From: Alexei Starovoitov <ast@fb.com>
Date: Wed, 23 Aug 2017 15:10:26 +0100
Subject: selftests/bpf: add a test for a pruning bug in the verifier
Patch-mainline: v4.14-rc1
Git-commit: df20cb7ec17577c94ef93fa86c7c80958046a01e
References: bsc#1109837
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 <ast@fb.com>
[ecree@solarflare.com: added test-name and patch description]
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
tools/testing/selftests/bpf/test_verifier.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -6503,6 +6503,34 @@ 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)