[PATCH net] bpf/verifier: reject BPF_ALU64|BPF_END
From: Edward Cree <hidden>
Date: 2017-09-15 13:43:27
Subsystem:
bpf [core], bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
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 <redacted>
---
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)