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| author |   John Fastabend <john.fastabend@gmail.com> | 2020-05-21 13:08:06 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2020-05-21 17:44:25 -0700 |
| commit | f9b16ec0eeb75337aef38954a4066e6eecd7cfe5 (patch) | |
| tree | 3358afdf6dfb99ab7c596fd19c9f0452633bbdfc /tools/testing/selftests/bpf | |
| parent | bpf: Selftests, verifier case for non null pointer check branch taken (diff) | |
| download | wireguard-linux-f9b16ec0eeb75337aef38954a4066e6eecd7cfe5.tar.xz wireguard-linux-f9b16ec0eeb75337aef38954a4066e6eecd7cfe5.zip | |
bpf: Selftests, verifier case for non null pointer map value branch
When we have pointer type that is known to be non-null we only follow
the non-null branch. This adds tests to cover the map_value pointer
returned from a map lookup. To force an error if both branches are
followed we do an ALU op on R10.
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159009168650.6313.7434084136067263554.stgit@john-Precision-5820-Tower
Diffstat (limited to 'tools/testing/selftests/bpf')
| -rw-r--r-- | tools/testing/selftests/bpf/verifier/value_or_null.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/verifier/value_or_null.c b/tools/testing/selftests/bpf/verifier/value_or_null.c index 860d4a71cd83..3ecb70a3d939 100644 --- a/tools/testing/selftests/bpf/verifier/value_or_null.c +++ b/tools/testing/selftests/bpf/verifier/value_or_null.c @@ -150,3 +150,22 @@ .result_unpriv = REJECT, .flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, }, +{ + "map lookup and null branch prediction", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, 10), + BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_1, -8), + 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_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2), + BPF_JMP_IMM(BPF_JNE, BPF_REG_6, 0, 1), + BPF_ALU64_IMM(BPF_ADD, BPF_REG_10, 10), + BPF_EXIT_INSN(), + }, + .fixup_map_hash_8b = { 4 }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, +}, |