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authorbolshevik2018-04-17 20:33:04 +0200
committerrfjakob2018-04-17 20:33:04 +0200
commit12b32aa06c0475d60ee51b3753052ac2e4d09308 (patch)
tree2b880d5e2a96f0992e9ba0fc54df85a6a18969ae /internal/fusefrontend
parent12832851c68ce6ba2907b5d5fefc2a5e49f7c36a (diff)
Improved xattr handling on non-linux systems (#227)
* Fixed xattr filtering for MacOS. "system." and "user." prefixes are only relevant for Linux. * Small cleanup and additional tests.
Diffstat (limited to 'internal/fusefrontend')
-rw-r--r--internal/fusefrontend/xattr.go37
-rw-r--r--internal/fusefrontend/xattr_linux.go15
-rw-r--r--internal/fusefrontend/xattr_linux_unit_test.go13
-rw-r--r--internal/fusefrontend/xattr_notlinux.go8
-rw-r--r--internal/fusefrontend/xattr_unit_test.go12
5 files changed, 51 insertions, 34 deletions
diff --git a/internal/fusefrontend/xattr.go b/internal/fusefrontend/xattr.go
index faaebd4..f3e7532 100644
--- a/internal/fusefrontend/xattr.go
+++ b/internal/fusefrontend/xattr.go
@@ -16,11 +16,6 @@ import (
// xattr names are encrypted like file names, but with a fixed IV.
var xattrNameIV = []byte("xattr_name_iv_xx")
-// Only allow the "user" namespace, block "trusted" and "security", as
-// these may be interpreted by the system, and we don't want to cause
-// trouble with our encrypted garbage.
-var xattrUserPrefix = "user."
-
// We store encrypted xattrs under this prefix plus the base64-encoded
// encrypted original name.
var xattrStorePrefix = "user.gocryptfs."
@@ -31,15 +26,12 @@ func (fs *FS) GetXAttr(path string, attr string, context *fuse.Context) ([]byte,
if fs.isFiltered(path) {
return nil, fuse.EPERM
}
- if !strings.HasPrefix(attr, xattrUserPrefix) {
+ if disallowedXAttrName(attr) {
// "ls -l" queries security.selinux, system.posix_acl_access, system.posix_acl_default
// and throws error messages if it gets something else than ENODATA.
return nil, fuse.ENODATA
}
- cAttr, err := fs.encryptXattrName(attr)
- if err != nil {
- return nil, fuse.ToStatus(err)
- }
+ cAttr := fs.encryptXattrName(attr)
cPath, err := fs.getBackingPath(path)
if err != nil {
return nil, fuse.ToStatus(err)
@@ -65,14 +57,15 @@ func (fs *FS) SetXAttr(path string, attr string, data []byte, flags int, context
if flags != 0 {
return fuse.EPERM
}
- cPath, err := fs.getBackingPath(path)
- if err != nil {
- return fuse.ToStatus(err)
+ if disallowedXAttrName(attr) {
+ return fuse.EPERM
}
- cAttr, err := fs.encryptXattrName(attr)
+
+ cPath, err := fs.getBackingPath(path)
if err != nil {
return fuse.ToStatus(err)
}
+ cAttr := fs.encryptXattrName(attr)
// xattr data is encrypted like a symlink target
cData64 := []byte(fs.encryptSymlinkTarget(string(data)))
return unpackXattrErr(xattr.Set(cPath, cAttr, cData64))
@@ -83,14 +76,14 @@ func (fs *FS) RemoveXAttr(path string, attr string, context *fuse.Context) fuse.
if fs.isFiltered(path) {
return fuse.EPERM
}
- cPath, err := fs.getBackingPath(path)
- if err != nil {
- return fuse.ToStatus(err)
+ if disallowedXAttrName(attr) {
+ return fuse.EPERM
}
- cAttr, err := fs.encryptXattrName(attr)
+ cPath, err := fs.getBackingPath(path)
if err != nil {
return fuse.ToStatus(err)
}
+ cAttr := fs.encryptXattrName(attr)
return unpackXattrErr(xattr.Remove(cPath, cAttr))
}
@@ -124,14 +117,10 @@ func (fs *FS) ListXAttr(path string, context *fuse.Context) ([]string, fuse.Stat
}
// encryptXattrName transforms "user.foo" to "user.gocryptfs.a5sAd4XAa47f5as6dAf"
-func (fs *FS) encryptXattrName(attr string) (cAttr string, err error) {
- // Reject anything that does not start with "user."
- if !strings.HasPrefix(attr, xattrUserPrefix) {
- return "", syscall.EPERM
- }
+func (fs *FS) encryptXattrName(attr string) (cAttr string) {
// xattr names are encrypted like file names, but with a fixed IV.
cAttr = xattrStorePrefix + fs.nameTransform.EncryptName(attr, xattrNameIV)
- return cAttr, nil
+ return cAttr
}
func (fs *FS) decryptXattrName(cAttr string) (attr string, err error) {
diff --git a/internal/fusefrontend/xattr_linux.go b/internal/fusefrontend/xattr_linux.go
new file mode 100644
index 0000000..ebe42b1
--- /dev/null
+++ b/internal/fusefrontend/xattr_linux.go
@@ -0,0 +1,15 @@
+// +build linux
+
+// Package fusefrontend interfaces directly with the go-fuse library.
+package fusefrontend
+
+import "strings"
+
+// Only allow the "user" namespace, block "trusted" and "security", as
+// these may be interpreted by the system, and we don't want to cause
+// trouble with our encrypted garbage.
+const xattrUserPrefix = "user."
+
+func disallowedXAttrName(attr string) bool {
+ return !strings.HasPrefix(attr, xattrUserPrefix)
+}
diff --git a/internal/fusefrontend/xattr_linux_unit_test.go b/internal/fusefrontend/xattr_linux_unit_test.go
new file mode 100644
index 0000000..5fea58b
--- /dev/null
+++ b/internal/fusefrontend/xattr_linux_unit_test.go
@@ -0,0 +1,13 @@
+// +build linux
+
+package fusefrontend
+
+import (
+ "testing"
+)
+
+func TestDisallowedLinuxAttributes(t *testing.T) {
+ if !disallowedXAttrName("xxxx") {
+ t.Fatalf("Names that don't start with 'user.' should fail")
+ }
+}
diff --git a/internal/fusefrontend/xattr_notlinux.go b/internal/fusefrontend/xattr_notlinux.go
new file mode 100644
index 0000000..aa9c981
--- /dev/null
+++ b/internal/fusefrontend/xattr_notlinux.go
@@ -0,0 +1,8 @@
+// +build !linux
+
+// Package fusefrontend interfaces directly with the go-fuse library.
+package fusefrontend
+
+func disallowedXAttrName(attr string) bool {
+ return false
+}
diff --git a/internal/fusefrontend/xattr_unit_test.go b/internal/fusefrontend/xattr_unit_test.go
index ea5d3bb..c5c9360 100644
--- a/internal/fusefrontend/xattr_unit_test.go
+++ b/internal/fusefrontend/xattr_unit_test.go
@@ -4,7 +4,6 @@ package fusefrontend
// "xattr_integration_test.go" in the test/xattr package.
import (
- "syscall"
"testing"
"github.com/rfjakob/gocryptfs/internal/contentenc"
@@ -24,18 +23,11 @@ func newTestFS() *FS {
func TestEncryptDecryptXattrName(t *testing.T) {
fs := newTestFS()
- _, err := fs.encryptXattrName("xxxx")
- if err != syscall.EPERM {
- t.Fatalf("Names that don't start with 'user.' should fail")
- }
attr1 := "user.foo123456789"
- cAttr, err := fs.encryptXattrName(attr1)
- if err != nil {
- t.Fatal(err)
- }
+ cAttr := fs.encryptXattrName(attr1)
t.Logf("cAttr=%v", cAttr)
attr2, err := fs.decryptXattrName(cAttr)
- if attr1 != attr2 {
+ if attr1 != attr2 || err != nil {
t.Fatalf("Decrypt mismatch: %v != %v", attr1, attr2)
}
}