Re: [PATCH] PM: hibernate: Allow hibernation opt-in when locked down

Please ignore this patch; the approach was wrong.

I'll follow up with a v2.

On Thu, 9 Jul 2026 12:23:11 -0700, Sean Rhodes <[email protected]> wrote:
> Kernel lockdown disables hibernation because the resume image cannot be
> verified before it is restored. On systems where external platform or
> storage policy protects the hibernation image from offline modification,
> users may still need hibernation while lockdown is active.
>
> Add a hibernate=allow_locked_down command line option to make that opt-in
> explicit. This only bypasses the LOCKDOWN_HIBERNATION gate; nohibernate,
> secretmem and CXL memory restrictions still apply.
>
> The kernel does not validate the external policy or authenticate the image
> with this option.
>
> Build-tested with Fedora config:
> make O=../linux-lockdown-hibernate-build kernel/power/hibernate.o
>
> Signed-off-by: Sean Rhodes <[email protected]>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 5 +++++
> kernel/power/hibernate.c | 6 +++++-
> 2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index b5493a7f8f22..0d20ad9c7d78 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1967,6 +1967,11 @@ Kernel parameters
> protect_image Turn on image protection during restoration
> (that will set all pages holding image data
> during restoration read-only).
> + allow_locked_down
> + Allow hibernation even when kernel lockdown would
> + otherwise disable it. The kernel does not verify
> + the hibernation image; only use this when external
> + policy protects the image from offline modification.
>
> hibernate.compressor= [HIBERNATION] Compression algorithm to be
> used with hibernation.
> diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
> index d2479c69d71a..71232eece9a3 100644
> --- a/kernel/power/hibernate.c
> +++ b/kernel/power/hibernate.c
> @@ -41,6 +41,7 @@
> static int nocompress;
> static int noresume;
> static int nohibernate;
> +static bool allow_locked_down_hibernation;
> static int resume_wait;
> static unsigned int resume_delay;
> static char resume_file[256] = CONFIG_PM_STD_PARTITION;
> @@ -109,7 +110,8 @@ bool hibernation_in_progress(void)
> bool hibernation_available(void)
> {
> return nohibernate == 0 &&
> - !security_locked_down(LOCKDOWN_HIBERNATION) &&
> + (allow_locked_down_hibernation ||
> + !security_locked_down(LOCKDOWN_HIBERNATION)) &&
> !secretmem_active() && !cxl_mem_active();
> }
>
> @@ -1433,6 +1435,8 @@ static int __init hibernate_setup(char *str)
> } else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)
> && !strncmp(str, "protect_image", 13)) {
> enable_restore_image_protection();
> + } else if (!strncmp(str, "allow_locked_down", 17)) {
> + allow_locked_down_hibernation = true;
> }
> return 1;
> }
> --
> 2.53.0