diff options
| author | Armin Wolf <W_Armin@gmx.de> | 2023-10-20 23:10:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-11-20 11:08:18 +0100 |
| commit | e0bf076b734a2fab92d8fddc2b8b03462eee7097 (patch) | |
| tree | 7350a4d49a963ba92992f89fb0bb06f02f1767bd | |
| parent | c57e81d5e5384e6ac400759b08e67d125ba054a1 (diff) | |
platform/x86: wmi: Fix opening of char device
[ Upstream commit eba9ac7abab91c8f6d351460239108bef5e7a0b6 ]
Since commit fa1f68db6ca7 ("drivers: misc: pass miscdevice pointer via
file private data"), the miscdevice stores a pointer to itself inside
filp->private_data, which means that private_data will not be NULL when
wmi_char_open() is called. This might cause memory corruption should
wmi_char_open() be unable to find its driver, something which can
happen when the associated WMI device is deleted in wmi_free_devices().
Fix the problem by using the miscdevice pointer to retrieve the WMI
device data associated with a char device using container_of(). This
also avoids wmi_char_open() picking a wrong WMI device bound to a
driver with the same name as the original driver.
Fixes: 44b6b7661132 ("platform/x86: wmi: create userspace interface for drivers")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://lore.kernel.org/r/20231020211005.38216-5-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/platform/x86/wmi.c | 20 |
1 files changed, 6 insertions, 14 deletions
diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c index 530778dbdd09..63265ab96424 100644 --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -827,21 +827,13 @@ static int wmi_dev_match(struct device *dev, struct device_driver *driver) } static int wmi_char_open(struct inode *inode, struct file *filp) { - const char *driver_name = filp->f_path.dentry->d_iname; - struct wmi_block *wblock; - struct wmi_block *next; - - list_for_each_entry_safe(wblock, next, &wmi_block_list, list) { - if (!wblock->dev.dev.driver) - continue; - if (strcmp(driver_name, wblock->dev.dev.driver->name) == 0) { - filp->private_data = wblock; - break; - } - } + /* + * The miscdevice already stores a pointer to itself + * inside filp->private_data + */ + struct wmi_block *wblock = container_of(filp->private_data, struct wmi_block, char_dev); - if (!filp->private_data) - return -ENODEV; + filp->private_data = wblock; return nonseekable_open(inode, filp); } |