'skb' buffer address information leakage

[Dison River <pwn2river@xxxxxxxxx>]

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.