1.8 KiB
CVE-2024-26718
Description
In the Linux kernel, the following vulnerability has been resolved:dm-crypt, dm-verity: disable taskletsTasklets have an inherent problem with memory corruption. The functiontasklet_action_common calls tasklet_trylock, then it calls the taskletcallback and then it calls tasklet_unlock. If the tasklet callback freesthe structure that contains the tasklet or if it calls some code that mayfree it, tasklet_unlock will write into free memory.The commits 8e14f610159d and d9a02e016aaf try to fix it for dm-crypt, butit is not a sufficient fix and the data corruption can still happen [1].There is no fix for dm-verity and dm-verity will write into free memorywith every tasklet-processed bio.There will be atomic workqueues implemented in the kernel 6.9 [2]. Theywill have better interface and they will not suffer from the memorycorruption problem.But we need something that stops the memory corruption now and that can bebackported to the stable kernels. So, I'm proposing this commit thatdisables tasklets in both dm-crypt and dm-verity. This commit doesn'tremove the tasklet support, because the tasklet code will be reused whenatomic workqueues will be implemented.[1] https://lore.kernel.org/all/d390d7ee-f142-44d3-822a-87949e14608b@suse.de/T/[2] https://lore.kernel.org/lkml/20240130091300.2968534-1-tj@kernel.org/
POC
Reference
No PoCs from references.