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-rw-r--r--crypto/crypto.go46
-rw-r--r--crypto/key.go95
-rw-r--r--crypto/rand.go9
-rw-r--r--filesystem/filesystem.go148
-rw-r--r--filesystem/filesystem_test.go23
-rw-r--r--filesystem/mountpoint.go76
-rw-r--r--filesystem/mountpoint_test.go9
-rw-r--r--filesystem/path.go10
-rw-r--r--metadata/checks.go193
-rw-r--r--metadata/policy.go111
-rw-r--r--metadata/policy_test.go13
-rw-r--r--pam/login.go14
-rw-r--r--util/errors.go45
13 files changed, 386 insertions, 406 deletions
diff --git a/crypto/crypto.go b/crypto/crypto.go
index c6d6619..967243d 100644
--- a/crypto/crypto.go
+++ b/crypto/crypto.go
@@ -46,9 +46,9 @@ import (
"crypto/sha256"
"crypto/sha512"
"encoding/hex"
- "errors"
"unsafe"
+ "github.com/pkg/errors"
"golang.org/x/crypto/hkdf"
"fscrypt/metadata"
@@ -57,34 +57,29 @@ import (
// Crypto error values
var (
- ErrBadAuth = errors.New("key authentication check failed")
- ErrNegitiveLength = errors.New("negative length requested for key")
- ErrKeyAlloc = util.SystemError("could not allocate memory for key")
- ErrKeyFree = util.SystemError("could not free memory of key")
- ErrKeyringLocate = util.SystemError("could not locate the session keyring")
- ErrKeyringInsert = util.SystemError("could not insert key into the session keyring")
- ErrKeyringSearch = util.SystemError("could not find key in the session keyring")
- ErrKeyringDelete = util.SystemError("could not delete key from the session keyring")
- ErrRecoveryCode = errors.New("provided recovery code had incorrect format")
- ErrLowEntropy = util.SystemError("insufficient entropy in pool to generate random bytes")
- ErrRandNotSupported = util.SystemError("getrandom() not implemented; kernel must be v3.17 or later")
- ErrRandFailed = util.SystemError("cannot get random bytes")
+ ErrBadAuth = errors.New("key authentication check failed")
+ ErrNegitiveLength = errors.New("keys cannot have negative lengths")
+ ErrRecoveryCode = errors.New("invalid recovery code")
+ ErrGetrandomFail = util.SystemError("getrandom() failed")
+ ErrKeyAlloc = util.SystemError("could not allocate memory for key")
+ ErrKeyFree = util.SystemError("could not free memory of key")
+ ErrKeyringLocate = util.SystemError("could not locate the session keyring")
+ ErrKeyringInsert = util.SystemError("could not insert key into the session keyring")
+ ErrKeyringSearch = errors.New("could not find key with descriptor")
+ ErrKeyringDelete = util.SystemError("could not delete key from the session keyring")
)
// panicInputLength panics if "name" has invalid length (expected != actual)
func panicInputLength(name string, expected, actual int) {
- if expected != actual {
- util.NeverError(util.InvalidLengthError(name, expected, actual))
+ if err := util.CheckValidLength(expected, actual); err != nil {
+ panic(errors.Wrap(err, name))
}
}
// checkWrappingKey returns an error if the wrapping key has the wrong length
func checkWrappingKey(wrappingKey *Key) error {
- l := wrappingKey.Len()
- if l != metadata.InternalKeyLen {
- return util.InvalidLengthError("wrapping key", metadata.InternalKeyLen, l)
- }
- return nil
+ err := util.CheckValidLength(metadata.InternalKeyLen, wrappingKey.Len())
+ return errors.Wrap(err, "wrapping key")
}
// stretchKey stretches a key of length KeyLen using unsalted HKDF to make two
@@ -140,14 +135,14 @@ func getHMAC(key *Key, data ...[]byte) []byte {
// and an HMAC to verify the wrapping key was correct. All of this is included
// in the returned WrappedKeyData structure.
func Wrap(wrappingKey, secretKey *Key) (*metadata.WrappedKeyData, error) {
- err := checkWrappingKey(wrappingKey)
- if err != nil {
+ if err := checkWrappingKey(wrappingKey); err != nil {
return nil, err
}
data := &metadata.WrappedKeyData{EncryptedKey: make([]byte, secretKey.Len())}
// Get random IV
+ var err error
if data.IV, err = NewRandomBuffer(metadata.IVLen); err != nil {
return nil, err
}
@@ -251,8 +246,11 @@ use it in "id" mode to provide extra protection against side-channel
attacks. For more info see: https://github.com/P-H-C/phc-winner-argon2
*/
func PassphraseHash(passphrase *Key, salt []byte, costs *metadata.HashingCosts) (*Key, error) {
- if len(salt) != metadata.SaltLen {
- return nil, util.InvalidLengthError("salt", metadata.SaltLen, len(salt))
+ if err := util.CheckValidLength(metadata.SaltLen, len(salt)); err != nil {
+ return nil, errors.Wrap(err, "passphrase hashing salt")
+ }
+ if err := costs.CheckValidity(); err != nil {
+ return nil, errors.Wrap(err, "passphrase hashing costs")
}
// This key will hold the hashing output
diff --git a/crypto/key.go b/crypto/key.go
index 852b213..2394eef 100644
--- a/crypto/key.go
+++ b/crypto/key.go
@@ -30,6 +30,8 @@ import (
"runtime"
"unsafe"
+ "github.com/pkg/errors"
+
"golang.org/x/sys/unix"
"fscrypt/metadata"
@@ -98,8 +100,7 @@ func newBlankKey(length int) (*Key, error) {
if length == 0 {
return &Key{data: nil}, nil
} else if length < 0 {
- log.Printf("key length of %d is invalid", length)
- return nil, ErrNegitiveLength
+ return nil, errors.Wrapf(ErrNegitiveLength, "length of %d requested", length)
}
flags := keyMmapFlags
@@ -123,9 +124,11 @@ func newBlankKey(length int) (*Key, error) {
// Wipe destroys a Key by zeroing and freeing the memory. The data is zeroed
// even if Wipe returns an error, which occurs if we are unable to unlock or
-// free the key memory. Calling Wipe() multiple times on a key has no effect.
+// free the key memory. Wipe does nothing if the key is already wiped or is nil.
func (key *Key) Wipe() error {
- if key.data != nil {
+ // We do nothing if key or key.data is nil so that Wipe() is idempotent
+ // and so Wipe() can be called on keys which have already been cleared.
+ if key != nil && key.data != nil {
data := key.data
key.data = nil
@@ -224,56 +227,50 @@ func NewFixedLengthKeyFromReader(reader io.Reader, length int) (*Key, error) {
return key, nil
}
-// addPayloadToSessionKeyring adds the payload to the current session keyring as
-// type logon, returning an error on failure.
-func addPayloadToSessionKeyring(payload []byte, description string) error {
- // We cannot add directly to KEY_SPEC_SESSION_KEYRING, as that will make
- // a new session keyring if one does not exist, which will be garbage
- // collected when the process terminates. Instead, we first get the ID
- // of the KEY_SPEC_SESSION_KEYRING, which will return the user session
- // keyring if a session keyring does not exist.
+// getKeyring returns the id of the session keyring, or the id of the user
+// session keyring if session keyring does not exist. We cannot directly use
+// KEY_SPEC_SESSION_KEYRING, as that will make a new session keyring if one does
+// not exist, which will be garbage collected when the process terminates.
+func getKeyring() (int, error) {
keyringID, err := unix.KeyctlGetKeyringID(unix.KEY_SPEC_SESSION_KEYRING, false)
log.Printf("unix.KeyctlGetKeyringID(KEY_SPEC_SESSION_KEYRING) = %d, %v", keyringID, err)
if err != nil {
- return ErrKeyringLocate
+ return 0, errors.Wrap(ErrKeyringLocate, err.Error())
}
+ return keyringID, nil
+}
- keyID, err := unix.AddKey(keyType, description, payload, keyringID)
- log.Printf("unix.AddKey(%s, %s, <payload>, %d) = %d, %v",
- keyType, description, keyringID, keyID, err)
+// FindPolicyKey tries to locate a policy key in the kernel keyring with the
+// provided descriptor and service. The keyring and key ids are returned if we
+// can find the key. An error is returned if the key does not exist.
+func FindPolicyKey(descriptor, service string) (keyringID, keyID int, err error) {
+ keyringID, err = getKeyring()
if err != nil {
- return ErrKeyringInsert
+ return
}
- return nil
-}
-// FindPolicyKey tries to locate a policy key in the kernel keyring with the
-// provided descriptor and service. The key id is returned if we can find the
-// key. An error is returned if the key does not exist.
-func FindPolicyKey(descriptor, service string) (int, error) {
description := service + descriptor
- keyID, err := unix.KeyctlSearch(unix.KEY_SPEC_SESSION_KEYRING, keyType, description, 0)
- log.Printf("unix.KeyctlSearch(KEY_SPEC_SESSION_KEYRING, %s, %s, 0) = %d, %v",
- keyType, description, keyID, err)
+ keyID, err = unix.KeyctlSearch(keyringID, keyType, description, 0)
+ log.Printf("unix.KeyctlSearch(%d, %s, %s) = %d, %v", keyringID, keyType, description, keyID, err)
if err != nil {
- return 0, ErrKeyringSearch
+ err = errors.Wrap(ErrKeyringSearch, err.Error())
}
- return keyID, nil
+ return
}
// RemovePolicyKey tries to remove a policy key from the kernel keyring with the
// provided descriptor and service. An error is returned if the key does not
// exist.
func RemovePolicyKey(descriptor, service string) error {
- keyID, err := FindPolicyKey(descriptor, service)
+ keyringID, keyID, err := FindPolicyKey(descriptor, service)
if err != nil {
return err
}
- _, err = unix.KeyctlInt(unix.KEYCTL_UNLINK, keyID, unix.KEY_SPEC_SESSION_KEYRING, 0, 0)
- log.Printf("unix.KeyctlUnlink(%d, KEY_SPEC_SESSION_KEYRING) = %v", keyID, err)
+ _, err = unix.KeyctlInt(unix.KEYCTL_UNLINK, keyID, keyringID, 0, 0)
+ log.Printf("unix.KeyctlUnlink(%d, %d) = %v", keyID, keyringID, err)
if err != nil {
- return ErrKeyringDelete
+ return errors.Wrap(ErrKeyringDelete, err.Error())
}
return nil
}
@@ -282,12 +279,11 @@ func RemovePolicyKey(descriptor, service string) error {
// provided descriptor, provided service prefix, and type logon. The key and
// descriptor must have the appropriate lengths.
func InsertPolicyKey(key *Key, descriptor, service string) error {
- if key.Len() != metadata.PolicyKeyLen {
- return util.InvalidLengthError("Policy Key", metadata.PolicyKeyLen, key.Len())
+ if err := util.CheckValidLength(metadata.PolicyKeyLen, key.Len()); err != nil {
+ return errors.Wrap(err, "policy key")
}
-
- if len(descriptor) != metadata.DescriptorLen {
- return util.InvalidLengthError("Descriptor", metadata.DescriptorLen, len(descriptor))
+ if err := util.CheckValidLength(metadata.DescriptorLen, len(descriptor)); err != nil {
+ return errors.Wrap(err, "descriptor")
}
// Create our payload (containing an FscryptKey)
@@ -304,10 +300,18 @@ func InsertPolicyKey(key *Key, descriptor, service string) error {
fscryptKey.Size = metadata.PolicyKeyLen
copy(fscryptKey.Raw[:], key.data)
- if err := addPayloadToSessionKeyring(payload.data, service+descriptor); err != nil {
+ keyringID, err := getKeyring()
+ if err != nil {
return err
}
+ description := service + descriptor
+ keyID, err := unix.AddKey(keyType, description, payload.data, keyringID)
+ log.Printf("unix.AddKey(%s, %s, <payload>, %d) = %d, %v",
+ keyType, description, keyringID, keyID, err)
+ if err != nil {
+ return errors.Wrap(ErrKeyringInsert, err.Error())
+ }
return nil
}
@@ -326,8 +330,8 @@ var (
// WARNING: This recovery key is enough to derive the original key, so it must
// be given the same level of protection as a raw cryptographic key.
func WriteRecoveryCode(key *Key, writer io.Writer) error {
- if key.Len() != metadata.PolicyKeyLen {
- return util.InvalidLengthError("key", metadata.PolicyKeyLen, key.Len())
+ if err := util.CheckValidLength(metadata.PolicyKeyLen, key.Len()); err != nil {
+ return errors.Wrap(err, "recovery key")
}
// We store the base32 encoded data (without separators) in a temp key
@@ -374,8 +378,8 @@ func ReadRecoveryCode(reader io.Reader) (*Key, error) {
for blockStart := blockSize; blockStart < encodedLength; blockStart += blockSize {
r.Read(inputSeparator)
if r.Err() == nil && !bytes.Equal(separator, inputSeparator) {
- log.Printf("separator of %q is invalid", inputSeparator)
- return nil, ErrRecoveryCode
+ err := errors.Wrapf(ErrRecoveryCode, "invalid seperator %q", inputSeparator)
+ return nil, err
}
blockEnd := util.MinInt(blockStart+blockSize, encodedLength)
@@ -384,8 +388,7 @@ func ReadRecoveryCode(reader io.Reader) (*Key, error) {
// If any reads have failed, return the error
if r.Err() != nil {
- log.Printf("error while reading recovery code: %v", r.Err())
- return nil, ErrRecoveryCode
+ return nil, errors.Wrapf(ErrRecoveryCode, "read error %v", r.Err())
}
// Now we decode the key, resizing if necessary
@@ -394,9 +397,7 @@ func ReadRecoveryCode(reader io.Reader) (*Key, error) {
return nil, err
}
if _, err = encoding.Decode(decodedKey.data, encodedKey.data); err != nil {
- decodedKey.Wipe()
- log.Printf("error decoding recovery code: %v", err)
- return nil, ErrRecoveryCode
+ return nil, errors.Wrap(ErrRecoveryCode, err.Error())
}
return decodedKey.resize(metadata.PolicyKeyLen)
}
diff --git a/crypto/rand.go b/crypto/rand.go
index d2948d0..0778ebd 100644
--- a/crypto/rand.go
+++ b/crypto/rand.go
@@ -21,8 +21,8 @@ package crypto
import (
"io"
- "log"
+ "github.com/pkg/errors"
"golang.org/x/sys/unix"
)
@@ -58,11 +58,10 @@ func (r randReader) Read(buffer []byte) (int, error) {
case nil:
return n, nil
case unix.EAGAIN:
- return 0, ErrLowEntropy
+ return 0, errors.Wrap(ErrGetrandomFail, "insufficient entropy in pool")
case unix.ENOSYS:
- return 0, ErrRandNotSupported
+ return 0, errors.Wrap(ErrGetrandomFail, "kernel must be v3.17 or later")
default:
- log.Printf("unix.Getrandom failed: %v", err)
- return 0, ErrRandFailed
+ return 0, errors.Wrap(ErrGetrandomFail, err.Error())
}
}
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)
}
diff --git a/filesystem/filesystem_test.go b/filesystem/filesystem_test.go
index 33ab10b..bcf4f38 100644
--- a/filesystem/filesystem_test.go
+++ b/filesystem/filesystem_test.go
@@ -20,14 +20,16 @@
package filesystem
import (
- "fmt"
"os"
"path/filepath"
"reflect"
"testing"
+ "github.com/pkg/errors"
+
. "fscrypt/crypto"
. "fscrypt/metadata"
+ . "fscrypt/util"
)
var (
@@ -37,17 +39,14 @@ var (
wrappedPolicyKey, _ = Wrap(fakeProtectorKey, fakePolicyKey)
)
-// Gets the mount corresponding to TEST_FILESYSTEM_ROOT
+// Gets the mount corresponding to the integration test path.
func getTestMount() (*Mount, error) {
- mountpoint := os.Getenv("TEST_FILESYSTEM_ROOT")
- if mountpoint == "" {
- return nil, fmt.Errorf("set TEST_FILESYSTEM_ROOT to a mountpoint")
- }
- mnt, err := GetMount(mountpoint)
+ mountpoint, err := TestPath()
if err != nil {
- return nil, fmt.Errorf("bad TEST_FILESYSTEM_ROOT: %s", err)
+ return nil, err
}
- return mnt, nil
+ mnt, err := GetMount(mountpoint)
+ return mnt, errors.Wrapf(err, TestEnvVarName)
}
func getFakeProtector() *ProtectorData {
@@ -92,7 +91,7 @@ func TestSetup(t *testing.T) {
t.Error(err)
}
- os.RemoveAll(mnt.baseDir())
+ os.RemoveAll(mnt.BaseDir())
}
// Tests that we can remove all of the metadata
@@ -106,7 +105,7 @@ func TestRemoveAllMetadata(t *testing.T) {
t.Fatal(err)
}
- if isDir(mnt.baseDir()) {
+ if isDir(mnt.BaseDir()) {
t.Error("metadata was not removed")
}
}
@@ -279,7 +278,7 @@ func TestLinkedProtector(t *testing.T) {
// Get the protector though the second system
_, err = fakeMnt.GetRegularProtector(protector.ProtectorDescriptor)
- if err == nil || err.(FSError).Err != ErrNoMetadata {
+ if errors.Cause(err) != ErrNoMetadata {
t.Fatal(err)
}
diff --git a/filesystem/mountpoint.go b/filesystem/mountpoint.go
index 1a4b10f..1fc41be 100644
--- a/filesystem/mountpoint.go
+++ b/filesystem/mountpoint.go
@@ -42,10 +42,11 @@ import (
"fmt"
"log"
"path/filepath"
+ "sort"
"strings"
"sync"
- "fscrypt/metadata"
+ "github.com/pkg/errors"
)
var (
@@ -75,7 +76,8 @@ func getMountInfo() error {
// Load the mount information from mountpoints_filename
fileHandle := C.setmntent(C.mountpoints_filename, C.read_mode)
if fileHandle == nil {
- return ErrBadLoad
+ return errors.Wrapf(ErrGlobalMountInfo, "could not read %q",
+ C.GoString(C.mountpoints_filename))
}
defer C.endmntent(fileHandle)
@@ -84,7 +86,7 @@ func getMountInfo() error {
C.blkid_put_cache(cache)
}
if C.blkid_get_cache(&cache, nil) != 0 {
- return ErrBadLoad
+ return errors.Wrap(ErrGlobalMountInfo, "could not read blkid cache")
}
for {
@@ -105,11 +107,12 @@ func getMountInfo() error {
// Skip invalid mountpoints
var err error
if mnt.Path, err = cannonicalizePath(mnt.Path); err != nil {
- log.Print(err)
+ log.Printf("getting mnt_dir: %v", err)
continue
}
// We can only use mountpoints that are directories for fscrypt.
if !isDir(mnt.Path) {
+ log.Printf("mnt_dir %v: not a directory", mnt.Path)
continue
}
@@ -127,41 +130,22 @@ func getMountInfo() error {
}
}
-// checkSupport returns an error if the specified mount does not support
-// filesystem-level encryption.
-func checkSupport(mount *Mount) error {
- // Getting a policy on a filesystem which supports encryption should
- // either return the policy or say there isn't one. Anything else
- // indicates a problem with support.
- _, err := metadata.GetPolicy(mount.Path)
- if err == nil || err == metadata.ErrNotEncrypted {
- log.Printf("%s filesystem at %q supports encryption (got %v)",
- mount.Filesystem, mount.Path, err)
- return nil
- }
-
- log.Printf("%s filesystem at %q probably doesn't support encryption (got %v)",
- mount.Filesystem, mount.Path, err)
- return err
-}
-
-// AllSupportedFilesystems lists all the Mounts which could support filesystem
-// encryption. This doesn't mean they necessarily do or that they are being used
-// with fscrypt.
-func AllSupportedFilesystems() ([]*Mount, error) {
+// AllFilesystems lists all the Mounts on the current system ordered by path.
+// Use CheckSetup() to see if they are used with fscrypt.
+func AllFilesystems() ([]*Mount, error) {
mountMutex.Lock()
defer mountMutex.Unlock()
if err := getMountInfo(); err != nil {
return nil, err
}
- var supportedMounts []*Mount
- for _, mount := range mountsByPath {
- if checkSupport(mount) == nil {
- supportedMounts = append(supportedMounts, mount)
- }
+ mounts := make([]*Mount, len(mountsByPath))
+ for i, mount := range mountsByPath {
+ mounts[i] = mount
}
- return supportedMounts, nil
+
+ sort.Sort(PathSorter(mounts))
+ return mounts, nil
}
// UpdateMountInfo updates the filesystem mountpoint maps with the current state
@@ -176,9 +160,9 @@ func UpdateMountInfo() error {
// FindMount returns the corresponding Mount object for some path in a
// filesystem. Note that in the case of a bind mounts there may be two Mount
// objects for the same underlying filesystem. An error is returned if the path
-// is invalid, we cannot load the required mount data, or the filesystem does
-// not support filesystem encryption. If a filesystem has been updated since the
-// last call to one of the mount functions, run UpdateMountInfo to see changes.
+// is invalid or we cannot load the required mount data. If a filesystem has
+// been updated since the last call to one of the mount functions, run
+// UpdateMountInfo to see changes.
func FindMount(path string) (*Mount, error) {
path, err := cannonicalizePath(path)
if err != nil {
@@ -194,23 +178,22 @@ func FindMount(path string) (*Mount, error) {
// Traverse up the directory tree until we find a mountpoint
for {
if mnt, ok := mountsByPath[path]; ok {
- return mnt, checkSupport(mnt)
+ return mnt, nil
}
// Move to the parent directory unless we have reached the root.
parent := filepath.Dir(path)
if parent == path {
- return nil, ErrRootNotMount
+ return nil, errors.Wrap(ErrNotAMountpoint, path)
}
path = parent
}
}
// GetMount returns the Mount object with a matching mountpoint. An error is
-// returned if the path is invalid, we cannot load the required mount data, or
-// the filesystem does not support filesystem encryption. If a filesystem has
-// been updated since the last call to one of the mount functions, run
-// UpdateMountInfo to see changes.
+// returned if the path is invalid or we cannot load the required mount data. If
+// a filesystem has been updated since the last call to one of the mount
+// functions, run UpdateMountInfo to see changes.
func GetMount(mountpoint string) (*Mount, error) {
mountpoint, err := cannonicalizePath(mountpoint)
if err != nil {
@@ -224,11 +207,10 @@ func GetMount(mountpoint string) (*Mount, error) {
}
if mnt, ok := mountsByPath[mountpoint]; ok {
- return mnt, checkSupport(mnt)
+ return mnt, nil
}
- log.Printf("%q is not a filesystem mountpoint", mountpoint)
- return nil, ErrInvalidMount
+ return nil, errors.Wrap(ErrNotAMountpoint, mountpoint)
}
// getMountsFromLink returns the Mount objects which match the provided link.
@@ -251,7 +233,7 @@ func getMountsFromLink(link string) ([]*Mount, error) {
log.Printf("blkid_evaluate_spec(%q, <cache>) = %q", link, deviceName)
if deviceName == "" {
- return nil, ErrNoLink
+ return nil, errors.Wrapf(ErrFollowLink, "link %q is invalid", link)
}
deviceName, err := cannonicalizePath(deviceName)
if err != nil {
@@ -268,7 +250,7 @@ func getMountsFromLink(link string) ([]*Mount, error) {
return mnts, nil
}
- return nil, ErrNoLink
+ return nil, errors.Wrapf(ErrFollowLink, "device %q is invalid", deviceName)
}
// makeLink returns a link of the form <token>=<value> where value is the tag
@@ -297,7 +279,7 @@ func makeLink(mnt *Mount, token string) (string, error) {
log.Printf("blkid_get_tag_value(<cache>, %s, %s) = %s", token, deviceEntry, value)
if value == "" {
- return "", ErrCannotLink
+ return "", errors.Wrapf(ErrMakeLink, "no %s", token)
}
return fmt.Sprintf("%s=%s", token, C.GoString(cValue)), nil
}
diff --git a/filesystem/mountpoint_test.go b/filesystem/mountpoint_test.go
index 5523451..5d53dc1 100644
--- a/filesystem/mountpoint_test.go
+++ b/filesystem/mountpoint_test.go
@@ -39,14 +39,6 @@ func printMountInfo() {
}
}
-func printSupportedMounts() {
- fmt.Println("\nSupported Mountpoints:")
- mnts, _ := AllSupportedFilesystems()
- for _, mnt := range mnts {
- fmt.Println(mnt)
- }
-}
-
func TestLoadMountInfo(t *testing.T) {
if err := UpdateMountInfo(); err != nil {
t.Error(err)
@@ -56,7 +48,6 @@ func TestLoadMountInfo(t *testing.T) {
func TestPrintMountInfo(t *testing.T) {
// Uncomment to see the mount info in the tests
// printMountInfo()
- // printSupportedMounts()
// t.Fail()
}
diff --git a/filesystem/path.go b/filesystem/path.go
index 3be1859..d788a6b 100644
--- a/filesystem/path.go
+++ b/filesystem/path.go
@@ -23,6 +23,8 @@ import (
"log"
"os"
"path/filepath"
+
+ "github.com/pkg/errors"
)
// We only check the unix permissions and the sticky bit
@@ -34,8 +36,14 @@ func cannonicalizePath(path string) (string, error) {
if err != nil {
return "", err
}
+ path, err = filepath.EvalSymlinks(path)
+
+ // Get a better error if we have an invalid path
+ if pathErr, ok := err.(*os.PathError); ok {
+ err = errors.Wrap(pathErr.Err, pathErr.Path)
+ }
- return filepath.EvalSymlinks(path)
+ return path, err
}
// loggedStat runs os.Stat, but it logs the error if stat returns any error
diff --git a/metadata/checks.go b/metadata/checks.go
index 5d0ce59..074d79e 100644
--- a/metadata/checks.go
+++ b/metadata/checks.go
@@ -20,178 +20,177 @@
package metadata
import (
- "log"
-
"github.com/golang/protobuf/proto"
+ "github.com/pkg/errors"
"fscrypt/util"
)
+var errNotInitialized = errors.New("not initialized")
+
// Metadata is the interface to all of the protobuf structures that can be
-// checked with the IsValid method.
+// checked for validity.
type Metadata interface {
- IsValid() bool
+ CheckValidity() error
proto.Message
}
-// checkValidLength returns true if expected == actual, otherwise it logs an
-// InvalidLengthError.
-func checkValidLength(name string, expected int, actual int) bool {
- if expected != actual {
- log.Print(util.InvalidLengthError(name, expected, actual))
- return false
+// CheckValidity ensures the mode has a name and isn't empty.
+func (m EncryptionOptions_Mode) CheckValidity() error {
+ if m == EncryptionOptions_default {
+ return errNotInitialized
}
- return true
-}
-
-// IsValid ensures the mode has a name and isn't empty.
-func (m EncryptionOptions_Mode) IsValid() bool {
if m.String() == "" {
- log.Print("Encryption mode cannot be the empty string")
- return false
- }
- if m == EncryptionOptions_default {
- log.Print("Encryption mode must be set to a non-default value")
- return false
+ return errors.Errorf("unknown %d", m)
}
- return true
+ return nil
}
-// IsValid ensures the source has a name and isn't empty.
-func (s SourceType) IsValid() bool {
- if s.String() == "" {
- log.Print("SourceType cannot be the empty string")
- return false
- }
+// CheckValidity ensures the source has a name and isn't empty.
+func (s SourceType) CheckValidity() error {
if s == SourceType_default {
- log.Print("SourceType must be set to a non-default value")
- return false
+ return errNotInitialized
+ }
+ if s.String() == "" {
+ return errors.Errorf("unknown %d", s)
}
- return true
+ return nil
}
-// IsValid ensures the hash costs will be accepted by Argon2.
-func (h *HashingCosts) IsValid() bool {
+// CheckValidity ensures the hash costs will be accepted by Argon2.
+func (h *HashingCosts) CheckValidity() error {
if h == nil {
- log.Print("HashingCosts not initialized")
- return false
+ return errNotInitialized
}
- if h.Time == 0 {
- log.Print("Hashing time cost not initialized")
- return false
+ if h.Time <= 0 {
+ return errors.Errorf("time=%d is not positive", h.Time)
}
- if h.Parallelism == 0 {
- log.Print("Hashing parallelism cost not initialized")
- return false
+ if h.Parallelism <= 0 {
+ return errors.Errorf("parallelism=%d is not positive", h.Parallelism)
}
minMemory := 8 * h.Parallelism
if h.Memory < minMemory {
- log.Printf("Hashing memory cost must be at least %d", minMemory)
- return false
+ return errors.Errorf("memory=%d is less than minimum (%d)", h.Memory, minMemory)
}
- return true
+ return nil
}
-// IsValid ensures our buffers are the correct length (or just exist).
-func (w *WrappedKeyData) IsValid() bool {
+// CheckValidity ensures our buffers are the correct length.
+func (w *WrappedKeyData) CheckValidity() error {
if w == nil {
- log.Print("WrappedKeyData not initialized")
- return false
+ return errNotInitialized
}
if len(w.EncryptedKey) == 0 {
- log.Print("EncryptedKey not initialized")
- return false
+ return errors.Wrap(errNotInitialized, "encrypted key")
+ }
+ if err := util.CheckValidLength(IVLen, len(w.IV)); err != nil {
+ return errors.Wrap(err, "IV")
}
- return checkValidLength("IV", IVLen, len(w.IV)) &&
- checkValidLength("HMAC", HMACLen, len(w.Hmac))
+ return errors.Wrap(util.CheckValidLength(HMACLen, len(w.Hmac)), "HMAC")
}
-// IsValid ensures our ProtectorData has the correct fields for its source.
-func (p *ProtectorData) IsValid() bool {
+// CheckValidity ensures our ProtectorData has the correct fields for its source.
+func (p *ProtectorData) CheckValidity() error {
if p == nil {
- log.Print("ProtectorData not initialized")
- return false
+ return errNotInitialized
+ }
+
+ if err := p.Source.CheckValidity(); err != nil {
+ return errors.Wrap(err, "protector source")
}
// Source specific checks
switch p.Source {
case SourceType_pam_passphrase:
if p.Uid < 0 {
- log.Print("The UID should never be negative")
- return false
+ return errors.Errorf("UID=%d is negative", p.Uid)
}
fallthrough
case SourceType_custom_passphrase:
- if !p.Costs.IsValid() || !checkValidLength("Salt", SaltLen, len(p.Salt)) {
- return false
+ if err := p.Costs.CheckValidity(); err != nil {
+ return errors.Wrap(err, "passphrase hashing costs")
+ }
+ if err := util.CheckValidLength(SaltLen, len(p.Salt)); err != nil {
+ return errors.Wrap(err, "passphrase hashing salt")
}
}
// Generic checks
- return p.Source.IsValid() &&
- p.WrappedKey.IsValid() &&
- checkValidLength("EncryptedKey", InternalKeyLen, len(p.WrappedKey.EncryptedKey)) &&
- checkValidLength("ProtectorDescriptor", DescriptorLen, len(p.ProtectorDescriptor))
+ if err := p.WrappedKey.CheckValidity(); err != nil {
+ return errors.Wrap(err, "wrapped protector key")
+ }
+ if err := util.CheckValidLength(DescriptorLen, len(p.ProtectorDescriptor)); err != nil {
+ return errors.Wrap(err, "protector descriptor")
+ }
+ err := util.CheckValidLength(InternalKeyLen, len(p.WrappedKey.EncryptedKey))
+ return errors.Wrap(err, "encrypted protector key")
}
-// IsValid ensures each of the options is valid.
-func (e *EncryptionOptions) IsValid() bool {
+// CheckValidity ensures each of the options is valid.
+func (e *EncryptionOptions) CheckValidity() error {
if e == nil {
- log.Print("EncryptionOptions not initialized")
- return false
+ return errNotInitialized
}
if _, ok := util.Index(e.Padding, paddingArray); !ok {
- log.Printf("Padding of %d is invalid", e.Padding)
- return false
+ return errors.Errorf("padding of %d is invalid", e.Padding)
}
-
- return e.Contents.IsValid() && e.Filenames.IsValid()
+ if err := e.Contents.CheckValidity(); err != nil {
+ return errors.Wrap(err, "contents encryption mode")
+ }
+ return errors.Wrap(e.Filenames.CheckValidity(), "filenames encryption mode")
}
-// IsValid ensures the fields are valid and have the correct lengths.
-func (w *WrappedPolicyKey) IsValid() bool {
+// CheckValidity ensures the fields are valid and have the correct lengths.
+func (w *WrappedPolicyKey) CheckValidity() error {
if w == nil {
- log.Print("WrappedPolicyKey not initialized")
- return false
+ return errNotInitialized
}
- return w.WrappedKey.IsValid() &&
- checkValidLength("EncryptedKey", PolicyKeyLen, len(w.WrappedKey.EncryptedKey)) &&
- checkValidLength("ProtectorDescriptor", DescriptorLen, len(w.ProtectorDescriptor))
+ if err := w.WrappedKey.CheckValidity(); err != nil {
+ return errors.Wrap(err, "wrapped key")
+ }
+ if err := util.CheckValidLength(PolicyKeyLen, len(w.WrappedKey.EncryptedKey)); err != nil {
+ return errors.Wrap(err, "encrypted key")
+ }
+ err := util.CheckValidLength(DescriptorLen, len(w.ProtectorDescriptor))
+ return errors.Wrap(err, "wrapping protector descriptor")
}
-// IsValid ensures the fields and each wrapped key are valid.
-func (p *PolicyData) IsValid() bool {
+// CheckValidity ensures the fields and each wrapped key are valid.
+func (p *PolicyData) CheckValidity() error {
if p == nil {
- log.Print("PolicyData not initialized")
- return false
+ return errNotInitialized
}
// Check each wrapped key
- for _, w := range p.WrappedPolicyKeys {
- if !w.IsValid() {
- return false
+ for i, w := range p.WrappedPolicyKeys {
+ if err := w.CheckValidity(); err != nil {
+ return errors.Wrapf(err, "policy key slot %d", i)
}
}
- return p.Options.IsValid() &&
- checkValidLength("KeyDescriptor", DescriptorLen, len(p.KeyDescriptor))
+ if err := util.CheckValidLength(DescriptorLen, len(p.KeyDescriptor)); err != nil {
+ return errors.Wrap(err, "policy key descriptor")
+ }
+
+ return errors.Wrap(p.Options.CheckValidity(), "policy options")
}
-// IsValid ensures the Config has all the necessary info for its Source.
-func (c *Config) IsValid() bool {
+// CheckValidity ensures the Config has all the necessary info for its Source.
+func (c *Config) CheckValidity() error {
// General checks
if c == nil {
- log.Print("Config not initialized")
- return false
+ return errNotInitialized
}
- if !c.Source.IsValid() || !c.Options.IsValid() {
- return false
+ if err := c.Source.CheckValidity(); err != nil {
+ return errors.Wrap(err, "default config source")
}
// Source specific checks
switch c.Source {
case SourceType_pam_passphrase, SourceType_custom_passphrase:
- return c.HashCosts.IsValid()
- default:
- return true
+ if err := c.HashCosts.CheckValidity(); err != nil {
+ return errors.Wrap(err, "config hashing costs")
+ }
}
+
+ return errors.Wrap(c.Options.CheckValidity(), "config options")
}
diff --git a/metadata/policy.go b/metadata/policy.go
index ac2fde7..259fe04 100644
--- a/metadata/policy.go
+++ b/metadata/policy.go
@@ -22,12 +22,12 @@ package metadata
import (
"encoding/hex"
- "errors"
- "fmt"
"log"
+ "math"
"os"
"unsafe"
+ "github.com/pkg/errors"
"golang.org/x/sys/unix"
"fscrypt/util"
@@ -35,25 +35,18 @@ import (
// Encryption specific errors
var (
- ErrEncryptionNotSupported = errors.New("filesystem encryption not supported")
- ErrEncryptionDisabled = errors.New("filesystem encryption disabled in the kernel config")
+ ErrEncryptionNotSupported = errors.New("encryption not supported")
+ ErrEncryptionNotEnabled = errors.New("encryption not enabled")
ErrNotEncrypted = errors.New("file or directory not encrypted")
ErrEncrypted = errors.New("file or directory already encrypted")
ErrBadEncryptionOptions = util.SystemError("invalid encryption options provided")
)
-// policyIoctl is a wrapper for the ioctl syscall. If opens the file at the path
-// and passes the correct pointers and file descriptors to the IOCTL syscall.
-// This function also takes some of the unclear errors returned by the syscall
-// and translates then into more specific error strings.
-func policyIoctl(path string, request uintptr, policy *unix.FscryptPolicy) error {
- file, err := os.Open(path)
- if err != nil {
- // For PathErrors, we just want the underlying error
- return util.UnderlyingError(err)
- }
- defer file.Close()
-
+// policyIoctl is a wrapper for the ioctl syscall. It passes the correct
+// pointers and file descriptors to the IOCTL syscall. This function also takes
+// some of the unclear errors returned by the syscall and translates then into
+// more specific error strings.
+func policyIoctl(file *os.File, request uintptr, policy *unix.FscryptPolicy) error {
// The returned errno value can sometimes give strange errors, so we
// return encryption specific errors.
_, _, errno := unix.Syscall(unix.SYS_IOCTL, file.Fd(), request, uintptr(unsafe.Pointer(policy)))
@@ -63,7 +56,7 @@ func policyIoctl(path string, request uintptr, policy *unix.FscryptPolicy) error
case unix.ENOTTY:
return ErrEncryptionNotSupported
case unix.EOPNOTSUPP:
- return ErrEncryptionDisabled
+ return ErrEncryptionNotEnabled
case unix.ENODATA, unix.ENOENT:
// ENOENT was returned instead of ENODATA on some filesystems before v4.11.
return ErrNotEncrypted
@@ -86,10 +79,16 @@ var (
// the KeyDescriptor and the encryption options). Returns an error if the
// path is not encrypted or the policy couldn't be retrieved.
func GetPolicy(path string) (*PolicyData, error) {
- var policy unix.FscryptPolicy
- if err := policyIoctl(path, unix.FS_IOC_GET_ENCRYPTION_POLICY, &policy); err != nil {
+ file, err := os.Open(path)
+ if err != nil {
return nil, err
}
+ defer file.Close()
+
+ var policy unix.FscryptPolicy
+ if err := policyIoctl(file, unix.FS_IOC_GET_ENCRYPTION_POLICY, &policy); err != nil {
+ return nil, errors.Wrapf(err, "get encryption policy %s", path)
+ }
// Convert the padding flag into an amount of padding
paddingFlag := int64(policy.Flags & unix.FS_POLICY_FLAGS_PAD_MASK)
@@ -97,8 +96,7 @@ func GetPolicy(path string) (*PolicyData, error) {
// This lookup should always succeed
padding, ok := util.Lookup(paddingFlag, flagsArray, paddingArray)
if !ok {
- log.Printf("padding flag of %x not found", paddingFlag)
- util.NeverError(util.SystemError("invalid padding flag"))
+ log.Panicf("padding flag of %x not found", paddingFlag)
}
return &PolicyData{
@@ -115,22 +113,25 @@ func GetPolicy(path string) (*PolicyData, error) {
// policy. Returns an error if we cannot set the policy for any reason (not a
// directory, invalid options or KeyDescriptor, etc).
func SetPolicy(path string, data *PolicyData) error {
- // Convert the padding value to a flag
- paddingFlag, ok := util.Lookup(data.Options.Padding, paddingArray, flagsArray)
- if !ok {
- return util.InvalidInput(fmt.Sprintf("padding of %d", data.Options.Padding))
+ file, err := os.Open(path)
+ if err != nil {
+ return err
+ }
+ defer file.Close()
+
+ if err := data.CheckValidity(); err != nil {
+ return errors.Wrap(err, "invalid policy")
}
- // Convert the policyDescriptor to a byte array
- if len(data.KeyDescriptor) != DescriptorLen {
- return util.InvalidLengthError(
- "policy descriptor", DescriptorLen, len(data.KeyDescriptor))
+ // This lookup should always succeed (as policy is valid)
+ paddingFlag, ok := util.Lookup(data.Options.Padding, paddingArray, flagsArray)
+ if !ok {
+ log.Panicf("padding of %d was not found", data.Options.Padding)
}
descriptorBytes, err := hex.DecodeString(data.KeyDescriptor)
if err != nil {
- return util.InvalidInput(
- fmt.Sprintf("policy descriptor of %s: %v", data.KeyDescriptor, err))
+ return errors.New("invalid descriptor: " + data.KeyDescriptor)
}
policy := unix.FscryptPolicy{
@@ -141,24 +142,50 @@ func SetPolicy(path string, data *PolicyData) error {
}
copy(policy.Master_key_descriptor[:], descriptorBytes)
- if err = policyIoctl(path, unix.FS_IOC_SET_ENCRYPTION_POLICY, &policy); err != nil {
+ if err = policyIoctl(file, unix.FS_IOC_SET_ENCRYPTION_POLICY, &policy); err == unix.EINVAL {
// Before kernel v4.11, many different errors all caused unix.EINVAL to be returned.
// We try to disambiguate this error here. This disambiguation will not always give
// the correct error due to a potential race condition on path.
- if err == unix.EINVAL {
+ if info, statErr := os.Stat(path); statErr != nil || !info.IsDir() {
// Checking if the path is not a directory
- if info, err := os.Stat(path); err != nil || !info.IsDir() {
- return unix.ENOTDIR
- }
+ err = unix.ENOTDIR
+ } else if _, policyErr := GetPolicy(path); policyErr == nil {
// Checking if a policy is already set on this directory
- if _, err := GetPolicy(path); err == nil {
- return ErrEncrypted
- }
- // Could not get a more detailed error, return generic "bad options".
- return ErrBadEncryptionOptions
+ err = ErrEncrypted
+ } else {
+ // Default to generic "bad options".
+ err = ErrBadEncryptionOptions
}
+ }
+
+ return errors.Wrapf(err, "set encryption policy %s", path)
+}
+
+// CheckSupport returns an error if the filesystem containing path does not
+// support filesystem encryption. This can be for many reasons including an
+// incompatible kernel or filesystem or not enabling the right feature flags.
+func CheckSupport(path string) error {
+ file, err := os.Open(path)
+ if err != nil {
return err
}
+ defer file.Close()
+
+ // On supported directories, giving a bad policy will return EINVAL
+ badPolicy := unix.FscryptPolicy{
+ Version: math.MaxUint8,
+ Contents_encryption_mode: math.MaxUint8,
+ Filenames_encryption_mode: math.MaxUint8,
+ Flags: math.MaxUint8,
+ }
- return nil
+ err = policyIoctl(file, unix.FS_IOC_SET_ENCRYPTION_POLICY, &badPolicy)
+ switch err {
+ case nil:
+ log.Panicf(`FS_IOC_SET_ENCRYPTION_POLICY succeeded when it should have failed.
+ Please open an issue, filesystem %q may be corrupted.`, path)
+ case unix.EINVAL, unix.EACCES:
+ return nil
+ }
+ return err
}
diff --git a/metadata/policy_test.go b/metadata/policy_test.go
index 6dc2567..58e19d7 100644
--- a/metadata/policy_test.go
+++ b/metadata/policy_test.go
@@ -25,6 +25,8 @@ import (
"path/filepath"
"reflect"
"testing"
+
+ . "fscrypt/util"
)
const goodDescriptor = "0123456789abcdef"
@@ -34,13 +36,14 @@ var goodPolicy = &PolicyData{
Options: DefaultOptions,
}
-// Creates a temporary directory in TEST_FILESYSTEM_ROOT for testing. Fails if
-// the root directory is not specified.
+// Creates a temporary directory for testing.
func createTestDirectory() (directory string, err error) {
- baseDirectory := os.Getenv("TEST_FILESYSTEM_ROOT")
+ baseDirectory, err := TestPath()
+ if err != nil {
+ return
+ }
if s, err := os.Stat(baseDirectory); err != nil || !s.IsDir() {
- return "", fmt.Errorf("invalid directory %q: "+
- "set TEST_FILESYSTEM_ROOT to be a valid directory", baseDirectory)
+ return "", fmt.Errorf("%s: %q is not a valid directory", TestEnvVarName, baseDirectory)
}
directoryPath := filepath.Join(baseDirectory, "test")
diff --git a/pam/login.go b/pam/login.go
index 63041de..d80d719 100644
--- a/pam/login.go
+++ b/pam/login.go
@@ -31,11 +31,12 @@ package pam
import "C"
import (
- "fmt"
"log"
"sync"
"unsafe"
+ "github.com/pkg/errors"
+
"fscrypt/crypto"
"fscrypt/util"
)
@@ -43,8 +44,9 @@ import (
// Global state is needed for the PAM callback, so we guard this function with a
// lock. tokenToCheck is only ever non-nil when loginLock is held.
var (
- loginLock sync.Mutex
- tokenToCheck *crypto.Key
+ ErrPamInternal = util.SystemError("internal pam error")
+ loginLock sync.Mutex
+ tokenToCheck *crypto.Key
)
// unexpectedMessage logs an error encountered in the PAM callback.
@@ -95,14 +97,14 @@ func IsUserLoginToken(username string, token *crypto.Key) (_ bool, err error) {
// Start the pam transaction with the desired conversation and handle.
returnCode := C.pam_start(C.fscrypt_service, cUsername, &conv, &handle)
if returnCode != C.PAM_SUCCESS {
- return false, util.SystemError(fmt.Sprintf("pam_start returned %d", returnCode))
+ return false, errors.Wrapf(ErrPamInternal, "pam_start() = %d", returnCode)
}
defer func() {
// End the PAM transaction, setting the error if appropriate.
returnCode = C.pam_end(handle, returnCode)
if returnCode != C.PAM_SUCCESS && err == nil {
- err = util.SystemError(fmt.Sprintf("pam_end returned %d", returnCode))
+ err = errors.Wrapf(ErrPamInternal, "pam_end() = %d", returnCode)
}
}()
@@ -115,6 +117,6 @@ func IsUserLoginToken(username string, token *crypto.Key) (_ bool, err error) {
return false, nil
default:
// PAM didn't give us an answer to the authentication question
- return false, util.SystemError(fmt.Sprintf("pam_authenticate returned %d", returnCode))
+ return false, errors.Wrapf(ErrPamInternal, "pam_authenticate() = %d", returnCode)
}
}
diff --git a/util/errors.go b/util/errors.go
index e5eea4b..2a865a3 100644
--- a/util/errors.go
+++ b/util/errors.go
@@ -89,18 +89,12 @@ func (e *ErrWriter) Err() error {
return e.err
}
-// InvalidInput is an error that should indicate either bad input from a caller
-// of a public package function.
-type InvalidInput string
-
-func (i InvalidInput) Error() string {
- return "invalid input: " + string(i)
-}
-
-// InvalidLengthError indicates name should have had length expected.
-func InvalidLengthError(name string, expected int, actual int) InvalidInput {
- message := fmt.Sprintf("length of %s: expected=%d, actual=%d", name, expected, actual)
- return InvalidInput(message)
+// CheckValidLength returns an invalid length error if expected != actual
+func CheckValidLength(expected, actual int) error {
+ if expected == actual {
+ return nil
+ }
+ return fmt.Errorf("expected length of %d, got %d", expected, actual)
}
// SystemError is an error that should indicate something has gone wrong in the
@@ -119,20 +113,17 @@ func NeverError(err error) {
}
}
-// UnderlyingError returns the underlying error for known os error types and
-// logs the full error. From: src/os/error.go
-func UnderlyingError(err error) error {
- var newErr error
- switch typedErr := err.(type) {
- case *os.PathError:
- newErr = typedErr.Err
- case *os.LinkError:
- newErr = typedErr.Err
- case *os.SyscallError:
- newErr = typedErr.Err
- default:
- return err
+// TestEnvVarName is the name on an environment variable that should be set to
+// an empty mountpoint. This is only used for integration tests.
+var TestEnvVarName = "TEST_FILESYSTEM_ROOT"
+
+// TestPath returns a the path specified by TestEnvVarName. The function
+// panics if the environment variable is not set. This function is only used for
+// integration tests.
+func TestPath() (string, error) {
+ path := os.Getenv(TestEnvVarName)
+ if path == "" {
+ return "", fmt.Errorf("%s: environment variable not set", TestEnvVarName)
}
- log.Print(err)
- return newErr
+ return path, nil
}
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-10 17:29:06 +0000