Merge release-20200115.0-9-g07f2584 (automated)

9 files changed, 115 insertions, 66 deletions

diff --git a/pkg/sentry/fs/copy_up.go b/pkg/sentry/fs/copy_up.go
index 734177e90..e03e3e417 100644
--- a/pkg/sentry/fs/copy_up.go
+++ b/pkg/sentry/fs/copy_up.go
@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"io"
 
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/memmap"
@@ -395,12 +396,12 @@ func copyContentsLocked(ctx context.Context, upper *Inode, lower *Inode, size in
 // Size and permissions are set on upper when the file content is copied
 // and when the file is created respectively.
 func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error {
-	// Extract attributes fro the lower filesystem.
+	// Extract attributes from the lower filesystem.
 	lowerAttr, err := lower.UnstableAttr(ctx)
 	if err != nil {
 		return err
 	}
-	lowerXattr, err := lower.Listxattr()
+	lowerXattr, err := lower.ListXattr(ctx)
 	if err != nil && err != syserror.EOPNOTSUPP {
 		return err
 	}
@@ -421,11 +422,11 @@ func copyAttributesLocked(ctx context.Context, upper *Inode, lower *Inode) error
 		if isXattrOverlay(name) {
 			continue
 		}
-		value, err := lower.Getxattr(name)
+		value, err := lower.GetXattr(ctx, name, linux.XATTR_SIZE_MAX)
 		if err != nil {
 			return err
 		}
-		if err := upper.InodeOperations.Setxattr(upper, name, value); err != nil {
+		if err := upper.InodeOperations.SetXattr(ctx, upper, name, value, 0 /* flags */); err != nil {
 			return err
 		}
 	}
diff --git a/pkg/sentry/fs/file_overlay.go b/pkg/sentry/fs/file_overlay.go
index 8a633b1ba..8991207b4 100644
--- a/pkg/sentry/fs/file_overlay.go
+++ b/pkg/sentry/fs/file_overlay.go
@@ -475,7 +475,7 @@ func readdirEntries(ctx context.Context, o *overlayEntry) (*SortedDentryMap, err
 			// Skip this name if it is a negative entry in the
 			// upper or there exists a whiteout for it.
 			if o.upper != nil {
-				if overlayHasWhiteout(o.upper, name) {
+				if overlayHasWhiteout(ctx, o.upper, name) {
 					continue
 				}
 			}
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index adf5ec69c..df7b74855 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -15,6 +15,7 @@
 package fsutil
 
 import (
+	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/context"
 	"gvisor.dev/gvisor/pkg/sentry/fs"
 	ktime "gvisor.dev/gvisor/pkg/sentry/kernel/time"
@@ -202,7 +203,7 @@ func (i *InodeSimpleAttributes) NotifyModificationAndStatusChange(ctx context.Co
 }
 
 // InodeSimpleExtendedAttributes implements
-// fs.InodeOperations.{Get,Set,List}xattr.
+// fs.InodeOperations.{Get,Set,List}Xattr.
 //
 // +stateify savable
 type InodeSimpleExtendedAttributes struct {
@@ -211,8 +212,8 @@ type InodeSimpleExtendedAttributes struct {
 	xattrs map[string]string
 }
 
-// Getxattr implements fs.InodeOperations.Getxattr.
-func (i *InodeSimpleExtendedAttributes) Getxattr(_ *fs.Inode, name string) (string, error) {
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (i *InodeSimpleExtendedAttributes) GetXattr(_ context.Context, _ *fs.Inode, name string, _ uint64) (string, error) {
 	i.mu.RLock()
 	value, ok := i.xattrs[name]
 	i.mu.RUnlock()
@@ -222,19 +223,31 @@ func (i *InodeSimpleExtendedAttributes) Getxattr(_ *fs.Inode, name string) (stri
 	return value, nil
 }
 
-// Setxattr implements fs.InodeOperations.Setxattr.
-func (i *InodeSimpleExtendedAttributes) Setxattr(_ *fs.Inode, name, value string) error {
+// SetXattr implements fs.InodeOperations.SetXattr.
+func (i *InodeSimpleExtendedAttributes) SetXattr(_ context.Context, _ *fs.Inode, name, value string, flags uint32) error {
 	i.mu.Lock()
+	defer i.mu.Unlock()
 	if i.xattrs == nil {
+		if flags&linux.XATTR_REPLACE != 0 {
+			return syserror.ENODATA
+		}
 		i.xattrs = make(map[string]string)
 	}
+
+	_, ok := i.xattrs[name]
+	if ok && flags&linux.XATTR_CREATE != 0 {
+		return syserror.EEXIST
+	}
+	if !ok && flags&linux.XATTR_REPLACE != 0 {
+		return syserror.ENODATA
+	}
+
 	i.xattrs[name] = value
-	i.mu.Unlock()
 	return nil
 }
 
-// Listxattr implements fs.InodeOperations.Listxattr.
-func (i *InodeSimpleExtendedAttributes) Listxattr(_ *fs.Inode) (map[string]struct{}, error) {
+// ListXattr implements fs.InodeOperations.ListXattr.
+func (i *InodeSimpleExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
 	i.mu.RLock()
 	names := make(map[string]struct{}, len(i.xattrs))
 	for name := range i.xattrs {
@@ -436,18 +449,18 @@ func (InodeNotSymlink) Getlink(context.Context, *fs.Inode) (*fs.Dirent, error) {
 // extended attributes.
 type InodeNoExtendedAttributes struct{}
 
-// Getxattr implements fs.InodeOperations.Getxattr.
-func (InodeNoExtendedAttributes) Getxattr(*fs.Inode, string) (string, error) {
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (InodeNoExtendedAttributes) GetXattr(context.Context, *fs.Inode, string, uint64) (string, error) {
 	return "", syserror.EOPNOTSUPP
 }
 
-// Setxattr implements fs.InodeOperations.Setxattr.
-func (InodeNoExtendedAttributes) Setxattr(*fs.Inode, string, string) error {
+// SetXattr implements fs.InodeOperations.SetXattr.
+func (InodeNoExtendedAttributes) SetXattr(context.Context, *fs.Inode, string, string, uint32) error {
 	return syserror.EOPNOTSUPP
 }
 
-// Listxattr implements fs.InodeOperations.Listxattr.
-func (InodeNoExtendedAttributes) Listxattr(*fs.Inode) (map[string]struct{}, error) {
+// ListXattr implements fs.InodeOperations.ListXattr.
+func (InodeNoExtendedAttributes) ListXattr(context.Context, *fs.Inode) (map[string]struct{}, error) {
 	return nil, syserror.EOPNOTSUPP
 }
 
diff --git a/pkg/sentry/fs/gofer/context_file.go b/pkg/sentry/fs/gofer/context_file.go
index 44b72582a..2125dafef 100644
--- a/pkg/sentry/fs/gofer/context_file.go
+++ b/pkg/sentry/fs/gofer/context_file.go
@@ -59,6 +59,20 @@ func (c *contextFile) setAttr(ctx context.Context, valid p9.SetAttrMask, attr p9
 	return err
 }
 
+func (c *contextFile) getXattr(ctx context.Context, name string, size uint64) (string, error) {
+	ctx.UninterruptibleSleepStart(false)
+	val, err := c.file.GetXattr(name, size)
+	ctx.UninterruptibleSleepFinish(false)
+	return val, err
+}
+
+func (c *contextFile) setXattr(ctx context.Context, name, value string, flags uint32) error {
+	ctx.UninterruptibleSleepStart(false)
+	err := c.file.SetXattr(name, value, flags)
+	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 245fe2ef1..98d1a8a48 100644
--- a/pkg/sentry/fs/gofer/inode.go
+++ b/pkg/sentry/fs/gofer/inode.go
@@ -38,8 +38,7 @@ import (
 //
 // +stateify savable
 type inodeOperations struct {
-	fsutil.InodeNotVirtual           `state:"nosave"`
-	fsutil.InodeNoExtendedAttributes `state:"nosave"`
+	fsutil.InodeNotVirtual `state:"nosave"`
 
 	// fileState implements fs.CachedFileObject. It exists
 	// to break a circular load dependency between inodeOperations
@@ -604,6 +603,21 @@ func (i *inodeOperations) Truncate(ctx context.Context, inode *fs.Inode, length
 	return i.fileState.file.setAttr(ctx, p9.SetAttrMask{Size: true}, p9.SetAttr{Size: uint64(length)})
 }
 
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (i *inodeOperations) GetXattr(ctx context.Context, inode *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 {
+	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
+}
+
 // Allocate implements fs.InodeOperations.Allocate.
 func (i *inodeOperations) Allocate(ctx context.Context, inode *fs.Inode, offset, length int64) error {
 	// This can only be called for files anyway.
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index 468043df0..ee9d301ef 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -261,28 +261,28 @@ func (i *Inode) UnstableAttr(ctx context.Context) (UnstableAttr, error) {
 	return i.InodeOperations.UnstableAttr(ctx, i)
 }
 
-// Getxattr calls i.InodeOperations.Getxattr with i as the Inode.
-func (i *Inode) Getxattr(name string) (string, error) {
+// GetXattr calls i.InodeOperations.GetXattr with i as the Inode.
+func (i *Inode) GetXattr(ctx context.Context, name string, size uint64) (string, error) {
 	if i.overlay != nil {
-		return overlayGetxattr(i.overlay, name)
+		return overlayGetXattr(ctx, i.overlay, name, size)
 	}
-	return i.InodeOperations.Getxattr(i, name)
+	return i.InodeOperations.GetXattr(ctx, i, name, size)
 }
 
-// Setxattr calls i.InodeOperations.Setxattr with i as the Inode.
-func (i *Inode) Setxattr(name, value string) error {
+// SetXattr calls i.InodeOperations.SetXattr with i as the Inode.
+func (i *Inode) SetXattr(ctx context.Context, name, value string, flags uint32) error {
 	if i.overlay != nil {
-		return overlaySetxattr(i.overlay, name, value)
+		return overlaySetxattr(ctx, i.overlay, name, value, flags)
 	}
-	return i.InodeOperations.Setxattr(i, name, value)
+	return i.InodeOperations.SetXattr(ctx, i, name, value, flags)
 }
 
-// Listxattr calls i.InodeOperations.Listxattr with i as the Inode.
-func (i *Inode) Listxattr() (map[string]struct{}, error) {
+// ListXattr calls i.InodeOperations.ListXattr with i as the Inode.
+func (i *Inode) ListXattr(ctx context.Context) (map[string]struct{}, error) {
 	if i.overlay != nil {
-		return overlayListxattr(i.overlay)
+		return overlayListXattr(ctx, i.overlay)
 	}
-	return i.InodeOperations.Listxattr(i)
+	return i.InodeOperations.ListXattr(ctx, i)
 }
 
 // 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 5cde9d215..13261cb81 100644
--- a/pkg/sentry/fs/inode_operations.go
+++ b/pkg/sentry/fs/inode_operations.go
@@ -170,20 +170,27 @@ type InodeOperations interface {
 	// file system events.
 	UnstableAttr(ctx context.Context, inode *Inode) (UnstableAttr, error)
 
-	// Getxattr retrieves the value of extended attribute name. Inodes that
-	// do not support extended attributes return EOPNOTSUPP. Inodes that
-	// support extended attributes but don't have a value at name return
+	// GetXattr retrieves the value of extended attribute specified by name.
+	// Inodes that do not support extended attributes return EOPNOTSUPP. Inodes
+	// that support extended attributes but don't have a value at name return
 	// ENODATA.
-	Getxattr(inode *Inode, name string) (string, error)
+	//
+	// If this is called through the getxattr(2) syscall, size indicates the
+	// size of the buffer that the application has allocated to hold the
+	// attribute value. If the value is 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.
+	GetXattr(ctx context.Context, inode *Inode, name string, size uint64) (string, error)
 
-	// Setxattr sets the value of extended attribute name. Inodes that
-	// do not support extended attributes return EOPNOTSUPP.
-	Setxattr(inode *Inode, name, value string) error
+	// SetXattr sets the value of extended attribute specified by name. Inodes
+	// that do not support extended attributes return EOPNOTSUPP.
+	SetXattr(ctx context.Context, inode *Inode, name, value string, flags uint32) error
 
-	// Listxattr returns the set of all extended attributes names that
+	// ListXattr returns the set of all extended attributes names that
 	// have values. Inodes that do not support extended attributes return
 	// EOPNOTSUPP.
-	Listxattr(inode *Inode) (map[string]struct{}, error)
+	ListXattr(ctx context.Context, inode *Inode) (map[string]struct{}, 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 13d11e001..b90da20d0 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -25,13 +25,13 @@ import (
 	"gvisor.dev/gvisor/pkg/syserror"
 )
 
-func overlayHasWhiteout(parent *Inode, name string) bool {
-	s, err := parent.Getxattr(XattrOverlayWhiteout(name))
+func overlayHasWhiteout(ctx context.Context, parent *Inode, name string) bool {
+	s, err := parent.GetXattr(ctx, XattrOverlayWhiteout(name), 1)
 	return err == nil && s == "y"
 }
 
-func overlayCreateWhiteout(parent *Inode, name string) error {
-	return parent.InodeOperations.Setxattr(parent, XattrOverlayWhiteout(name), "y")
+func overlayCreateWhiteout(ctx context.Context, parent *Inode, name string) error {
+	return parent.InodeOperations.SetXattr(ctx, parent, XattrOverlayWhiteout(name), "y", 0 /* flags */)
 }
 
 func overlayWriteOut(ctx context.Context, o *overlayEntry) error {
@@ -89,7 +89,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
 		}
 
 		// Are we done?
-		if overlayHasWhiteout(parent.upper, name) {
+		if overlayHasWhiteout(ctx, parent.upper, name) {
 			if upperInode == nil {
 				parent.copyMu.RUnlock()
 				if negativeUpperChild {
@@ -345,7 +345,7 @@ func overlayRemove(ctx context.Context, o *overlayEntry, parent *Dirent, child *
 		}
 	}
 	if child.Inode.overlay.lowerExists {
-		if err := overlayCreateWhiteout(o.upper, child.name); err != nil {
+		if err := overlayCreateWhiteout(ctx, o.upper, child.name); err != nil {
 			return err
 		}
 	}
@@ -426,7 +426,7 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena
 		return err
 	}
 	if renamed.Inode.overlay.lowerExists {
-		if err := overlayCreateWhiteout(oldParent.Inode.overlay.upper, oldName); err != nil {
+		if err := overlayCreateWhiteout(ctx, oldParent.Inode.overlay.upper, oldName); err != nil {
 			return err
 		}
 	}
@@ -528,7 +528,7 @@ func overlayUnstableAttr(ctx context.Context, o *overlayEntry) (UnstableAttr, er
 	return attr, err
 }
 
-func overlayGetxattr(o *overlayEntry, name string) (string, error) {
+func overlayGetXattr(ctx context.Context, o *overlayEntry, name string, size uint64) (string, error) {
 	// Hot path. This is how the overlay checks for whiteout files.
 	// Avoid defers.
 	var (
@@ -544,31 +544,31 @@ func overlayGetxattr(o *overlayEntry, name string) (string, error) {
 
 	o.copyMu.RLock()
 	if o.upper != nil {
-		s, err = o.upper.Getxattr(name)
+		s, err = o.upper.GetXattr(ctx, name, size)
 	} else {
-		s, err = o.lower.Getxattr(name)
+		s, err = o.lower.GetXattr(ctx, name, size)
 	}
 	o.copyMu.RUnlock()
 	return s, err
 }
 
 // TODO(b/146028302): Support setxattr for overlayfs.
-func overlaySetxattr(o *overlayEntry, name, value string) error {
+func overlaySetxattr(ctx context.Context, o *overlayEntry, name, value string, flags uint32) error {
 	return syserror.EOPNOTSUPP
 }
 
-func overlayListxattr(o *overlayEntry) (map[string]struct{}, error) {
+func overlayListXattr(ctx context.Context, o *overlayEntry) (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()
+		names, err = o.upper.ListXattr(ctx)
 	} else {
-		names, err = o.lower.Listxattr()
+		names, err = o.lower.ListXattr(ctx)
 	}
 	for name := range names {
-		// Same as overlayGetxattr, we shouldn't forward along
+		// Same as overlayGetXattr, we shouldn't forward along
 		// overlay attributes.
 		if strings.HasPrefix(XattrOverlayPrefix, name) {
 			delete(names, name)
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index 69089c8a8..0f718e236 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -148,19 +148,19 @@ func (d *Dir) CreateFifo(ctx context.Context, dir *fs.Inode, name string, perms
 	return d.ramfsDir.CreateFifo(ctx, dir, name, perms)
 }
 
-// Getxattr implements fs.InodeOperations.Getxattr.
-func (d *Dir) Getxattr(i *fs.Inode, name string) (string, error) {
-	return d.ramfsDir.Getxattr(i, name)
+// GetXattr implements fs.InodeOperations.GetXattr.
+func (d *Dir) GetXattr(ctx context.Context, i *fs.Inode, name string, size uint64) (string, error) {
+	return d.ramfsDir.GetXattr(ctx, i, name, size)
 }
 
-// Setxattr implements fs.InodeOperations.Setxattr.
-func (d *Dir) Setxattr(i *fs.Inode, name, value string) error {
-	return d.ramfsDir.Setxattr(i, name, value)
+// SetXattr implements fs.InodeOperations.SetXattr.
+func (d *Dir) SetXattr(ctx context.Context, i *fs.Inode, name, value string, flags uint32) error {
+	return d.ramfsDir.SetXattr(ctx, i, name, value, flags)
 }
 
-// Listxattr implements fs.InodeOperations.Listxattr.
-func (d *Dir) Listxattr(i *fs.Inode) (map[string]struct{}, error) {
-	return d.ramfsDir.Listxattr(i)
+// 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)
 }
 
 // Lookup implements fs.InodeOperations.Lookup.