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-rw-r--r--pkg/sentry/fsimpl/gofer/filesystem.go32
-rw-r--r--pkg/sentry/fsimpl/kernfs/filesystem.go28
-rw-r--r--pkg/sentry/fsimpl/overlay/filesystem.go42
-rw-r--r--pkg/sentry/fsimpl/tmpfs/filesystem.go23
4 files changed, 100 insertions, 25 deletions
diff --git a/pkg/sentry/fsimpl/gofer/filesystem.go b/pkg/sentry/fsimpl/gofer/filesystem.go
index a3903db33..9a90351e5 100644
--- a/pkg/sentry/fsimpl/gofer/filesystem.go
+++ b/pkg/sentry/fsimpl/gofer/filesystem.go
@@ -834,7 +834,14 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
var ds *[]*dentry
fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckCaching(ctx, &ds)
+ unlocked := false
+ unlock := func() {
+ if !unlocked {
+ fs.renameMuRUnlockAndCheckCaching(ctx, &ds)
+ unlocked = true
+ }
+ }
+ defer unlock()
start := rp.Start().Impl().(*dentry)
if !start.cachedMetadataAuthoritative() {
@@ -851,7 +858,10 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
if mustCreate {
return nil, syserror.EEXIST
}
- return start.openLocked(ctx, rp, &opts)
+ start.IncRef()
+ defer start.DecRef(ctx)
+ unlock()
+ return start.open(ctx, rp, &opts)
}
afterTrailingSymlink:
@@ -901,11 +911,15 @@ afterTrailingSymlink:
if rp.MustBeDir() && !child.isDir() {
return nil, syserror.ENOTDIR
}
- return child.openLocked(ctx, rp, &opts)
+ child.IncRef()
+ defer child.DecRef(ctx)
+ unlock()
+ return child.open(ctx, rp, &opts)
}
-// Preconditions: fs.renameMu must be locked.
-func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
+// Preconditions: The caller must hold no locks (since opening pipes may block
+// indefinitely).
+func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
ats := vfs.AccessTypesForOpenFlags(opts)
if err := d.checkPermissions(rp.Credentials(), ats); err != nil {
return nil, err
@@ -968,7 +982,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
return nil, syserror.ENXIO
}
if d.fs.iopts.OpenSocketsByConnecting {
- return d.connectSocketLocked(ctx, opts)
+ return d.openSocketByConnecting(ctx, opts)
}
case linux.S_IFIFO:
if d.isSynthetic() {
@@ -977,7 +991,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
}
if vfd == nil {
- if vfd, err = d.openSpecialFileLocked(ctx, mnt, opts); err != nil {
+ if vfd, err = d.openSpecialFile(ctx, mnt, opts); err != nil {
return nil, err
}
}
@@ -996,7 +1010,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
return vfd, err
}
-func (d *dentry) connectSocketLocked(ctx context.Context, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
+func (d *dentry) openSocketByConnecting(ctx context.Context, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
if opts.Flags&linux.O_DIRECT != 0 {
return nil, syserror.EINVAL
}
@@ -1016,7 +1030,7 @@ func (d *dentry) connectSocketLocked(ctx context.Context, opts *vfs.OpenOptions)
return fd, nil
}
-func (d *dentry) openSpecialFileLocked(ctx context.Context, mnt *vfs.Mount, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
+func (d *dentry) openSpecialFile(ctx context.Context, mnt *vfs.Mount, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
ats := vfs.AccessTypesForOpenFlags(opts)
if opts.Flags&linux.O_DIRECT != 0 {
return nil, syserror.EINVAL
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index d7edb6342..3e5192edd 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -397,15 +397,21 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
// Do not create new file.
if opts.Flags&linux.O_CREAT == 0 {
fs.mu.RLock()
- defer fs.processDeferredDecRefs(ctx)
- defer fs.mu.RUnlock()
vfsd, inode, err := fs.walkExistingLocked(ctx, rp)
if err != nil {
+ fs.mu.RUnlock()
+ fs.processDeferredDecRefs(ctx)
return nil, err
}
if err := inode.CheckPermissions(ctx, rp.Credentials(), ats); err != nil {
+ fs.mu.RUnlock()
+ fs.processDeferredDecRefs(ctx)
return nil, err
}
+ inode.IncRef()
+ defer inode.DecRef(ctx)
+ fs.mu.RUnlock()
+ fs.processDeferredDecRefs(ctx)
return inode.Open(ctx, rp, vfsd, opts)
}
@@ -414,7 +420,14 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
vfsd := rp.Start()
inode := vfsd.Impl().(*Dentry).inode
fs.mu.Lock()
- defer fs.mu.Unlock()
+ unlocked := false
+ unlock := func() {
+ if !unlocked {
+ fs.mu.Unlock()
+ unlocked = true
+ }
+ }
+ defer unlock()
if rp.Done() {
if rp.MustBeDir() {
return nil, syserror.EISDIR
@@ -425,6 +438,9 @@ func (fs *Filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
if err := inode.CheckPermissions(ctx, rp.Credentials(), ats); err != nil {
return nil, err
}
+ inode.IncRef()
+ defer inode.DecRef(ctx)
+ unlock()
return inode.Open(ctx, rp, vfsd, opts)
}
afterTrailingSymlink:
@@ -466,6 +482,9 @@ afterTrailingSymlink:
}
child := childVFSD.Impl().(*Dentry)
parentVFSD.Impl().(*Dentry).InsertChild(pc, child)
+ child.inode.IncRef()
+ defer child.inode.DecRef(ctx)
+ unlock()
return child.inode.Open(ctx, rp, childVFSD, opts)
}
if err != nil {
@@ -499,6 +518,9 @@ afterTrailingSymlink:
if err := child.inode.CheckPermissions(ctx, rp.Credentials(), ats); err != nil {
return nil, err
}
+ child.inode.IncRef()
+ defer child.inode.DecRef(ctx)
+ unlock()
return child.inode.Open(ctx, rp, &child.vfsd, opts)
}
diff --git a/pkg/sentry/fsimpl/overlay/filesystem.go b/pkg/sentry/fsimpl/overlay/filesystem.go
index 986b36ead..86d0164b4 100644
--- a/pkg/sentry/fsimpl/overlay/filesystem.go
+++ b/pkg/sentry/fsimpl/overlay/filesystem.go
@@ -717,17 +717,33 @@ 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) {
mayCreate := opts.Flags&linux.O_CREAT != 0
mustCreate := opts.Flags&(linux.O_CREAT|linux.O_EXCL) == (linux.O_CREAT | linux.O_EXCL)
+ mayWrite := vfs.AccessTypesForOpenFlags(&opts).MayWrite()
var ds *[]*dentry
fs.renameMu.RLock()
- defer fs.renameMuRUnlockAndCheckDrop(ctx, &ds)
+ unlocked := false
+ unlock := func() {
+ if !unlocked {
+ fs.renameMuRUnlockAndCheckDrop(ctx, &ds)
+ unlocked = true
+ }
+ }
+ defer unlock()
start := rp.Start().Impl().(*dentry)
if rp.Done() {
if mustCreate {
return nil, syserror.EEXIST
}
- return start.openLocked(ctx, rp, &opts)
+ if mayWrite {
+ if err := start.copyUpLocked(ctx); err != nil {
+ return nil, err
+ }
+ }
+ start.IncRef()
+ defer start.DecRef(ctx)
+ unlock()
+ return start.openCopiedUp(ctx, rp, &opts)
}
afterTrailingSymlink:
@@ -767,20 +783,24 @@ afterTrailingSymlink:
start = parent
goto afterTrailingSymlink
}
- return child.openLocked(ctx, rp, &opts)
+ if mayWrite {
+ if err := child.copyUpLocked(ctx); err != nil {
+ return nil, err
+ }
+ }
+ child.IncRef()
+ defer child.DecRef(ctx)
+ unlock()
+ return child.openCopiedUp(ctx, rp, &opts)
}
-// Preconditions: fs.renameMu must be locked.
-func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
+// Preconditions: If vfs.AccessTypesForOpenFlags(opts).MayWrite(), then d has
+// been copied up.
+func (d *dentry) openCopiedUp(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions) (*vfs.FileDescription, error) {
ats := vfs.AccessTypesForOpenFlags(opts)
if err := d.checkPermissions(rp.Credentials(), ats); err != nil {
return nil, err
}
- if ats.MayWrite() {
- if err := d.copyUpLocked(ctx); err != nil {
- return nil, err
- }
- }
mnt := rp.Mount()
// Directory FDs open FDs from each layer when directory entries are read,
@@ -792,7 +812,7 @@ func (d *dentry) openLocked(ctx context.Context, rp *vfs.ResolvingPath, opts *vf
return nil, syserror.EISDIR
}
// Can't open directories writably.
- if ats&vfs.MayWrite != 0 {
+ if ats.MayWrite() {
return nil, syserror.EISDIR
}
if opts.Flags&linux.O_DIRECT != 0 {
diff --git a/pkg/sentry/fsimpl/tmpfs/filesystem.go b/pkg/sentry/fsimpl/tmpfs/filesystem.go
index cb8b2d944..b0ec177e6 100644
--- a/pkg/sentry/fsimpl/tmpfs/filesystem.go
+++ b/pkg/sentry/fsimpl/tmpfs/filesystem.go
@@ -307,18 +307,28 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
// don't need fs.mu for writing.
if opts.Flags&linux.O_CREAT == 0 {
fs.mu.RLock()
- defer fs.mu.RUnlock()
d, err := resolveLocked(ctx, rp)
if err != nil {
+ fs.mu.RUnlock()
return nil, err
}
+ d.IncRef()
+ defer d.DecRef(ctx)
+ fs.mu.RUnlock()
return d.open(ctx, rp, &opts, false /* afterCreate */)
}
mustCreate := opts.Flags&linux.O_EXCL != 0
start := rp.Start().Impl().(*dentry)
fs.mu.Lock()
- defer fs.mu.Unlock()
+ unlocked := false
+ unlock := func() {
+ if !unlocked {
+ fs.mu.Unlock()
+ unlocked = true
+ }
+ }
+ defer unlock()
if rp.Done() {
// Reject attempts to open mount root directory with O_CREAT.
if rp.MustBeDir() {
@@ -327,6 +337,9 @@ func (fs *filesystem) OpenAt(ctx context.Context, rp *vfs.ResolvingPath, opts vf
if mustCreate {
return nil, syserror.EEXIST
}
+ start.IncRef()
+ defer start.DecRef(ctx)
+ unlock()
return start.open(ctx, rp, &opts, false /* afterCreate */)
}
afterTrailingSymlink:
@@ -364,6 +377,7 @@ afterTrailingSymlink:
creds := rp.Credentials()
child := fs.newDentry(fs.newRegularFile(creds.EffectiveKUID, creds.EffectiveKGID, opts.Mode))
parentDir.insertChildLocked(child, name)
+ unlock()
fd, err := child.open(ctx, rp, &opts, true)
if err != nil {
return nil, err
@@ -392,9 +406,14 @@ afterTrailingSymlink:
if rp.MustBeDir() && !child.inode.isDir() {
return nil, syserror.ENOTDIR
}
+ child.IncRef()
+ defer child.DecRef(ctx)
+ unlock()
return child.open(ctx, rp, &opts, false)
}
+// Preconditions: The caller must hold no locks (since opening pipes may block
+// indefinitely).
func (d *dentry) open(ctx context.Context, rp *vfs.ResolvingPath, opts *vfs.OpenOptions, afterCreate bool) (*vfs.FileDescription, error) {
ats := vfs.AccessTypesForOpenFlags(opts)
if !afterCreate {
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-05 23:40:55 +0000