Description

In the Linux kernel, the following vulnerability has been resolved: scsi: imm: Fix use-after-free bug caused by unfinished delayed work The delayed work item 'imm_tq' is initialized in imm_attach() and scheduled via imm_queuecommand() for processing SCSI commands. When the IMM parallel port SCSI host adapter is detached through imm_detach(), the imm_struct device instance is deallocated. However, the delayed work might still be pending or executing when imm_detach() is called, leading to use-after-free bugs when the work function imm_interrupt() accesses the already freed imm_struct memory. The race condition can occur as follows: CPU 0(detach thread) | CPU 1 | imm_queuecommand() | imm_queuecommand_lck() imm_detach() | schedule_delayed_work() kfree(dev) //FREE | imm_interrupt() | dev = container_of(...) //USE dev-> //USE Add disable_delayed_work_sync() in imm_detach() to guarantee proper cancellation of the delayed work item before imm_struct is deallocated.

References 4

• git.kernel.org https://git.kernel.org/stable/c/31ab2aad7a7b7501e904a09bf361e44671f66092
• git.kernel.org https://git.kernel.org/stable/c/48dd41fa2d6c6a0c50e714deeba06ffe7f91961b
• git.kernel.org https://git.kernel.org/stable/c/9e434426cc23ad5e2aad649327b59aea00294b13
• git.kernel.org https://git.kernel.org/stable/c/ab58153ec64fa3fc9aea09ca09dc9322e0b54a7c

Remediation