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https://issues.apache.org/jira/browse/CASSANDRA-13626?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16146990#comment-16146990
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Sam Tunnicliffe edited comment on CASSANDRA-13626 at 8/30/17 10:01 AM:
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bq.checkpw does an even worse job of failing nicely
In what way(s)? Checking with a few strings that would be caught by this
validation, {{checkpw}} seems to behave as expected.
This validation would help us detect that we have stored invalid hash values,
so that could be useful in diagnosing unexpected auth failures & debugging
their causes. That will obviously require logging when the validation fails
before throwing the {{AuthenticationException}}, so we should separate it from
the actual {{checkPw}} call.
On the actual validation, the 22 character component is actually the salt, not
the cost - the bcrypt format is {{$<id>$<cost>$<salt><digest>}}. Cost, salt and
digest are all fixed length (2, 22 & 31 chars repectively), whereas id may be 1
or 2 chars, though we have only ever used a version of jbcrypt that generates
the 2 char variant. So we could simplify that check to {{length == 60}}. If
{{checkpw}} *is* correctly returning false when the stored hash is invalid
though, we only really need to do the validation on failure, in which case we
could a more thorough check than simply looking at the length, if that's
worthwhile.
EDIT: I know it's a pretty trivial change, but it would be nice to add some
tests to go with it.
was (Author: beobal):
bq.checkpw does an even worse job of failing nicely
In what way(s)? Checking with a few strings that would be caught by this
validation, {{checkpw}} seems to behave as expected.
This validation would help us detect that we have stored invalid hash values,
so that could be useful in diagnosing unexpected auth failures & debugging
their causes. That will obviously require logging when the validation fails
before throwing the {{AuthenticationException}}, so we should separate it from
the actual {{checkPw}} call.
On the actual validation, the 22 character component is actually the salt, not
the cost - the bcrypt format is {{$<id>$<cost>$<salt><digest>}}. Cost, salt and
digest are all fixed length (2, 22 & 31 chars repectively), whereas id may be 1
or 2 chars, though we have only ever used a version of jbcrypt that generates
the 2 char variant. So we could simplify that check to {{length == 60}}. If
{{checkpw}} *is* correctly returning false when the stored hash is invalid
though, we only really need to do the validation on failure, in which case we
could a more thorough check than simply looking at the length, if that's
worthwhile.
> Check hashed password matches expected bcrypt hash format before checking
> -------------------------------------------------------------------------
>
> Key: CASSANDRA-13626
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13626
> Project: Cassandra
> Issue Type: Bug
> Components: Auth
> Reporter: Jeff Jirsa
> Assignee: Jeff Jirsa
> Priority: Minor
> Fix For: 3.0.x, 3.11.x, 4.x
>
>
> We use {{Bcrypt.checkpw}} in the auth subsystem, but do a reasonably poor job
> of guaranteeing that the hashed password we send to it is really a hashed
> password, and {{checkpw}} does an even worse job of failing nicely. We should
> at least sanity check the hash complies with the expected format prior to
> validating.
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