tipc: fix uninit skb->data in tipc_nl_compat_dumpit()

__tipc_nl_compat_dumpit() has two callers, and it expects them to
pass a valid nlmsghdr via arg->data. This header is artificial and
crafted just for __tipc_nl_compat_dumpit().

tipc_nl_compat_publ_dump() does so by putting a genlmsghdr as well
as some nested attribute, TIPC_NLA_SOCK. But the other caller
tipc_nl_compat_dumpit() does not, this leaves arg->data uninitialized
on this call path.

Fix this by just adding a similar nlmsghdr without any payload in
tipc_nl_compat_dumpit().

This bug exists since day 1, but the recent commit 6ea67769ff33
("net: tipc: prepare attrs in __tipc_nl_compat_dumpit()") makes it
easier to appear.

Reported-and-tested-by: [email protected]
Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat")
Cc: Jon Maloy <[email protected]>
Cc: Ying Xue <[email protected]>
Cc: Richard Alpe <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
Acked-by: Ying Xue <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions