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path: root/internal/fusefrontend_reverse/node_helpers.go
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Diffstat (limited to 'internal/fusefrontend_reverse/node_helpers.go')
-rw-r--r--internal/fusefrontend_reverse/node_helpers.go84
1 files changed, 82 insertions, 2 deletions
diff --git a/internal/fusefrontend_reverse/node_helpers.go b/internal/fusefrontend_reverse/node_helpers.go
index 24cdbd1..df9de9b 100644
--- a/internal/fusefrontend_reverse/node_helpers.go
+++ b/internal/fusefrontend_reverse/node_helpers.go
@@ -5,8 +5,24 @@ import (
"path/filepath"
"syscall"
+ "golang.org/x/sys/unix"
+
"github.com/hanwen/go-fuse/v2/fs"
"github.com/hanwen/go-fuse/v2/fuse"
+
+ "github.com/rfjakob/gocryptfs/internal/pathiv"
+ "github.com/rfjakob/gocryptfs/internal/syscallcompat"
+)
+
+const (
+ // File names are padded to 16-byte multiples, encrypted and
+ // base64-encoded. We can encode at most 176 bytes to stay below the 255
+ // bytes limit:
+ // * base64(176 bytes) = 235 bytes
+ // * base64(192 bytes) = 256 bytes (over 255!)
+ // But the PKCS#7 padding is at least one byte. This means we can only use
+ // 175 bytes for the file name.
+ shortNameMax = 175
)
// translateSize translates the ciphertext size in `out` into plaintext size.
@@ -36,13 +52,13 @@ func (n *Node) rootNode() *RootNode {
// If you pass a `child` file name, the (dirfd, cName) pair will refer to
// a child of this node.
// If `child` is empty, the (dirfd, cName) pair refers to this node itself.
-func (n *Node) prepareAtSyscall(child string) (dirfd int, cName string, errno syscall.Errno) {
+func (n *Node) prepareAtSyscall(child string) (dirfd int, pName string, errno syscall.Errno) {
p := n.Path()
if child != "" {
p = filepath.Join(p, child)
}
rn := n.rootNode()
- dirfd, cName, err := rn.openBackingDir(p)
+ dirfd, pName, err := rn.openBackingDir(p)
if err != nil {
errno = fs.ToErrno(err)
}
@@ -71,3 +87,67 @@ func (n *Node) isRoot() bool {
rn := n.rootNode()
return &rn.Node == n
}
+
+func (n *Node) lookupLongnameName(ctx context.Context, nameFile string, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
+ dirfd, pName1, errno := n.prepareAtSyscall("")
+ if errno != 0 {
+ return
+ }
+ defer syscall.Close(dirfd)
+
+ // Find the file the gocryptfs.longname.XYZ.name file belongs to in the
+ // directory listing
+ fd, err := syscallcompat.Openat(dirfd, pName1, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NOFOLLOW, 0)
+ if err != nil {
+ errno = fs.ToErrno(err)
+ return
+ }
+ diriv := pathiv.Derive(n.Path(), pathiv.PurposeDirIV)
+ rn := n.rootNode()
+ pName, cFullname, errno := rn.findLongnameParent(fd, diriv, nameFile)
+ if errno != 0 {
+ return
+ }
+ // Get attrs from parent file
+ st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
+ if err != nil {
+ errno = fs.ToErrno(err)
+ return
+ }
+ var vf *virtualFile
+ vf, errno = n.newVirtualFile([]byte(cFullname), st, inoTagNameFile)
+ if errno != 0 {
+ return nil, errno
+ }
+ out.Attr = vf.attr
+ // Create child node
+ id := fs.StableAttr{Mode: uint32(vf.attr.Mode), Gen: 1, Ino: vf.attr.Ino}
+ ch = n.NewInode(ctx, vf, id)
+ return
+
+}
+
+// lookupDiriv returns a new Inode for a gocryptfs.diriv file inside `n`.
+func (n *Node) lookupDiriv(ctx context.Context, out *fuse.EntryOut) (ch *fs.Inode, errno syscall.Errno) {
+ dirfd, pName, errno := n.prepareAtSyscall("")
+ if errno != 0 {
+ return
+ }
+ defer syscall.Close(dirfd)
+ st, err := syscallcompat.Fstatat2(dirfd, pName, unix.AT_SYMLINK_NOFOLLOW)
+ if err != nil {
+ errno = fs.ToErrno(err)
+ return
+ }
+ content := pathiv.Derive(n.Path(), pathiv.PurposeDirIV)
+ var vf *virtualFile
+ vf, errno = n.newVirtualFile(content, st, inoTagDirIV)
+ if errno != 0 {
+ return nil, errno
+ }
+ out.Attr = vf.attr
+ // Create child node
+ id := fs.StableAttr{Mode: uint32(vf.attr.Mode), Gen: 1, Ino: vf.attr.Ino}
+ ch = n.NewInode(ctx, vf, id)
+ return
+}