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Diffstat (limited to 'pkg/sentry/vfs/vfs.go')
-rw-r--r--pkg/sentry/vfs/vfs.go332
1 files changed, 269 insertions, 63 deletions
diff --git a/pkg/sentry/vfs/vfs.go b/pkg/sentry/vfs/vfs.go
index 7262b0d0a..ea2db7031 100644
--- a/pkg/sentry/vfs/vfs.go
+++ b/pkg/sentry/vfs/vfs.go
@@ -28,9 +28,11 @@
package vfs
import (
+ "fmt"
"sync"
"gvisor.dev/gvisor/pkg/abi/linux"
+ "gvisor.dev/gvisor/pkg/fspath"
"gvisor.dev/gvisor/pkg/sentry/context"
"gvisor.dev/gvisor/pkg/sentry/kernel/auth"
"gvisor.dev/gvisor/pkg/syserror"
@@ -73,23 +75,29 @@ type VirtualFilesystem struct {
// mountpoints is analogous to Linux's mountpoint_hashtable.
mountpoints map[*Dentry]map[*Mount]struct{}
+ // devices contains all registered Devices. devices is protected by
+ // devicesMu.
+ devicesMu sync.RWMutex
+ devices map[devTuple]*registeredDevice
+
+ // fsTypes contains all registered FilesystemTypes. fsTypes is protected by
+ // fsTypesMu.
+ fsTypesMu sync.RWMutex
+ fsTypes map[string]*registeredFilesystemType
+
// filesystems contains all Filesystems. filesystems is protected by
// filesystemsMu.
filesystemsMu sync.Mutex
filesystems map[*Filesystem]struct{}
-
- // fsTypes contains all FilesystemTypes that are usable in the
- // VirtualFilesystem. fsTypes is protected by fsTypesMu.
- fsTypesMu sync.RWMutex
- fsTypes map[string]FilesystemType
}
// New returns a new VirtualFilesystem with no mounts or FilesystemTypes.
func New() *VirtualFilesystem {
vfs := &VirtualFilesystem{
mountpoints: make(map[*Dentry]map[*Mount]struct{}),
+ devices: make(map[devTuple]*registeredDevice),
+ fsTypes: make(map[string]*registeredFilesystemType),
filesystems: make(map[*Filesystem]struct{}),
- fsTypes: make(map[string]FilesystemType),
}
vfs.mounts.Init()
return vfs
@@ -111,11 +119,11 @@ type PathOperation struct {
// are borrowed from the provider of the PathOperation (i.e. the caller of
// the VFS method to which the PathOperation was passed).
//
- // Invariants: Start.Ok(). If Pathname.Absolute, then Start == Root.
+ // Invariants: Start.Ok(). If Path.Absolute, then Start == Root.
Start VirtualDentry
// Path is the pathname traversed by this operation.
- Pathname string
+ Path fspath.Path
// If FollowFinalSymlink is true, and the Dentry traversed by the final
// path component represents a symbolic link, the symbolic link should be
@@ -126,10 +134,7 @@ type PathOperation struct {
// GetDentryAt returns a VirtualDentry representing the given path, at which a
// file must exist. A reference is taken on the returned VirtualDentry.
func (vfs *VirtualFilesystem) GetDentryAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *GetDentryOptions) (VirtualDentry, error) {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return VirtualDentry{}, err
- }
+ rp := vfs.getResolvingPath(creds, pop)
for {
d, err := rp.mount.fs.impl.GetDentryAt(ctx, rp, *opts)
if err == nil {
@@ -148,6 +153,33 @@ func (vfs *VirtualFilesystem) GetDentryAt(ctx context.Context, creds *auth.Crede
}
}
+// Preconditions: pop.Path.Begin.Ok().
+func (vfs *VirtualFilesystem) getParentDirAndName(ctx context.Context, creds *auth.Credentials, pop *PathOperation) (VirtualDentry, string, error) {
+ rp := vfs.getResolvingPath(creds, pop)
+ for {
+ parent, err := rp.mount.fs.impl.GetParentDentryAt(ctx, rp)
+ if err == nil {
+ parentVD := VirtualDentry{
+ mount: rp.mount,
+ dentry: parent,
+ }
+ rp.mount.IncRef()
+ name := rp.Component()
+ vfs.putResolvingPath(rp)
+ return parentVD, name, nil
+ }
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.GetParentDentryAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
+ if !rp.handleError(err) {
+ vfs.putResolvingPath(rp)
+ return VirtualDentry{}, "", err
+ }
+ }
+}
+
// LinkAt creates a hard link at newpop representing the existing file at
// oldpop.
func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credentials, oldpop, newpop *PathOperation) error {
@@ -155,21 +187,36 @@ func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credential
if err != nil {
return err
}
- rp, err := vfs.getResolvingPath(creds, newpop)
- if err != nil {
+
+ if !newpop.Path.Begin.Ok() {
oldVD.DecRef()
- return err
+ if newpop.Path.Absolute {
+ return syserror.EEXIST
+ }
+ return syserror.ENOENT
+ }
+ if newpop.FollowFinalSymlink {
+ oldVD.DecRef()
+ ctx.Warningf("VirtualFilesystem.LinkAt: file creation paths can't follow final symlink")
+ return syserror.EINVAL
}
+
+ rp := vfs.getResolvingPath(creds, newpop)
for {
err := rp.mount.fs.impl.LinkAt(ctx, rp, oldVD)
if err == nil {
- oldVD.DecRef()
vfs.putResolvingPath(rp)
+ oldVD.DecRef()
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.LinkAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
- oldVD.DecRef()
vfs.putResolvingPath(rp)
+ oldVD.DecRef()
return err
}
}
@@ -177,19 +224,32 @@ func (vfs *VirtualFilesystem) LinkAt(ctx context.Context, creds *auth.Credential
// MkdirAt creates a directory at the given path.
func (vfs *VirtualFilesystem) MkdirAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *MkdirOptions) error {
+ if !pop.Path.Begin.Ok() {
+ if pop.Path.Absolute {
+ return syserror.EEXIST
+ }
+ return syserror.ENOENT
+ }
+ if pop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.MkdirAt: file creation paths can't follow final symlink")
+ return syserror.EINVAL
+ }
// "Under Linux, apart from the permission bits, the S_ISVTX mode bit is
// also honored." - mkdir(2)
opts.Mode &= 0777 | linux.S_ISVTX
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return err
- }
+
+ rp := vfs.getResolvingPath(creds, pop)
for {
err := rp.mount.fs.impl.MkdirAt(ctx, rp, *opts)
if err == nil {
vfs.putResolvingPath(rp)
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.MkdirAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
vfs.putResolvingPath(rp)
return err
@@ -200,16 +260,29 @@ func (vfs *VirtualFilesystem) MkdirAt(ctx context.Context, creds *auth.Credentia
// MknodAt creates a file of the given mode at the given path. It returns an
// error from the syserror package.
func (vfs *VirtualFilesystem) MknodAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *MknodOptions) error {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return nil
+ if !pop.Path.Begin.Ok() {
+ if pop.Path.Absolute {
+ return syserror.EEXIST
+ }
+ return syserror.ENOENT
+ }
+ if pop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.MknodAt: file creation paths can't follow final symlink")
+ return syserror.EINVAL
}
+
+ rp := vfs.getResolvingPath(creds, pop)
for {
- if err = rp.mount.fs.impl.MknodAt(ctx, rp, *opts); err == nil {
+ err := rp.mount.fs.impl.MknodAt(ctx, rp, *opts)
+ if err != nil {
vfs.putResolvingPath(rp)
return nil
}
- // Handle mount traversals.
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.MknodAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
vfs.putResolvingPath(rp)
return err
@@ -259,10 +332,7 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential
if opts.Flags&linux.O_NOFOLLOW != 0 {
pop.FollowFinalSymlink = false
}
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return nil, err
- }
+ rp := vfs.getResolvingPath(creds, pop)
if opts.Flags&linux.O_DIRECTORY != 0 {
rp.mustBeDir = true
rp.mustBeDirOrig = true
@@ -282,10 +352,7 @@ func (vfs *VirtualFilesystem) OpenAt(ctx context.Context, creds *auth.Credential
// ReadlinkAt returns the target of the symbolic link at the given path.
func (vfs *VirtualFilesystem) ReadlinkAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) (string, error) {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return "", err
- }
+ rp := vfs.getResolvingPath(creds, pop)
for {
target, err := rp.mount.fs.impl.ReadlinkAt(ctx, rp)
if err == nil {
@@ -301,25 +368,59 @@ func (vfs *VirtualFilesystem) ReadlinkAt(ctx context.Context, creds *auth.Creden
// RenameAt renames the file at oldpop to newpop.
func (vfs *VirtualFilesystem) RenameAt(ctx context.Context, creds *auth.Credentials, oldpop, newpop *PathOperation, opts *RenameOptions) error {
- oldVD, err := vfs.GetDentryAt(ctx, creds, oldpop, &GetDentryOptions{})
- if err != nil {
- return err
+ if !oldpop.Path.Begin.Ok() {
+ if oldpop.Path.Absolute {
+ return syserror.EBUSY
+ }
+ return syserror.ENOENT
+ }
+ if oldpop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.RenameAt: source path can't follow final symlink")
+ return syserror.EINVAL
}
- rp, err := vfs.getResolvingPath(creds, newpop)
+
+ oldParentVD, oldName, err := vfs.getParentDirAndName(ctx, creds, oldpop)
if err != nil {
- oldVD.DecRef()
return err
}
+ if oldName == "." || oldName == ".." {
+ oldParentVD.DecRef()
+ return syserror.EBUSY
+ }
+
+ if !newpop.Path.Begin.Ok() {
+ oldParentVD.DecRef()
+ if newpop.Path.Absolute {
+ return syserror.EBUSY
+ }
+ return syserror.ENOENT
+ }
+ if newpop.FollowFinalSymlink {
+ oldParentVD.DecRef()
+ ctx.Warningf("VirtualFilesystem.RenameAt: destination path can't follow final symlink")
+ return syserror.EINVAL
+ }
+
+ rp := vfs.getResolvingPath(creds, newpop)
+ renameOpts := *opts
+ if oldpop.Path.Dir {
+ renameOpts.MustBeDir = true
+ }
for {
- err := rp.mount.fs.impl.RenameAt(ctx, rp, oldVD, *opts)
+ err := rp.mount.fs.impl.RenameAt(ctx, rp, oldParentVD, oldName, renameOpts)
if err == nil {
- oldVD.DecRef()
vfs.putResolvingPath(rp)
+ oldParentVD.DecRef()
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.RenameAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
- oldVD.DecRef()
vfs.putResolvingPath(rp)
+ oldParentVD.DecRef()
return err
}
}
@@ -327,16 +428,29 @@ func (vfs *VirtualFilesystem) RenameAt(ctx context.Context, creds *auth.Credenti
// RmdirAt removes the directory at the given path.
func (vfs *VirtualFilesystem) RmdirAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) error {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return err
+ if !pop.Path.Begin.Ok() {
+ if pop.Path.Absolute {
+ return syserror.EBUSY
+ }
+ return syserror.ENOENT
+ }
+ if pop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.RmdirAt: file deletion paths can't follow final symlink")
+ return syserror.EINVAL
}
+
+ rp := vfs.getResolvingPath(creds, pop)
for {
err := rp.mount.fs.impl.RmdirAt(ctx, rp)
if err == nil {
vfs.putResolvingPath(rp)
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.RmdirAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
vfs.putResolvingPath(rp)
return err
@@ -346,10 +460,7 @@ func (vfs *VirtualFilesystem) RmdirAt(ctx context.Context, creds *auth.Credentia
// SetStatAt changes metadata for the file at the given path.
func (vfs *VirtualFilesystem) SetStatAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *SetStatOptions) error {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return err
- }
+ rp := vfs.getResolvingPath(creds, pop)
for {
err := rp.mount.fs.impl.SetStatAt(ctx, rp, *opts)
if err == nil {
@@ -365,10 +476,7 @@ func (vfs *VirtualFilesystem) SetStatAt(ctx context.Context, creds *auth.Credent
// StatAt returns metadata for the file at the given path.
func (vfs *VirtualFilesystem) StatAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, opts *StatOptions) (linux.Statx, error) {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return linux.Statx{}, err
- }
+ rp := vfs.getResolvingPath(creds, pop)
for {
stat, err := rp.mount.fs.impl.StatAt(ctx, rp, *opts)
if err == nil {
@@ -385,10 +493,7 @@ func (vfs *VirtualFilesystem) StatAt(ctx context.Context, creds *auth.Credential
// StatFSAt returns metadata for the filesystem containing the file at the
// given path.
func (vfs *VirtualFilesystem) StatFSAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) (linux.Statfs, error) {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return linux.Statfs{}, err
- }
+ rp := vfs.getResolvingPath(creds, pop)
for {
statfs, err := rp.mount.fs.impl.StatFSAt(ctx, rp)
if err == nil {
@@ -404,16 +509,29 @@ func (vfs *VirtualFilesystem) StatFSAt(ctx context.Context, creds *auth.Credenti
// SymlinkAt creates a symbolic link at the given path with the given target.
func (vfs *VirtualFilesystem) SymlinkAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation, target string) error {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return err
+ if !pop.Path.Begin.Ok() {
+ if pop.Path.Absolute {
+ return syserror.EEXIST
+ }
+ return syserror.ENOENT
}
+ if pop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.SymlinkAt: file creation paths can't follow final symlink")
+ return syserror.EINVAL
+ }
+
+ rp := vfs.getResolvingPath(creds, pop)
for {
err := rp.mount.fs.impl.SymlinkAt(ctx, rp, target)
if err == nil {
vfs.putResolvingPath(rp)
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.SymlinkAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
if !rp.handleError(err) {
vfs.putResolvingPath(rp)
return err
@@ -423,16 +541,104 @@ func (vfs *VirtualFilesystem) SymlinkAt(ctx context.Context, creds *auth.Credent
// UnlinkAt deletes the non-directory file at the given path.
func (vfs *VirtualFilesystem) UnlinkAt(ctx context.Context, creds *auth.Credentials, pop *PathOperation) error {
- rp, err := vfs.getResolvingPath(creds, pop)
- if err != nil {
- return err
+ if !pop.Path.Begin.Ok() {
+ if pop.Path.Absolute {
+ return syserror.EBUSY
+ }
+ return syserror.ENOENT
}
+ if pop.FollowFinalSymlink {
+ ctx.Warningf("VirtualFilesystem.UnlinkAt: file deletion paths can't follow final symlink")
+ return syserror.EINVAL
+ }
+
+ rp := vfs.getResolvingPath(creds, pop)
for {
err := rp.mount.fs.impl.UnlinkAt(ctx, rp)
if err == nil {
vfs.putResolvingPath(rp)
return nil
}
+ if checkInvariants {
+ if rp.canHandleError(err) && rp.Done() {
+ panic(fmt.Sprintf("%T.UnlinkAt() consumed all path components and returned %T", rp.mount.fs.impl, err))
+ }
+ }
+ if !rp.handleError(err) {
+ vfs.putResolvingPath(rp)
+ return err
+ }
+ }
+}
+
+// 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 := vfs.getResolvingPath(creds, pop)
+ 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 := vfs.getResolvingPath(creds, pop)
+ 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 := vfs.getResolvingPath(creds, pop)
+ 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 := vfs.getResolvingPath(creds, pop)
+ 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
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 09:46:08 +0000