Fix talloc memory heirarchy bug. If there's an SMB2 sessionsetup in flight when we're shut down, we end up freeing the struct smbXsrv_session *session pointer twice.

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Mon Sep 10 23:34:06 CEST 2012 on sn-devel-104

1 files changed, 36 insertions, 5 deletions

diff --git a/source3/smbd/smb2_sesssetup.c b/source3/smbd/smb2_sesssetup.c
index a03abf73aa..61b5519d97 100644
--- a/source3/smbd/smb2_sesssetup.c
+++ b/source3/smbd/smb2_sesssetup.c
@@ -439,8 +439,16 @@ struct smbd_smb2_session_setup_state {
 	uint16_t out_session_flags;
 	DATA_BLOB out_security_buffer;
 	uint64_t out_session_id;
+	/* The following pointer is owned by state->session. */
+	struct smbd_smb2_session_setup_state **pp_self_ref;
 };
 
+static int pp_self_ref_destructor(struct smbd_smb2_session_setup_state **pp_state)
+{
+	(*pp_state)->session = NULL;
+	return 0;
+}
+
 static int smbd_smb2_session_setup_state_destructor(struct smbd_smb2_session_setup_state *state)
 {
 	/*
@@ -454,6 +462,24 @@ static int smbd_smb2_session_setup_state_destructor(struct smbd_smb2_session_set
 static void smbd_smb2_session_setup_gensec_done(struct tevent_req *subreq);
 static void smbd_smb2_session_setup_previous_done(struct tevent_req *subreq);
 
+/************************************************************************
+ We have to tag the state->session pointer with memory talloc'ed
+ on it to ensure it gets NULL'ed out if the underlying struct smbXsrv_session
+ is deleted by shutdown whilst this request is in flight.
+************************************************************************/
+
+static NTSTATUS tag_state_session_ptr(struct smbd_smb2_session_setup_state *state)
+{
+	state->pp_self_ref = talloc_zero(state->session,
+			struct smbd_smb2_session_setup_state *);
+	if (state->pp_self_ref == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	*state->pp_self_ref = state;
+	talloc_set_destructor(state->pp_self_ref, pp_self_ref_destructor);
+	return NT_STATUS_OK;
+}
+
 static struct tevent_req *smbd_smb2_session_setup_send(TALLOC_CTX *mem_ctx,
 					struct tevent_context *ev,
 					struct smbd_smb2_request *smb2req,
@@ -522,6 +548,11 @@ static struct tevent_req *smbd_smb2_session_setup_send(TALLOC_CTX *mem_ctx,
 		}
 	}
 
+	status = tag_state_session_ptr(state);
+	if (tevent_req_nterror(req, status)) {
+		return tevent_req_post(req, ev);
+	}
+
 	if (state->session->gensec == NULL) {
 		status = auth_generic_prepare(state->session,
 					      state->session->connection->remote_address,
@@ -577,7 +608,7 @@ static void smbd_smb2_session_setup_gensec_done(struct tevent_req *subreq)
 	if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 		state->out_session_id = state->session->global->session_wire_id;
 		/* we want to keep the session */
-		state->session = NULL;
+		TALLOC_FREE(state->pp_self_ref);
 		tevent_req_nterror(req, status);
 		return;
 	}
@@ -617,7 +648,7 @@ static void smbd_smb2_session_setup_gensec_done(struct tevent_req *subreq)
 			return;
 		}
 		/* we want to keep the session */
-		state->session = NULL;
+		TALLOC_FREE(state->pp_self_ref);
 		tevent_req_done(req);
 		return;
 	}
@@ -633,7 +664,7 @@ static void smbd_smb2_session_setup_gensec_done(struct tevent_req *subreq)
 	}
 
 	/* we want to keep the session */
-	state->session = NULL;
+	TALLOC_FREE(state->pp_self_ref);
 	tevent_req_done(req);
 	return;
 }
@@ -664,7 +695,7 @@ static void smbd_smb2_session_setup_previous_done(struct tevent_req *subreq)
 			return;
 		}
 		/* we want to keep the session */
-		state->session = NULL;
+		TALLOC_FREE(state->pp_self_ref);
 		tevent_req_done(req);
 		return;
 	}
@@ -680,7 +711,7 @@ static void smbd_smb2_session_setup_previous_done(struct tevent_req *subreq)
 	}
 
 	/* we want to keep the session */
-	state->session = NULL;
+	TALLOC_FREE(state->pp_self_ref);
 	tevent_req_done(req);
 	return;
 }