netdev - Re: [PATCH iproute2-next v2] bpf: replace snprintf with asprintf when dealing with long buffers

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Date:   Thu, 19 Sep 2019 08:48:50 -0600
From:   David Ahern <dsahern@...il.com>
To:     Andrea Claudi <aclaudi@...hat.com>, netdev@...r.kernel.org
Cc:     stephen@...workplumber.org, dsahern@...nel.org
Subject: Re: [PATCH iproute2-next v2] bpf: replace snprintf with asprintf when
 dealing with long buffers

On 9/16/19 7:00 AM, Andrea Claudi wrote:
> This reduces stack usage, as asprintf allocates memory on the heap.
> 
> This indirectly fixes a snprintf truncation warning (from gcc v9.2.1):
> 
> bpf.c: In function ‘bpf_get_work_dir’:
> bpf.c:784:49: warning: ‘snprintf’ output may be truncated before the last format character [-Wformat-truncation=]
>   784 |  snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
>       |                                                 ^
> bpf.c:784:2: note: ‘snprintf’ output between 2 and 4097 bytes into a destination of size 4096
>   784 |  snprintf(bpf_wrk_dir, sizeof(bpf_wrk_dir), "%s/", mnt);
>       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Fixes: e42256699cac ("bpf: make tc's bpf loader generic and move into lib")
> Signed-off-by: Andrea Claudi <aclaudi@...hat.com>
> ---
>  lib/bpf.c | 155 ++++++++++++++++++++++++++++++++++++++++--------------
>  1 file changed, 116 insertions(+), 39 deletions(-)
> 

applied to iproute2-next. Thanks