[PATCH net] bpf/verifier: reject BPF_ALU64|BPF_END

[Edward Cree]

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 <ec...@solarflare.com>
---
 kernel/bpf/verifier.c                       |  3 ++-
 tools/testing/selftests/bpf/test_verifier.c | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 477b693..799b245 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 8eb0995..26f3250 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)