From 5eac692b841633be3e85f0125c59fa02af103989 Mon Sep 17 00:00:00 2001
From: Juergen Gross <jgross@suse.com>
Date: Tue, 13 Sep 2022 07:35:08 +0200
Subject: tools/xenstore: fix connection->id usage

Don't use conn->id for privilege checks, but domain_is_unprivileged().

This is part of XSA-326.

Reported-by: Julien Grall <jgrall@amazon.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>

diff --git a/tools/xenstore/xenstored_control.c b/tools/xenstore/xenstored_control.c
index 7b4300ef7777..adb8d51b043b 100644
--- a/tools/xenstore/xenstored_control.c
+++ b/tools/xenstore/xenstored_control.c
@@ -891,7 +891,7 @@ int do_control(struct connection *conn, struct buffered_data *in)
 	unsigned int cmd, num, off;
 	char **vec = NULL;
 
-	if (conn->id != 0)
+	if (domain_is_unprivileged(conn))
 		return EACCES;
 
 	off = get_string(in, 0);
diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h
index b9b50e81c7b4..b1a70488b989 100644
--- a/tools/xenstore/xenstored_core.h
+++ b/tools/xenstore/xenstored_core.h
@@ -123,7 +123,7 @@ struct connection
 	/* The index of pollfd in global pollfd array */
 	int pollfd_idx;
 
-	/* Who am I? 0 for socket connections. */
+	/* Who am I? Domid of connection. */
 	unsigned int id;
 
 	/* Is this connection ignored? */
diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c
index 54432907fc76..ee1b09031a3b 100644
--- a/tools/xenstore/xenstored_transaction.c
+++ b/tools/xenstore/xenstored_transaction.c
@@ -477,7 +477,8 @@ int do_transaction_start(struct connection *conn, struct buffered_data *in)
 	if (conn->transaction)
 		return EBUSY;
 
-	if (conn->id && conn->transaction_started > quota_max_transaction)
+	if (domain_is_unprivileged(conn) &&
+	    conn->transaction_started > quota_max_transaction)
 		return ENOSPC;
 
 	/* Attach transaction to input for autofree until it's complete */