Automated rollback of changelist 255263686

PiperOrigin-RevId: 255679453

1 files changed, 6 insertions, 0 deletions

diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index b247fa514..24b769cfc 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -567,6 +567,12 @@ func overlayCheck(ctx context.Context, o *overlayEntry, p PermMask) error {
 	if o.upper != nil {
 		err = o.upper.check(ctx, p)
 	} else {
+		if p.Write {
+			// Since writes will be redirected to the upper filesystem, the lower
+			// filesystem need not be writable, but must be readable for copy-up.
+			p.Write = false
+			p.Read = true
+		}
 		err = o.lower.check(ctx, p)
 	}
 	o.copyMu.RUnlock()