diff options
-rwxr-xr-x | pkg/sentry/vfs/file_description.go | 49 | ||||
-rwxr-xr-x | pkg/sentry/vfs/file_description_impl_util.go | 25 | ||||
-rwxr-xr-x | pkg/sentry/vfs/filesystem.go | 16 | ||||
-rwxr-xr-x | pkg/sentry/vfs/options.go | 14 | ||||
-rwxr-xr-x | pkg/sentry/vfs/testutil.go | 20 | ||||
-rwxr-xr-x | pkg/sentry/vfs/vfs.go | 87 |
6 files changed, 209 insertions, 2 deletions
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go index 6575afd16..c5a9adca3 100755 --- a/pkg/sentry/vfs/file_description.go +++ b/pkg/sentry/vfs/file_description.go @@ -22,6 +22,7 @@ import ( "gvisor.dev/gvisor/pkg/sentry/context" "gvisor.dev/gvisor/pkg/sentry/memmap" "gvisor.dev/gvisor/pkg/sentry/usermem" + "gvisor.dev/gvisor/pkg/syserror" "gvisor.dev/gvisor/pkg/waiter" ) @@ -212,7 +213,21 @@ type FileDescriptionImpl interface { // Ioctl implements the ioctl(2) syscall. Ioctl(ctx context.Context, uio usermem.IO, args arch.SyscallArguments) (uintptr, error) - // TODO: extended attributes; file locking + // Listxattr returns all extended attribute names for the file. + Listxattr(ctx context.Context) ([]string, error) + + // Getxattr returns the value associated with the given extended attribute + // for the file. + Getxattr(ctx context.Context, name string) (string, error) + + // Setxattr changes the value associated with the given extended attribute + // for the file. + Setxattr(ctx context.Context, opts SetxattrOptions) error + + // Removexattr removes the given extended attribute from the file. + Removexattr(ctx context.Context, name string) error + + // TODO: file locking } // Dirent holds the information contained in struct linux_dirent64. @@ -329,6 +344,38 @@ func (fd *FileDescription) Ioctl(ctx context.Context, uio usermem.IO, args arch. return fd.impl.Ioctl(ctx, uio, args) } +// Listxattr returns all extended attribute names for the file represented by +// fd. +func (fd *FileDescription) Listxattr(ctx context.Context) ([]string, error) { + names, err := fd.impl.Listxattr(ctx) + if err == syserror.ENOTSUP { + // Linux doesn't actually return ENOTSUP in this case; instead, + // fs/xattr.c:vfs_listxattr() falls back to allowing the security + // subsystem to return security extended attributes, which by default + // don't exist. + return nil, nil + } + return names, err +} + +// Getxattr returns the value associated with the given extended attribute for +// the file represented by fd. +func (fd *FileDescription) Getxattr(ctx context.Context, name string) (string, error) { + return fd.impl.Getxattr(ctx, name) +} + +// Setxattr changes the value associated with the given extended attribute for +// the file represented by fd. +func (fd *FileDescription) Setxattr(ctx context.Context, opts SetxattrOptions) error { + return fd.impl.Setxattr(ctx, opts) +} + +// Removexattr removes the given extended attribute from the file represented +// by fd. +func (fd *FileDescription) Removexattr(ctx context.Context, name string) error { + return fd.impl.Removexattr(ctx, name) +} + // SyncFS instructs the filesystem containing fd to execute the semantics of // syncfs(2). func (fd *FileDescription) SyncFS(ctx context.Context) error { diff --git a/pkg/sentry/vfs/file_description_impl_util.go b/pkg/sentry/vfs/file_description_impl_util.go index aae023254..3df49991c 100755 --- a/pkg/sentry/vfs/file_description_impl_util.go +++ b/pkg/sentry/vfs/file_description_impl_util.go @@ -127,6 +127,31 @@ func (FileDescriptionDefaultImpl) Ioctl(ctx context.Context, uio usermem.IO, arg return 0, syserror.ENOTTY } +// Listxattr implements FileDescriptionImpl.Listxattr analogously to +// inode_operations::listxattr == NULL in Linux. +func (FileDescriptionDefaultImpl) Listxattr(ctx context.Context) ([]string, error) { + // This isn't exactly accurate; see FileDescription.Listxattr. + return nil, syserror.ENOTSUP +} + +// Getxattr implements FileDescriptionImpl.Getxattr analogously to +// inode::i_opflags & IOP_XATTR == 0 in Linux. +func (FileDescriptionDefaultImpl) Getxattr(ctx context.Context, name string) (string, error) { + return "", syserror.ENOTSUP +} + +// Setxattr implements FileDescriptionImpl.Setxattr analogously to +// inode::i_opflags & IOP_XATTR == 0 in Linux. +func (FileDescriptionDefaultImpl) Setxattr(ctx context.Context, opts SetxattrOptions) error { + return syserror.ENOTSUP +} + +// Removexattr implements FileDescriptionImpl.Removexattr analogously to +// inode::i_opflags & IOP_XATTR == 0 in Linux. +func (FileDescriptionDefaultImpl) Removexattr(ctx context.Context, name string) error { + return syserror.ENOTSUP +} + // DirectoryFileDescriptionDefaultImpl may be embedded by implementations of // FileDescriptionImpl that always represent directories to obtain // implementations of non-directory I/O methods that return EISDIR. diff --git a/pkg/sentry/vfs/filesystem.go b/pkg/sentry/vfs/filesystem.go index 8011eba3f..b766614e7 100755 --- a/pkg/sentry/vfs/filesystem.go +++ b/pkg/sentry/vfs/filesystem.go @@ -186,6 +186,20 @@ type FilesystemImpl interface { // UnlinkAt removes the non-directory file at rp. UnlinkAt(ctx context.Context, rp *ResolvingPath) error + // ListxattrAt returns all extended attribute names for the file at rp. + ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) + + // GetxattrAt returns the value associated with the given extended + // attribute for the file at rp. + GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) + + // SetxattrAt changes the value associated with the given extended + // attribute for the file at rp. + SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error + + // RemovexattrAt removes the given extended attribute from the file at rp. + RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error + // PrependPath prepends a path from vd to vd.Mount().Root() to b. // // If vfsroot.Ok(), it is the contextual VFS root; if it is encountered @@ -208,7 +222,7 @@ type FilesystemImpl interface { // Preconditions: vd.Mount().Filesystem().Impl() == this FilesystemImpl. PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error - // TODO: extended attributes; inotify_add_watch(); bind() + // TODO: inotify_add_watch(); bind() } // PrependPathAtVFSRootError is returned by implementations of diff --git a/pkg/sentry/vfs/options.go b/pkg/sentry/vfs/options.go index 3ecbc8fc1..97ee4a446 100755 --- a/pkg/sentry/vfs/options.go +++ b/pkg/sentry/vfs/options.go @@ -101,6 +101,20 @@ type SetStatOptions struct { Stat linux.Statx } +// SetxattrOptions contains options to VirtualFilesystem.SetxattrAt(), +// FilesystemImpl.SetxattrAt(), FileDescription.Setxattr(), and +// FileDescriptionImpl.Setxattr(). +type SetxattrOptions struct { + // Name is the name of the extended attribute being mutated. + Name string + + // Value is the extended attribute's new value. + Value string + + // Flags contains flags as specified for setxattr/lsetxattr/fsetxattr(2). + Flags uint32 +} + // StatOptions contains options to VirtualFilesystem.StatAt(), // FilesystemImpl.StatAt(), FileDescription.Stat(), and // FileDescriptionImpl.Stat(). diff --git a/pkg/sentry/vfs/testutil.go b/pkg/sentry/vfs/testutil.go index 7a1d9e383..d94117bce 100755 --- a/pkg/sentry/vfs/testutil.go +++ b/pkg/sentry/vfs/testutil.go @@ -117,6 +117,26 @@ func (fs *FDTestFilesystem) UnlinkAt(ctx context.Context, rp *ResolvingPath) err return syserror.EPERM } +// ListxattrAt implements FilesystemImpl.ListxattrAt. +func (fs *FDTestFilesystem) ListxattrAt(ctx context.Context, rp *ResolvingPath) ([]string, error) { + return nil, syserror.EPERM +} + +// GetxattrAt implements FilesystemImpl.GetxattrAt. +func (fs *FDTestFilesystem) GetxattrAt(ctx context.Context, rp *ResolvingPath, name string) (string, error) { + return "", syserror.EPERM +} + +// SetxattrAt implements FilesystemImpl.SetxattrAt. +func (fs *FDTestFilesystem) SetxattrAt(ctx context.Context, rp *ResolvingPath, opts SetxattrOptions) error { + return syserror.EPERM +} + +// RemovexattrAt implements FilesystemImpl.RemovexattrAt. +func (fs *FDTestFilesystem) RemovexattrAt(ctx context.Context, rp *ResolvingPath, name string) error { + return syserror.EPERM +} + // PrependPath implements FilesystemImpl.PrependPath. func (fs *FDTestFilesystem) PrependPath(ctx context.Context, vfsroot, vd VirtualDentry, b *fspath.Builder) error { b.PrependComponent(fmt.Sprintf("vfs.fdTestDentry:%p", vd.dentry.impl.(*fdTestDentry))) diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go index 7262b0d0a..e60898d7c 100755 --- a/pkg/sentry/vfs/vfs.go +++ b/pkg/sentry/vfs/vfs.go @@ -440,6 +440,93 @@ func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credenti } } +// ListxattrAt returns all extended attribute names for the file at the given +// path. +func (vfs *VirtualFilesystem) ListxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) ([]string, error) { + rp, err := vfs.getResolvingPath(creds, pop) + if err != nil { + return nil, err + } + for { + names, err := rp.mount.fs.impl.ListxattrAt(ctx, rp) + if err == nil { + vfs.putResolvingPath(rp) + return names, nil + } + if err == syserror.ENOTSUP { + // Linux doesn't actually return ENOTSUP in this case; instead, + // fs/xattr.c:vfs_listxattr() falls back to allowing the security + // subsystem to return security extended attributes, which by + // default don't exist. + vfs.putResolvingPath(rp) + return nil, nil + } + if !rp.handleError(err) { + vfs.putResolvingPath(rp) + return nil, err + } + } +} + +// GetxattrAt returns the value associated with the given extended attribute +// for the file at the given path. +func (vfs *VirtualFilesystem) GetxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, name string) (string, error) { + rp, err := vfs.getResolvingPath(creds, pop) + if err != nil { + return "", err + } + for { + val, err := rp.mount.fs.impl.GetxattrAt(ctx, rp, name) + if err == nil { + vfs.putResolvingPath(rp) + return val, nil + } + if !rp.handleError(err) { + vfs.putResolvingPath(rp) + return "", err + } + } +} + +// SetxattrAt changes the value associated with the given extended attribute +// for the file at the given path. +func (vfs *VirtualFilesystem) SetxattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *SetxattrOptions) error { + rp, err := vfs.getResolvingPath(creds, pop) + if err != nil { + return err + } + for { + err := rp.mount.fs.impl.SetxattrAt(ctx, rp, *opts) + if err == nil { + vfs.putResolvingPath(rp) + return nil + } + if !rp.handleError(err) { + vfs.putResolvingPath(rp) + return err + } + } +} + +// RemovexattrAt removes the given extended attribute from the file at rp. +func (vfs *VirtualFilesystem) RemovexattrAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, name string) error { + rp, err := vfs.getResolvingPath(creds, pop) + if err != nil { + return err + } + for { + err := rp.mount.fs.impl.RemovexattrAt(ctx, rp, name) + if err == nil { + vfs.putResolvingPath(rp) + return nil + } + if !rp.handleError(err) { + vfs.putResolvingPath(rp) + return err + } + } +} + // SyncAllFilesystems has the semantics of Linux's sync(2). func (vfs *VirtualFilesystem) SyncAllFilesystems(ctx context.Context) error { fss := make(map[*Filesystem]struct{}) |