[U-Boot] [EXT] Re: [PATCH 4/6] spl: mmc: support loading i.MX container format file

Marek Vasut marex at denx.de
Wed Jun 5 13:24:40 UTC 2019

On 6/5/19 5:03 AM, Peng Fan wrote:
>>>>> It is not duplication of FIT. Container support the similar function
>>>>> of FIT image, but it is not only that.
>>>> So what is it ?
>> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.
>> nxp.com%2Fdocs%2Fen%2Freference-manual%2FIMX8DQXPRM.pdf&da
>> ta=02%7C
>> 01%7Cpeng.fan%40nxp.com%7C72216052f4234a93ad1f08d6e95ed782%7C6
>> 86ea1d3b
>> c2b4c6fa92cd99c5c301635%7C0%7C1%7C636952990895125305&sdat
>> a=KO%2B0e
>> E3v%2FkHuJ%2BhR7mBgc4NWXxbMUupfubXXu%2BueIWo%3D&reserv
>> ed=0
>>> Chapter 5 has information about container set and container.
>> Thanks, any specific part of those 80 pages ?
> Figure 5-24. Container Format has a picture about a single container.
> i.MX8 container also support container sets, support encrypt blob,
> certificates, SRK management. Support signature to the whole container,
> no need single image inside container.

Isn't that all supported in fitImage too ?

>>>> I don't think I get it. Why would I, as an iMX8 user, want to pick
>>>> custom new vendor-specific format over years-proven generic fitImage?
>>> We not against FIT, we already use FIT on i.MX8M, to let spl to
>>> authenticate FIT image using ROM HAB, not using crypto driver.
>> Great
>>>> What is the selling point here ?
>>> We would not introduce cypto driver in SPL stage, that means HAB FIT
>>> and AHAB container needs to be dropped when SPL loading other images.
>>> ROM already provides API for bootloader to authenticate images,
>>> introducing complex crypto driver in SPL could enlarge code size and
>>> make things complicated.
>> Ah I see, so it's all making the whole crypto simpler by offloading the hard
>> parts into the firmware, which just magically handles everything , without
>> having much extra code in the SPL ?
> Yes. Use what ROM provides will make things easier for U-Boot.

Is it possible to perform a security audit on the ROM as easily as on
U-Boot ? I mean, U-Boot is free software, the source is available, so
security researchers can easily scrutinize it. Is the ROM ?

Best regards,
Marek Vasut

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