I live in California. I rented a house from a homeowner that is apparently in foreclosure. Did former Pres. Bush pass a law allowing tenants to remain in a home if it was in foreclosure without their knowledge?

No President Bush did not sign any federal law,

But California has a state law, that the renter may stay without paying any rent while it is in a foreclosure status. And it is possible to sue for rent already paid from the point it because that way ( not that they have anything normally)

But you willl still have to move once it is foreclosed by the lender when they evict you.