Yogesh Gaikwad ed6a6af64c SAML: Make alias for signing key optional (elastic/x-pack-elasticsearch#4248)
We specify an alias for signing key, but when we just have
a single key in key store this is an additional setting which
is annoying. This PR addresses this issue by making it optional.

- Changes in SamlRealmSettings to make signing/encryption
  key alias optional
- Checks if none of the keys are useful for given operation
  signing or encryption throws an error.
- Checks for no of aliases in key-store, if more than one and alias
  is not specified throws error.
- If an alias is not specified and there is just one alias in
  keystore then use it as the credential.
- Unit Tests

Note: A side effect of this change the above-mentioned behavior is
it's also applicable for encryption keys currently, but it is going
to change when fixing elastic/x-pack-elasticsearch#3980 for supporting multiple encryption keys.

relates elastic/x-pack-elasticsearch#3981

Original commit: elastic/x-pack-elasticsearch@2b5af1d8a8
2018-04-06 10:43:35 +10:00
..