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-rw-r--r--pkg/sentry/fsimpl/ext/file_description.go19
-rw-r--r--pkg/sentry/fsimpl/ext/inode.go9
-rw-r--r--pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go16
-rw-r--r--pkg/sentry/fsimpl/kernfs/fd_impl_util.go16
-rw-r--r--pkg/sentry/fsimpl/memfs/filesystem.go11
-rw-r--r--pkg/sentry/fsimpl/memfs/memfs.go14
-rw-r--r--pkg/sentry/fsimpl/memfs/named_pipe.go2
-rw-r--r--pkg/sentry/vfs/file_description.go141
-rw-r--r--pkg/sentry/vfs/file_description_impl_util_test.go2
9 files changed, 107 insertions, 123 deletions
diff --git a/pkg/sentry/fsimpl/ext/file_description.go b/pkg/sentry/fsimpl/ext/file_description.go
index 5eca2b83f..841274daf 100644
--- a/pkg/sentry/fsimpl/ext/file_description.go
+++ b/pkg/sentry/fsimpl/ext/file_description.go
@@ -26,13 +26,6 @@ import (
type fileDescription struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
-
- // flags is the same as vfs.OpenOptions.Flags which are passed to
- // vfs.FilesystemImpl.OpenAt.
- // TODO(b/134676337): syscalls like read(2), write(2), fchmod(2), fchown(2),
- // fgetxattr(2), ioctl(2), mmap(2) should fail with EBADF if O_PATH is set.
- // Only close(2), fstat(2), fstatfs(2) should work.
- flags uint32
}
func (fd *fileDescription) filesystem() *filesystem {
@@ -43,18 +36,6 @@ func (fd *fileDescription) inode() *inode {
return fd.vfsfd.Dentry().Impl().(*dentry).inode
}
-// StatusFlags implements vfs.FileDescriptionImpl.StatusFlags.
-func (fd *fileDescription) StatusFlags(ctx context.Context) (uint32, error) {
- return fd.flags, nil
-}
-
-// SetStatusFlags implements vfs.FileDescriptionImpl.SetStatusFlags.
-func (fd *fileDescription) SetStatusFlags(ctx context.Context, flags uint32) error {
- // None of the flags settable by fcntl(F_SETFL) are supported, so this is a
- // no-op.
- return nil
-}
-
// Stat implements vfs.FileDescriptionImpl.Stat.
func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
var stat linux.Statx
diff --git a/pkg/sentry/fsimpl/ext/inode.go b/pkg/sentry/fsimpl/ext/inode.go
index 24249525c..b2cc826c7 100644
--- a/pkg/sentry/fsimpl/ext/inode.go
+++ b/pkg/sentry/fsimpl/ext/inode.go
@@ -157,10 +157,9 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32) (*v
switch in.impl.(type) {
case *regularFile:
var fd regularFileFD
- fd.flags = flags
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
return &fd.vfsfd, nil
case *directory:
// Can't open directories writably. This check is not necessary for a read
@@ -169,10 +168,9 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32) (*v
return nil, syserror.EISDIR
}
var fd directoryFD
- fd.flags = flags
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
return &fd.vfsfd, nil
case *symlink:
if flags&linux.O_PATH == 0 {
@@ -180,10 +178,9 @@ func (in *inode) open(rp *vfs.ResolvingPath, vfsd *vfs.Dentry, flags uint32) (*v
return nil, syserror.ELOOP
}
var fd symlinkFD
- fd.flags = flags
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
return &fd.vfsfd, nil
default:
panic(fmt.Sprintf("unknown inode type: %T", in.impl))
diff --git a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
index 30c06baf0..51102ce48 100644
--- a/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
+++ b/pkg/sentry/fsimpl/kernfs/dynamic_bytes_file.go
@@ -65,17 +65,15 @@ type DynamicBytesFD struct {
vfsfd vfs.FileDescription
inode Inode
- flags uint32
}
// Init initializes a DynamicBytesFD.
func (fd *DynamicBytesFD) Init(m *vfs.Mount, d *vfs.Dentry, data vfs.DynamicBytesSource, flags uint32) {
m.IncRef() // DecRef in vfs.FileDescription.vd.DecRef on final ref.
d.IncRef() // DecRef in vfs.FileDescription.vd.DecRef on final ref.
- fd.flags = flags
fd.inode = d.Impl().(*Dentry).inode
fd.SetDataSource(data)
- fd.vfsfd.Init(fd, m, d)
+ fd.vfsfd.Init(fd, flags, m, d, &vfs.FileDescriptionOptions{})
}
// Seek implements vfs.FileDescriptionImpl.Seek.
@@ -117,15 +115,3 @@ func (fd *DynamicBytesFD) SetStat(context.Context, vfs.SetStatOptions) error {
// DynamicBytesFiles are immutable.
return syserror.EPERM
}
-
-// StatusFlags implements vfs.FileDescriptionImpl.StatusFlags.
-func (fd *DynamicBytesFD) StatusFlags(ctx context.Context) (uint32, error) {
- return fd.flags, nil
-}
-
-// SetStatusFlags implements vfs.FileDescriptionImpl.SetStatusFlags.
-func (fd *DynamicBytesFD) SetStatusFlags(ctx context.Context, flags uint32) error {
- // None of the flags settable by fcntl(F_SETFL) are supported, so this is a
- // no-op.
- return nil
-}
diff --git a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
index d6c18937a..bd402330f 100644
--- a/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
+++ b/pkg/sentry/fsimpl/kernfs/fd_impl_util.go
@@ -39,7 +39,6 @@ type GenericDirectoryFD struct {
vfsfd vfs.FileDescription
children *OrderedChildren
- flags uint32
off int64
}
@@ -48,8 +47,7 @@ func (fd *GenericDirectoryFD) Init(m *vfs.Mount, d *vfs.Dentry, children *Ordere
m.IncRef() // DecRef in vfs.FileDescription.vd.DecRef on final ref.
d.IncRef() // DecRef in vfs.FileDescription.vd.DecRef on final ref.
fd.children = children
- fd.flags = flags
- fd.vfsfd.Init(fd, m, d)
+ fd.vfsfd.Init(fd, flags, m, d, &vfs.FileDescriptionOptions{})
}
// VFSFileDescription returns a pointer to the vfs.FileDescription representing
@@ -180,18 +178,6 @@ func (fd *GenericDirectoryFD) Seek(ctx context.Context, offset int64, whence int
return offset, nil
}
-// StatusFlags implements vfs.FileDescriptionImpl.StatusFlags.
-func (fd *GenericDirectoryFD) StatusFlags(ctx context.Context) (uint32, error) {
- return fd.flags, nil
-}
-
-// SetStatusFlags implements vfs.FileDescriptionImpl.SetStatusFlags.
-func (fd *GenericDirectoryFD) SetStatusFlags(ctx context.Context, flags uint32) error {
- // None of the flags settable by fcntl(F_SETFL) are supported, so this is a
- // no-op.
- return nil
-}
-
// Stat implements vfs.FileDescriptionImpl.Stat.
func (fd *GenericDirectoryFD) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
fs := fd.filesystem()
diff --git a/pkg/sentry/fsimpl/memfs/filesystem.go b/pkg/sentry/fsimpl/memfs/filesystem.go
index 22f1e811f..af4389459 100644
--- a/pkg/sentry/fsimpl/memfs/filesystem.go
+++ b/pkg/sentry/fsimpl/memfs/filesystem.go
@@ -282,9 +282,8 @@ func (fs *filesystem) MknodAt(ctx context.Context, rp *vfs.ResolvingPath, opts v
func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vfs.OpenOptions) (*vfs.FileDescription, error) {
// Filter out flags that are not supported by memfs. O_DIRECTORY and
// O_NOFOLLOW have no effect here (they're handled by VFS by setting
- // appropriate bits in rp), but are returned by
- // FileDescriptionImpl.StatusFlags(). O_NONBLOCK is supported only by
- // pipes.
+ // appropriate bits in rp), but are visible in FD status flags. O_NONBLOCK
+ // is supported only by pipes.
opts.Flags &= linux.O_ACCMODE | linux.O_CREAT | linux.O_EXCL | linux.O_TRUNC | linux.O_DIRECTORY | linux.O_NOFOLLOW | linux.O_NONBLOCK
if opts.Flags&linux.O_CREAT == 0 {
@@ -384,7 +383,6 @@ func (i *inode) open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentr
switch impl := i.impl.(type) {
case *regularFile:
var fd regularFileFD
- fd.flags = flags
fd.readable = vfs.MayReadFileWithOpenFlags(flags)
fd.writable = vfs.MayWriteFileWithOpenFlags(flags)
if fd.writable {
@@ -395,7 +393,7 @@ func (i *inode) open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentr
}
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
if flags&linux.O_TRUNC != 0 {
impl.mu.Lock()
impl.data = impl.data[:0]
@@ -411,8 +409,7 @@ func (i *inode) open(ctx context.Context, rp *vfs.ResolvingPath, vfsd *vfs.Dentr
var fd directoryFD
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
- fd.flags = flags
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
return &fd.vfsfd, nil
case *symlink:
// Can't open symlinks without O_PATH (which is unimplemented).
diff --git a/pkg/sentry/fsimpl/memfs/memfs.go b/pkg/sentry/fsimpl/memfs/memfs.go
index 4cb2a4e0f..9d509f6e4 100644
--- a/pkg/sentry/fsimpl/memfs/memfs.go
+++ b/pkg/sentry/fsimpl/memfs/memfs.go
@@ -261,8 +261,6 @@ func (i *inode) direntType() uint8 {
type fileDescription struct {
vfsfd vfs.FileDescription
vfs.FileDescriptionDefaultImpl
-
- flags uint32 // status flags; immutable
}
func (fd *fileDescription) filesystem() *filesystem {
@@ -273,18 +271,6 @@ func (fd *fileDescription) inode() *inode {
return fd.vfsfd.Dentry().Impl().(*dentry).inode
}
-// StatusFlags implements vfs.FileDescriptionImpl.StatusFlags.
-func (fd *fileDescription) StatusFlags(ctx context.Context) (uint32, error) {
- return fd.flags, nil
-}
-
-// SetStatusFlags implements vfs.FileDescriptionImpl.SetStatusFlags.
-func (fd *fileDescription) SetStatusFlags(ctx context.Context, flags uint32) error {
- // None of the flags settable by fcntl(F_SETFL) are supported, so this is a
- // no-op.
- return nil
-}
-
// Stat implements vfs.FileDescriptionImpl.Stat.
func (fd *fileDescription) Stat(ctx context.Context, opts vfs.StatOptions) (linux.Statx, error) {
var stat linux.Statx
diff --git a/pkg/sentry/fsimpl/memfs/named_pipe.go b/pkg/sentry/fsimpl/memfs/named_pipe.go
index 91cb4b1fc..d5060850e 100644
--- a/pkg/sentry/fsimpl/memfs/named_pipe.go
+++ b/pkg/sentry/fsimpl/memfs/named_pipe.go
@@ -57,6 +57,6 @@ func newNamedPipeFD(ctx context.Context, np *namedPipe, rp *vfs.ResolvingPath, v
mnt := rp.Mount()
mnt.IncRef()
vfsd.IncRef()
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, flags, mnt, vfsd, &vfs.FileDescriptionOptions{})
return &fd.vfsfd, nil
}
diff --git a/pkg/sentry/vfs/file_description.go b/pkg/sentry/vfs/file_description.go
index c5a9adca3..df03886c3 100644
--- a/pkg/sentry/vfs/file_description.go
+++ b/pkg/sentry/vfs/file_description.go
@@ -20,6 +20,7 @@ import (
"gvisor.dev/gvisor/pkg/abi/linux"
"gvisor.dev/gvisor/pkg/sentry/arch"
"gvisor.dev/gvisor/pkg/sentry/context"
+ "gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/sentry/memmap"
"gvisor.dev/gvisor/pkg/sentry/usermem"
"gvisor.dev/gvisor/pkg/syserror"
@@ -39,49 +40,43 @@ type FileDescription struct {
// operations.
refs int64
+ // statusFlags contains status flags, "initialized by open(2) and possibly
+ // modified by fcntl()" - fcntl(2). statusFlags is accessed using atomic
+ // memory operations.
+ statusFlags uint32
+
// vd is the filesystem location at which this FileDescription was opened.
// A reference is held on vd. vd is immutable.
vd VirtualDentry
+ opts FileDescriptionOptions
+
// impl is the FileDescriptionImpl associated with this Filesystem. impl is
// immutable. This should be the last field in FileDescription.
impl FileDescriptionImpl
}
+// FileDescriptionOptions contains options to FileDescription.Init().
+type FileDescriptionOptions struct {
+ // If AllowDirectIO is true, allow O_DIRECT to be set on the file. This is
+ // usually only the case if O_DIRECT would actually have an effect.
+ AllowDirectIO bool
+}
+
// Init must be called before first use of fd. It takes ownership of references
-// on mnt and d held by the caller.
-func (fd *FileDescription) Init(impl FileDescriptionImpl, mnt *Mount, d *Dentry) {
+// on mnt and d held by the caller. statusFlags is the initial file description
+// status flags, which is usually the full set of flags passed to open(2).
+func (fd *FileDescription) Init(impl FileDescriptionImpl, statusFlags uint32, mnt *Mount, d *Dentry, opts *FileDescriptionOptions) {
fd.refs = 1
+ fd.statusFlags = statusFlags | linux.O_LARGEFILE
fd.vd = VirtualDentry{
mount: mnt,
dentry: d,
}
+ fd.opts = *opts
fd.impl = impl
}
-// Impl returns the FileDescriptionImpl associated with fd.
-func (fd *FileDescription) Impl() FileDescriptionImpl {
- return fd.impl
-}
-
-// Mount returns the mount on which fd was opened. It does not take a reference
-// on the returned Mount.
-func (fd *FileDescription) Mount() *Mount {
- return fd.vd.mount
-}
-
-// Dentry returns the dentry at which fd was opened. It does not take a
-// reference on the returned Dentry.
-func (fd *FileDescription) Dentry() *Dentry {
- return fd.vd.dentry
-}
-
-// VirtualDentry returns the location at which fd was opened. It does not take
-// a reference on the returned VirtualDentry.
-func (fd *FileDescription) VirtualDentry() VirtualDentry {
- return fd.vd
-}
-
// IncRef increments fd's reference count.
func (fd *FileDescription) IncRef() {
atomic.AddInt64(&fd.refs, 1)
@@ -113,6 +108,82 @@ func (fd *FileDescription) DecRef() {
}
}
+// Mount returns the mount on which fd was opened. It does not take a reference
+// on the returned Mount.
+func (fd *FileDescription) Mount() *Mount {
+ return fd.vd.mount
+}
+
+// Dentry returns the dentry at which fd was opened. It does not take a
+// reference on the returned Dentry.
+func (fd *FileDescription) Dentry() *Dentry {
+ return fd.vd.dentry
+}
+
+// VirtualDentry returns the location at which fd was opened. It does not take
+// a reference on the returned VirtualDentry.
+func (fd *FileDescription) VirtualDentry() VirtualDentry {
+ return fd.vd
+}
+
+// StatusFlags returns file description status flags, as for fcntl(F_GETFL).
+func (fd *FileDescription) StatusFlags() uint32 {
+ return atomic.LoadUint32(&fd.statusFlags)
+}
+
+// SetStatusFlags sets file description status flags, as for fcntl(F_SETFL).
+func (fd *FileDescription) SetStatusFlags(ctx context.Context, creds *auth.Credentials, flags uint32) error {
+ // Compare Linux's fs/fcntl.c:setfl().
+ oldFlags := fd.StatusFlags()
+ // Linux documents this check as "O_APPEND cannot be cleared if the file is
+ // marked as append-only and the file is open for write", which would make
+ // sense. However, the check as actually implemented seems to be "O_APPEND
+ // cannot be changed if the file is marked as append-only".
+ if (flags^oldFlags)&linux.O_APPEND != 0 {
+ stat, err := fd.impl.Stat(ctx, StatOptions{
+ // There is no mask bit for stx_attributes.
+ Mask: 0,
+ // Linux just reads inode::i_flags directly.
+ Sync: linux.AT_STATX_DONT_SYNC,
+ })
+ if err != nil {
+ return err
+ }
+ if (stat.AttributesMask&linux.STATX_ATTR_APPEND != 0) && (stat.Attributes&linux.STATX_ATTR_APPEND != 0) {
+ return syserror.EPERM
+ }
+ }
+ if (flags&linux.O_NOATIME != 0) && (oldFlags&linux.O_NOATIME == 0) {
+ stat, err := fd.impl.Stat(ctx, StatOptions{
+ Mask: linux.STATX_UID,
+ // Linux's inode_owner_or_capable() just reads inode::i_uid
+ // directly.
+ Sync: linux.AT_STATX_DONT_SYNC,
+ })
+ if err != nil {
+ return err
+ }
+ if stat.Mask&linux.STATX_UID == 0 {
+ return syserror.EPERM
+ }
+ if !CanActAsOwner(creds, auth.KUID(stat.UID)) {
+ return syserror.EPERM
+ }
+ }
+ if flags&linux.O_DIRECT != 0 && !fd.opts.AllowDirectIO {
+ return syserror.EINVAL
+ }
+ // TODO(jamieliu): FileDescriptionImpl.SetOAsync()?
+ const settableFlags = linux.O_APPEND | linux.O_ASYNC | linux.O_DIRECT | linux.O_NOATIME | linux.O_NONBLOCK
+ atomic.StoreUint32(&fd.statusFlags, (oldFlags&^settableFlags)|(flags&settableFlags))
+ return nil
+}
+
+// Impl returns the FileDescriptionImpl associated with fd.
+func (fd *FileDescription) Impl() FileDescriptionImpl {
+ return fd.impl
+}
+
// FileDescriptionImpl contains implementation details for an FileDescription.
// Implementations of FileDescriptionImpl should contain their associated
// FileDescription by value as their first field.
@@ -132,14 +203,6 @@ type FileDescriptionImpl interface {
// prevent the file descriptor from being closed.
OnClose(ctx context.Context) error
- // StatusFlags returns file description status flags, as for
- // fcntl(F_GETFL).
- StatusFlags(ctx context.Context) (uint32, error)
-
- // SetStatusFlags sets file description status flags, as for
- // fcntl(F_SETFL).
- SetStatusFlags(ctx context.Context, flags uint32) error
-
// Stat returns metadata for the file represented by the FileDescription.
Stat(ctx context.Context, opts StatOptions) (linux.Statx, error)
@@ -264,18 +327,6 @@ func (fd *FileDescription) OnClose(ctx context.Context) error {
return fd.impl.OnClose(ctx)
}
-// StatusFlags returns file description status flags, as for fcntl(F_GETFL).
-func (fd *FileDescription) StatusFlags(ctx context.Context) (uint32, error) {
- flags, err := fd.impl.StatusFlags(ctx)
- flags |= linux.O_LARGEFILE
- return flags, err
-}
-
-// SetStatusFlags sets file description status flags, as for fcntl(F_SETFL).
-func (fd *FileDescription) SetStatusFlags(ctx context.Context, flags uint32) error {
- return fd.impl.SetStatusFlags(ctx, flags)
-}
-
// Stat returns metadata for the file represented by fd.
func (fd *FileDescription) Stat(ctx context.Context, opts StatOptions) (linux.Statx, error) {
return fd.impl.Stat(ctx, opts)
diff --git a/pkg/sentry/vfs/file_description_impl_util_test.go b/pkg/sentry/vfs/file_description_impl_util_test.go
index ac7799296..678be07fe 100644
--- a/pkg/sentry/vfs/file_description_impl_util_test.go
+++ b/pkg/sentry/vfs/file_description_impl_util_test.go
@@ -48,7 +48,7 @@ type genCountFD struct {
func newGenCountFD(mnt *Mount, vfsd *Dentry) *FileDescription {
var fd genCountFD
- fd.vfsfd.Init(&fd, mnt, vfsd)
+ fd.vfsfd.Init(&fd, 0 /* statusFlags */, mnt, vfsd, &FileDescriptionOptions{})
fd.DynamicBytesFileDescriptionImpl.SetDataSource(&fd)
return &fd.vfsfd
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 01:52:08 +0000