CVE-2018-16886 etcd: Improper Authentication in auth/store.go:AuthInfoFromTLS() via gRPC-gateway

[Paul Harvey <pharvey () redhat com>]

Hello,

etcd versions 3.2.0 through 3.3.10 are vulnerable to an improper
authentication issue when role-based access control (RBAC) is used and
client-cert-auth is enabled. If an etcd client server TLS certificate
contains a Common Name (CN) which matches a valid RBAC username, a
remote attacker may authenticate as that user with any valid (trusted)
client certificate in a REST API request to the gRPC-gateway.

Upstream issue:
https://github.com/etcd-io/etcd/pull/10366

Upstream changelog:
https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.3.md#security-authentication
https://github.com/etcd-io/etcd/blob/1eee465a43720d713bb69f7b7f5e120135fdb1ac/CHANGELOG-3.2.md#security-authentication

This issue was reported by Matt Wheeler (Osirium)

-- 
Paul Harvey / Red Hat Product Security