Am Donnerstag, 31. August 2017, 18:17:09 CEST schrieb Eugene Syromyatnikov:

Hi Eugene,

On Thu, Aug 31, 2017 at 6:07 PM, Stephan Mueller [off-list ref] 

wrote:

quoted

Am Donnerstag, 31. August 2017, 17:58:36 CEST schrieb Eugene
Syromyatnikov:

Hi Eugene,

quoted

+field is a null-terminated string no longer than
+.B CRYPTO_MAX_ALG_NAME
+(128 bytes as of this writing) which specifies hash name

Is it necessary to specify that size? Note, up to 4.11 it was 64 bytes.
Also, it must be a valid cipher name as mentioned. Thus, I do not think
the size is relevant here considering the requirement to use a proper
name.

Right, it's probably more important for syscall decoding, but not for
the documentation. However, my understanding is that cipher template
can be specified (like "rfc4106(gcm(aes))"), and I'm not sure how deep
this nesting can be and whether it is possible to reach algorithm name
limit this way (by employing the usage of driver name instead of
common name, for example—as I understood, it is also possible). It
probably makes more sense to just mention this limit in the ERRORS
section instead.

CRYPTO_MAX_ALG_NAME is given a size that all allowed cipher names can be 
represented.

Somehow in the 4.12 release cycle, somebody found a very obscure yet valid 
name for a symmetric cipher that exceeded the 64 byte limit causing the bump 
to 128 bytes.

Though, that obscure name is no SHASH. All SHASH keyed digest cipher names are 
below 64 bytes.

quoted

Otherwise, the KDF documentation looks good.

Ciao
Stephan

Ciao
Stephan
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