CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the "sloppy-logic-analyzer" driver, where a use-after-free condition can occur due to improper handling of the debugfs trigger file during device unbinding. This flaw allows a root user to exploit the race condition, potentially leading to arbitrary memory writes and system instability. Organizations utilizing affected Linux kernel versions, particularly those employing the gpio-sloppy-logic-analyzer driver, should prioritize patching to mitigate the risk of exploitation.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: gpio: sloppy-logic-analyzer: fix use-after-free via debugfs trigger on unbind The "trigger" debugfs file has a hand-rolled ->write handler (trigger_write()) that dereferences the per-device gpio_la_poll_priv. The file is created with debugfs_create_file_unsafe(), and the handler never takes a debugfs reference. Nothing keeps the object alive while the handler runs. priv is allocated with devm_kzalloc(). devres frees it when the platform device is unbound. debugfs_create_file_unsafe() installs no full_proxy wrapper, so debugfs_remove_recursive() in gpio_la_poll_remove() does not wait for an in-flight trigger_write(). The blob_lock taken there does not help, because trigger_write() never takes it. A write that races an unbind therefore writes into freed memory: trigger_write() gpio_la_poll_remove() priv = m->private buf = memdup_user() [may sleep] mutex_lock(&priv->blob_lock) debugfs_remove_recursive() [no wait] mutex_unlock(&priv->blob_lock) (remove returns; devres frees priv) priv->trig_data = buf <-- use-after-free write priv->trig_len = count The race is reachable by root via /sys/bus/platform/drivers/gpio-sloppy-logic-analyzer/unbind. Create "trigger" with debugfs_create_file() instead. Its full_proxy wrapper makes debugfs_remove_recursive() drain any in-flight ->write before it returns. The use-after-free is confirmed under KASAN with a minimal reproducer of the same debugfs_create_file_unsafe() plus devm_kzalloc() pattern (available on request); it produces a slab-use-after-free write in the handler.