[$] Securely suspending LUKS-encrypted disks

Post Syndicated from daroc original https://lwn.net/Articles/1090568/

When a laptop is asleep, its memory is not unreadable. The right
tooling can attach to the computer’s memory bus and read out its contents, and

cold-boot attacks
can theoretically read values from memory for a short time
after the computer loses power. That
is really an unavoidable fact about the hardware, but some users would still
like to ensure that, even if this happens, their long-term encryption keys, such as
the key for full-disk encryption, remain unreadable. In June 2026, Ingo
Blechschmidt

discovered
that Linux kernel versions after 6.9 (released in
May 2024)
were not erasing disk-encryption keys when a laptop was put to sleep, even
when configured to do so. He quickly identified a potential fix, which has been
merged, but it was not a comprehensive solution.