5 files changed, 15 insertions, 4 deletions
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index f4ddfa406..2d43dff1d 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -344,6 +344,10 @@ func (i *Inode) SetTimestamps(ctx context.Context, d *Dirent, ts TimeSpec) error
 
 // Truncate calls i.InodeOperations.Truncate with i as the Inode.
 func (i *Inode) Truncate(ctx context.Context, d *Dirent, size int64) error {
+	if IsDir(i.StableAttr) {
+		return syserror.EISDIR
+	}
+
 	if i.overlay != nil {
 		return overlayTruncate(ctx, i.overlay, d, size)
 	}
diff --git a/pkg/sentry/fs/tty/master.go b/pkg/sentry/fs/tty/master.go
index 19b7557d5..bc56be696 100644
--- a/pkg/sentry/fs/tty/master.go
+++ b/pkg/sentry/fs/tty/master.go
@@ -32,6 +32,7 @@ import (
 // +stateify savable
 type masterInodeOperations struct {
 	fsutil.SimpleFileInode
+	fsutil.InodeNoopTruncate
 
 	// d is the containing dir.
 	d *dirInodeOperations
diff --git a/pkg/sentry/fs/tty/slave.go b/pkg/sentry/fs/tty/slave.go
index 944c4ada1..4cbea0367 100644
--- a/pkg/sentry/fs/tty/slave.go
+++ b/pkg/sentry/fs/tty/slave.go
@@ -31,6 +31,7 @@ import (
 // +stateify savable
 type slaveInodeOperations struct {
 	fsutil.SimpleFileInode
+	fsutil.InodeNoopTruncate
 
 	// d is the containing dir.
 	d *dirInodeOperations
diff --git a/pkg/sentry/fs/tty/tty_state_autogen.go b/pkg/sentry/fs/tty/tty_state_autogen.go
index c54600104..676e531c7 100755
--- a/pkg/sentry/fs/tty/tty_state_autogen.go
+++ b/pkg/sentry/fs/tty/tty_state_autogen.go
@@ -101,12 +101,14 @@ func (x *masterInodeOperations) beforeSave() {}
 func (x *masterInodeOperations) save(m state.Map) {
 	x.beforeSave()
 	m.Save("SimpleFileInode", &x.SimpleFileInode)
+	m.Save("InodeNoopTruncate", &x.InodeNoopTruncate)
 	m.Save("d", &x.d)
 }
 
 func (x *masterInodeOperations) afterLoad() {}
 func (x *masterInodeOperations) load(m state.Map) {
 	m.Load("SimpleFileInode", &x.SimpleFileInode)
+	m.Load("InodeNoopTruncate", &x.InodeNoopTruncate)
 	m.Load("d", &x.d)
 }
 
@@ -146,6 +148,7 @@ func (x *slaveInodeOperations) beforeSave() {}
 func (x *slaveInodeOperations) save(m state.Map) {
 	x.beforeSave()
 	m.Save("SimpleFileInode", &x.SimpleFileInode)
+	m.Save("InodeNoopTruncate", &x.InodeNoopTruncate)
 	m.Save("d", &x.d)
 	m.Save("t", &x.t)
 }
@@ -153,6 +156,7 @@ func (x *slaveInodeOperations) save(m state.Map) {
 func (x *slaveInodeOperations) afterLoad() {}
 func (x *slaveInodeOperations) load(m state.Map) {
 	m.Load("SimpleFileInode", &x.SimpleFileInode)
+	m.Load("InodeNoopTruncate", &x.InodeNoopTruncate)
 	m.Load("d", &x.d)
 	m.Load("t", &x.t)
 }
diff --git a/pkg/sentry/syscalls/linux/sys_file.go b/pkg/sentry/syscalls/linux/sys_file.go
index b9a8e3e21..167c2b60b 100644
--- a/pkg/sentry/syscalls/linux/sys_file.go
+++ b/pkg/sentry/syscalls/linux/sys_file.go
@@ -169,10 +169,11 @@ func openAt(t *kernel.Task, dirFD int32, addr usermem.Addr, flags uint) (fd uint
 			if dirPath {
 				return syserror.ENOTDIR
 			}
-			if flags&linux.O_TRUNC != 0 {
-				if err := d.Inode.Truncate(t, d, 0); err != nil {
-					return err
-				}
+		}
+
+		if flags&linux.O_TRUNC != 0 {
+			if err := d.Inode.Truncate(t, d, 0); err != nil {
+				return err
 			}
 		}