Hi Daniel,
2017-01-12 (02:21 +0100) ~ Daniel Borkmann <dan...@iogearbox.net>
> When structs are used to store temporary state in cb[] buffer that is
> used with programs and among tail calls, then the generated code will
> not always access the buffer in bpf_w chunks. We can ease programming
> of it and let this act more natural by allowing for aligned b/h/w/dw
> sized access for cb[] ctx member. Various test cases are attached as
> well for the selftest suite. Potentially, this can also be reused for
> other program types to pass data around.
>
> Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
> Acked-by: Alexei Starovoitov <a...@kernel.org>
> ---
> kernel/bpf/verifier.c | 8 +-
> net/core/filter.c | 41 ++-
> tools/testing/selftests/bpf/test_verifier.c | 442
> +++++++++++++++++++++++++++-
> 3 files changed, 478 insertions(+), 13 deletions(-)
>
[...]
> diff --git a/tools/testing/selftests/bpf/test_verifier.c
> b/tools/testing/selftests/bpf/test_verifier.c
> index 9bb4534..f664bed 100644
> --- a/tools/testing/selftests/bpf/test_verifier.c
> +++ b/tools/testing/selftests/bpf/test_verifier.c
> @@ -859,15 +859,451 @@ struct test_val {
[...]
> + {
> + "check cb access: doulbe, oob 5",
> + .insns = {
> + BPF_MOV64_IMM(BPF_REG_0, 0),
> + BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
> + offsetof(struct __sk_buff, cb[4]) + 8),
> + BPF_EXIT_INSN(),
> + },
> + .errstr = "invalid bpf_context access",
> + .result = REJECT,
> + },
Nitpicking: typo ("doulbe").
Regards,
Quentin
