Fix LUKS header checksum reference for reencryption - #3053
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The origin LUKS header checksum stored in /root/.luks.header is used by the kiwi dracut code to decide if the initial reencryption of the root device should happen. The checksum is calculated over the header backup file which is at the same time the file the resulting checksum gets written to. Since the checksum handler returned by get_checksum_handler() calculates the digest lazily when digest() is called, and the call happened inside the open(..., 'w') context, the header backup was already truncated at that point. The stored reference was therefore always the digest of an empty file (e3b0c442... for sha256) and could never match the digest calculated at boot time. As a consequence reencrypt_luks() silently skipped the reencryption and the image stayed encrypted with the build time credentials. Calculate the digest before the file is opened for writing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
schaefi
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September 21, 2026 08:25
schaefi
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Great catch, thanks much 👍
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There was a regression when implementing sha512 support: header checksum is computed too late and end-up being null.
This is breaking SL Micro 6.2 Encrypted image when booting with FIPS. It is only visible in FIPS environment due to other bugs in fde-tools causing re-encryption to fail if kiwi re-encryption fails in the first place ( openSUSE/fde-tools#54 and openSUSE/fde-tools#57 ).