[PATCH] ima: debugging late_initcall_sync measurements

[David Safford]

On Thu, Apr 30, 2026 at 5:43 PM Mimi Zohar <zohar at linux.ibm.com> wrote:
>
> On Thu, 2026-04-30 at 10:48 +0100, Yeoreum Yun wrote:
> > With above change I confirmed there is no meaurement log
> > between boot_aggregate and boot_aggregate_late except "kernel_version"
> > But this is ignorable since this UTS measurement is done in
> > "ima_init_core() (old: ima_init())" and it is part of ima initialisation.
> >
> > 1. ima_policy=tcb
> >
> >   # cat /sys/kernel/security/ima/ascii_runtime_measurements
> >   10 0adefe762c149c7cec19da62f0da1297fcfbffff ima-ng sha256:0000000000000000000000000000000000000000000000000000000000000000 boot_aggregate
> >   10 4e5d73ebadfd8f850cb93ce4de755ba148a9a7d5 ima-ng sha256:0000000000000000000000000000000000000000000000000000000000000000 boot_aggregate_late
> >   10 7c23cc970eceec906f7a41bc2fbde770d7092209 ima-ng sha256:72ade6ae3d35cfe5ede7a77b1c0ed1d1782a899445fdcb219c0e994a084a70d5 /bin/busybox
snip
> >
> > 2. ima_policy=critical_data
> >
> >   # cat /sys/kernel/security/ima/ascii_runtime_measurements
> >   10 0adefe762c149c7cec19da62f0da1297fcfbffff ima-ng sha256:0000000000000000000000000000000000000000000000000000000000000000 boot_aggregate
> >   10 49ab61dd97ea2f759edcb6c6a3387ac67f0aa576 ima-buf sha256:0c907aab3261194f16b0c2a422a82f145bc9b9ecb8fdb633fa43e3e5379f0af2 kernel_version 372e312e302d7263312b // Ignorable since it's generated by ima_init(_core)().
> >   10 4e5d73ebadfd8f850cb93ce4de755ba148a9a7d5 ima-ng sha256:0000000000000000000000000000000000000000000000000000000000000000 boot_aggregate_late
> >
> > Therefore, init_ima() could move into late_initcall_sync like v1 did:
> >   - https://lore.kernel.org/all/20260417175759.3191279-2-yeoreum.yun@arm.com/
>
> Thanks, Yeoreum.  It's a bit premature to claim it's "safe" to move the
> initcall.  Hopefully others will respond.
>
> Mimi

I have also run with this patch on a number of bare metal and virtual machines,
running everything from default Fedora 44 to a version with everything turned on
(uefi secure boot, UKI with sdboot stub measurements, IMA measurement
and appraisal enabled,
all systemd measurements on, and systemd using the TPM for root
partition decryption.)
I too see only the kernel_version event between the normal and late
calls, if ima_policy=critical_data.

dave