By Kelly Geraldine Malone THE CANADIAN PRESS Buffy Sainte-Marie, a musician known for decades of Indigenous activism, says she’s always been honest that she doesn’t know the identity of her birth parents ahead of a CBC report expected to question her First Nations ancestry. “I don’t know where I’m from or who my birth parents were, and I will never know. Which is why to be questioned in this way today is painful,” Sainte-Marie said Thursday in a statement. “To those who question my truth, I say with love, I know who I am.” Sainte-Marie, who’s in her early 80s, said she was contacted last month by CBC and called allegations about her identity “deeply hurtful.” CBC’s investigative show “The Fifth Estate” is scheduled to air an episode titled “Making…