From ebdf58b9ebf366ac6dbf500c0f4f4d211451bb44 Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Sun, 21 Jun 2020 12:42:18 +0200
Subject: v2api: implement GetAttr and Readdir

---
 internal/fusefrontend/node_dir_ops.go | 97 +++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)
 create mode 100644 internal/fusefrontend/node_dir_ops.go

(limited to 'internal/fusefrontend/node_dir_ops.go')

diff --git a/internal/fusefrontend/node_dir_ops.go b/internal/fusefrontend/node_dir_ops.go
new file mode 100644
index 0000000..38d0940
--- /dev/null
+++ b/internal/fusefrontend/node_dir_ops.go
@@ -0,0 +1,97 @@
+package fusefrontend
+
+import (
+	"context"
+	"path/filepath"
+	"syscall"
+
+	"github.com/hanwen/go-fuse/v2/fs"
+	"github.com/hanwen/go-fuse/v2/fuse"
+
+	"github.com/rfjakob/gocryptfs/internal/configfile"
+	"github.com/rfjakob/gocryptfs/internal/nametransform"
+	"github.com/rfjakob/gocryptfs/internal/syscallcompat"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
+)
+
+func (n *Node) Readdir(ctx context.Context) (fs.DirStream, syscall.Errno) {
+	rn := n.rootNode()
+	p := n.path()
+	dirName := filepath.Base(p)
+	parentDirFd, cDirName, err := rn.openBackingDir(p)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	defer syscall.Close(parentDirFd)
+
+	// Read ciphertext directory
+	var cipherEntries []fuse.DirEntry
+	fd, err := syscallcompat.Openat(parentDirFd, cDirName, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NOFOLLOW, 0)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	defer syscall.Close(fd)
+	cipherEntries, err = syscallcompat.Getdents(fd)
+	if err != nil {
+		return nil, fs.ToErrno(err)
+	}
+	// Get DirIV (stays nil if PlaintextNames is used)
+	var cachedIV []byte
+	if !rn.args.PlaintextNames {
+		// Read the DirIV from disk
+		cachedIV, err = nametransform.ReadDirIVAt(fd)
+		if err != nil {
+			tlog.Warn.Printf("OpenDir %q: could not read %s: %v", cDirName, nametransform.DirIVFilename, err)
+			return nil, syscall.EIO
+		}
+	}
+	// Decrypted directory entries
+	var plain []fuse.DirEntry
+	// Filter and decrypt filenames
+	for i := range cipherEntries {
+		cName := cipherEntries[i].Name
+		if dirName == "." && cName == configfile.ConfDefaultName {
+			// silently ignore "gocryptfs.conf" in the top level dir
+			continue
+		}
+		if rn.args.PlaintextNames {
+			plain = append(plain, cipherEntries[i])
+			continue
+		}
+		if cName == nametransform.DirIVFilename {
+			// silently ignore "gocryptfs.diriv" everywhere if dirIV is enabled
+			continue
+		}
+		// Handle long file name
+		isLong := nametransform.LongNameNone
+		if rn.args.LongNames {
+			isLong = nametransform.NameType(cName)
+		}
+		if isLong == nametransform.LongNameContent {
+			cNameLong, err := nametransform.ReadLongNameAt(fd, cName)
+			if err != nil {
+				tlog.Warn.Printf("OpenDir %q: invalid entry %q: Could not read .name: %v",
+					cDirName, cName, err)
+				rn.reportMitigatedCorruption(cName)
+				continue
+			}
+			cName = cNameLong
+		} else if isLong == nametransform.LongNameFilename {
+			// ignore "gocryptfs.longname.*.name"
+			continue
+		}
+		name, err := rn.nameTransform.DecryptName(cName, cachedIV)
+		if err != nil {
+			tlog.Warn.Printf("OpenDir %q: invalid entry %q: %v",
+				cDirName, cName, err)
+			rn.reportMitigatedCorruption(cName)
+			continue
+		}
+		// Override the ciphertext name with the plaintext name but reuse the rest
+		// of the structure
+		cipherEntries[i].Name = name
+		plain = append(plain, cipherEntries[i])
+	}
+
+	return fs.NewListDirStream(plain), 0
+}
-- 
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