Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (powerz) Fix use-after-free on USB disconnect
After powerz_disconnect() frees the URB and releases the mutex, a subsequent powerz_read() call can acquire the mutex and call powerz_read_data(), which dereferences the freed URB pointer.
Fix by:
- Setting priv->urb to NULL in powerz_disconnect() so that powerz_read_data() can detect the disconnected state.
- Adding a !priv->urb check at the start of powerz_read_data() to return -ENODEV on a disconnected device.
- Moving usb_set_intfdata() before hwmon registration so the disconnect handler can always find the priv pointer.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux-hwe @ 4.15.0 (+15 more)
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (powerz) Fix use-after-free on USB disconnect
After powerz_disconnect() frees the URB and releases the mutex, a subsequent powerz_read() call can acquire the mutex and call powerz_read_data(), which dereferences the freed URB pointer.
Fix by:
- Setting priv->urb to NULL in powerz_disconnect() so that powerz_read_data() can detect the disconnected state.
- Adding a !priv->urb check at the start of powerz_read_data() to return -ENODEV on a disconnected device.
- Moving usb_set_intfdata() before hwmon registration so the disconnect handler can always find the priv pointer.