diff options
| -rw-r--r-- | internal/fusefrontend/xattr.go | 83 | ||||
| -rw-r--r-- | internal/fusefrontend/xattr_darwin.go | 78 | ||||
| -rw-r--r-- | internal/fusefrontend/xattr_linux.go | 62 | ||||
| -rw-r--r-- | internal/syscallcompat/sys_common.go | 23 | ||||
| -rw-r--r-- | tests/xattr/xattr_integration_test.go | 30 |
5 files changed, 201 insertions, 75 deletions
diff --git a/internal/fusefrontend/xattr.go b/internal/fusefrontend/xattr.go index 2248bad..1de9cac 100644 --- a/internal/fusefrontend/xattr.go +++ b/internal/fusefrontend/xattr.go @@ -2,16 +2,11 @@ package fusefrontend import ( - "fmt" - "runtime" "strings" "syscall" - "golang.org/x/sys/unix" - "github.com/hanwen/go-fuse/fuse" - "github.com/rfjakob/gocryptfs/internal/syscallcompat" "github.com/rfjakob/gocryptfs/internal/tlog" ) @@ -36,18 +31,11 @@ func (fs *FS) GetXAttr(relPath string, attr string, context *fuse.Context) ([]by return nil, _EOPNOTSUPP } - // O_NONBLOCK to not block on FIFOs. - fd, err := fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_NONBLOCK) - if err != nil { - return nil, fuse.ToStatus(err) - } - defer syscall.Close(fd) - cAttr := fs.encryptXattrName(attr) - cData, err := syscallcompat.Fgetxattr(fd, cAttr) - if err != nil { - return nil, fuse.ToStatus(err) + cData, status := fs.getXAttr(relPath, cAttr, context) + if !status.Ok() { + return nil, status } data, err := fs.decryptXattrValue(cData) @@ -69,26 +57,10 @@ func (fs *FS) SetXAttr(relPath string, attr string, data []byte, flags int, cont return _EOPNOTSUPP } - // O_NONBLOCK to not block on FIFOs. - fd, err := fs.openBackingFile(relPath, syscall.O_WRONLY|syscall.O_NONBLOCK) - // Directories cannot be opened read-write. Retry. - if err == syscall.EISDIR { - fd, err = fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK) - } - if err != nil { - return fuse.ToStatus(err) - } - defer syscall.Close(fd) - flags = filterXattrSetFlags(flags) cAttr := fs.encryptXattrName(attr) cData := fs.encryptXattrValue(data) - - err = unix.Fsetxattr(fd, cAttr, cData, flags) - if err != nil { - return fuse.ToStatus(err) - } - return fuse.OK + return fs.setXAttr(relPath, cAttr, cData, flags, context) } // RemoveXAttr - FUSE call. @@ -102,23 +74,8 @@ func (fs *FS) RemoveXAttr(relPath string, attr string, context *fuse.Context) fu return _EOPNOTSUPP } - // O_NONBLOCK to not block on FIFOs. - fd, err := fs.openBackingFile(relPath, syscall.O_WRONLY|syscall.O_NONBLOCK) - // Directories cannot be opened read-write. Retry. - if err == syscall.EISDIR { - fd, err = fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK) - } - if err != nil { - return fuse.ToStatus(err) - } - defer syscall.Close(fd) - cAttr := fs.encryptXattrName(attr) - err = unix.Fremovexattr(fd, cAttr) - if err != nil { - return fuse.ToStatus(err) - } - return fuse.OK + return fs.removeXAttr(relPath, cAttr, context) } // ListXAttr - FUSE call. Lists extended attributes on the file at "relPath". @@ -128,32 +85,10 @@ func (fs *FS) ListXAttr(relPath string, context *fuse.Context) ([]string, fuse.S if fs.isFiltered(relPath) { return nil, fuse.EPERM } - var cNames []string - var err error - if runtime.GOOS == "linux" { - dirfd, cName, err2 := fs.openBackingDir(relPath) - if err2 != nil { - return nil, fuse.ToStatus(err2) - } - defer syscall.Close(dirfd) - procPath := fmt.Sprintf("/proc/self/fd/%d/%s", dirfd, cName) - cNames, err = syscallcompat.Llistxattr(procPath) - } else { - // O_NONBLOCK to not block on FIFOs. - fd, err2 := fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_NONBLOCK) - // On a symlink, openBackingFile fails with ELOOP. Let's pretend there - // can be no xattrs on symlinks, and always return an empty result. - if err2 == syscall.ELOOP { - return nil, fuse.OK - } - if err2 != nil { - return nil, fuse.ToStatus(err2) - } - defer syscall.Close(fd) - cNames, err = syscallcompat.Flistxattr(fd) - } - if err != nil { - return nil, fuse.ToStatus(err) + + cNames, status := fs.listXAttr(relPath, context) + if !status.Ok() { + return nil, status } names := make([]string, 0, len(cNames)) diff --git a/internal/fusefrontend/xattr_darwin.go b/internal/fusefrontend/xattr_darwin.go index 8760480..741eb6c 100644 --- a/internal/fusefrontend/xattr_darwin.go +++ b/internal/fusefrontend/xattr_darwin.go @@ -3,6 +3,16 @@ // Package fusefrontend interfaces directly with the go-fuse library. package fusefrontend +import ( + "syscall" + + "golang.org/x/sys/unix" + + "github.com/hanwen/go-fuse/fuse" + + "github.com/rfjakob/gocryptfs/internal/syscallcompat" +) + func disallowedXAttrName(attr string) bool { return false } @@ -14,3 +24,71 @@ func filterXattrSetFlags(flags int) int { return flags &^ XATTR_NOSECURITY } + +func (fs *FS) getXAttr(relPath string, cAttr string, context *fuse.Context) ([]byte, fuse.Status) { + // O_NONBLOCK to not block on FIFOs. + fd, err := fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_NONBLOCK) + if err != nil { + return nil, fuse.ToStatus(err) + } + defer syscall.Close(fd) + + cData, err := syscallcompat.Fgetxattr(fd, cAttr) + if err != nil { + return nil, fuse.ToStatus(err) + } + + return cData, fuse.OK +} + +func (fs *FS) setXAttr(relPath string, cAttr string, cData []byte, flags int, context *fuse.Context) fuse.Status { + // O_NONBLOCK to not block on FIFOs. + fd, err := fs.openBackingFile(relPath, syscall.O_WRONLY|syscall.O_NONBLOCK) + // Directories cannot be opened read-write. Retry. + if err == syscall.EISDIR { + fd, err = fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK) + } + if err != nil { + return fuse.ToStatus(err) + } + defer syscall.Close(fd) + + err = unix.Fsetxattr(fd, cAttr, cData, flags) + return fuse.ToStatus(err) +} + +func (fs *FS) removeXAttr(relPath string, cAttr string, context *fuse.Context) fuse.Status { + // O_NONBLOCK to not block on FIFOs. + fd, err := fs.openBackingFile(relPath, syscall.O_WRONLY|syscall.O_NONBLOCK) + // Directories cannot be opened read-write. Retry. + if err == syscall.EISDIR { + fd, err = fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_DIRECTORY|syscall.O_NONBLOCK) + } + if err != nil { + return fuse.ToStatus(err) + } + defer syscall.Close(fd) + + err = unix.Fremovexattr(fd, cAttr) + return fuse.ToStatus(err) +} + +func (fs *FS) listXAttr(relPath string, context *fuse.Context) ([]string, fuse.Status) { + // O_NONBLOCK to not block on FIFOs. + fd, err := fs.openBackingFile(relPath, syscall.O_RDONLY|syscall.O_NONBLOCK) + // On a symlink, openBackingFile fails with ELOOP. Let's pretend there + // can be no xattrs on symlinks, and always return an empty result. + if err == syscall.ELOOP { + return nil, fuse.OK + } + if err != nil { + return nil, fuse.ToStatus(err) + } + defer syscall.Close(fd) + + cNames, err := syscallcompat.Flistxattr(fd) + if err != nil { + return nil, fuse.ToStatus(err) + } + return cNames, fuse.OK +} diff --git a/internal/fusefrontend/xattr_linux.go b/internal/fusefrontend/xattr_linux.go index fd3b7e5..3a64412 100644 --- a/internal/fusefrontend/xattr_linux.go +++ b/internal/fusefrontend/xattr_linux.go @@ -4,7 +4,15 @@ package fusefrontend import ( + "fmt" "strings" + "syscall" + + "golang.org/x/sys/unix" + + "github.com/hanwen/go-fuse/fuse" + + "github.com/rfjakob/gocryptfs/internal/syscallcompat" ) // Only allow the "user" namespace, block "trusted" and "security", as @@ -19,3 +27,57 @@ func disallowedXAttrName(attr string) bool { func filterXattrSetFlags(flags int) int { return flags } + +func (fs *FS) getXAttr(relPath string, cAttr string, context *fuse.Context) ([]byte, fuse.Status) { + dirfd, cName, err := fs.openBackingDir(relPath) + if err != nil { + return nil, fuse.ToStatus(err) + } + defer syscall.Close(dirfd) + + procPath := fmt.Sprintf("/proc/self/fd/%d/%s", dirfd, cName) + cData, err := syscallcompat.Lgetxattr(procPath, cAttr) + if err != nil { + return nil, fuse.ToStatus(err) + } + return cData, fuse.OK +} + +func (fs *FS) setXAttr(relPath string, cAttr string, cData []byte, flags int, context *fuse.Context) fuse.Status { + dirfd, cName, err := fs.openBackingDir(relPath) + if err != nil { + return fuse.ToStatus(err) + } + defer syscall.Close(dirfd) + + procPath := fmt.Sprintf("/proc/self/fd/%d/%s", dirfd, cName) + err = unix.Lsetxattr(procPath, cAttr, cData, flags) + return fuse.ToStatus(err) +} + +func (fs *FS) removeXAttr(relPath string, cAttr string, context *fuse.Context) fuse.Status { + dirfd, cName, err := fs.openBackingDir(relPath) + if err != nil { + return fuse.ToStatus(err) + } + defer syscall.Close(dirfd) + + procPath := fmt.Sprintf("/proc/self/fd/%d/%s", dirfd, cName) + err = unix.Lremovexattr(procPath, cAttr) + return fuse.ToStatus(err) +} + +func (fs *FS) listXAttr(relPath string, context *fuse.Context) ([]string, fuse.Status) { + dirfd, cName, err := fs.openBackingDir(relPath) + if err != nil { + return nil, fuse.ToStatus(err) + } + defer syscall.Close(dirfd) + + procPath := fmt.Sprintf("/proc/self/fd/%d/%s", dirfd, cName) + cNames, err := syscallcompat.Llistxattr(procPath) + if err != nil { + return nil, fuse.ToStatus(err) + } + return cNames, fuse.OK +} diff --git a/internal/syscallcompat/sys_common.go b/internal/syscallcompat/sys_common.go index 4ce0208..a1aa66d 100644 --- a/internal/syscallcompat/sys_common.go +++ b/internal/syscallcompat/sys_common.go @@ -84,6 +84,29 @@ func Fgetxattr(fd int, attr string) (val []byte, err error) { return val, nil } +// Lgetxattr is a wrapper around unix.Lgetxattr that handles the buffer sizing. +func Lgetxattr(path string, attr string) (val []byte, err error) { + // See the buffer sizing comments in Fgetxattr. + // TODO: smarter buffer sizing? + buf := make([]byte, XATTR_BUFSZ) + sz, err := unix.Lgetxattr(path, attr, buf) + if err == syscall.ERANGE { + // Do NOT return ERANGE - the user might retry ad inifinitum! + return nil, syscall.EOVERFLOW + } + if err != nil { + return nil, err + } + if sz >= XATTR_SIZE_MAX { + return nil, syscall.EOVERFLOW + } + // Copy only the actually used bytes to a new (smaller) buffer + // so "buf" never leaves the function and can be allocated on the stack. + val = make([]byte, sz) + copy(val, buf) + return val, nil +} + // Flistxattr is a wrapper for unix.Flistxattr that handles buffer sizing and // parsing the returned blob to a string slice. func Flistxattr(fd int) (attrs []string, err error) { diff --git a/tests/xattr/xattr_integration_test.go b/tests/xattr/xattr_integration_test.go index f182fd9..29c3e84 100644 --- a/tests/xattr/xattr_integration_test.go +++ b/tests/xattr/xattr_integration_test.go @@ -129,7 +129,7 @@ func TestSetGetRmDir(t *testing.T) { fn := test_helpers.DefaultPlainDir + "/TestSetGetRmDir" err := syscall.Mkdir(fn, 0700) if err != nil { - t.Fatalf("creating fifo failed: %v", err) + t.Fatalf("creating directory failed: %v", err) } setGetRmList(fn) } @@ -316,3 +316,31 @@ func TestSet0200File(t *testing.T) { t.Error(err) } } + +// Listing xattrs should work even when we don't have read access +func TestList0000Dir(t *testing.T) { + fn := test_helpers.DefaultPlainDir + "/TestList0000Dir" + err := syscall.Mkdir(fn, 0000) + if err != nil { + t.Fatalf("creating directory failed: %v", err) + } + _, err = xattr.LList(fn) + os.Chmod(fn, 0700) + if err != nil { + t.Error(err) + } +} + +// Setting xattrs should work even when we don't have read access +func TestSet0200Dir(t *testing.T) { + fn := test_helpers.DefaultPlainDir + "/TestSet0200Dir" + err := syscall.Mkdir(fn, 0200) + if err != nil { + t.Fatalf("creating directory failed: %v", err) + } + err = xattr.LSet(fn, "user.foo", []byte("bar")) + os.Chmod(fn, 0700) + if err != nil { + t.Error(err) + } +} |