CyberRota Analysis
AI-GeneratedThe vulnerability in the Linux kernel affects the Atmel MultiMediaCard Interface (MMC) driver, specifically in the `atmci_remove` function, where a use-after-free condition can occur due to a race condition between module removal and queued work. This can lead to potential exploitation, allowing an attacker to execute arbitrary code or cause system instability. Organizations using affected Linux systems, particularly those relying on the Atmel MMC driver, should prioritize patching to mitigate this risk.
Original NVD Description
In the Linux kernel, the following vulnerability has been resolved: mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition In atmci_probe, &host->bh_work is bound with atmci_work_func, and atmci_interrupt, atmci_timeout_timer and atmci_dma_complete can all queue this work on system_bh_wq. If we remove the module, atmci_remove makes cleanup and the memory allocated for host with devm_kzalloc() is released after the remove callback returns, while the work mentioned above may still be pending or running. The sequence of operations that may lead to a UAF bug is as follows: CPU0 CPU1 | atmci_interrupt | queue_work(system_bh_wq, | &host->bh_work) atmci_remove | atmci_cleanup_slot(...) | atmci_writel(host, ATMCI_IDR, ~0UL) | timer_delete_sync(&host->timer) | dma_release_channel(host->dma.chan) | free_irq(platform_get_irq(pdev, 0), host) | | atmci_work_func | // use host // devm resources released after | // remove returns, host is freed | | // use host (use-after-free) Fix it by canceling the work after all the sources that can schedule it (IRQ handler, timeout timer and DMA completion callback) have been stopped, and before proceeding with the remaining cleanup in atmci_remove.