On Mon, Nov 04, 2024 at 04:36:09PM +0100, Steffen Eiden wrote:
> Enable the list IOCTL to provide lists longer than one page (85 entries).
> The list IOCTL now accepts any argument length in page granularity.
> It fills the argument up to this length with entries until the list
> ends. User space unaware of this enhancement will still receive one page
> of data and an uv_rc 0x0100.
>
> Signed-off-by: Steffen Eiden <seiden@xxxxxxxxxxxxx>
> ---
> v3: remove upper boundary (8 pages) for arg len
...
> +static int uvio_get_list(void *zpage, struct uvio_ioctl_cb *uv_ioctl)
> +{
> + const size_t data_off = offsetof(struct uv_secret_list, secrets);
> + u8 __user *user_buf = (u8 __user *)uv_ioctl->argument_addr;
> + struct uv_secret_list *list = zpage;
> + u16 num_secrets_stored = 0;
> + size_t user_off = data_off;
> + size_t copy_len;
> +
> + do {
> + uv_list_secrets(list, list->next_secret_idx, &uv_ioctl->uv_rc,
> + &uv_ioctl->uv_rrc);
> + if (uv_ioctl->uv_rc != UVC_RC_EXECUTED &&
> + uv_ioctl->uv_rc != UVC_RC_MORE_DATA)
> + break;
> +
> + copy_len = sizeof(list->secrets[0]) * list->num_secr_stored;
> + WARN_ON(copy_len > sizeof(list->secrets));
Is this really possible? Without checking the documentation I guess
this is not possible and therefore the WARN_ON() should be removed.
If however this can be possible then this should be turned into a
WARN_ON_ONCE().
> + if (copy_to_user(user_buf + user_off, list->secrets, copy_len))
> + return -EFAULT;
...and in addition, if the above would be possible this _could_ copy
random kernel data to user space. Not good.
