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-rw-r--r--pkg/p9/client_file.go33
-rw-r--r--pkg/p9/file.go16
-rw-r--r--pkg/p9/handlers.go33
-rw-r--r--pkg/p9/messages.go199
-rw-r--r--pkg/p9/p9.go4
-rw-r--r--pkg/p9/version.go8
-rw-r--r--pkg/sentry/fs/copy_up.go2
-rw-r--r--pkg/sentry/fs/fsutil/inode.go20
-rw-r--r--pkg/sentry/fs/gofer/context_file.go14
-rw-r--r--pkg/sentry/fs/gofer/inode.go13
-rw-r--r--pkg/sentry/fs/inode.go14
-rw-r--r--pkg/sentry/fs/inode_operations.go13
-rw-r--r--pkg/sentry/fs/inode_overlay.go18
-rw-r--r--pkg/sentry/fs/tmpfs/tmpfs.go9
-rw-r--r--pkg/sentry/syscalls/linux/linux64_amd64.go27
-rw-r--r--pkg/sentry/syscalls/linux/linux64_arm64.go37
-rw-r--r--pkg/sentry/syscalls/linux/sys_xattr.go200
17 files changed, 560 insertions, 100 deletions
diff --git a/pkg/p9/client_file.go b/pkg/p9/client_file.go
index 0254e4ccc..2ee07b664 100644
--- a/pkg/p9/client_file.go
+++ b/pkg/p9/client_file.go
@@ -194,6 +194,39 @@ func (c *clientFile) SetXattr(name, value string, flags uint32) error {
return c.client.sendRecv(&Tsetxattr{FID: c.fid, Name: name, Value: value, Flags: flags}, &Rsetxattr{})
}
+// ListXattr implements File.ListXattr.
+func (c *clientFile) ListXattr(size uint64) (map[string]struct{}, error) {
+ if atomic.LoadUint32(&c.closed) != 0 {
+ return nil, syscall.EBADF
+ }
+ if !versionSupportsListRemoveXattr(c.client.version) {
+ return nil, syscall.EOPNOTSUPP
+ }
+
+ rlistxattr := Rlistxattr{}
+ if err := c.client.sendRecv(&Tlistxattr{FID: c.fid, Size: size}, &rlistxattr); err != nil {
+ return nil, err
+ }
+
+ xattrs := make(map[string]struct{}, len(rlistxattr.Xattrs))
+ for _, x := range rlistxattr.Xattrs {
+ xattrs[x] = struct{}{}
+ }
+ return xattrs, nil
+}
+
+// RemoveXattr implements File.RemoveXattr.
+func (c *clientFile) RemoveXattr(name string) error {
+ if atomic.LoadUint32(&c.closed) != 0 {
+ return syscall.EBADF
+ }
+ if !versionSupportsListRemoveXattr(c.client.version) {
+ return syscall.EOPNOTSUPP
+ }
+
+ return c.client.sendRecv(&Tremovexattr{FID: c.fid, Name: name}, &Rremovexattr{})
+}
+
// Allocate implements File.Allocate.
func (c *clientFile) Allocate(mode AllocateMode, offset, length uint64) error {
if atomic.LoadUint32(&c.closed) != 0 {
diff --git a/pkg/p9/file.go b/pkg/p9/file.go
index 4607cfcdf..d4ffbc8e3 100644
--- a/pkg/p9/file.go
+++ b/pkg/p9/file.go
@@ -105,6 +105,22 @@ type File interface {
// TODO(b/127675828): Determine concurrency guarantees once implemented.
SetXattr(name, value string, flags uint32) error
+ // ListXattr lists the names of the extended attributes on this node.
+ //
+ // Size indicates the size of the buffer that has been allocated to hold the
+ // attribute list. If the list would be larger than size, implementations may
+ // return ERANGE to indicate that the buffer is too small, but they are also
+ // free to ignore the hint entirely (i.e. the value returned may be larger
+ // than size). All size checking is done independently at the syscall layer.
+ //
+ // TODO(b/148303075): Determine concurrency guarantees once implemented.
+ ListXattr(size uint64) (map[string]struct{}, error)
+
+ // RemoveXattr removes extended attributes on this node.
+ //
+ // TODO(b/148303075): Determine concurrency guarantees once implemented.
+ RemoveXattr(name string) error
+
// Allocate allows the caller to directly manipulate the allocated disk space
// for the file. See fallocate(2) for more details.
Allocate(mode AllocateMode, offset, length uint64) error
diff --git a/pkg/p9/handlers.go b/pkg/p9/handlers.go
index 7d6653a07..2ac45eb80 100644
--- a/pkg/p9/handlers.go
+++ b/pkg/p9/handlers.go
@@ -942,6 +942,39 @@ func (t *Tsetxattr) handle(cs *connState) message {
}
// handle implements handler.handle.
+func (t *Tlistxattr) handle(cs *connState) message {
+ ref, ok := cs.LookupFID(t.FID)
+ if !ok {
+ return newErr(syscall.EBADF)
+ }
+ defer ref.DecRef()
+
+ xattrs, err := ref.file.ListXattr(t.Size)
+ if err != nil {
+ return newErr(err)
+ }
+ xattrList := make([]string, 0, len(xattrs))
+ for x := range xattrs {
+ xattrList = append(xattrList, x)
+ }
+ return &Rlistxattr{Xattrs: xattrList}
+}
+
+// handle implements handler.handle.
+func (t *Tremovexattr) handle(cs *connState) message {
+ ref, ok := cs.LookupFID(t.FID)
+ if !ok {
+ return newErr(syscall.EBADF)
+ }
+ defer ref.DecRef()
+
+ if err := ref.file.RemoveXattr(t.Name); err != nil {
+ return newErr(err)
+ }
+ return &Rremovexattr{}
+}
+
+// handle implements handler.handle.
func (t *Treaddir) handle(cs *connState) message {
ref, ok := cs.LookupFID(t.Directory)
if !ok {
diff --git a/pkg/p9/messages.go b/pkg/p9/messages.go
index ceb723d86..b1cede5f5 100644
--- a/pkg/p9/messages.go
+++ b/pkg/p9/messages.go
@@ -174,11 +174,11 @@ type Rflush struct {
}
// Decode implements encoder.Decode.
-func (*Rflush) Decode(b *buffer) {
+func (*Rflush) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rflush) Encode(b *buffer) {
+func (*Rflush) Encode(*buffer) {
}
// Type implements message.Type.
@@ -188,7 +188,7 @@ func (*Rflush) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rflush) String() string {
- return fmt.Sprintf("RFlush{}")
+ return "RFlush{}"
}
// Twalk is a walk request.
@@ -300,11 +300,11 @@ type Rclunk struct {
}
// Decode implements encoder.Decode.
-func (*Rclunk) Decode(b *buffer) {
+func (*Rclunk) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rclunk) Encode(b *buffer) {
+func (*Rclunk) Encode(*buffer) {
}
// Type implements message.Type.
@@ -314,7 +314,7 @@ func (*Rclunk) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rclunk) String() string {
- return fmt.Sprintf("Rclunk{}")
+ return "Rclunk{}"
}
// Tremove is a remove request.
@@ -350,11 +350,11 @@ type Rremove struct {
}
// Decode implements encoder.Decode.
-func (*Rremove) Decode(b *buffer) {
+func (*Rremove) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rremove) Encode(b *buffer) {
+func (*Rremove) Encode(*buffer) {
}
// Type implements message.Type.
@@ -364,7 +364,7 @@ func (*Rremove) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rremove) String() string {
- return fmt.Sprintf("Rremove{}")
+ return "Rremove{}"
}
// Rlerror is an error response.
@@ -745,16 +745,16 @@ func (*Rlink) Type() MsgType {
}
// Decode implements encoder.Decode.
-func (*Rlink) Decode(b *buffer) {
+func (*Rlink) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rlink) Encode(b *buffer) {
+func (*Rlink) Encode(*buffer) {
}
// String implements fmt.Stringer.
func (r *Rlink) String() string {
- return fmt.Sprintf("Rlink{}")
+ return "Rlink{}"
}
// Trenameat is a rename request.
@@ -803,11 +803,11 @@ type Rrenameat struct {
}
// Decode implements encoder.Decode.
-func (*Rrenameat) Decode(b *buffer) {
+func (*Rrenameat) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rrenameat) Encode(b *buffer) {
+func (*Rrenameat) Encode(*buffer) {
}
// Type implements message.Type.
@@ -817,7 +817,7 @@ func (*Rrenameat) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rrenameat) String() string {
- return fmt.Sprintf("Rrenameat{}")
+ return "Rrenameat{}"
}
// Tunlinkat is an unlink request.
@@ -861,11 +861,11 @@ type Runlinkat struct {
}
// Decode implements encoder.Decode.
-func (*Runlinkat) Decode(b *buffer) {
+func (*Runlinkat) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Runlinkat) Encode(b *buffer) {
+func (*Runlinkat) Encode(*buffer) {
}
// Type implements message.Type.
@@ -875,7 +875,7 @@ func (*Runlinkat) Type() MsgType {
// String implements fmt.Stringer.
func (r *Runlinkat) String() string {
- return fmt.Sprintf("Runlinkat{}")
+ return "Runlinkat{}"
}
// Trename is a rename request.
@@ -922,11 +922,11 @@ type Rrename struct {
}
// Decode implements encoder.Decode.
-func (*Rrename) Decode(b *buffer) {
+func (*Rrename) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rrename) Encode(b *buffer) {
+func (*Rrename) Encode(*buffer) {
}
// Type implements message.Type.
@@ -936,7 +936,7 @@ func (*Rrename) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rrename) String() string {
- return fmt.Sprintf("Rrename{}")
+ return "Rrename{}"
}
// Treadlink is a readlink request.
@@ -1409,11 +1409,11 @@ type Rsetattr struct {
}
// Decode implements encoder.Decode.
-func (*Rsetattr) Decode(b *buffer) {
+func (*Rsetattr) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rsetattr) Encode(b *buffer) {
+func (*Rsetattr) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1423,7 +1423,7 @@ func (*Rsetattr) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rsetattr) String() string {
- return fmt.Sprintf("Rsetattr{}")
+ return "Rsetattr{}"
}
// Tallocate is an allocate request. This is an extension to 9P protocol, not
@@ -1466,11 +1466,11 @@ type Rallocate struct {
}
// Decode implements encoder.Decode.
-func (*Rallocate) Decode(b *buffer) {
+func (*Rallocate) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rallocate) Encode(b *buffer) {
+func (*Rallocate) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1480,7 +1480,71 @@ func (*Rallocate) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rallocate) String() string {
- return fmt.Sprintf("Rallocate{}")
+ return "Rallocate{}"
+}
+
+// Tlistxattr is a listxattr request.
+type Tlistxattr struct {
+ // FID refers to the file on which to list xattrs.
+ FID FID
+
+ // Size is the buffer size for the xattr list.
+ Size uint64
+}
+
+// Decode implements encoder.Decode.
+func (t *Tlistxattr) Decode(b *buffer) {
+ t.FID = b.ReadFID()
+ t.Size = b.Read64()
+}
+
+// Encode implements encoder.Encode.
+func (t *Tlistxattr) Encode(b *buffer) {
+ b.WriteFID(t.FID)
+ b.Write64(t.Size)
+}
+
+// Type implements message.Type.
+func (*Tlistxattr) Type() MsgType {
+ return MsgTlistxattr
+}
+
+// String implements fmt.Stringer.
+func (t *Tlistxattr) String() string {
+ return fmt.Sprintf("Tlistxattr{FID: %d, Size: %d}", t.FID, t.Size)
+}
+
+// Rlistxattr is a listxattr response.
+type Rlistxattr struct {
+ // Xattrs is a list of extended attribute names.
+ Xattrs []string
+}
+
+// Decode implements encoder.Decode.
+func (r *Rlistxattr) Decode(b *buffer) {
+ n := b.Read16()
+ r.Xattrs = r.Xattrs[:0]
+ for i := 0; i < int(n); i++ {
+ r.Xattrs = append(r.Xattrs, b.ReadString())
+ }
+}
+
+// Encode implements encoder.Encode.
+func (r *Rlistxattr) Encode(b *buffer) {
+ b.Write16(uint16(len(r.Xattrs)))
+ for _, x := range r.Xattrs {
+ b.WriteString(x)
+ }
+}
+
+// Type implements message.Type.
+func (*Rlistxattr) Type() MsgType {
+ return MsgRlistxattr
+}
+
+// String implements fmt.Stringer.
+func (r *Rlistxattr) String() string {
+ return fmt.Sprintf("Rlistxattr{Xattrs: %v}", r.Xattrs)
}
// Txattrwalk walks extended attributes.
@@ -1594,11 +1658,11 @@ type Rxattrcreate struct {
}
// Decode implements encoder.Decode.
-func (r *Rxattrcreate) Decode(b *buffer) {
+func (r *Rxattrcreate) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (r *Rxattrcreate) Encode(b *buffer) {
+func (r *Rxattrcreate) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1608,7 +1672,7 @@ func (*Rxattrcreate) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rxattrcreate) String() string {
- return fmt.Sprintf("Rxattrcreate{}")
+ return "Rxattrcreate{}"
}
// Tgetxattr is a getxattr request.
@@ -1719,11 +1783,11 @@ type Rsetxattr struct {
}
// Decode implements encoder.Decode.
-func (r *Rsetxattr) Decode(b *buffer) {
+func (r *Rsetxattr) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (r *Rsetxattr) Encode(b *buffer) {
+func (r *Rsetxattr) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1733,7 +1797,60 @@ func (*Rsetxattr) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rsetxattr) String() string {
- return fmt.Sprintf("Rsetxattr{}")
+ return "Rsetxattr{}"
+}
+
+// Tremovexattr is a removexattr request.
+type Tremovexattr struct {
+ // FID refers to the file on which to set xattrs.
+ FID FID
+
+ // Name is the attribute name.
+ Name string
+}
+
+// Decode implements encoder.Decode.
+func (t *Tremovexattr) Decode(b *buffer) {
+ t.FID = b.ReadFID()
+ t.Name = b.ReadString()
+}
+
+// Encode implements encoder.Encode.
+func (t *Tremovexattr) Encode(b *buffer) {
+ b.WriteFID(t.FID)
+ b.WriteString(t.Name)
+}
+
+// Type implements message.Type.
+func (*Tremovexattr) Type() MsgType {
+ return MsgTremovexattr
+}
+
+// String implements fmt.Stringer.
+func (t *Tremovexattr) String() string {
+ return fmt.Sprintf("Tremovexattr{FID: %d, Name: %s}", t.FID, t.Name)
+}
+
+// Rremovexattr is a removexattr response.
+type Rremovexattr struct {
+}
+
+// Decode implements encoder.Decode.
+func (r *Rremovexattr) Decode(*buffer) {
+}
+
+// Encode implements encoder.Encode.
+func (r *Rremovexattr) Encode(*buffer) {
+}
+
+// Type implements message.Type.
+func (*Rremovexattr) Type() MsgType {
+ return MsgRremovexattr
+}
+
+// String implements fmt.Stringer.
+func (r *Rremovexattr) String() string {
+ return "Rremovexattr{}"
}
// Treaddir is a readdir request.
@@ -1880,11 +1997,11 @@ type Rfsync struct {
}
// Decode implements encoder.Decode.
-func (*Rfsync) Decode(b *buffer) {
+func (*Rfsync) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rfsync) Encode(b *buffer) {
+func (*Rfsync) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1894,7 +2011,7 @@ func (*Rfsync) Type() MsgType {
// String implements fmt.Stringer.
func (r *Rfsync) String() string {
- return fmt.Sprintf("Rfsync{}")
+ return "Rfsync{}"
}
// Tstatfs is a stat request.
@@ -1980,11 +2097,11 @@ type Rflushf struct {
}
// Decode implements encoder.Decode.
-func (*Rflushf) Decode(b *buffer) {
+func (*Rflushf) Decode(*buffer) {
}
// Encode implements encoder.Encode.
-func (*Rflushf) Encode(b *buffer) {
+func (*Rflushf) Encode(*buffer) {
}
// Type implements message.Type.
@@ -1994,7 +2111,7 @@ func (*Rflushf) Type() MsgType {
// String implements fmt.Stringer.
func (*Rflushf) String() string {
- return fmt.Sprintf("Rflushf{}")
+ return "Rflushf{}"
}
// Twalkgetattr is a walk request.
@@ -2484,6 +2601,8 @@ func init() {
msgRegistry.register(MsgRgetattr, func() message { return &Rgetattr{} })
msgRegistry.register(MsgTsetattr, func() message { return &Tsetattr{} })
msgRegistry.register(MsgRsetattr, func() message { return &Rsetattr{} })
+ msgRegistry.register(MsgTlistxattr, func() message { return &Tlistxattr{} })
+ msgRegistry.register(MsgRlistxattr, func() message { return &Rlistxattr{} })
msgRegistry.register(MsgTxattrwalk, func() message { return &Txattrwalk{} })
msgRegistry.register(MsgRxattrwalk, func() message { return &Rxattrwalk{} })
msgRegistry.register(MsgTxattrcreate, func() message { return &Txattrcreate{} })
@@ -2492,6 +2611,8 @@ func init() {
msgRegistry.register(MsgRgetxattr, func() message { return &Rgetxattr{} })
msgRegistry.register(MsgTsetxattr, func() message { return &Tsetxattr{} })
msgRegistry.register(MsgRsetxattr, func() message { return &Rsetxattr{} })
+ msgRegistry.register(MsgTremovexattr, func() message { return &Tremovexattr{} })
+ msgRegistry.register(MsgRremovexattr, func() message { return &Rremovexattr{} })
msgRegistry.register(MsgTreaddir, func() message { return &Treaddir{} })
msgRegistry.register(MsgRreaddir, func() message { return &Rreaddir{} })
msgRegistry.register(MsgTfsync, func() message { return &Tfsync{} })
diff --git a/pkg/p9/p9.go b/pkg/p9/p9.go
index 5ab00d625..20ab31f7a 100644
--- a/pkg/p9/p9.go
+++ b/pkg/p9/p9.go
@@ -335,6 +335,8 @@ const (
MsgRgetattr = 25
MsgTsetattr = 26
MsgRsetattr = 27
+ MsgTlistxattr = 28
+ MsgRlistxattr = 29
MsgTxattrwalk = 30
MsgRxattrwalk = 31
MsgTxattrcreate = 32
@@ -343,6 +345,8 @@ const (
MsgRgetxattr = 35
MsgTsetxattr = 36
MsgRsetxattr = 37
+ MsgTremovexattr = 38
+ MsgRremovexattr = 39
MsgTreaddir = 40
MsgRreaddir = 41
MsgTfsync = 50
diff --git a/pkg/p9/version.go b/pkg/p9/version.go
index 34a15eb55..09cde9f5a 100644
--- a/pkg/p9/version.go
+++ b/pkg/p9/version.go
@@ -26,7 +26,7 @@ const (
//
// Clients are expected to start requesting this version number and
// to continuously decrement it until a Tversion request succeeds.
- highestSupportedVersion uint32 = 10
+ highestSupportedVersion uint32 = 11
// lowestSupportedVersion is the lowest supported version X in a
// version string of the format 9P2000.L.Google.X.
@@ -167,3 +167,9 @@ func VersionSupportsOpenTruncateFlag(v uint32) bool {
func versionSupportsGetSetXattr(v uint32) bool {
return v >= 10
}
+
+// versionSupportsListRemoveXattr returns true if version v supports
+// the Tlistxattr and Tremovexattr messages.
+func versionSupportsListRemoveXattr(v uint32) bool {
+ return v >= 11
+}
diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go
index f6c79e51b..b060a12ff 100644
--- a/pkg/sentry/fs/copy_up.go
+++ b/pkg/sentry/fs/copy_up.go
@@ -401,7 +401,7 @@ func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error
if err != nil {
return err
}
- lowerXattr, err := lower.ListXattr(ctx)
+ lowerXattr, err := lower.ListXattr(ctx, linux.XATTR_SIZE_MAX)
if err != nil && err != syserror.EOPNOTSUPP {
return err
}
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index 252830572..daecc4ffe 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -247,7 +247,7 @@ func (i *InodeSimpleExtendedAttributes) SetXattr(_ context.Context, _ *fs.Inode,
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
+func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
i.mu.RLock()
names := make(map[string]struct{}, len(i.xattrs))
for name := range i.xattrs {
@@ -257,6 +257,17 @@ func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (m
return names, nil
}
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (i *InodeSimpleExtendedAttributes) RemoveXattr(_ context.Context, _ *fs.Inode, name string) error {
+ i.mu.RLock()
+ defer i.mu.RUnlock()
+ if _, ok := i.xattrs[name]; ok {
+ delete(i.xattrs, name)
+ return nil
+ }
+ return syserror.ENOATTR
+}
+
// staticFile is a file with static contents. It is returned by
// InodeStaticFileGetter.GetFile.
//
@@ -460,10 +471,15 @@ func (InodeNoExtendedAttributes) SetXattr(context.Context, *fs.Inode, string, st
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
+func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode, uint64) (map[string]struct{}, error) {
return nil, syserror.EOPNOTSUPP
}
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (InodeNoExtendedAttributes) RemoveXattr(context.Context, *fs.Inode, string) error {
+ return syserror.EOPNOTSUPP
+}
+
// InodeNoopRelease implements fs.InodeOperations.Release as a noop.
type InodeNoopRelease struct{}
diff --git a/pkg/sentry/fs/gofer/context_file.go b/pkg/sentry/fs/gofer/context_file.go
index 3da818aed..125907d70 100644
--- a/pkg/sentry/fs/gofer/context_file.go
+++ b/pkg/sentry/fs/gofer/context_file.go
@@ -73,6 +73,20 @@ func (c *contextFile) setXattr(ctx context.Context, name, value string, flags ui
return err
}
+func (c *contextFile) listXattr(ctx context.Context, size uint64) (map[string]struct{}, error) {
+ ctx.UninterruptibleSleepStart(false)
+ xattrs, err := c.file.ListXattr(size)
+ ctx.UninterruptibleSleepFinish(false)
+ return xattrs, err
+}
+
+func (c *contextFile) removeXattr(ctx context.Context, name string) error {
+ ctx.UninterruptibleSleepStart(false)
+ err := c.file.RemoveXattr(name)
+ ctx.UninterruptibleSleepFinish(false)
+ return err
+}
+
func (c *contextFile) allocate(ctx context.Context, mode p9.AllocateMode, offset, length uint64) error {
ctx.UninterruptibleSleepStart(false)
err := c.file.Allocate(mode, offset, length)
diff --git a/pkg/sentry/fs/gofer/inode.go b/pkg/sentry/fs/gofer/inode.go
index ac28174d2..1c934981b 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -604,18 +604,23 @@ func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length
}
// GetXattr implements fs.InodeOperations.GetXattr.
-func (i *inodeOperations) GetXattr(ctx context.Context, inode *fs.Inode, name string, size uint64) (string, error) {
+func (i *inodeOperations) GetXattr(ctx context.Context, _ *fs.Inode, name string, size uint64) (string, error) {
return i.fileState.file.getXattr(ctx, name, size)
}
// SetXattr implements fs.InodeOperations.SetXattr.
-func (i *inodeOperations) SetXattr(ctx context.Context, inode *fs.Inode, name string, value string, flags uint32) error {
+func (i *inodeOperations) SetXattr(ctx context.Context, _ *fs.Inode, name string, value string, flags uint32) error {
return i.fileState.file.setXattr(ctx, name, value, flags)
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (i *inodeOperations) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
- return nil, syscall.EOPNOTSUPP
+func (i *inodeOperations) ListXattr(ctx context.Context, _ *fs.Inode, size uint64) (map[string]struct{}, error) {
+ return i.fileState.file.listXattr(ctx, size)
+}
+
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (i *inodeOperations) RemoveXattr(ctx context.Context, _ *fs.Inode, name string) error {
+ return i.fileState.file.removeXattr(ctx, name)
}
// Allocate implements fs.InodeOperations.Allocate.
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index b66c091ab..55fb71c16 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -278,11 +278,19 @@ func (i *Inode) SetXattr(ctx context.Context, d *Dirent, name, value string, fla
}
// ListXattr calls i.InodeOperations.ListXattr with i as the Inode.
-func (i *Inode) ListXattr(ctx context.Context) (map[string]struct{}, error) {
+func (i *Inode) ListXattr(ctx context.Context, size uint64) (map[string]struct{}, error) {
if i.overlay != nil {
- return overlayListXattr(ctx, i.overlay)
+ return overlayListXattr(ctx, i.overlay, size)
}
- return i.InodeOperations.ListXattr(ctx, i)
+ return i.InodeOperations.ListXattr(ctx, i, size)
+}
+
+// RemoveXattr calls i.InodeOperations.RemoveXattr with i as the Inode.
+func (i *Inode) RemoveXattr(ctx context.Context, d *Dirent, name string) error {
+ if i.overlay != nil {
+ return overlayRemoveXattr(ctx, i.overlay, d, name)
+ }
+ return i.InodeOperations.RemoveXattr(ctx, i, name)
}
// CheckPermission will check if the caller may access this file in the
diff --git a/pkg/sentry/fs/inode_operations.go b/pkg/sentry/fs/inode_operations.go
index 70f2eae96..2bbfb72ef 100644
--- a/pkg/sentry/fs/inode_operations.go
+++ b/pkg/sentry/fs/inode_operations.go
@@ -190,7 +190,18 @@ type InodeOperations interface {
// ListXattr returns the set of all extended attributes names that
// have values. Inodes that do not support extended attributes return
// EOPNOTSUPP.
- ListXattr(ctx context.Context, inode *Inode) (map[string]struct{}, error)
+ //
+ // If this is called through the listxattr(2) syscall, size indicates the
+ // size of the buffer that the application has allocated to hold the
+ // attribute list. If the list would be larger than size, implementations may
+ // return ERANGE to indicate that the buffer is too small, but they are also
+ // free to ignore the hint entirely. All size checking is done independently
+ // at the syscall layer.
+ ListXattr(ctx context.Context, inode *Inode, size uint64) (map[string]struct{}, error)
+
+ // RemoveXattr removes an extended attribute specified by name. Inodes that
+ // do not support extended attributes return EOPNOTSUPP.
+ RemoveXattr(ctx context.Context, inode *Inode, name string) error
// Check determines whether an Inode can be accessed with the
// requested permission mask using the context (which gives access
diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index 4729b4aac..5ada33a32 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -564,15 +564,15 @@ func overlaySetxattr(ctx context.Context, o *overlayEntry, d *Dirent, name, valu
return o.upper.SetXattr(ctx, d, name, value, flags)
}
-func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{}, error) {
+func overlayListXattr(ctx context.Context, o *overlayEntry, size uint64) (map[string]struct{}, error) {
o.copyMu.RLock()
defer o.copyMu.RUnlock()
var names map[string]struct{}
var err error
if o.upper != nil {
- names, err = o.upper.ListXattr(ctx)
+ names, err = o.upper.ListXattr(ctx, size)
} else {
- names, err = o.lower.ListXattr(ctx)
+ names, err = o.lower.ListXattr(ctx, size)
}
for name := range names {
// Same as overlayGetXattr, we shouldn't forward along
@@ -584,6 +584,18 @@ func overlayListXattr(ctx context.Context, o *overlayEntry) (map[string]struct{}
return names, err
}
+func overlayRemoveXattr(ctx context.Context, o *overlayEntry, d *Dirent, name string) error {
+ // Don't allow changes to overlay xattrs through a removexattr syscall.
+ if strings.HasPrefix(XattrOverlayPrefix, name) {
+ return syserror.EPERM
+ }
+
+ if err := copyUp(ctx, d); err != nil {
+ return err
+ }
+ return o.upper.RemoveXattr(ctx, d, name)
+}
+
func overlayCheck(ctx context.Context, o *overlayEntry, p PermMask) error {
o.copyMu.RLock()
// Hot path. Avoid defers.
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index c00cef0a5..3c2b583ae 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -159,8 +159,13 @@ func (d *Dir) SetXattr(ctx context.Context, i *fs.Inode, name, value string, fla
}
// ListXattr implements fs.InodeOperations.ListXattr.
-func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode) (map[string]struct{}, error) {
- return d.ramfsDir.ListXattr(ctx, i)
+func (d *Dir) ListXattr(ctx context.Context, i *fs.Inode, size uint64) (map[string]struct{}, error) {
+ return d.ramfsDir.ListXattr(ctx, i, size)
+}
+
+// RemoveXattr implements fs.InodeOperations.RemoveXattr.
+func (d *Dir) RemoveXattr(ctx context.Context, i *fs.Inode, name string) error {
+ return d.ramfsDir.RemoveXattr(ctx, i, name)
}
// Lookup implements fs.InodeOperations.Lookup.
diff --git a/pkg/sentry/syscalls/linux/linux64_amd64.go b/pkg/sentry/syscalls/linux/linux64_amd64.go
index 588f8b087..79066ad2a 100644
--- a/pkg/sentry/syscalls/linux/linux64_amd64.go
+++ b/pkg/sentry/syscalls/linux/linux64_amd64.go
@@ -228,21 +228,18 @@ var AMD64 = &kernel.SyscallTable{
185: syscalls.Error("security", syserror.ENOSYS, "Not implemented in Linux.", nil),
186: syscalls.Supported("gettid", Gettid),
187: syscalls.Supported("readahead", Readahead),
- // TODO(b/148303075): Enable set/getxattr (in their various
- // forms) once we also have list and removexattr. The JVM
- // assumes that if get/set exist, then list and remove do too.
- 188: syscalls.ErrorWithEvent("setxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 189: syscalls.ErrorWithEvent("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 190: syscalls.ErrorWithEvent("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 191: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 192: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 193: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 194: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 195: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 196: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 197: syscalls.ErrorWithEvent("removexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 198: syscalls.ErrorWithEvent("lremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 199: syscalls.ErrorWithEvent("fremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
+ 188: syscalls.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil),
+ 189: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil),
+ 190: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil),
+ 191: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil),
+ 192: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil),
+ 193: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil),
+ 194: syscalls.PartiallySupported("listxattr", ListXattr, "Only supported for tmpfs", nil),
+ 195: syscalls.PartiallySupported("llistxattr", LListXattr, "Only supported for tmpfs", nil),
+ 196: syscalls.PartiallySupported("flistxattr", FListXattr, "Only supported for tmpfs", nil),
+ 197: syscalls.PartiallySupported("removexattr", RemoveXattr, "Only supported for tmpfs", nil),
+ 198: syscalls.PartiallySupported("lremovexattr", LRemoveXattr, "Only supported for tmpfs", nil),
+ 199: syscalls.PartiallySupported("fremovexattr", FRemoveXattr, "Only supported for tmpfs", nil),
200: syscalls.Supported("tkill", Tkill),
201: syscalls.Supported("time", Time),
202: syscalls.PartiallySupported("futex", Futex, "Robust futexes not supported.", nil),
diff --git a/pkg/sentry/syscalls/linux/linux64_arm64.go b/pkg/sentry/syscalls/linux/linux64_arm64.go
index 06e5ee401..7421619de 100644
--- a/pkg/sentry/syscalls/linux/linux64_arm64.go
+++ b/pkg/sentry/syscalls/linux/linux64_arm64.go
@@ -36,26 +36,23 @@ var ARM64 = &kernel.SyscallTable{
},
AuditNumber: linux.AUDIT_ARCH_AARCH64,
Table: map[uintptr]kernel.Syscall{
- 0: syscalls.PartiallySupported("io_setup", IoSetup, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 1: syscalls.PartiallySupported("io_destroy", IoDestroy, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 2: syscalls.PartiallySupported("io_submit", IoSubmit, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 3: syscalls.PartiallySupported("io_cancel", IoCancel, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- 4: syscalls.PartiallySupported("io_getevents", IoGetevents, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
- // TODO(b/148303075): Enable set/getxattr (in their various
- // forms) once we also have list and removexattr. The JVM
- // assumes that if get/set exist, then list and remove do too.
- 5: syscalls.ErrorWithEvent("setxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 6: syscalls.ErrorWithEvent("lsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 7: syscalls.ErrorWithEvent("fsetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 8: syscalls.ErrorWithEvent("getxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 9: syscalls.ErrorWithEvent("lgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 10: syscalls.ErrorWithEvent("fgetxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 11: syscalls.ErrorWithEvent("listxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 13: syscalls.ErrorWithEvent("llistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 13: syscalls.ErrorWithEvent("flistxattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 14: syscalls.ErrorWithEvent("removexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 15: syscalls.ErrorWithEvent("lremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
- 16: syscalls.ErrorWithEvent("fremovexattr", syserror.ENOTSUP, "Requires filesystem support.", []string{"gvisor.dev/issue/1636"}),
+ 0: syscalls.PartiallySupported("io_setup", IoSetup, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 1: syscalls.PartiallySupported("io_destroy", IoDestroy, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 2: syscalls.PartiallySupported("io_submit", IoSubmit, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 3: syscalls.PartiallySupported("io_cancel", IoCancel, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 4: syscalls.PartiallySupported("io_getevents", IoGetevents, "Generally supported with exceptions. User ring optimizations are not implemented.", []string{"gvisor.dev/issue/204"}),
+ 5: syscalls.PartiallySupported("setxattr", SetXattr, "Only supported for tmpfs.", nil),
+ 6: syscalls.PartiallySupported("lsetxattr", LSetXattr, "Only supported for tmpfs.", nil),
+ 7: syscalls.PartiallySupported("fsetxattr", FSetXattr, "Only supported for tmpfs.", nil),
+ 8: syscalls.PartiallySupported("getxattr", GetXattr, "Only supported for tmpfs.", nil),
+ 9: syscalls.PartiallySupported("lgetxattr", LGetXattr, "Only supported for tmpfs.", nil),
+ 10: syscalls.PartiallySupported("fgetxattr", FGetXattr, "Only supported for tmpfs.", nil),
+ 11: syscalls.PartiallySupported("listxattr", ListXattr, "Only supported for tmpfs", nil),
+ 12: syscalls.PartiallySupported("llistxattr", LListXattr, "Only supported for tmpfs", nil),
+ 13: syscalls.PartiallySupported("flistxattr", FListXattr, "Only supported for tmpfs", nil),
+ 14: syscalls.PartiallySupported("removexattr", RemoveXattr, "Only supported for tmpfs", nil),
+ 15: syscalls.PartiallySupported("lremovexattr", LRemoveXattr, "Only supported for tmpfs", nil),
+ 16: syscalls.PartiallySupported("fremovexattr", FRemoveXattr, "Only supported for tmpfs", nil),
17: syscalls.Supported("getcwd", Getcwd),
18: syscalls.CapError("lookup_dcookie", linux.CAP_SYS_ADMIN, "", nil),
19: syscalls.Supported("eventfd2", Eventfd2),
diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go
index efb95555c..342337726 100644
--- a/pkg/sentry/syscalls/linux/sys_xattr.go
+++ b/pkg/sentry/syscalls/linux/sys_xattr.go
@@ -72,7 +72,7 @@ func getXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink
}
valueLen := 0
- err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
return syserror.ENOTDIR
}
@@ -172,7 +172,7 @@ func setXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink
return 0, nil, err
}
- return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(root *fs.Dirent, d *fs.Dirent, _ uint) error {
+ return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
return syserror.ENOTDIR
}
@@ -187,12 +187,12 @@ func setXattr(t *kernel.Task, d *fs.Dirent, nameAddr, valueAddr usermem.Addr, si
return syserror.EINVAL
}
- if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
return err
}
- name, err := copyInXattrName(t, nameAddr)
- if err != nil {
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
return err
}
@@ -226,12 +226,18 @@ func copyInXattrName(t *kernel.Task, nameAddr usermem.Addr) (string, error) {
return name, nil
}
+// Restrict xattrs to regular files and directories.
+//
+// TODO(b/148380782): In Linux, this restriction technically only applies to
+// xattrs in the "user.*" namespace. Make file type checks specific to the
+// namespace once we allow other xattr prefixes.
+func xattrFileTypeOk(i *fs.Inode) bool {
+ return fs.IsRegular(i.StableAttr) || fs.IsDir(i.StableAttr)
+}
+
func checkXattrPermissions(t *kernel.Task, i *fs.Inode, perms fs.PermMask) error {
// Restrict xattrs to regular files and directories.
- //
- // In Linux, this restriction technically only applies to xattrs in the
- // "user.*" namespace, but we don't allow any other xattr prefixes anyway.
- if !fs.IsRegular(i.StableAttr) && !fs.IsDir(i.StableAttr) {
+ if !xattrFileTypeOk(i) {
if perms.Write {
return syserror.EPERM
}
@@ -240,3 +246,179 @@ func checkXattrPermissions(t *kernel.Task, i *fs.Inode, perms fs.PermMask) error
return i.CheckPermission(t, perms)
}
+
+// ListXattr implements linux syscall listxattr(2).
+func ListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return listXattrFromPath(t, args, true)
+}
+
+// LListXattr implements linux syscall llistxattr(2).
+func LListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return listXattrFromPath(t, args, false)
+}
+
+// FListXattr implements linux syscall flistxattr(2).
+func FListXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ listAddr := args[1].Pointer()
+ size := uint64(args[2].SizeT())
+
+ // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH.
+ f := t.GetFile(fd)
+ if f == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer f.DecRef()
+
+ n, err := listXattr(t, f.Dirent, listAddr, size)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return uintptr(n), nil, nil
+}
+
+func listXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ listAddr := args[1].Pointer()
+ size := uint64(args[2].SizeT())
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ n := 0
+ err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return syserror.ENOTDIR
+ }
+
+ n, err = listXattr(t, d, listAddr, size)
+ return err
+ })
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return uintptr(n), nil, nil
+}
+
+func listXattr(t *kernel.Task, d *fs.Dirent, addr usermem.Addr, size uint64) (int, error) {
+ if !xattrFileTypeOk(d.Inode) {
+ return 0, nil
+ }
+
+ // If listxattr(2) is called with size 0, the buffer size needed to contain
+ // the xattr list will be returned successfully even if it is nonzero. In
+ // that case, we need to retrieve the entire list so we can compute and
+ // return the correct size.
+ requestedSize := size
+ if size == 0 || size > linux.XATTR_SIZE_MAX {
+ requestedSize = linux.XATTR_SIZE_MAX
+ }
+ xattrs, err := d.Inode.ListXattr(t, requestedSize)
+ if err != nil {
+ return 0, err
+ }
+
+ // TODO(b/148380782): support namespaces other than "user".
+ for x := range xattrs {
+ if !strings.HasPrefix(x, linux.XATTR_USER_PREFIX) {
+ delete(xattrs, x)
+ }
+ }
+
+ listSize := xattrListSize(xattrs)
+ if listSize > linux.XATTR_SIZE_MAX {
+ return 0, syserror.E2BIG
+ }
+ if uint64(listSize) > requestedSize {
+ return 0, syserror.ERANGE
+ }
+
+ // Don't copy out the attributes if size is 0.
+ if size == 0 {
+ return listSize, nil
+ }
+
+ buf := make([]byte, 0, listSize)
+ for x := range xattrs {
+ buf = append(buf, []byte(x)...)
+ buf = append(buf, 0)
+ }
+ if _, err := t.CopyOutBytes(addr, buf); err != nil {
+ return 0, err
+ }
+
+ return len(buf), nil
+}
+
+func xattrListSize(xattrs map[string]struct{}) int {
+ size := 0
+ for x := range xattrs {
+ size += len(x) + 1
+ }
+ return size
+}
+
+// RemoveXattr implements linux syscall removexattr(2).
+func RemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return removeXattrFromPath(t, args, true)
+}
+
+// LRemoveXattr implements linux syscall lremovexattr(2).
+func LRemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ return removeXattrFromPath(t, args, false)
+}
+
+// FRemoveXattr implements linux syscall fremovexattr(2).
+func FRemoveXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
+ fd := args[0].Int()
+ nameAddr := args[1].Pointer()
+
+ // TODO(b/113957122): Return EBADF if the fd was opened with O_PATH.
+ f := t.GetFile(fd)
+ if f == nil {
+ return 0, nil, syserror.EBADF
+ }
+ defer f.DecRef()
+
+ return 0, nil, removeXattr(t, f.Dirent, nameAddr)
+}
+
+func removeXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink bool) (uintptr, *kernel.SyscallControl, error) {
+ pathAddr := args[0].Pointer()
+ nameAddr := args[1].Pointer()
+
+ path, dirPath, err := copyInPath(t, pathAddr, false /* allowEmpty */)
+ if err != nil {
+ return 0, nil, err
+ }
+
+ return 0, nil, fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
+ if dirPath && !fs.IsDir(d.Inode.StableAttr) {
+ return syserror.ENOTDIR
+ }
+
+ return removeXattr(t, d, nameAddr)
+ })
+}
+
+// removeXattr implements removexattr(2) from the given *fs.Dirent.
+func removeXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr) error {
+ name, err := copyInXattrName(t, nameAddr)
+ if err != nil {
+ return err
+ }
+
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Write: true}); err != nil {
+ return err
+ }
+
+ if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
+ return syserror.EOPNOTSUPP
+ }
+
+ return d.Inode.RemoveXattr(t, d, name)
+}