bpf/verifier: reject BPF_ALU64|BPF_END

BugLink: http://bugs.launchpad.net/bugs/1729105


[ Upstream commit e67b8a68 ]

Neither ___bpf_prog_run nor the JITs accept it.
Also adds a new test case.

Fixes: 17a52670 ("bpf: verifier (add verifier core)")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/bpf/verifier.c

@@ -1044,7 +1044,8 @@ static int check_alu_op(struct verifier_env *env, struct bpf_insn *insn)
 			}
 		} else {
 			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
-			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64)) {
+			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
+			    BPF_CLASS(insn->code) == BPF_ALU64) {
 				verbose("BPF_END uses reserved fields\n");
 				return -EINVAL;
 			}