bpf/verifier: reject BPF_ALU64|BPF_END

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

Fixes: 17a5267067f3 ("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>

2 files changed, 18 insertions, 1 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 477b6932c3c1..799b2451ef2d 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2292,7 +2292,8 @@ static int check_alu_op(struct bpf_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;
                         }
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 8eb09950258b..26f3250bdcd2 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -6629,6 +6629,22 @@ static struct bpf_test tests[] = {
                 .result = REJECT,
                 .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
         },
+        {
+                "invalid 64-bit BPF_END",
+                .insns = {
+                        BPF_MOV32_IMM(BPF_REG_0, 0),
+                        {
+                                .code  = BPF_ALU64 | BPF_END | BPF_TO_LE,
+                                .dst_reg = BPF_REG_0,
+                                .src_reg = 0,
+                                .off   = 0,
+                                .imm   = 32,
+                        },
+                        BPF_EXIT_INSN(),
+                },
+                .errstr = "BPF_END uses reserved fields",
+                .result = REJECT,
+        },
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)