.Error())
}
data, err := proto.Marshal(md)
@@ -322,20 +299,20 @@ func (m *Mount) addMetadata(path string, md metadata.Metadata) error {
func (m *Mount) getMetadata(path string, md metadata.Metadata) error {
data, err := ioutil.ReadFile(path)
if err != nil {
+ log.Printf("could not read metadata at %q", path)
if os.IsNotExist(err) {
- return ErrNoMetadata
+ return errors.Wrapf(ErrNoMetadata, "descriptor %s", filepath.Base(path))
}
return err
}
- if err = proto.Unmarshal(data, md); err != nil {
- log.Print(err)
- return ErrCorruptMetadata
+ if err := proto.Unmarshal(data, md); err != nil {
+ return errors.Wrap(ErrCorruptMetadata, err.Error())
}
- if !md.IsValid() {
- log.Printf("data retrieved at %q is not valid", path)
- return ErrCorruptMetadata
+ if err := md.CheckValidity(); err != nil {
+ log.Printf("metadata at %q is not valid", path)
+ return errors.Wrap(ErrCorruptMetadata, err.Error())
}
log.Printf("successfully read metadata from %q", path)
@@ -346,8 +323,9 @@ func (m *Mount) getMetadata(path string, md metadata.Metadata) error {
// path. Works with regular or linked metadata.
func (m *Mount) removeMetadata(path string) error {
if err := os.Remove(path); err != nil {
+ log.Printf("could not remove metadata at %q", path)
if os.IsNotExist(err) {
- return ErrNoMetadata
+ return errors.Wrapf(ErrNoMetadata, "descriptor %s", filepath.Base(path))
}
return err
}
@@ -429,11 +407,13 @@ func (m *Mount) GetProtector(descriptor string) (*Mount, *metadata.ProtectorData
}
for _, mnt := range mnts {
- if data, err := mnt.GetRegularProtector(descriptor); err == nil {
+ if data, err := mnt.GetRegularProtector(descriptor); err != nil {
+ log.Print(err)
+ } else {
return mnt, data, nil
}
}
- return nil, nil, m.err(ErrOldLink)
+ return nil, nil, m.err(errors.Wrapf(ErrLinkExpired, "protector %s", descriptor))
}
// RemoveProtector deletes the protector metadata (or an link to another
@@ -445,7 +425,7 @@ func (m *Mount) RemoveProtector(descriptor string) error {
// We first try to remove the linkedProtector. If that metadata does not
// exist, we try to remove the normal protector.
err := m.removeMetadata(m.linkedProtectorPath(descriptor))
- if err == ErrNoMetadata {
+ if errors.Cause(err) == ErrNoMetadata {
err = m.removeMetadata(m.protectorPath(descriptor))
}
return m.err(err)
@@ -457,7 +437,7 @@ func (m *Mount) ListProtectors() ([]string, error) {
if err := m.CheckSetup(); err != nil {
return nil, err
}
- protectors, err := m.listDirectory(m.protectorDir())
+ protectors, err := m.listDirectory(m.ProtectorDir())
return protectors, m.err(err)
}
@@ -492,7 +472,7 @@ func (m *Mount) ListPolicies() ([]string, error) {
if err := m.CheckSetup(); err != nil {
return nil, err
}
- policies, err := m.listDirectory(m.policyDir())
+ policies, err := m.listDirectory(m.PolicyDir())
return policies, m.err(err)
}
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-10 17:03:37 +0000