s3:auth Add comment to clarify usage of session keys.

Explain why we have what looks like a duplicate of session keys.
It is in fact not a duplicate.

1 files changed, 10 insertions, 0 deletions

diff --git a/source3/include/auth.h b/source3/include/auth.h
index ba8b23b645..fbd73ae48d 100644
--- a/source3/include/auth.h
+++ b/source3/include/auth.h
@@ -53,6 +53,16 @@ struct auth_serversupplied_info {
 
 	NT_USER_TOKEN *ptok;
 
+	/* This is the final session key, as used by SMB signing, and
+	 * (truncated to 16 bytes) encryption on the SAMR and LSA pipes
+	 * when over ncacn_np.
+	 * It is calculated by NTLMSSP from the session key in the info3,
+	 * and is  set from the Kerberos session key using
+	 * krb5_auth_con_getremotesubkey().
+	 *
+	 * Bootom line, it is not the same as the session keys in info3.
+	 */
+
 	DATA_BLOB user_session_key;
 	DATA_BLOB lm_session_key;