[PATCH v8 4/8] bpftool: Ensure task comm is always NUL-terminated

[Justin Stitt]

Hi,

On Wed, Aug 28, 2024 at 11:03:17AM GMT, Yafang Shao wrote:
> Let's explicitly ensure the destination string is NUL-terminated. This way,
> it won't be affected by changes to the source string.
> 
> Signed-off-by: Yafang Shao <laoar.shao at gmail.com>
> Reviewed-by: Quentin Monnet <qmo at kernel.org>
> ---
>  tools/bpf/bpftool/pids.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/tools/bpf/bpftool/pids.c b/tools/bpf/bpftool/pids.c
> index 9b898571b49e..23f488cf1740 100644
> --- a/tools/bpf/bpftool/pids.c
> +++ b/tools/bpf/bpftool/pids.c
> @@ -54,6 +54,7 @@ static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
>  		ref = &refs->refs[refs->ref_cnt];
>  		ref->pid = e->pid;
>  		memcpy(ref->comm, e->comm, sizeof(ref->comm));
> +		ref->comm[sizeof(ref->comm) - 1] = '\0';

...

>  		refs->ref_cnt++;
>  
>  		return;
> @@ -77,6 +78,7 @@ static void add_ref(struct hashmap *map, struct pid_iter_entry *e)
>  	ref = &refs->refs[0];
>  	ref->pid = e->pid;
>  	memcpy(ref->comm, e->comm, sizeof(ref->comm));
> +	ref->comm[sizeof(ref->comm) - 1] = '\0';

Excuse my ignorance, do we not have a strscpy() equivalent usable in bpf
code?

>  	refs->ref_cnt = 1;
>  	refs->has_bpf_cookie = e->has_bpf_cookie;
>  	refs->bpf_cookie = e->bpf_cookie;
> -- 
> 2.43.5
> 

Thanks
Justin