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-rw-r--r--pkg/sentry/fsimpl/gofer/filesystem.go35
-rw-r--r--pkg/sentry/fsimpl/gofer/special_file.go28
2 files changed, 39 insertions, 24 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index 7ca0cf3f4..7f2181216 100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
@@ -877,10 +877,15 @@ func (d *dentry) openSpecialFileLocked(ctx context.Context, mnt *vfs.Mount, opts
if err != nil {
return nil, err
}
+ seekable := d.fileType() == linux.S_IFREG
fd := &specialFileFD{
- handle: h,
+ handle: h,
+ seekable: seekable,
}
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &d.vfsd, &vfs.FileDescriptionOptions{
+ DenyPRead: !seekable,
+ DenyPWrite: !seekable,
+ }); err != nil {
h.close(ctx)
return nil, err
}
@@ -911,7 +916,11 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
creds := rp.Credentials()
name := rp.Component()
- fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, (p9.OpenFlags)(opts.Flags), (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
+ // Filter file creation flags and O_LARGEFILE out; the create RPC already
+ // has the semantics of O_CREAT|O_EXCL, while some servers will choke on
+ // O_LARGEFILE.
+ createFlags := p9.OpenFlags(opts.Flags &^ (linux.O_CREAT | linux.O_EXCL | linux.O_NOCTTY | linux.O_TRUNC | linux.O_LARGEFILE))
+ fdobj, openFile, createQID, _, err := dirfile.create(ctx, name, createFlags, (p9.FileMode)(opts.Mode), (p9.UID)(creds.EffectiveKUID), (p9.GID)(creds.EffectiveKGID))
if err != nil {
dirfile.close(ctx)
return nil, err
@@ -919,7 +928,7 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
// Then we need to walk to the file we just created to get a non-open fid
// representing it, and to get its metadata. This must use d.file since, as
// explained above, dirfile was invalidated by dirfile.Create().
- walkQID, nonOpenFile, attrMask, attr, err := d.file.walkGetAttrOne(ctx, name)
+ _, nonOpenFile, attrMask, attr, err := d.file.walkGetAttrOne(ctx, name)
if err != nil {
openFile.close(ctx)
if fdobj != nil {
@@ -927,17 +936,6 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
return nil, err
}
- // Sanity-check that we walked to the file we created.
- if createQID.Path != walkQID.Path {
- // Probably due to concurrent remote filesystem mutation?
- ctx.Warningf("gofer.dentry.createAndOpenChildLocked: created file has QID %v before walk, QID %v after (interop=%v)", createQID, walkQID, d.fs.opts.interop)
- nonOpenFile.close(ctx)
- openFile.close(ctx)
- if fdobj != nil {
- fdobj.Close()
- }
- return nil, syserror.EAGAIN
- }
// Construct the new dentry.
child, err := d.fs.newDentry(ctx, nonOpenFile, createQID, attrMask, &attr)
@@ -983,16 +981,21 @@ func (d *dentry) createAndOpenChildLocked(ctx context.Context, rp *vfs.Resolving
}
childVFSFD = &fd.vfsfd
} else {
+ seekable := child.fileType() == linux.S_IFREG
fd := &specialFileFD{
handle: handle{
file: openFile,
fd: -1,
},
+ seekable: seekable,
}
if fdobj != nil {
fd.handle.fd = int32(fdobj.Release())
}
- if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{}); err != nil {
+ if err := fd.vfsfd.Init(fd, opts.Flags, mnt, &child.vfsd, &vfs.FileDescriptionOptions{
+ DenyPRead: !seekable,
+ DenyPWrite: !seekable,
+ }); err != nil {
fd.handle.close(ctx)
return nil, err
}
diff --git a/pkg/sentry/fsimpl/gofer/special_file.go b/pkg/sentry/fsimpl/gofer/special_file.go
index 507e0e276..a464e6a94 100644
--- a/pkg/sentry/fsimpl/gofer/special_file.go
+++ b/pkg/sentry/fsimpl/gofer/special_file.go
@@ -33,13 +33,14 @@ import (
type specialFileFD struct {
fileDescription
- // handle is immutable.
+ // handle is used for file I/O. handle is immutable.
handle handle
- // off is the file offset. off is protected by mu. (POSIX 2.9.7 only
- // requires operations using the file offset to be atomic for regular files
- // and symlinks; however, since specialFileFD may be used for regular
- // files, we apply this atomicity unconditionally.)
+ // seekable is true if this file description represents a file for which
+ // file offset is significant, i.e. a regular file. seekable is immutable.
+ seekable bool
+
+ // If seekable is true, off is the file offset. off is protected by mu.
mu sync.Mutex
off int64
}
@@ -63,7 +64,7 @@ func (fd *specialFileFD) OnClose(ctx context.Context) error {
// PRead implements vfs.FileDescriptionImpl.PRead.
func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offset int64, opts vfs.ReadOptions) (int64, error) {
- if offset < 0 {
+ if fd.seekable && offset < 0 {
return 0, syserror.EINVAL
}
if opts.Flags != 0 {
@@ -91,6 +92,10 @@ func (fd *specialFileFD) PRead(ctx context.Context, dst usermem.IOSequence, offs
// Read implements vfs.FileDescriptionImpl.Read.
func (fd *specialFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts vfs.ReadOptions) (int64, error) {
+ if !fd.seekable {
+ return fd.PRead(ctx, dst, -1, opts)
+ }
+
fd.mu.Lock()
n, err := fd.PRead(ctx, dst, fd.off, opts)
fd.off += n
@@ -100,14 +105,14 @@ func (fd *specialFileFD) Read(ctx context.Context, dst usermem.IOSequence, opts
// PWrite implements vfs.FileDescriptionImpl.PWrite.
func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, offset int64, opts vfs.WriteOptions) (int64, error) {
- if offset < 0 {
+ if fd.seekable && offset < 0 {
return 0, syserror.EINVAL
}
if opts.Flags != 0 {
return 0, syserror.EOPNOTSUPP
}
- if fd.dentry().fileType() == linux.S_IFREG {
+ if fd.seekable {
limit, err := vfs.CheckLimit(ctx, offset, src.NumBytes())
if err != nil {
return 0, err
@@ -130,6 +135,10 @@ func (fd *specialFileFD) PWrite(ctx context.Context, src usermem.IOSequence, off
// Write implements vfs.FileDescriptionImpl.Write.
func (fd *specialFileFD) Write(ctx context.Context, src usermem.IOSequence, opts vfs.WriteOptions) (int64, error) {
+ if !fd.seekable {
+ return fd.PWrite(ctx, src, -1, opts)
+ }
+
fd.mu.Lock()
n, err := fd.PWrite(ctx, src, fd.off, opts)
fd.off += n
@@ -139,6 +148,9 @@ func (fd *specialFileFD) Write(ctx context.Context, src usermem.IOSequence, opts
// Seek implements vfs.FileDescriptionImpl.Seek.
func (fd *specialFileFD) Seek(ctx context.Context, offset int64, whence int32) (int64, error) {
+ if !fd.seekable {
+ return 0, syserror.ESPIPE
+ }
fd.mu.Lock()
defer fd.mu.Unlock()
switch whence {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 05:24:30 +0000