Who are the mahrams with whom a woman is permitted to travel for Hajj?

The mahram who accompanies a woman on a journey is her husband, or someone to whom she is permanently forbidden to marry due to lineage, affinity, or fosterage. It is stipulated that the prohibition must be permanent, not temporary, and must be due to a permissible cause. Mahrams by lineage are: fathers and grandfathers (from both sides), sons and grandsons and granddaughters (however far down), brothers and their sons, and sisters' sons, paternal uncles, and maternal uncles. What is forbidden by lineage is also forbidden by fosterage. Mahrams by affinity are: the husband's fathers and grandfathers, the husband's sons and grandsons, the husbands of daughters and the husbands of granddaughters (from sons and daughters), and the husbands of mothers (on condition that the marriage with the mother was consummated).