[dpdk-dev] [RFC 3/5] bpf: fix validation of eal_divmod

[Ananyev, Konstantin]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Stephen Hemminger
> Sent: Tuesday, November 6, 2018 9:49 PM
> To: dev at dpdk.org
> Cc: Stephen Hemminger <stephen at networkplumber.org>
> Subject: [dpdk-dev] [RFC 3/5] bpf: fix validation of eal_divmod
> 
> Coverity spotted self assignment in BPF eval_divmod.

Yep, there is one.
As I remember I have to add it because one of old versions 
of compiler (clang???) complained about 'variable being used uninitialized'.

> This looks like a bug where the incoming source register
> should have been used instead.

Nope, that's a wrong guess.
We shouldn't do it here.
Konstantin

> 
> Coverity issue: 302850
> Fixes: 8021917293d0 ("bpf: add extra validation for input BPF program")
> Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> ---
>  lib/librte_bpf/bpf_validate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/lib/librte_bpf/bpf_validate.c b/lib/librte_bpf/bpf_validate.c
> index 83983efc4e5c..b768f72c4c02 100644
> --- a/lib/librte_bpf/bpf_validate.c
> +++ b/lib/librte_bpf/bpf_validate.c
> @@ -512,7 +512,7 @@ eval_divmod(uint32_t op, struct bpf_reg_val *rd, struct bpf_reg_val *rs,
>  		if (op == BPF_MOD)
>  			rd->u.max = RTE_MIN(rd->u.max, rs->u.max - 1);
>  		else
> -			rd->u.max = rd->u.max;
> +			rd->u.max = rs->u.max;
>  		rd->u.min = 0;
>  	}
> 
> --
> 2.17.1