In previous versions of Fedora, the `crypt_r` function returned
`nullptr` when a requested hashing algorithm was not supported.
This is consistent with the documentation of the function in its man
page.
As of Fedora 28, the function's behavior changes so that the encrypted
text is not `nullptr` on error, but instead the string "*0".
The info pages for `crypt_r` clarify somewhat (and contradict the man
pages):
Some implementations return `NULL` on failure, and others return an
_invalid_ hashed passphrase, which will begin with a `*` and will
not be the same as SALT.
Because of this change of behavior, users running Scylla on a Fedora 28
machine which was upgraded from a previous release would not be able to
authenticate: an unsupported hashing algorithm would be selected,
producing encrypted text that did not match the entry in the table.
With this change, unsupported algorithms are correctly detected and
users should be able to continue to authenticate themselves.
Fixes#3637.
Signed-off-by: Jesse Haber-Kucharsky <jhaberku@scylladb.com>
Message-Id: <bcd708f3ec195870fa2b0d147c8910fb63db7e0e.1533322594.git.jhaberku@scylladb.com>
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