On Wed, 2018-10-10 at 18:11 +0000, justin.l...@dell.com wrote:
<snip>
> +
> + len = nla_len(info->attrs[NCSI_ATTR_DATA]);
> + if (len < sizeof(struct ncsi_pkt_hdr)) {
> + netdev_info(ndp->ndev.dev, "NCSI: no command to send %u\n",
> + package_id);
> + ret = -EINVAL;
> + goto out_netlink;
> + } else {
> + data = (unsigned char *)nla_data(info->attrs[NCSI_ATTR_DATA]);
> + }
I only just noticed this, the call to nla_len() can cause a null-dereference if
the NCSI_ATTR_DATA attribute isn't present; we need to make sure it exists
before accessing it in info->attrs.
eg:
root@ozrom2-bmc:~# ./ncsi-netlink -l 2 -p 0 -c 0 --cmd
[ 81.399837] Unable to handle kernel NULL pointer dereference at virtual
address 00000000
[ 81.409092] pgd = ddaa9fa6
[ 81.413084] [00000000] *pgd=9702c831, *pte=00000000, *ppte=00000000
[ 81.420729] Internal error: Oops: 17 [#1] ARM
[ 81.426447] CPU: 0 PID: 1028 Comm: ncsi-netlink Not tainted
4.18.8-sammj-00144-gbc129f31bfa5 #12
...
[ 81.874434] Kernel panic - not syncing: Fatal exception
Cheers,
Sam
