Re: [PATCH] ifstat: Add NULL pointer check for result of ll_index_to_name()

[Stephen Hemminger <stephen@networkplumber.org>]

On Sat,  6 Jan 2024 23:10:10 +0300
Maks Mishin <maks.mishinfz@gmail.com> wrote:

> Result of ll_index_to_name() function do not being checked for NULL
> pointer before using in strdup() function.
> Add intermediate variable `name` for result of ll_index_to_name()
> function. Function result -1 when `name` is NULL.
> 
> Signed-off-by: Maks Mishin <maks.mishinFZ@gmail.com>
> ---
>  misc/ifstat.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/misc/ifstat.c b/misc/ifstat.c
> index f6f9ba50..e6c38812 100644
> --- a/misc/ifstat.c
> +++ b/misc/ifstat.c
> @@ -129,7 +129,12 @@ static int get_nlmsg_extended(struct nlmsghdr *m, void *arg)
>  		abort();
>  
>  	n->ifindex = ifsm->ifindex;
> -	n->name = strdup(ll_index_to_name(ifsm->ifindex));
> +	
> +	const char* name = ll_index_to_name(ifsm->ifindex);
> +	if (name == NULL) {
> +		return -1;
> +	}
> +	n->name = strdup(name);
>  
>  	if (sub_type == NO_SUB_TYPE) {
>  		memcpy(&n->val, RTA_DATA(tb[filter_type]), sizeof(n->val));

iproute follows kernel coding style.
checkpatch complains about this patch.

Also, there are several more strdup() calls in ifstat.

### [PATCH] ifstat: Add NULL pointer check for result of ll_index_to_name()

ERROR:TRAILING_WHITESPACE: trailing whitespace
#105: FILE: misc/ifstat.c:132:
+^I$

ERROR:POINTER_LOCATION: "foo* bar" should be "foo *bar"
#106: FILE: misc/ifstat.c:133:
+	const char* name = ll_index_to_name(ifsm->ifindex);

WARNING:BRACES: braces {} are not necessary for single statement blocks
#107: FILE: misc/ifstat.c:134:
+	if (name == NULL) {
+		return -1;
+	}

total: 2 errors, 1 warnings, 13 lines checked