On Thu, Sep 15, 2016 at 08:12:27PM +0100, Jakub Kicinski wrote:
> When running as parser interpret BPF_LD | BPF_IMM | BPF_DW
> instructions as loading CONST_IMM with the value stored
> in imm. The verifier will continue not recognizing those
> due to concerns about search space/program complexity
> increase.
>
> Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
> ---
> v3:
> - limit to parsers.
> ---
> kernel/bpf/verifier.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index d93e78331b90..f5bed7cce08d 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -1766,9 +1766,19 @@ static int check_ld_imm(struct bpf_verifier_env *env,
> struct bpf_insn *insn)
> if (err)
> return err;
>
> - if (insn->src_reg == 0)
> - /* generic move 64-bit immediate into a register */
> + if (insn->src_reg == 0) {
> + /* generic move 64-bit immediate into a register,
> + * only analyzer needs to collect the ld_imm value.
> + */
> + u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
> +
> + if (!env->analyzer_ops)
> + return 0;
the check makes sense. thanks.
Acked-by: Alexei Starovoitov <a...@kernel.org>
