openrisc: fix arbitrary kernel memory access via or1k_atomic syscallgrafted

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]
Fixes: 9d02a4283e9c ("OpenRISC: Boot code")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Ahmet Memis <ali@iusegentoo.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/drivers/thunderbolt/configfs.c b/drivers/thunderbolt/configfs.c
new file mode 100644
index 000000000..dc6bc363d
--- /dev/null
+++ b/drivers/thunderbolt/configfs.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ConfigFS support
+ *
+ * Copyright (C) 2026, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/configfs.h>
+#include <linux/export.h>
+
+#include "tb.h"
+
+static const struct config_item_type tb_root_group_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct configfs_subsystem tb_configfs = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "thunderbolt",
+			.ci_type = &tb_root_group_type,
+		},
+	},
+};
+
+/**
+ * tb_configfs_register_group() - Register Thunderbolt ConfigFS group
+ * @group: Group to register.
+ *
+ * Registers the new @group under Thunderbolt subsystem ConfigFS.
+ *
+ * Return: 0% in case of success, negative errno otherwise.
+ */
+int tb_configfs_register_group(struct config_group *group)
+{
+	return configfs_register_group(&tb_configfs.su_group, group);
+}
+EXPORT_SYMBOL_GPL(tb_configfs_register_group);
+
+/**
+ * tb_configfs_unregister_group() - Unregister previously registered group
+ * @group: Group to unregister.
+ */
+void tb_configfs_unregister_group(struct config_group *group)
+{
+	configfs_unregister_group(group);
+}
+EXPORT_SYMBOL_GPL(tb_configfs_unregister_group);
+
+int tb_configfs_init(void)
+{
+	config_group_init(&tb_configfs.su_group);
+	mutex_init(&tb_configfs.su_mutex);
+	return configfs_register_subsystem(&tb_configfs);
+}
+
+void tb_configfs_exit(void)
+{
+	configfs_unregister_subsystem(&tb_configfs);
+}