+++ /dev/null
-From: Linus Lüssing <linus.luessing@c0d3.blue>
-Date: Thu, 6 Jul 2017 07:02:25 +0200
-Subject: [PATCH] batman-adv: fix TT sync flag inconsistencies
-
-This patch fixes an issue in the translation table code potentially
-leading to a TT Request + Response storm. The issue may occur for nodes
-involving BLA and an inconsistent configuration of the batman-adv AP
-isolation feature. However, since the new multicast optimizations, a
-single, malformed packet may lead to a mesh-wide, persistent
-Denial-of-Service, too.
-
-The issue occurs because nodes are currently OR-ing the TT sync flags of
-all originators announcing a specific MAC address via the
-translation table. When an intermediate node now receives a TT Request
-and wants to answer this on behave of the destination node then this
-intermediate node now responds with an altered flag field and broken
-CRC. The next OGM of the real destination will lead to a CRC mismatch
-and triggering a TT Request and Response again.
-
-Furthermore, the OR-ing is currently never undone as long as at least
-one originator announcing the according MAC address remains, leading to
-the potential persistency of this issue.
-
-This patch fixes this issue by storing the flags used in the CRC
-calculation on a a per TT orig entry basis to be able to respond with
-the correct, original flags in an intermediate TT Response for one
-thing. And to be able to correctly unset sync flags once all nodes
-announcing a sync flag vanish for another.
-
-Fixes: fa614fd04692 ("batman-adv: fix tt_global_entries flags update")
-Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
-Acked-by: Antonio Quartulli <a@unstable.cc>
-Signed-off-by: Sven Eckelmann <sven@narfation.org>
-
-Origin: other, https://patchwork.open-mesh.org/patch/17072/
----
- net/batman-adv/translation-table.c | 60 ++++++++++++++++++++++++++++++++------
- net/batman-adv/types.h | 2 ++
- 2 files changed, 53 insertions(+), 9 deletions(-)
-
-diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
-index e1133bc634b5e8ed9a4639677e577a0d52e7c1d5..8a3ce79b1307b7f260ce2f64e96bdacfb9a322f0 100644
---- a/net/batman-adv/translation-table.c
-+++ b/net/batman-adv/translation-table.c
-@@ -1549,9 +1549,41 @@ batadv_tt_global_entry_has_orig(const struct batadv_tt_global_entry *entry,
- return found;
- }
-
-+/**
-+ * batadv_tt_global_sync_flags - update TT sync flags
-+ * @tt_global: the TT global entry to update sync flags in
-+ *
-+ * Updates the sync flag bits in the tt_global flag attribute with a logical
-+ * OR of all sync flags from any of its TT orig entries.
-+ */
-+static void
-+batadv_tt_global_sync_flags(struct batadv_tt_global_entry *tt_global)
-+{
-+ struct batadv_tt_orig_list_entry *orig_entry;
-+ const struct hlist_head *head;
-+ u16 flags = BATADV_NO_FLAGS;
-+
-+ rcu_read_lock();
-+ head = &tt_global->orig_list;
-+ hlist_for_each_entry_rcu(orig_entry, head, list)
-+ flags |= orig_entry->flags;
-+ rcu_read_unlock();
-+
-+ flags |= tt_global->common.flags & (~BATADV_TT_SYNC_MASK);
-+ tt_global->common.flags = flags;
-+}
-+
-+/**
-+ * batadv_tt_global_orig_entry_add - add or update a TT orig entry
-+ * @tt_global: the TT global entry to add an orig entry in
-+ * @orig_node: the originator to add an orig entry for
-+ * @ttvn: translation table version number of this changeset
-+ * @flags: TT sync flags
-+ */
- static void
- batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
-- struct batadv_orig_node *orig_node, int ttvn)
-+ struct batadv_orig_node *orig_node, int ttvn,
-+ u8 flags)
- {
- struct batadv_tt_orig_list_entry *orig_entry;
-
-@@ -1561,7 +1593,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
- * was added during a "temporary client detection"
- */
- orig_entry->ttvn = ttvn;
-- goto out;
-+ orig_entry->flags = flags;
-+ goto sync_flags;
- }
-
- orig_entry = kmem_cache_zalloc(batadv_tt_orig_cache, GFP_ATOMIC);
-@@ -1573,6 +1606,7 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
- batadv_tt_global_size_inc(orig_node, tt_global->common.vid);
- orig_entry->orig_node = orig_node;
- orig_entry->ttvn = ttvn;
-+ orig_entry->flags = flags;
- kref_init(&orig_entry->refcount);
-
- spin_lock_bh(&tt_global->list_lock);
-@@ -1582,6 +1616,8 @@ batadv_tt_global_orig_entry_add(struct batadv_tt_global_entry *tt_global,
- spin_unlock_bh(&tt_global->list_lock);
- atomic_inc(&tt_global->orig_list_count);
-
-+sync_flags:
-+ batadv_tt_global_sync_flags(tt_global);
- out:
- if (orig_entry)
- batadv_tt_orig_list_entry_put(orig_entry);
-@@ -1703,10 +1739,10 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
- }
-
- /* the change can carry possible "attribute" flags like the
-- * TT_CLIENT_WIFI, therefore they have to be copied in the
-+ * TT_CLIENT_TEMP, therefore they have to be copied in the
- * client entry
- */
-- common->flags |= flags;
-+ common->flags |= flags & (~BATADV_TT_SYNC_MASK);
-
- /* If there is the BATADV_TT_CLIENT_ROAM flag set, there is only
- * one originator left in the list and we previously received a
-@@ -1723,7 +1759,8 @@ static bool batadv_tt_global_add(struct batadv_priv *bat_priv,
- }
- add_orig_entry:
- /* add the new orig_entry (if needed) or update it */
-- batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn);
-+ batadv_tt_global_orig_entry_add(tt_global_entry, orig_node, ttvn,
-+ flags & BATADV_TT_SYNC_MASK);
-
- batadv_dbg(BATADV_DBG_TT, bat_priv,
- "Creating new global tt entry: %pM (vid: %d, via %pM)\n",
-@@ -1946,6 +1983,7 @@ batadv_tt_global_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
- struct batadv_tt_orig_list_entry *orig,
- bool best)
- {
-+ u16 flags = (common->flags & (~BATADV_TT_SYNC_MASK)) | orig->flags;
- void *hdr;
- struct batadv_orig_node_vlan *vlan;
- u8 last_ttvn;
-@@ -1975,7 +2013,7 @@ batadv_tt_global_dump_subentry(struct sk_buff *msg, u32 portid, u32 seq,
- nla_put_u8(msg, BATADV_ATTR_TT_LAST_TTVN, last_ttvn) ||
- nla_put_u32(msg, BATADV_ATTR_TT_CRC32, crc) ||
- nla_put_u16(msg, BATADV_ATTR_TT_VID, common->vid) ||
-- nla_put_u32(msg, BATADV_ATTR_TT_FLAGS, common->flags))
-+ nla_put_u32(msg, BATADV_ATTR_TT_FLAGS, flags))
- goto nla_put_failure;
-
- if (best && nla_put_flag(msg, BATADV_ATTR_FLAG_BEST))
-@@ -2589,6 +2627,7 @@ static u32 batadv_tt_global_crc(struct batadv_priv *bat_priv,
- unsigned short vid)
- {
- struct batadv_hashtable *hash = bat_priv->tt.global_hash;
-+ struct batadv_tt_orig_list_entry *tt_orig;
- struct batadv_tt_common_entry *tt_common;
- struct batadv_tt_global_entry *tt_global;
- struct hlist_head *head;
-@@ -2627,8 +2666,9 @@ static u32 batadv_tt_global_crc(struct batadv_priv *bat_priv,
- /* find out if this global entry is announced by this
- * originator
- */
-- if (!batadv_tt_global_entry_has_orig(tt_global,
-- orig_node))
-+ tt_orig = batadv_tt_global_orig_entry_find(tt_global,
-+ orig_node);
-+ if (!tt_orig)
- continue;
-
- /* use network order to read the VID: this ensures that
-@@ -2640,10 +2680,12 @@ static u32 batadv_tt_global_crc(struct batadv_priv *bat_priv,
- /* compute the CRC on flags that have to be kept in sync
- * among nodes
- */
-- flags = tt_common->flags & BATADV_TT_SYNC_MASK;
-+ flags = tt_orig->flags;
- crc_tmp = crc32c(crc_tmp, &flags, sizeof(flags));
-
- crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
-+
-+ batadv_tt_orig_list_entry_put(tt_orig);
- }
- rcu_read_unlock();
- }
-diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
-index ea43a64492479809fe6bdf95b436792078f50e9f..a62795868794103d7e712ba91def5997dc3a5779 100644
---- a/net/batman-adv/types.h
-+++ b/net/batman-adv/types.h
-@@ -1260,6 +1260,7 @@ struct batadv_tt_global_entry {
- * struct batadv_tt_orig_list_entry - orig node announcing a non-mesh client
- * @orig_node: pointer to orig node announcing this non-mesh client
- * @ttvn: translation table version number which added the non-mesh client
-+ * @flags: per orig entry TT sync flags
- * @list: list node for batadv_tt_global_entry::orig_list
- * @refcount: number of contexts the object is used
- * @rcu: struct used for freeing in an RCU-safe manner
-@@ -1267,6 +1268,7 @@ struct batadv_tt_global_entry {
- struct batadv_tt_orig_list_entry {
- struct batadv_orig_node *orig_node;
- u8 ttvn;
-+ u8 flags;
- struct hlist_node list;
- struct kref refcount;
- struct rcu_head rcu;
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