linux/net/netlink
Jason A. Donenfeld 41c87425a1 netlink: do not set cb_running if dump's start() errs
It turns out that multiple places can call netlink_dump(), which means
it's still possible to dereference partially initialized values in
dump() that were the result of a faulty returned start().

This fixes the issue by calling start() _before_ setting cb_running to
true, so that there's no chance at all of hitting the dump() function
through any indirect paths.

It also moves the call to start() to be when the mutex is held. This has
the nice side effect of serializing invocations to start(), which is
likely desirable anyway. It also prevents any possible other races that
might come out of this logic.

In testing this with several different pieces of tricky code to trigger
these issues, this commit fixes all avenues that I'm aware of.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-10-09 10:27:49 -07:00
..
af_netlink.c netlink: do not set cb_running if dump's start() errs 2017-10-09 10:27:49 -07:00
af_netlink.h netlink: extended ACK reporting 2017-04-13 13:58:20 -04:00
diag.c netlink/diag: report flags for netlink sockets 2017-04-05 07:13:56 -07:00
genetlink.c netlink: pass extended ACK struct where available 2017-04-13 13:58:22 -04:00
Kconfig netlink: remove mmapped netlink support 2016-02-18 11:42:18 -05:00
Makefile netlink: Diag core and basic socket info dumping (v2) 2013-03-21 12:38:03 -04:00