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, 111 insertions, 0 deletions

diff --git a/net/ieee802154/sysfs.c b/net/ieee802154/sysfs.c
new file mode 100644
index 000000000..6708160eb
--- /dev/null
+++ b/net/ieee802154/sysfs.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Authors:
+ * Alexander Aring <aar@pengutronix.de>
+ *
+ * Based on: net/wireless/sysfs.c
+ */
+
+#include <linux/device.h>
+#include <linux/rtnetlink.h>
+
+#include <net/cfg802154.h>
+
+#include "core.h"
+#include "sysfs.h"
+#include "rdev-ops.h"
+
+static inline struct cfg802154_registered_device *
+dev_to_rdev(struct device *dev)
+{
+	return container_of(dev, struct cfg802154_registered_device,
+			    wpan_phy.dev);
+}
+
+#define SHOW_FMT(name, fmt, member)					\
+static ssize_t name ## _show(struct device *dev,			\
+			     struct device_attribute *attr,		\
+			     char *buf)					\
+{									\
+	return sprintf(buf, fmt "\n", dev_to_rdev(dev)->member);	\
+}									\
+static DEVICE_ATTR_RO(name)
+
+SHOW_FMT(index, "%d", wpan_phy_idx);
+
+static ssize_t name_show(struct device *dev,
+			 struct device_attribute *attr,
+			 char *buf)
+{
+	struct wpan_phy *wpan_phy = &dev_to_rdev(dev)->wpan_phy;
+
+	return sprintf(buf, "%s\n", dev_name(&wpan_phy->dev));
+}
+static DEVICE_ATTR_RO(name);
+
+static void wpan_phy_release(struct device *dev)
+{
+	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);
+
+	cfg802154_dev_free(rdev);
+}
+
+static struct attribute *pmib_attrs[] = {
+	&dev_attr_index.attr,
+	&dev_attr_name.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(pmib);
+
+#ifdef CONFIG_PM_SLEEP
+static int wpan_phy_suspend(struct device *dev)
+{
+	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);
+	int ret = 0;
+
+	if (rdev->ops->suspend) {
+		rtnl_lock();
+		ret = rdev_suspend(rdev);
+		rtnl_unlock();
+	}
+
+	return ret;
+}
+
+static int wpan_phy_resume(struct device *dev)
+{
+	struct cfg802154_registered_device *rdev = dev_to_rdev(dev);
+	int ret = 0;
+
+	if (rdev->ops->resume) {
+		rtnl_lock();
+		ret = rdev_resume(rdev);
+		rtnl_unlock();
+	}
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(wpan_phy_pm_ops, wpan_phy_suspend, wpan_phy_resume);
+#define WPAN_PHY_PM_OPS (&wpan_phy_pm_ops)
+#else
+#define WPAN_PHY_PM_OPS NULL
+#endif
+
+const struct class wpan_phy_class = {
+	.name = "ieee802154",
+	.dev_release = wpan_phy_release,
+	.dev_groups = pmib_groups,
+	.pm = WPAN_PHY_PM_OPS,
+};
+
+int wpan_phy_sysfs_init(void)
+{
+	return class_register(&wpan_phy_class);
+}
+
+void wpan_phy_sysfs_exit(void)
+{
+	class_unregister(&wpan_phy_class);
+}