Sorry for the delay. I just had another look at the patch. Unfortunately, it doesn't work with Python 2.7.

/usr/bin/python2.7: No module named build

I think it's missing https://pypi.org/project/build/, but this package doesn't support Python 2.7 since version 0.6. Maybe installing version 0.5.1 of build for Python 2.7 would help.

I can replicate that and it works if you disable the use of the CRT. Looking at the key:

pkey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
 pkey[1]: 010001
 skey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
 skey[3]: F57D9F597750967DF272D9AC661DDC212D7C5CA4C6E91573A80756281351CDC3A2532B155D9251029F89A0A0807DF2BD177DC30FC6A847E07738B55606DF032ADAD8361E0AFEE9C0CF7D566793834977FAAE9C4B87132B94F665EFF463777CDE7EB89113FA3AAC194B6F2D30C40BE7C0DDE36A5855277C1E4D0204FC4C737BCB
 skey[4]: C4B135296B8F4390B953DDA84249FC8467CFF81FC715D1B5F3E01FCC8DC770813630AEA93982F2004705C4D272E07A10B1882AC5C09A45E88B14A1446B4C639B549420CE3BF90947E6E86503E426A8FDAC4C5CFC2809F5F0A1647ED5EE2457C054A40AA1F0666B28B2C970BE2093AE7B095A688B2D713CA8885826F23AFB37D9
 skey[5]: 0790A8E260C6CADC353FB3961D798EFD4F15F96752DA20B86841334C38861743DD7A1FEB2B750D0864F5901BE541B6C8FB63649B18FDC4A32A1233EF90872DCD35704A4B4063DB62752CF6A7FD00F086C6B1042A2B0CB6FB36B7D5269671DACF55242A838E60D514BA868354910CEB1C41FB9A43BF932B5036A6EFE35236FFC7

We discussed this forth and back with the RedHat people at our jour-fix to explain that the Kairo fix is done at the wrong layer - this needs to be done at the protocol layer and not in the building blocks. This is not covered by our security policy and @gniibe already came up with some extra support to help at the protocol layer. There are only a few use cases where this side-channel or the Minerva one (for ECDSA) should be considered (e.g. time stamping services). Generally required protection against DoS are also pat of the mitigation.

I left review comments in gitlab. One additional concern is license for mpi-mul-cs.c, original code not having copyright information... "does not have any copyright information, assuming public domain".

In T7129#186556, @werner wrote:

In PATCH GnuPG 12/15] sm: Avoid use of uninitialized variable I can't see where ERR was not initialized.

All except the above mentioned applied to master - will be backported to 2.4

In PATCH GnuPG 12/15] sm: Avoid use of uninitialized variable I can't see where ERR was not initialized.

Fair enough. This is more theoretical and could happen only on huge reads. Using ssize_t for read() return value is safe option, but really does not make sense to adhere to it in cases where the reads must be smaller.

I do not understand why there should be an integer overflow:

For OpenPGP cards >= v2.0 there is no PUK due to updated ISO standards but we use the term in Kleopatra for the Reset-Code.

Also required for an actium feature with UI.

Information about revocation keys can now be retrieved from a Key object (see T7118).