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, 165 insertions, 0 deletions

diff --git a/drivers/input/keyboard/ipaq-micro-keys.c b/drivers/input/keyboard/ipaq-micro-keys.c
new file mode 100644
index 000000000..ebd991de7
--- /dev/null
+++ b/drivers/input/keyboard/ipaq-micro-keys.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * h3600 atmel micro companion support, key subdevice
+ * based on previous kernel 2.4 version
+ * Author : Alessandro Gardich <gremlin@gremlin.it>
+ * Author : Linus Walleij <linus.walleij@linaro.org>
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/pm.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/input.h>
+#include <linux/platform_device.h>
+#include <linux/mfd/ipaq-micro.h>
+
+static const u16 micro_keycodes[] = {
+	KEY_RECORD,		/* 1:  Record button			*/
+	KEY_CALENDAR,		/* 2:  Calendar				*/
+	KEY_ADDRESSBOOK,	/* 3:  Contacts (looks like Outlook)	*/
+	KEY_MAIL,		/* 4:  Envelope (Q on older iPAQs)	*/
+	KEY_HOMEPAGE,		/* 5:  Start (looks like swoopy arrow)	*/
+	KEY_UP,			/* 6:  Up				*/
+	KEY_RIGHT,		/* 7:  Right				*/
+	KEY_LEFT,		/* 8:  Left				*/
+	KEY_DOWN,		/* 9:  Down				*/
+};
+
+struct ipaq_micro_keys {
+	struct ipaq_micro *micro;
+	struct input_dev *input;
+	u16 codes[ARRAY_SIZE(micro_keycodes)];
+};
+
+static void micro_key_receive(void *data, int len, unsigned char *msg)
+{
+	struct ipaq_micro_keys *keys = data;
+	int key, down;
+
+	if (len < 1)
+		return;
+
+	down = 0x80 & msg[0];
+	key  = 0x7f & msg[0];
+
+	if (key < ARRAY_SIZE(micro_keycodes)) {
+		input_report_key(keys->input, keys->codes[key], down);
+		input_sync(keys->input);
+	}
+}
+
+static void micro_key_start(struct ipaq_micro_keys *keys)
+{
+	guard(spinlock_irq)(&keys->micro->lock);
+
+	keys->micro->key = micro_key_receive;
+	keys->micro->key_data = keys;
+}
+
+static void micro_key_stop(struct ipaq_micro_keys *keys)
+{
+	guard(spinlock_irq)(&keys->micro->lock);
+
+	keys->micro->key = NULL;
+	keys->micro->key_data = NULL;
+}
+
+static int micro_key_open(struct input_dev *input)
+{
+	struct ipaq_micro_keys *keys = input_get_drvdata(input);
+
+	micro_key_start(keys);
+
+	return 0;
+}
+
+static void micro_key_close(struct input_dev *input)
+{
+	struct ipaq_micro_keys *keys = input_get_drvdata(input);
+
+	micro_key_stop(keys);
+}
+
+static int micro_key_probe(struct platform_device *pdev)
+{
+	struct ipaq_micro_keys *keys;
+	int error;
+	int i;
+
+	keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
+	if (!keys)
+		return -ENOMEM;
+
+	keys->micro = dev_get_drvdata(pdev->dev.parent);
+
+	keys->input = devm_input_allocate_device(&pdev->dev);
+	if (!keys->input)
+		return -ENOMEM;
+
+	keys->input->keycodesize = sizeof(micro_keycodes[0]);
+	keys->input->keycodemax = ARRAY_SIZE(micro_keycodes);
+	memcpy(keys->codes, micro_keycodes, sizeof(keys->codes));
+
+	keys->input->keycode = keys->codes;
+
+	__set_bit(EV_KEY, keys->input->evbit);
+	for (i = 0; i < ARRAY_SIZE(micro_keycodes); i++)
+		__set_bit(micro_keycodes[i], keys->input->keybit);
+
+	keys->input->name = "h3600 micro keys";
+	keys->input->open = micro_key_open;
+	keys->input->close = micro_key_close;
+	input_set_drvdata(keys->input, keys);
+
+	error = input_register_device(keys->input);
+	if (error)
+		return error;
+
+	platform_set_drvdata(pdev, keys);
+	return 0;
+}
+
+static int micro_key_suspend(struct device *dev)
+{
+	struct ipaq_micro_keys *keys = dev_get_drvdata(dev);
+
+	micro_key_stop(keys);
+
+	return 0;
+}
+
+static int micro_key_resume(struct device *dev)
+{
+	struct ipaq_micro_keys *keys = dev_get_drvdata(dev);
+	struct input_dev *input = keys->input;
+
+	guard(mutex)(&input->mutex);
+
+	if (input_device_enabled(input))
+		micro_key_start(keys);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(micro_key_dev_pm_ops,
+				micro_key_suspend, micro_key_resume);
+
+static struct platform_driver micro_key_device_driver = {
+	.driver = {
+		.name    = "ipaq-micro-keys",
+		.pm	= pm_sleep_ptr(&micro_key_dev_pm_ops),
+	},
+	.probe   = micro_key_probe,
+};
+module_platform_driver(micro_key_device_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("driver for iPAQ Atmel micro keys");
+MODULE_ALIAS("platform:ipaq-micro-keys");