Are Slipknot and Dimmu Borgir satanic bands ?

I have my doubts about it. Slipknot is freaking awesome, and some songs such as Psychosocial or Dead Memories aren't satanic at all, but the album covers, each of them symbolize something satanic: a goat, the pentagram etc. And about Dimmu Borgir, I think they're definitely satanic, correct me if I am wrong. Are they after all :/ ?