From f1a5178c589dbd9a1fe4f1b9fb943fbe64791b58 Mon Sep 17 00:00:00 2001
From: Nicolas Lacasse <nlacasse@google.com>
Date: Fri, 17 Jan 2020 14:20:00 -0800
Subject: [PATCH] Fix data race in MountNamespace.resolve.

We must hold fs.renameMu to access Dirent.parent.

PiperOrigin-RevId: 290340804
---
 pkg/sentry/fs/mounts.go | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/pkg/sentry/fs/mounts.go b/pkg/sentry/fs/mounts.go
index db3dfd096..a9627a9d1 100644
--- a/pkg/sentry/fs/mounts.go
+++ b/pkg/sentry/fs/mounts.go
@@ -609,8 +609,11 @@ func (mns *MountNamespace) resolve(ctx context.Context, root, node *Dirent, rema
 		}
 
 		// Find the node; we resolve relative to the current symlink's parent.
+		renameMu.RLock()
+		parent := node.parent
+		renameMu.RUnlock()
 		*remainingTraversals--
-		d, err := mns.FindInode(ctx, root, node.parent, targetPath, remainingTraversals)
+		d, err := mns.FindInode(ctx, root, parent, targetPath, remainingTraversals)
 		if err != nil {
 			return nil, err
 		}