Re: [RFC PATCH] net/memif: change socket listener owner uid/gid

[Stephen Hemminger]

On Tue, 15 Nov 2022 20:44:41 +0000
Junxiao Shi <g...@mail1.yoursunny.com> wrote:

> +static int
> +memif_set_owner_uid(const char *key __rte_unused, const char *value, void 
> *extra_args)
> +{
> +     uid_t *uid = (uid_t *)extra_args;
> +     *uid = strtoul(value, NULL, 10);
> +     return 0;
> +}
> +
> +static int
> +memif_set_owner_gid(const char *key __rte_unused, const char *value, void 
> *extra_args)
> +{
> +     gid_t *gid = (gid_t *)extra_args;
> +     *gid = strtoul(value, NULL, 10);
> +     return 0;
> +}
> +

This should be one function and it should check for valid arguments.
Things like not a number, extra characters, and out of range.

Modern Linux allows 32 bits of uid. with some values like -1 reserved.
On a 64 bit system like most DPDK usage, sizeof(unsigned long) is 64 bits.

Since uid and gid have same restrictions, then something like this (untested):

static int strtouid(const char *value, uint32_t *id)
{
        unsigned long val;
        char *endp;

        val = strtoul(value, &endp, 10);
        if (*value == '\0' || *endp != '\0')
                return -EINVAL;
        if (val >= UINT32_MAX)
                return -ERANGE;
        *id = val;
        return 0;
}