From 78004e9a87f240df03e2f73120d291763c32e0a7 Mon Sep 17 00:00:00 2001 From: Ali Ahmet Memis Date: Fri, 21 Aug 2026 01:45:27 +0000 Subject: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall 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 Signed-off-by: Stafford Horne --- drivers/misc/hmc6352.c | 143 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 drivers/misc/hmc6352.c (limited to 'drivers/misc/hmc6352.c') diff --git a/drivers/misc/hmc6352.c b/drivers/misc/hmc6352.c new file mode 100644 index 000000000..ff92c6edf --- /dev/null +++ b/drivers/misc/hmc6352.c @@ -0,0 +1,143 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * hmc6352.c - Honeywell Compass Driver + * + * Copyright (C) 2009 Intel Corp + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + * + * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + */ + +#include +#include +#include +#include +#include +#include +#include + +static DEFINE_MUTEX(compass_mutex); + +static int compass_command(struct i2c_client *c, u8 cmd) +{ + int ret = i2c_master_send(c, &cmd, 1); + if (ret < 0) + dev_warn(&c->dev, "command '%c' failed.\n", cmd); + return ret; +} + +static int compass_store(struct device *dev, const char *buf, size_t count, + const char *map) +{ + struct i2c_client *c = to_i2c_client(dev); + int ret; + unsigned long val; + + ret = kstrtoul(buf, 10, &val); + if (ret) + return ret; + if (val >= strlen(map)) + return -EINVAL; + val = array_index_nospec(val, strlen(map)); + mutex_lock(&compass_mutex); + ret = compass_command(c, map[val]); + mutex_unlock(&compass_mutex); + if (ret < 0) + return ret; + return count; +} + +static ssize_t compass_calibration_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + return compass_store(dev, buf, count, "EC"); +} + +static ssize_t compass_power_mode_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + return compass_store(dev, buf, count, "SW"); +} + +static ssize_t compass_heading_data_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct i2c_client *client = to_i2c_client(dev); + unsigned char i2c_data[2]; + int ret; + + mutex_lock(&compass_mutex); + ret = compass_command(client, 'A'); + if (ret != 1) { + mutex_unlock(&compass_mutex); + return ret; + } + msleep(10); /* sending 'A' cmd we need to wait for 7-10 millisecs */ + ret = i2c_master_recv(client, i2c_data, 2); + mutex_unlock(&compass_mutex); + if (ret < 0) { + dev_warn(dev, "i2c read data cmd failed\n"); + return ret; + } + ret = (i2c_data[0] << 8) | i2c_data[1]; + return sprintf(buf, "%d.%d\n", ret/10, ret%10); +} + + +static DEVICE_ATTR(heading0_input, S_IRUGO, compass_heading_data_show, NULL); +static DEVICE_ATTR(calibration, S_IWUSR, NULL, compass_calibration_store); +static DEVICE_ATTR(power_state, S_IWUSR, NULL, compass_power_mode_store); + +static struct attribute *mid_att_compass[] = { + &dev_attr_heading0_input.attr, + &dev_attr_calibration.attr, + &dev_attr_power_state.attr, + NULL +}; + +static const struct attribute_group m_compass_gr = { + .name = "hmc6352", + .attrs = mid_att_compass +}; + +static int hmc6352_probe(struct i2c_client *client) +{ + int res; + + res = sysfs_create_group(&client->dev.kobj, &m_compass_gr); + if (res) { + dev_err(&client->dev, "device_create_file failed\n"); + return res; + } + dev_info(&client->dev, "%s HMC6352 compass chip found\n", + client->name); + return 0; +} + +static void hmc6352_remove(struct i2c_client *client) +{ + sysfs_remove_group(&client->dev.kobj, &m_compass_gr); +} + +static const struct i2c_device_id hmc6352_id[] = { + { "hmc6352" }, + { } +}; + +MODULE_DEVICE_TABLE(i2c, hmc6352_id); + +static struct i2c_driver hmc6352_driver = { + .driver = { + .name = "hmc6352", + }, + .probe = hmc6352_probe, + .remove = hmc6352_remove, + .id_table = hmc6352_id, +}; + +module_i2c_driver(hmc6352_driver); + +MODULE_AUTHOR("Kalhan Trisal