Hi Heinrich,
2021年5月15日(土) 11:03 Heinrich Schuchardt xypron.glpk@gmx.de:
On 5/14/21 3:09 PM, Masami Hiramatsu wrote:
Hi all,
I think it's time to summarize the topics on this thread.
- tools/mkeficapsule, config options dependency
- The tools, especially useful and distributable tools like
mkeficapsule should not be changed by the target board configuration.
- Since there are target boards which don't need capsule
authentication, it should be configurable. That also can optimize the library dependency.
Thank you for providing this summary.
You described that the tool shall not depend on the target board configuration. Your sentence starting with "Since" contradicts this.
Ah, sorry for the confusion. Each bullet shows a different opinion on the topic.
As Ilias pointed out all Linux distributions come with an OpenSSL package. The library dependency is nothing to worry about.
OK, so this is for topic #1.
Capsule updates without authentication don't not make much sense in a world full of attacks.
and this is for topic #1 and maybe related to #4?
Hence, a configuration switch for the tool is not needed.
Thanks for clarifying your opinion!
Best regards
Heinrich
- tools/mkeficapsule, revert -K/-D options
- Since these options are for embedding a public key in the
devicetree, that is not related to the capsule file. Also, the same feature can be provided by a simple shell script.
- capsule authentication, key embedding method
- Embedding key in the devicetree is too fragile, especially, the
document says overwriting new device tree including key with fdt command. That is not for the product, only for proof of concept.
- Such a key should be embedded in the U-Boot, or hardware secure
storage so that the user can not change it. (BTW, I think there are more options, like embedding keys in SCP firmware, TF-A, or OP-TEE, outside of U-Boot)
- capsule authentication, authentication enablement
- The UEFI spec said IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED can be
supported but cleared (for the current running firmware). This means it is possible that the authentication feature is supported, but not enabled.
- For ensuring security, if U-Boot is compiled with
CONFIG_EFI_CAPSULE_AUTHETICATE=y, IMAGE_ATTRIBUTE_AUTHENTICATION_REQUIRED must always be set.
Are there any other topics on this thread? and any other comments on these topics?
Thank you,