The error correction can fix even problem with root hash.
For now, always return fail if initial check of root hash failed.
FIXME: The FEC verify code need to be rewritten to repair only
blocks where hash is wrong and the re-check hash after recovery,
inclkuding root hash.
Now we do not check hash after FEC recovery. The Reed-Solomon
decoder can then "repair" code wrongly if parity is too damaged.
For now, the information about FEC repaired errors is only
advisory, it does not mean device is fully repaireable.
Do not write more than needed header if hash area is not used later.
All space in hash area is then used in FEC calculation, so it makes
no sense to add unused area.
It does not make sense to upload volume keys in
kernel keyring if segment cipher is cipher_null.
The real volume_key is thrown away and replaced
with empty key anyway.
This bug enabled to create LUKS2 keyslots encrypted by
cipher_null when explicitely requested by user. LUKS2
was never meant to allow keyslot encryption with
cipher_null. cipher_null is meant for debug purposes
only as a segment cipher.
FEC (Forward Error Correction) data should cover the whole data area,
hashes (Merkle tree) and optionally additional metadata (located after hash area).
Unfortunately, if FEC data is stored in the same file as hash, the calculation
wrongly used the whole file size thus overlaps with FEC area itself.
This produces unusable and too large FEC data.
(There is not a problem if FEC image is a separate image.)
This patch fixes the problem, introducing FEC blocks calculation as:
-If hash device is in a separate image, metadata covers the whole rest of the image after hash area.
(Unchanged behaviour.)
-If hash and FEC device is in the image, metadata ends on the FEC area offset.
This should probably fix several issues reported with FEC wrong calculations.
Fixes: #554
If FEC was enabled, the error for bad root hash was replaced
by error correction (datga were ok, only root hash was wrong).
Do not run recovery test if root hash is incorrect.
To avoid confusion, use just one lib include and specify sub-directories
for format inclusions.
This should also help some analysis tools to find proper includes.
It is called from kernel crypt backend unconditionally with
the proper define in config.h but some static parrsers are not so clever.
Compilation will fail in linker phase anyway if wrongly used.
This fixes multiple issues found by coverity in the startup key
code and also makes the parsing less complicated -- we don't need
to loop through all metadata entries in the BEK file if we are
expecting only one metadata entry of a specific type.
These are false positives and gcc internal detection of this
pattern seems to be broken again.
In this path we must avoid memcpy the whole buffer, it can contain
some bytes after null char, so use MIN/strlen here.
