From e95489010b7abf6d360dfb7d88a41dfa9e0cc802 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 29 Nov 2016 12:35:19 -0500 Subject: [PATCH] bpf: add test for the verifier equal logic bug This is a test to verify that bpf: fix states equal logic for varlen access actually fixed the problem. The problem was if the register we added to our map register was UNKNOWN in both the false and true branches and the only thing that changed was the range then we'd incorrectly assume that the true branch was valid, which it really wasnt. This tests this case and properly fails without my fix in place and passes with it in place. Signed-off-by: Josef Bacik Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- tools/testing/selftests/bpf/test_verifier.c | 23 +++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index 3c4a1fbba2a0..5da2e9d7689c 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -2660,6 +2660,29 @@ static struct bpf_test tests[] = { .result = ACCEPT, .prog_type = BPF_PROG_TYPE_SCHED_CLS }, + { + "invalid map access from else condition", + .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, 6), + BPF_LDX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0), + BPF_JMP_IMM(BPF_JGE, BPF_REG_1, MAX_ENTRIES-1, 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1), + BPF_ALU64_IMM(BPF_LSH, BPF_REG_1, 2), + BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1), + BPF_ST_MEM(BPF_DW, BPF_REG_0, 0, offsetof(struct test_val, foo)), + BPF_EXIT_INSN(), + }, + .fixup_map2 = { 3 }, + .errstr = "R0 unbounded memory access, make sure to bounds check any array access into a map", + .result = REJECT, + .errstr_unpriv = "R0 pointer arithmetic prohibited", + .result_unpriv = REJECT, + }, }; static int probe_filter_length(const struct bpf_insn *fp) -- 2.20.1