diff options
Diffstat (limited to 'internal/fusefrontend/xattr.go')
| -rw-r--r-- | internal/fusefrontend/xattr.go | 101 |
1 files changed, 72 insertions, 29 deletions
diff --git a/internal/fusefrontend/xattr.go b/internal/fusefrontend/xattr.go index 816754c..045f963 100644 --- a/internal/fusefrontend/xattr.go +++ b/internal/fusefrontend/xattr.go @@ -1,15 +1,15 @@ // Package fusefrontend interfaces directly with the go-fuse library. package fusefrontend -// FUSE operations on paths - import ( "strings" "syscall" + "golang.org/x/sys/unix" + "github.com/hanwen/go-fuse/fuse" - "github.com/pkg/xattr" + "github.com/rfjakob/gocryptfs/internal/syscallcompat" "github.com/rfjakob/gocryptfs/internal/tlog" ) @@ -25,9 +25,7 @@ var xattrStorePrefix = "user.gocryptfs." // GetXAttr - FUSE call. Reads the value of extended attribute "attr". // -// This function is symlink-safe on Linux. -// Darwin does not have fgetxattr(2) nor /proc/self/fd. How to implement this -// on Darwin in a symlink-safe way? +// This function is symlink-safe through Fgetxattr. func (fs *FS) GetXAttr(relPath string, attr string, context *fuse.Context) ([]byte, fuse.Status) { if fs.isFiltered(relPath) { return nil, fuse.EPERM @@ -35,11 +33,20 @@ func (fs *FS) GetXAttr(relPath string, attr string, context *fuse.Context) ([]by if disallowedXAttrName(attr) { return nil, _EOPNOTSUPP } - cAttr := fs.encryptXattrName(attr) - cData, status := fs.getXattr(relPath, cAttr, context) + + file, fd, status := fs.getFileFd(relPath, context) if !status.Ok() { return nil, status } + defer file.Release() + + cAttr := fs.encryptXattrName(attr) + + cData, err := syscallcompat.Fgetxattr(fd, cAttr) + if err != nil { + return nil, fuse.ToStatus(err) + } + data, err := fs.decryptXattrValue(cData) if err != nil { tlog.Warn.Printf("GetXAttr: %v", err) @@ -50,9 +57,7 @@ func (fs *FS) GetXAttr(relPath string, attr string, context *fuse.Context) ([]by // SetXAttr - FUSE call. Set extended attribute. // -// This function is symlink-safe on Linux. -// Darwin does not have fsetxattr(2) nor /proc/self/fd. How to implement this -// on Darwin in a symlink-safe way? +// This function is symlink-safe through Fsetxattr. func (fs *FS) SetXAttr(relPath string, attr string, data []byte, flags int, context *fuse.Context) fuse.Status { if fs.isFiltered(relPath) { return fuse.EPERM @@ -60,17 +65,27 @@ func (fs *FS) SetXAttr(relPath string, attr string, data []byte, flags int, cont if disallowedXAttrName(attr) { return _EOPNOTSUPP } + + file, fd, status := fs.getFileFd(relPath, context) + if !status.Ok() { + return status + } + defer file.Release() + flags = filterXattrSetFlags(flags) cAttr := fs.encryptXattrName(attr) cData := fs.encryptXattrValue(data) - return fs.setXattr(relPath, cAttr, cData, flags, context) + + err := unix.Fsetxattr(fd, cAttr, cData, flags) + if err != nil { + return fuse.ToStatus(err) + } + return fuse.OK } // RemoveXAttr - FUSE call. // -// This function is symlink-safe on Linux. -// Darwin does not have fremovexattr(2) nor /proc/self/fd. How to implement this -// on Darwin in a symlink-safe way? +// This function is symlink-safe through Fremovexattr. func (fs *FS) RemoveXAttr(relPath string, attr string, context *fuse.Context) fuse.Status { if fs.isFiltered(relPath) { return fuse.EPERM @@ -78,23 +93,45 @@ func (fs *FS) RemoveXAttr(relPath string, attr string, context *fuse.Context) fu if disallowedXAttrName(attr) { return _EOPNOTSUPP } + + file, fd, status := fs.getFileFd(relPath, context) + if !status.Ok() { + return status + } + defer file.Release() + cAttr := fs.encryptXattrName(attr) - return fs.removeXAttr(relPath, cAttr, context) + err := unix.Fremovexattr(fd, cAttr) + if err != nil { + return fuse.ToStatus(err) + } + return fuse.OK } // ListXAttr - FUSE call. Lists extended attributes on the file at "relPath". // -// This function is symlink-safe on Linux. -// Darwin does not have flistxattr(2) nor /proc/self/fd. How to implement this -// on Darwin in a symlink-safe way? +// This function is symlink-safe through Flistxattr. func (fs *FS) ListXAttr(relPath string, context *fuse.Context) ([]string, fuse.Status) { if fs.isFiltered(relPath) { return nil, fuse.EPERM } - cNames, status := fs.listXAttr(relPath, context) + + file, fd, status := fs.getFileFd(relPath, context) + // On a symlink, getFileFd fails with ELOOP. Let's pretend there + // can be no xattrs on symlinks, and always return an empty result. + if status == fuse.Status(syscall.ELOOP) { + return nil, fuse.OK + } if !status.Ok() { return nil, status } + defer file.Release() + + cNames, err := syscallcompat.Flistxattr(fd) + if err != nil { + return nil, fuse.ToStatus(err) + } + names := make([]string, 0, len(cNames)) for _, curName := range cNames { if !strings.HasPrefix(curName, xattrStorePrefix) { @@ -163,16 +200,22 @@ func (fs *FS) decryptXattrValue(cData []byte) (data []byte, err error) { return fs.contentEnc.DecryptBlock([]byte(cData), 0, nil) } -// unpackXattrErr unpacks an error value that we got from xattr.LGet/LSet/etc -// and converts it to a fuse status. If err == nil, it returns fuse.OK. -func unpackXattrErr(err error) fuse.Status { - if err == nil { - return fuse.OK +// getFileFd calls fs.Open() on relative plaintext path "relPath" and returns +// the resulting fusefrontend.*File along with the underlying fd. The caller +// MUST call file.Release() when done with the file. The O_NONBLOCK flag is +// used to not block on FIFOs. +// +// Used by xattrGet() and friends. +func (fs *FS) getFileFd(relPath string, context *fuse.Context) (*File, int, fuse.Status) { + fuseFile, status := fs.Open(relPath, syscall.O_RDONLY|syscall.O_NONBLOCK, context) + if !status.Ok() { + return nil, -1, status } - err2, ok := err.(*xattr.Error) + file, ok := fuseFile.(*File) if !ok { - tlog.Warn.Printf("unpackXattrErr: cannot unpack err=%v", err) - return fuse.EIO + tlog.Warn.Printf("BUG: xattrGet: cast to *File failed") + fuseFile.Release() + return nil, -1, fuse.EIO } - return fuse.ToStatus(err2.Err) + return file, file.intFd(), fuse.OK } |