From a004f0d082458ce98114b59a3e5d41c2e74541d6 Mon Sep 17 00:00:00 2001 From: Dean Deng Date: Tue, 15 Sep 2020 14:50:45 -0700 Subject: Support setting STATX_SIZE for kernfs.InodeAttrs. Make setting STATX_SIZE a no-op, if it is valid for the given permissions and file type. Also update proc tests, which were overfitted before. Fixes #3842. Updates #1193. PiperOrigin-RevId: 331861087 --- pkg/sentry/fsimpl/kernfs/inode_impl_util.go | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'pkg/sentry/fsimpl') diff --git a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go index c0b863ba4..74408e322 100644 --- a/pkg/sentry/fsimpl/kernfs/inode_impl_util.go +++ b/pkg/sentry/fsimpl/kernfs/inode_impl_util.go @@ -259,9 +259,19 @@ func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *aut if opts.Stat.Mask == 0 { return nil } - if opts.Stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID) != 0 { + + // Note that not all fields are modifiable. For example, the file type and + // inode numbers are immutable after node creation. Setting the size is often + // allowed by kernfs files but does not do anything. If some other behavior is + // needed, the embedder should consider extending SetStat. + // + // TODO(gvisor.dev/issue/1193): Implement other stat fields like timestamps. + if opts.Stat.Mask&^(linux.STATX_MODE|linux.STATX_UID|linux.STATX_GID|linux.STATX_SIZE) != 0 { return syserror.EPERM } + if opts.Stat.Mask&linux.STATX_SIZE != 0 && a.Mode().IsDir() { + return syserror.EISDIR + } if err := vfs.CheckSetStat(ctx, creds, &opts, a.Mode(), auth.KUID(atomic.LoadUint32(&a.uid)), auth.KGID(atomic.LoadUint32(&a.gid))); err != nil { return err } @@ -284,13 +294,6 @@ func (a *InodeAttrs) SetStat(ctx context.Context, fs *vfs.Filesystem, creds *aut atomic.StoreUint32(&a.gid, stat.GID) } - // Note that not all fields are modifiable. For example, the file type and - // inode numbers are immutable after node creation. - - // TODO(gvisor.dev/issue/1193): Implement other stat fields like timestamps. - // Also, STATX_SIZE will need some special handling, because read-only static - // files should return EIO for truncate operations. - return nil } -- cgit v1.2.3