From: Stefan Hajnoczi <stefanha@redhat.com>

Date: Mon, 27 Jan 2020 19:01:28 +0000

Subject: [PATCH] virtiofsd: move to an empty network namespace

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

If the process is compromised there should be no network access.  Use an

empty network namespace to sandbox networking.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

(cherry picked from commit d74830d12ae233186ff74ddf64c552d26bb39e50)

---

 tools/virtiofsd/passthrough_ll.c | 14 ++++++++++++++

 1 file changed, 14 insertions(+)

diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c

index 0570453eef..27ab328722 100644

--- a/tools/virtiofsd/passthrough_ll.c

+++ b/tools/virtiofsd/passthrough_ll.c

@@ -1944,6 +1944,19 @@ static void print_capabilities(void)

     printf("}\n");

 }

+/*

+ * Called after our UNIX domain sockets have been created, now we can move to

+ * an empty network namespace to prevent TCP/IP and other network activity in

+ * case this process is compromised.

+ */

+static void setup_net_namespace(void)

+{

+    if (unshare(CLONE_NEWNET) != 0) {

+        fuse_log(FUSE_LOG_ERR, "unshare(CLONE_NEWNET): %m\n");

+        exit(1);

+    }

+}

+

 /* This magic is based on lxc's lxc_pivot_root() */

 static void setup_pivot_root(const char *source)

 {

@@ -2035,6 +2048,7 @@ static void setup_mount_namespace(const char *source)

  */

 static void setup_sandbox(struct lo_data *lo)

 {

+    setup_net_namespace();

     setup_mount_namespace(lo->source);

 }