Re: 'skb' buffer address information leakage

On Tue, 4 Jul 2017 13:12:18 +0800
Dison River [off-list ref] wrote:

Hi all:
I'd found several address leaks of "skb" buffer.When i have a
arbitrary address write vulnerability in kernel(enabled kASLR),I can
use skb's address find sk_destruct's address and overwrite it. And
then,invoke close(sock_fd) function can trigger the
shellcode(sk_destruct func).

In kernel 4.12-rc7
drivers/net/irda/vlsi_ir.c:326           seq_printf(seq, "skb=%p
data=%p hw=%p\n", rd->skb, rd->buf, rd->hw);
drivers/net/ethernet/netronome/nfp/nfp_net_debugfs.c:167
         seq_printf(file, " frag=%p", skb);
drivers/net/wireless/ath/wil6210/debugfs.c:926           seq_printf(s,
"  SKB = 0x%p\n", skb);

Thanks.

Debugfs support is optional with Netronome. If concerned about security,
then it should be disabled.

The WIIL6210 driver debugfs has other worse address leaks.
The whole debugfs support in this driver should be made optional
(or removed).

The VLSI /oroc interface likewise should just be removed (or made
optional). Most distributions do not build IRDA anymore anyway.