What is the test for a motion to vacate a sentence pursuant to section 2241 of the Criminal Code?

1 Rockstad presented this claim to the district court as a petition for a writ of habeas corpus, 28 U.S.C. Sec. 2241, and the district court treated it as such. However, the attack here is directed at Rockstad's conviction, not at the execution of his sentence. Therefore, the claim should have been brought as a motion to vacate sentence pursuant to 28 U.S.C. Sec. 2255. Grimes v. United States, 607 F.2d 6, 11 (2d Cir.1979). We are free to treat it as such. Miller v. United States, 564 F.2d 103, 105 (1st Cir.1977), cert. denied, 435 U.S. 931 (1978).