NTLM auth and sign - Allocate session key/client response dynamically

Start calculating auth response within a session.  Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure.  We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.

Only after a very first smb session succeeds, it copy/make its
session key, session key of smb connection.  This key stays with
the smb connection throughout its life.
sequence_number within server is set to 0x2.

The authentication Message Authentication Key (mak) which consists
of session key followed by client response within structure session_key
is now dynamic.  Every authentication type allocates the key + response
sized memory within its session structure and later either assigns or
frees it once the client response is sent and if session's session key
becomes connetion's session key.

ntlm/ntlmi authentication functions are rearranged.  A function
named setup_ntlm_resp(), similar to setup_ntlmv2_resp(), replaces
function cifs_calculate_session_key().

size of CIFS_SESS_KEY_SIZE is changed to 16, to reflect the byte size
of the key it holds.

Reviewed-by: Jeff Layton <jlayton@samba.org>
Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7e73176..c5807d3 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -175,6 +175,9 @@ cifs_reconnect(struct TCP_Server_Info *server)
 	}
 	server->sequence_number = 0;
 	server->session_estab = false;
+	kfree(server->session_key.response);
+	server->session_key.response = NULL;
+	server->session_key.len = 0;
 
 	spin_lock(&GlobalMid_Lock);
 	list_for_each(tmp, &server->pending_mid_q) {
@@ -1562,6 +1565,10 @@ cifs_put_tcp_session(struct TCP_Server_Info *server)
 
 	cifs_fscache_release_client_cookie(server);
 
+	kfree(server->session_key.response);
+	server->session_key.response = NULL;
+	server->session_key.len = 0;
+
 	task = xchg(&server->tsk, NULL);
 	if (task)
 		force_sig(SIGKILL, task);
@@ -3178,10 +3185,11 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses,
 	} else {
 		mutex_lock(&ses->server->srv_mutex);
 		if (!server->session_estab) {
-			memcpy(&server->session_key.data,
-				&ses->auth_key.data, ses->auth_key.len);
+			server->session_key.response = ses->auth_key.response;
 			server->session_key.len = ses->auth_key.len;
-			ses->server->session_estab = true;
+			server->sequence_number = 0x2;
+			server->session_estab = true;
+			ses->auth_key.response = NULL;
 		}
 		mutex_unlock(&server->srv_mutex);
 
@@ -3192,6 +3200,10 @@ int cifs_setup_session(unsigned int xid, struct cifsSesInfo *ses,
 		spin_unlock(&GlobalMid_Lock);
 	}
 
+	kfree(ses->auth_key.response);
+	ses->auth_key.response = NULL;
+	ses->auth_key.len = 0;
+
 	return rc;
 }