On 04/17, Kirill Tkhai wrote:
>
> +struct pidns_ioc_req {
> +/* Set vector of last pids in namespace hierarchy */
> +#define PIDNS_REQ_SET_LAST_PID_VEC 0x1
> + unsigned int req;
> + void __user *data;
> + unsigned int data_size;
> + char std_fields[0];
> +};
see below,
> +static long set_last_pid_vec(struct pid_namespace *pid_ns,
> + struct pidns_ioc_req *req)
> +{
> + char *str, *p;
> + int ret = 0;
> + pid_t pid;
> +
> + read_lock(&tasklist_lock);
> + if (!pid_ns->child_reaper)
> + ret = -EINVAL;
> + read_unlock(&tasklist_lock);
> + if (ret)
> + return ret;
why do you need to check ->child_reaper under tasklist_lock? this looks pointless.
In fact I do not understand how it is possible to hit pid_ns->child_reaper == NULL,
there must be at least one task in this namespace, otherwise you can't open a file
which has f_op == ns_file_operations, no?
> + if (req->data_size >= PAGE_SIZE)
> + return -EINVAL;
> + str = vmalloc(req->data_size + 1);
then I don't understand why it makes sense to use vmalloc()
> + if (!str)
> + return -ENOMEM;
> + if (copy_from_user(str, req->data, req->data_size)) {
> + ret = -EFAULT;
> + goto out_vfree;
> + }
> + str[req->data_size] = '\0';
> +
> + p = str;
> + while (p && *p != '\0') {
> + if (!ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN)) {
> + ret = -EPERM;
> + goto out_vfree;
> + }
> +
> + if (sscanf(p, "%d", &pid) != 1 || pid < 0 || pid > pid_max) {
> + ret = -EINVAL;
> + goto out_vfree;
> + }
Well, this is ioctl(), do we really want to parse the strings?
Can't we make
struct pidns_ioc_req {
...
int nr_pids;
pid_t pids[0];
}
and just use get_user() in a loop? This way we can avoid vmalloc() or anything
else altogether.
Oleg.
