irmd: Specify peer authentication contract

OAP accepted requests and responses without a certificate even when
the peer was expected to authenticate. An on-path attacker could
strip the certificate and signature from a flow allocation response
and substitute its own key exchange, silently downgrading the
handshake to unauthenticated.

Add an auth=required|optional policy to enc.conf, enforced per role: a
client config requires the server to present a valid certificate, a
server config requires the same from the client. Default is required
for client side (https), optional server side. The client side default
can be changed via OAP_CLIENT_AUTH_DEFAULT for testing.

Replace the bare 'none' keyword with encryption=none, which disables
encryption only: the digest and the authentication policy are kept, so
authenticated but unencrypted flows can be configured. Configs using
bare 'none' are now rejected.

Signed-off-by: Dimitri Staessens <dimitri@ouroboros.rocks>
Signed-off-by: Sander Vrijders <sander@ouroboros.rocks>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/ouroboros/crypt.h b/include/ouroboros/crypt.h
index 5e082bb9..255369e6 100644
--- a/include/ouroboros/crypt.h
+++ b/include/ouroboros/crypt.h
@@ -114,18 +114,23 @@ struct sec_config {
                 int          nid;
                 int          mode;
         } x; /* key exchange */
+
         struct {
                 const char * str;
                 int          nid;
         } k; /* kdf */
+
         struct {
                 const char * str;
                 int          nid;
         } c; /* cipher */
+
         struct {
                 const char * str;
                 int          nid;
         } d; /* digest */
+
+        bool req_auth; /* require peer authentication */
 };
 
 /* Helper macros to set sec_config fields consistently */