[PATCH net-next 1/4] selftests/bpf: add a test for a pruning bug in the verifier
DORMANTno replies
From: Edward Cree via iovisor-dev <hidden>
Date: 2017-08-22 13:26:09
Subsystem:
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
From: Alexei Starovoitov <redacted> The test makes a read through a map value pointer, then considers pruning a branch where the register holds an adjusted map value pointer. It should not prune, but currently it does. Signed-off-by: Alexei Starovoitov <redacted> [ecree-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org: added test-name and patch description] Signed-off-by: Edward Cree <ecree-s/n/eUQHGBpZroRs9YW3xA@public.gmane.org> --- tools/testing/selftests/bpf/test_verifier.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index c03542c..6ca1487 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c@@ -6487,6 +6487,34 @@ static struct bpf_test tests[] = { .result = REJECT, .prog_type = BPF_PROG_TYPE_LWT_IN, }, + { + "varlen_map_value_access pruning", + .insns = { + BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), + BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8), + BPF_LD_MAP_FD(BPF_REG_1, 0), + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, + BPF_FUNC_map_lookup_elem), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 8), + BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0), + BPF_MOV32_IMM(BPF_REG_2, MAX_ENTRIES), + BPF_JMP_REG(BPF_JSGT, BPF_REG_2, BPF_REG_1, 1), + BPF_MOV32_IMM(BPF_REG_1, 0), + BPF_ALU32_IMM(BPF_LSH, BPF_REG_1, 2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1), + BPF_JMP_IMM(BPF_JA, 0, 0, 0), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, + offsetof(struct test_val, foo)), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr_unpriv = "R0 leaks addr", + .errstr = "R0 unbounded memory access", + .result_unpriv = REJECT, + .result = REJECT, + .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, + }, }; static int probe_filter_length(const struct bpf_insn *fp)