diff options
| author |   Linus Lüssing <linus.luessing@c0d3.blue> | 2015-06-16 17:10:26 +0200 |
|---|---|---|
| committer |   Antonio Quartulli <antonio@meshcoding.com> | 2015-08-14 22:52:08 +0200 |
| commit | 8a4023c5b5e30b11f1f383186f4a7222b3b823cf (patch) | |
| tree | 47a3414f2843011b95fdad1c05e413c3957d050a /net/batman-adv/types.h | |
| parent | batman-adv: Make MCAST capability changes atomic (diff) | |
| download | linux-dev-8a4023c5b5e30b11f1f383186f4a7222b3b823cf.tar.xz linux-dev-8a4023c5b5e30b11f1f383186f4a7222b3b823cf.zip | |
batman-adv: Fix potential synchronization issues in mcast tvlv handler
So far the mcast tvlv handler did not anticipate the processing of
multiple incoming OGMs from the same originator at the same time. This
can lead to various issues:
* Broken refcounting: For instance two mcast handlers might both assume
that an originator just got multicast capabilities and will together
wrongly decrease mcast.num_disabled by two, potentially leading to
an integer underflow.
* Potential kernel panic on hlist_del_rcu(): Two mcast handlers might
one after another try to do an
hlist_del_rcu(&orig->mcast_want_all_*_node). The second one will
cause memory corruption / crashes.
(Reported by: Sven Eckelmann <sven@narfation.org>)
Right in the beginning the code path makes assumptions about the current
multicast related state of an originator and bases all updates on that. The
easiest and least error prune way to fix the issues in this case is to
serialize multiple mcast handler invocations with a spinlock.
Fixes: 60432d756cf0 ("batman-adv: Announce new capability via multicast TVLV")
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <antonio@meshcoding.com>
Diffstat (limited to '')
| -rw-r--r-- | net/batman-adv/types.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 1eeed1847bc7..55610a805b53 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -221,6 +221,7 @@ struct batadv_orig_bat_iv { * @batadv_dat_addr_t: address of the orig node in the distributed hash * @last_seen: time when last packet from this node was received * @bcast_seqno_reset: time when the broadcast seqno window was reset + * @mcast_handler_lock: synchronizes mcast-capability and -flag changes * @mcast_flags: multicast flags announced by the orig node * @mcast_want_all_unsnoop_node: a list node for the * mcast.want_all_unsnoopables list @@ -268,6 +269,8 @@ struct batadv_orig_node { unsigned long last_seen; unsigned long bcast_seqno_reset; #ifdef CONFIG_BATMAN_ADV_MCAST + /* synchronizes mcast tvlv specific orig changes */ + spinlock_t mcast_handler_lock; uint8_t mcast_flags; struct hlist_node mcast_want_all_unsnoopables_node; struct hlist_node mcast_want_all_ipv4_node; |