Re: [edk2-discuss] a question about X509 flag

Re: [edk2-discuss] a question about X509 flag

[Marvin Häuser]

Hey Wenyi,

Sorry, I cannot help with the time one, but "partial chain" is how 
virtually any other crypto-solution works out-of-the-box. Basically 
there is a disagreement about what defines a root certificate, and while 
some think it is the OpenSSL default of requiring a self-signed 
certificate for root, many people including myself strongly disagree and 
do not believe it follows from the RFCs. I'm not aware of any bad 
security implications of either model. So, this merely allows any 
certificate in the chain (the top one may be self-signed *if* it even is 
a certificate, it may just as well be a trusted public key for all we 
know) to be eligible to be added to the trust store and root a trust chain.

Further reading: https://github.com/openssl/openssl/issues/7871

Cc CryptoPkg maintainers and edk2-devel for further feedback

Best regards,
Marvin

On 27/09/2021 10:53, wenyi,xie via groups.io wrote:
> Hello,
>
> I have a question about flag set in X509_STORE. Does anyone know why need to set flags X509_V_FLAG_PARTIAL_CHAIN and X509_V_FLAG_NO_CHECK_TIME to X509Store in TlsNew() (CryptoPkg\Library\TlsLib\TlsInit.c)
>
> Thanks
> Wenyi
>
>
> 
>
>

Re: [edk2-discuss] a question about X509 flag

[wenyi,xie]

On 2021/9/27 17:21, Marvin Häuser wrote:
> Hey Wenyi,
> 
> Sorry, I cannot help with the time one, but "partial chain" is how virtually any other crypto-solution works out-of-the-box. Basically there is a disagreement about what defines a root certificate, and while some think it is the OpenSSL default of requiring a self-signed certificate for root, many people including myself strongly disagree and do not believe it follows from the RFCs. I'm not aware of any bad security implications of either model. So, this merely allows any certificate in the chain (the top one may be self-signed *if* it even is a certificate, it may just as well be a trusted public key for all we know) to be eligible to be added to the trust store and root a trust chain.
> 

Thank you for your explanation in detail, it helps a lot. X509_V_FLAG_PARTIAL_CHAIN is clear to me now.

Wenyi

> Further reading: https://github.com/openssl/openssl/issues/7871
> 
> Cc CryptoPkg maintainers and edk2-devel for further feedback
> 
> Best regards,
> Marvin
> 
> On 27/09/2021 10:53, wenyi,xie via groups.io wrote:
>> Hello,
>>
>> I have a question about flag set in X509_STORE. Does anyone know why need to set flags X509_V_FLAG_PARTIAL_CHAIN and X509_V_FLAG_NO_CHECK_TIME to X509Store in TlsNew() (CryptoPkg\Library\TlsLib\TlsInit.c)
>>
>> Thanks
>> Wenyi
>>
>>
>> 
>>
>>
> 
> .