From: Sascha Hauer <sha@pengutronix.de>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: barebox@lists.infradead.org, rcz@pengutronix.de, mfe@pengutronix.de
Subject: Re: [PATCH] Documentation: boards: imx: add some HAB documentation
Date: Thu, 21 Sep 2023 10:01:40 +0200 [thread overview]
Message-ID: <20230921080140.GW637806@pengutronix.de> (raw)
In-Reply-To: <20230919141552.44037-1-a.fatoum@pengutronix.de>
On Tue, Sep 19, 2023 at 04:15:52PM +0200, Ahmad Fatoum wrote:
> We could use some extra documentation on how to use the hab command to
> fuse a SoC and what output should be expected. Add this to the
> documentation. Procedure was done with HABv4 on i.MX8MM, which is not
> yet upstream[1], but should be equivalent for i.MX6.
Nice read! thanks, applied
Sascha
>
> [1]: https://lore.barebox.org/barebox/20230705144219.504194-1-r.czerwinski@pengutronix.de/
>
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
> Documentation/boards/imx.rst | 47 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/Documentation/boards/imx.rst b/Documentation/boards/imx.rst
> index 17465efdd9be..5a4f52b392d5 100644
> --- a/Documentation/boards/imx.rst
> +++ b/Documentation/boards/imx.rst
> @@ -178,6 +178,53 @@ It must be included in the board's flash header:
>
> Analogous to HABv4 options and a template exist for HABv3.
>
> +To verify HAB working as intended, install the ``barebox-*-s.img`` onto the
> +boot medium and trigger a power-on reset. barebox will read the HAB log on
> +startup and report any errors it finds. A good unfused boot looks like this::
> +
> + HABv4: Status: Operation completed successfully (0xf0)
> + HABv4: Config: Non-secure IC (0xf0)
> + HABv4: State: Non-secure state (0x66)
> + HABv4: No HAB Failure Events Found!
> +
> +To have the bootrom verify the barebox binary, the SRK hash needs to be burnt
> +into the fuses. As fuses can't be unburnt, the ``hab`` command should be used
> +instead of direct device access to not risk writing unrelated fuses::
> +
> + barebox$ hab -p -s SRK_1_2_3_4_fuse.bin
> +
> +Afterwards, images signed with a different key will trigger errors at barebox
> +startup, but system will still be able to boot to shell.
> +
> +To have the BootROM refuse booting differently signed images, the ``SRK_LOCK``
> +fuse needs to be burnt::
> +
> + barebox$ hab -p -l
> +
> +On next startup, barebox will report that the system is now locked::
> +
> + HABv4: Status: Operation completed successfully (0xf0)
> + HABv4: Config: Secure IC (0xcc)
> + HABv4: State: Trusted state (0x99)
> + HABv4: No HAB Failure Events Found!
> +
> +This can also be seen with the ``hab -i`` command::
> +
> + Current SRK hash: <some non-zero value>
> + secure mode
> +
> +Similarly, on supported SoCs, the ``bootrom -l`` command will indicate that
> +device is closed. Example output after booting via ``imx-usb-loader``::
> +
> +
> + [e0] Internal use
> + [11] Boot mode is Boot from Serial Download
> + [23] Secure config is Closed
> + [41] FUSE_SEL_VALUE Fuse is blown
> + [d0] Enters serial download processing
> + [a0] Image authentication result: PASS (0x000000f0) @3506438144 ticks
> + [00] End of list
> +
> Secure Boot on i.MX6
> ~~~~~~~~~~~~~~~~~~~~
>
> --
> 2.39.2
>
>
>
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prev parent reply other threads:[~2023-09-21 8:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-19 14:15 Ahmad Fatoum
2023-09-21 8:01 ` Sascha Hauer [this message]
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