Re: [PATCH 0/5 v2][RFC] Encryption and authentication for hibernate snapshot image
From: Pavel Machek
Date: Sun Jan 06 2019 - 13:10:42 EST
> This patchset is the implementation of encryption and authentication
> for hibernate snapshot image. The image will be encrypted by AES and
> authenticated by HMAC.
Ok, so you encrypt.
> The hibernate function can be used to snapshot memory pages to an image,
> then kernel restores the image to memory space in a appropriate time.
> There have secrets in snapshot image and cracker may modifies it for
> hacking system. Encryption and authentication of snapshot image can protect
> the system.
> Hibernate function requests the master key through key retention service.
> The snapshot master key can be a trusted key or a user defined key. The
> name of snapshot master key is fixed to "swsusp-kmk". User should loads
> swsusp-kmk to kernel by keyctl tool before the hibernation resume.
> e.g. The swsusp-kmk must be loaded before systemd-hibernate-resume
But if userspace has a key, encryption is useless against root.
> The TPM trusted key type is preferred to be the master key. But user
> defined key can also be used for testing or when the platform doesn't
> have TPM. User must be aware that the security of user key relies on
> user space. If the root account be compromised, then the user key will
> easy to be grabbed.
In the TPM case, does userland have access to the key?
Please explain your security goals.
> Lee, Chun-Yi (5):
> PM / hibernate: Create snapshot keys handler
> PM / hibernate: Generate and verify signature for snapshot image
> PM / hibernate: Encrypt snapshot image
> PM / hibernate: Erase the snapshot master key in snapshot pages
> PM / hibernate: An option to request that snapshot image must be
> Documentation/admin-guide/kernel-parameters.txt | 6 +
> include/linux/kernel.h | 3 +-
> kernel/panic.c | 1 +
> kernel/power/Kconfig | 25 +
> kernel/power/Makefile | 1 +
> kernel/power/hibernate.c | 59 ++-
> kernel/power/power.h | 59 +++
> kernel/power/snapshot.c | 576 +++++++++++++++++++++++-
> kernel/power/snapshot_key.c | 312 +++++++++++++
> kernel/power/swap.c | 6 +
> kernel/power/user.c | 12 +
> 11 files changed, 1042 insertions(+), 18 deletions(-)
> create mode 100644 kernel/power/snapshot_key.c
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