Merge release-20200818.0-58-g83a8b309e (automated)

15 files changed, 56 insertions, 40 deletions

diff --git a/pkg/sentry/fsimpl/devpts/root_inode_refs.go b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
index 051801202..068ee2f20 100644
--- a/pkg/sentry/fsimpl/devpts/root_inode_refs.go
+++ b/pkg/sentry/fsimpl/devpts/root_inode_refs.go
@@ -1,10 +1,10 @@
 package devpts
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/fuse/inode_refs.go b/pkg/sentry/fsimpl/fuse/inode_refs.go
index 6b9456e1d..5d1de6067 100644
--- a/pkg/sentry/fsimpl/fuse/inode_refs.go
+++ b/pkg/sentry/fsimpl/fuse/inode_refs.go
@@ -1,10 +1,10 @@
 package fuse
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
index babb3f664..abf4a9082 100644
--- a/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
+++ b/pkg/sentry/fsimpl/host/connected_endpoint_refs.go
@@ -1,10 +1,10 @@
 package host
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/host/inode_refs.go b/pkg/sentry/fsimpl/host/inode_refs.go
index 17f90ce4a..75b9f49e2 100644
--- a/pkg/sentry/fsimpl/host/inode_refs.go
+++ b/pkg/sentry/fsimpl/host/inode_refs.go
@@ -1,10 +1,10 @@
 package host
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/kernfs/dentry_refs.go b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
index 79863b3bc..b7125caee 100644
--- a/pkg/sentry/fsimpl/kernfs/dentry_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/dentry_refs.go
@@ -1,10 +1,10 @@
 package kernfs
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
index 478b04bdd..0ff013c97 100644
--- a/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
+++ b/pkg/sentry/fsimpl/kernfs/static_directory_refs.go
@@ -1,10 +1,10 @@
 package kernfs
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/overlay/filesystem.go b/pkg/sentry/fsimpl/overlay/filesystem.go
index a3cee4047..e720bfb0b 100644
--- a/pkg/sentry/fsimpl/overlay/filesystem.go
+++ b/pkg/sentry/fsimpl/overlay/filesystem.go
@@ -30,7 +30,7 @@ import (
 // _OVL_XATTR_OPAQUE is an extended attribute key whose value is set to "y" for
 // opaque directories.
 // Linux: fs/overlayfs/overlayfs.h:OVL_XATTR_OPAQUE
-const _OVL_XATTR_OPAQUE = "trusted.overlay.opaque"
+const _OVL_XATTR_OPAQUE = linux.XATTR_TRUSTED_PREFIX + "overlay.opaque"
 
 func isWhiteout(stat *linux.Statx) bool {
 	return stat.Mode&linux.S_IFMT == linux.S_IFCHR && stat.RdevMajor == 0 && stat.RdevMinor == 0
diff --git a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
index 9431c1506..454862d98 100644
--- a/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_dir_inode_refs.go
@@ -1,10 +1,10 @@
 package proc
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
index 872b20eb0..d2169be5b 100644
--- a/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/fd_info_dir_inode_refs.go
@@ -1,10 +1,10 @@
 package proc
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
index c6d9b3522..9b50f632c 100644
--- a/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/subtasks_inode_refs.go
@@ -1,10 +1,10 @@
 package proc
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/proc/task_inode_refs.go b/pkg/sentry/fsimpl/proc/task_inode_refs.go
index 714488450..c29272f9b 100644
--- a/pkg/sentry/fsimpl/proc/task_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/task_inode_refs.go
@@ -1,10 +1,10 @@
 package proc
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
index 22d9cc488..7e0b70f6c 100644
--- a/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
+++ b/pkg/sentry/fsimpl/proc/tasks_inode_refs.go
@@ -1,10 +1,10 @@
 package proc
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/sys/dir_refs.go b/pkg/sentry/fsimpl/sys/dir_refs.go
index 89609b198..d42edb20e 100644
--- a/pkg/sentry/fsimpl/sys/dir_refs.go
+++ b/pkg/sentry/fsimpl/sys/dir_refs.go
@@ -1,10 +1,10 @@
 package sys
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/tmpfs/inode_refs.go b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
index dbf0b2766..4f4037adb 100644
--- a/pkg/sentry/fsimpl/tmpfs/inode_refs.go
+++ b/pkg/sentry/fsimpl/tmpfs/inode_refs.go
@@ -1,10 +1,10 @@
 package tmpfs
 
 import (
-	"fmt"
 	"runtime"
 	"sync/atomic"
 
+	"fmt"
 	"gvisor.dev/gvisor/pkg/log"
 	refs_vfs1 "gvisor.dev/gvisor/pkg/refs"
 )
diff --git a/pkg/sentry/fsimpl/tmpfs/tmpfs.go b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
index a7fdf19ca..c4cec4130 100644
--- a/pkg/sentry/fsimpl/tmpfs/tmpfs.go
+++ b/pkg/sentry/fsimpl/tmpfs/tmpfs.go
@@ -631,49 +631,65 @@ func (i *inode) listxattr(size uint64) ([]string, error) {
 }
 
 func (i *inode) getxattr(creds *auth.Credentials, opts *vfs.GetxattrOptions) (string, error) {
-	if err := i.checkPermissions(creds, vfs.MayRead); err != nil {
+	if err := i.checkXattrPermissions(creds, opts.Name, vfs.MayRead); err != nil {
 		return "", err
 	}
-	if !strings.HasPrefix(opts.Name, linux.XATTR_USER_PREFIX) {
-		return "", syserror.EOPNOTSUPP
-	}
-	if !i.userXattrSupported() {
-		return "", syserror.ENODATA
-	}
 	return i.xattrs.Getxattr(opts)
 }
 
 func (i *inode) setxattr(creds *auth.Credentials, opts *vfs.SetxattrOptions) error {
-	if err := i.checkPermissions(creds, vfs.MayWrite); err != nil {
+	if err := i.checkXattrPermissions(creds, opts.Name, vfs.MayWrite); err != nil {
 		return err
 	}
-	if !strings.HasPrefix(opts.Name, linux.XATTR_USER_PREFIX) {
-		return syserror.EOPNOTSUPP
-	}
-	if !i.userXattrSupported() {
-		return syserror.EPERM
-	}
 	return i.xattrs.Setxattr(opts)
 }
 
 func (i *inode) removexattr(creds *auth.Credentials, name string) error {
-	if err := i.checkPermissions(creds, vfs.MayWrite); err != nil {
+	if err := i.checkXattrPermissions(creds, name, vfs.MayWrite); err != nil {
 		return err
 	}
-	if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
-		return syserror.EOPNOTSUPP
-	}
-	if !i.userXattrSupported() {
-		return syserror.EPERM
-	}
 	return i.xattrs.Removexattr(name)
 }
 
-// Extended attributes in the user.* namespace are only supported for regular
-// files and directories.
-func (i *inode) userXattrSupported() bool {
-	filetype := linux.S_IFMT & atomic.LoadUint32(&i.mode)
-	return filetype == linux.S_IFREG || filetype == linux.S_IFDIR
+func (i *inode) checkXattrPermissions(creds *auth.Credentials, name string, ats vfs.AccessTypes) error {
+	switch {
+	case ats&vfs.MayRead == vfs.MayRead:
+		if err := i.checkPermissions(creds, vfs.MayRead); err != nil {
+			return err
+		}
+	case ats&vfs.MayWrite == vfs.MayWrite:
+		if err := i.checkPermissions(creds, vfs.MayWrite); err != nil {
+			return err
+		}
+	default:
+		panic(fmt.Sprintf("checkXattrPermissions called with impossible AccessTypes: %v", ats))
+	}
+
+	switch {
+	case strings.HasPrefix(name, linux.XATTR_TRUSTED_PREFIX):
+		// The trusted.* namespace can only be accessed by privileged
+		// users.
+		if creds.HasCapability(linux.CAP_SYS_ADMIN) {
+			return nil
+		}
+		if ats&vfs.MayWrite == vfs.MayWrite {
+			return syserror.EPERM
+		}
+		return syserror.ENODATA
+	case strings.HasPrefix(name, linux.XATTR_USER_PREFIX):
+		// Extended attributes in the user.* namespace are only
+		// supported for regular files and directories.
+		filetype := linux.S_IFMT & atomic.LoadUint32(&i.mode)
+		if filetype == linux.S_IFREG || filetype == linux.S_IFDIR {
+			return nil
+		}
+		if ats&vfs.MayWrite == vfs.MayWrite {
+			return syserror.EPERM
+		}
+		return syserror.ENODATA
+
+	}
+	return syserror.EOPNOTSUPP
 }
 
 // fileDescription is embedded by tmpfs implementations of