Fix nasty bug that would come up only if a client connection to a remote

ldap server suddenly dies.
We were creating a wrong talloc hierarchy, so the event.fde was not
freed automatically as expected. This in turn made the event system call
the ldap io handlers with a null packet structure, causing a segfault.
Fix also the ordering in ldap_connection_dead()
Thanks to Metze for the huge help in tracking down this one.

5 files changed, 22 insertions, 15 deletions

diff --git a/source4/auth/gensec/gensec.h b/source4/auth/gensec/gensec.h
index 2830297ffe..84fc26d127 100644
--- a/source4/auth/gensec/gensec.h
+++ b/source4/auth/gensec/gensec.h
@@ -174,6 +174,7 @@ struct gensec_security;
 struct socket_context;
 
 NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
+			    TALLOC_CTX *mem_ctx, 
 			    struct socket_context *current_socket,
 			    struct event_context *ev,
 			    void (*recv_handler)(void *, uint16_t),
diff --git a/source4/auth/gensec/socket.c b/source4/auth/gensec/socket.c
index 27449bf610..319730e2ca 100644
--- a/source4/auth/gensec/socket.c
+++ b/source4/auth/gensec/socket.c
@@ -408,8 +408,10 @@ static NTSTATUS gensec_socket_send(struct socket_context *sock,
 }
 
 /* Turn a normal socket into a potentially GENSEC wrapped socket */
+/* CAREFUL: this function will steal 'current_socket' */
 
 NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
+			    TALLOC_CTX *mem_ctx,
 			    struct socket_context *current_socket,
 			    struct event_context *ev,
 			    void (*recv_handler)(void *, uint16_t),
@@ -420,7 +422,7 @@ NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
 	struct socket_context *new_sock;
 	NTSTATUS nt_status;
 
-	nt_status = socket_create_with_ops(current_socket, &gensec_socket_ops, &new_sock, 
+	nt_status = socket_create_with_ops(mem_ctx, &gensec_socket_ops, &new_sock, 
 					   SOCKET_TYPE_STREAM, current_socket->flags | SOCKET_FLAG_ENCRYPT);
 	if (!NT_STATUS_IS_OK(nt_status)) {
 		*new_socket = NULL;
@@ -432,22 +434,19 @@ NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
 	gensec_socket = talloc(new_sock, struct gensec_socket);
 	if (gensec_socket == NULL) {
 		*new_socket = NULL;
+		talloc_free(new_sock);
 		return NT_STATUS_NO_MEMORY;
 	}
 
 	new_sock->private_data       = gensec_socket;
 	gensec_socket->socket        = current_socket;
 
-	if (talloc_reference(gensec_socket, current_socket) == NULL) {
-		*new_socket = NULL;
-		return NT_STATUS_NO_MEMORY;
-	}
-
 	/* Nothing to do here, if we are not actually wrapping on this socket */
 	if (!gensec_have_feature(gensec_security, GENSEC_FEATURE_SEAL) &&
 	    !gensec_have_feature(gensec_security, GENSEC_FEATURE_SIGN)) {
 		
 		gensec_socket->wrap = false;
+		talloc_steal(gensec_socket, current_socket);
 		*new_socket = new_sock;
 		return NT_STATUS_OK;
 	}
@@ -469,6 +468,7 @@ NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
 	gensec_socket->packet = packet_init(gensec_socket);
 	if (gensec_socket->packet == NULL) {
 		*new_socket = NULL;
+		talloc_free(new_sock);
 		return NT_STATUS_NO_MEMORY;
 	}
 
@@ -481,6 +481,7 @@ NTSTATUS gensec_socket_init(struct gensec_security *gensec_security,
 
 	/* TODO: full-request that knows about maximum packet size */
 
+	talloc_steal(gensec_socket, current_socket);
 	*new_socket = new_sock;
 	return NT_STATUS_OK;
 }
diff --git a/source4/ldap_server/ldap_bind.c b/source4/ldap_server/ldap_bind.c
index 8357251a8f..20777e5261 100644
--- a/source4/ldap_server/ldap_bind.c
+++ b/source4/ldap_server/ldap_bind.c
@@ -208,6 +208,7 @@ static NTSTATUS ldapsrv_BindSASL(struct ldapsrv_call *call)
 		} else {
 			ctx->conn = conn;
 			status = gensec_socket_init(conn->gensec, 
+						    conn->connection,
 						    conn->connection->socket,
 						    conn->connection->event.ctx, 
 						    stream_io_handler_callback,
diff --git a/source4/libcli/ldap/ldap_bind.c b/source4/libcli/ldap/ldap_bind.c
index 65673116be..b66232c02e 100644
--- a/source4/libcli/ldap/ldap_bind.c
+++ b/source4/libcli/ldap/ldap_bind.c
@@ -387,6 +387,7 @@ _PUBLIC_ NTSTATUS ldap_bind_sasl(struct ldap_connection *conn,
 	if (NT_STATUS_IS_OK(status)) {
 		struct socket_context *sasl_socket;
 		status = gensec_socket_init(conn->gensec, 
+					    conn,
 					    conn->sock,
 					    conn->event.event_ctx, 
 					    ldap_read_io_handler,
diff --git a/source4/libcli/ldap/ldap_client.c b/source4/libcli/ldap/ldap_client.c
index 844238afdb..d7960f901a 100644
--- a/source4/libcli/ldap/ldap_client.c
+++ b/source4/libcli/ldap/ldap_client.c
@@ -77,6 +77,12 @@ static void ldap_connection_dead(struct ldap_connection *conn)
 {
 	struct ldap_request *req;
 
+	talloc_free(conn->sock);  /* this will also free event.fde */
+	talloc_free(conn->packet);
+	conn->sock = NULL;
+	conn->event.fde = NULL;
+	conn->packet = NULL;
+
 	/* return an error for any pending request ... */
 	while (conn->pending) {
 		req = conn->pending;
@@ -87,12 +93,6 @@ static void ldap_connection_dead(struct ldap_connection *conn)
 			req->async.fn(req);
 		}
 	}
-
-	talloc_free(conn->sock);  /* this will also free event.fde */
-	talloc_free(conn->packet);
-	conn->sock = NULL;
-	conn->event.fde = NULL;
-	conn->packet = NULL;
 }
 
 static void ldap_reconnect(struct ldap_connection *conn);
@@ -400,6 +400,7 @@ static void ldap_connect_got_sock(struct composite_context *ctx,
 	talloc_steal(conn, conn->sock);
 	if (conn->ldaps) {
 		struct socket_context *tls_socket;
+		struct socket_context *tmp_socket;
 		char *cafile = private_path(conn->sock, conn->lp_ctx, lp_tls_cafile(conn->lp_ctx));
 
 		if (!cafile || !*cafile) {
@@ -414,9 +415,11 @@ static void ldap_connect_got_sock(struct composite_context *ctx,
 			talloc_free(conn->sock);
 			return;
 		}
-		talloc_unlink(conn, conn->sock);
-		conn->sock = tls_socket;
-		talloc_steal(conn, conn->sock);
+
+		/* the original socket, must become a child of the tls socket */
+		tmp_socket = conn->sock;
+		conn->sock = talloc_steal(conn, tls_socket);
+		talloc_steal(conn->sock, tmp_socket);
 	}
 
 	conn->packet = packet_init(conn);