From 4ba104f468bbfc27362c393815d03aa18fb7a20f Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sat, 23 Feb 2019 14:27:10 +0100 Subject: batman-adv: Reduce claim hash refcnt only for removed entry The batadv_hash_remove is a function which searches the hashtable for an entry using a needle, a hashtable bucket selection function and a compare function. It will lock the bucket list and delete an entry when the compare function matches it with the needle. It returns the pointer to the hlist_node which matches or NULL when no entry matches the needle. The batadv_bla_del_claim is not itself protected in anyway to avoid that any other function is modifying the hashtable between the search for the entry and the call to batadv_hash_remove. It can therefore happen that the entry either doesn't exist anymore or an entry was deleted which is not the same object as the needle. In such an situation, the reference counter (for the reference stored in the hashtable) must not be reduced for the needle. Instead the reference counter of the actually removed entry has to be reduced. Otherwise the reference counter will underflow and the object might be freed before all its references were dropped. The kref helpers reported this problem as: refcount_t: underflow; use-after-free. Fixes: 23721387c409 ("batman-adv: add basic bridge loop avoidance code") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/bridge_loop_avoidance.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) (limited to 'net/batman-adv') diff --git a/net/batman-adv/bridge_loop_avoidance.c b/net/batman-adv/bridge_loop_avoidance.c index ef39aabdb694..4fb01108e5f5 100644 --- a/net/batman-adv/bridge_loop_avoidance.c +++ b/net/batman-adv/bridge_loop_avoidance.c @@ -803,6 +803,8 @@ static void batadv_bla_del_claim(struct batadv_priv *bat_priv, const u8 *mac, const unsigned short vid) { struct batadv_bla_claim search_claim, *claim; + struct batadv_bla_claim *claim_removed_entry; + struct hlist_node *claim_removed_node; ether_addr_copy(search_claim.addr, mac); search_claim.vid = vid; @@ -813,10 +815,18 @@ static void batadv_bla_del_claim(struct batadv_priv *bat_priv, batadv_dbg(BATADV_DBG_BLA, bat_priv, "%s(): %pM, vid %d\n", __func__, mac, batadv_print_vid(vid)); - batadv_hash_remove(bat_priv->bla.claim_hash, batadv_compare_claim, - batadv_choose_claim, claim); - batadv_claim_put(claim); /* reference from the hash is gone */ + claim_removed_node = batadv_hash_remove(bat_priv->bla.claim_hash, + batadv_compare_claim, + batadv_choose_claim, claim); + if (!claim_removed_node) + goto free_claim; + /* reference from the hash is gone */ + claim_removed_entry = hlist_entry(claim_removed_node, + struct batadv_bla_claim, hash_entry); + batadv_claim_put(claim_removed_entry); + +free_claim: /* don't need the reference from hash_find() anymore */ batadv_claim_put(claim); } -- cgit v1.2.3 From 3d65b9accab4a7ed5038f6df403fbd5e298398c7 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sat, 23 Feb 2019 14:27:10 +0100 Subject: batman-adv: Reduce tt_local hash refcnt only for removed entry The batadv_hash_remove is a function which searches the hashtable for an entry using a needle, a hashtable bucket selection function and a compare function. It will lock the bucket list and delete an entry when the compare function matches it with the needle. It returns the pointer to the hlist_node which matches or NULL when no entry matches the needle. The batadv_tt_local_remove is not itself protected in anyway to avoid that any other function is modifying the hashtable between the search for the entry and the call to batadv_hash_remove. It can therefore happen that the entry either doesn't exist anymore or an entry was deleted which is not the same object as the needle. In such an situation, the reference counter (for the reference stored in the hashtable) must not be reduced for the needle. Instead the reference counter of the actually removed entry has to be reduced. Otherwise the reference counter will underflow and the object might be freed before all its references were dropped. The kref helpers reported this problem as: refcount_t: underflow; use-after-free. Fixes: ef72706a0543 ("batman-adv: protect tt_local_entry from concurrent delete events") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/translation-table.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) (limited to 'net/batman-adv') diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index f73d79139ae7..b5cfc5068a90 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -1337,9 +1337,10 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr, unsigned short vid, const char *message, bool roaming) { + struct batadv_tt_local_entry *tt_removed_entry; struct batadv_tt_local_entry *tt_local_entry; u16 flags, curr_flags = BATADV_NO_FLAGS; - void *tt_entry_exists; + struct hlist_node *tt_removed_node; tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr, vid); if (!tt_local_entry) @@ -1368,15 +1369,18 @@ u16 batadv_tt_local_remove(struct batadv_priv *bat_priv, const u8 *addr, */ batadv_tt_local_event(bat_priv, tt_local_entry, BATADV_TT_CLIENT_DEL); - tt_entry_exists = batadv_hash_remove(bat_priv->tt.local_hash, + tt_removed_node = batadv_hash_remove(bat_priv->tt.local_hash, batadv_compare_tt, batadv_choose_tt, &tt_local_entry->common); - if (!tt_entry_exists) + if (!tt_removed_node) goto out; - /* extra call to free the local tt entry */ - batadv_tt_local_entry_put(tt_local_entry); + /* drop reference of remove hash entry */ + tt_removed_entry = hlist_entry(tt_removed_node, + struct batadv_tt_local_entry, + common.hash_entry); + batadv_tt_local_entry_put(tt_removed_entry); out: if (tt_local_entry) -- cgit v1.2.3 From f131a56880d10932931e74773fb8702894a94a75 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sat, 23 Feb 2019 14:27:10 +0100 Subject: batman-adv: Reduce tt_global hash refcnt only for removed entry The batadv_hash_remove is a function which searches the hashtable for an entry using a needle, a hashtable bucket selection function and a compare function. It will lock the bucket list and delete an entry when the compare function matches it with the needle. It returns the pointer to the hlist_node which matches or NULL when no entry matches the needle. The batadv_tt_global_free is not itself protected in anyway to avoid that any other function is modifying the hashtable between the search for the entry and the call to batadv_hash_remove. It can therefore happen that the entry either doesn't exist anymore or an entry was deleted which is not the same object as the needle. In such an situation, the reference counter (for the reference stored in the hashtable) must not be reduced for the needle. Instead the reference counter of the actually removed entry has to be reduced. Otherwise the reference counter will underflow and the object might be freed before all its references were dropped. The kref helpers reported this problem as: refcount_t: underflow; use-after-free. Fixes: 7683fdc1e886 ("batman-adv: protect the local and the global trans-tables with rcu") Reported-by: Martin Weinelt Signed-off-by: Sven Eckelmann Acked-by: Antonio Quartulli Signed-off-by: Simon Wunderlich --- net/batman-adv/translation-table.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'net/batman-adv') diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index b5cfc5068a90..26c4e2493ddf 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -616,14 +616,26 @@ static void batadv_tt_global_free(struct batadv_priv *bat_priv, struct batadv_tt_global_entry *tt_global, const char *message) { + struct batadv_tt_global_entry *tt_removed_entry; + struct hlist_node *tt_removed_node; + batadv_dbg(BATADV_DBG_TT, bat_priv, "Deleting global tt entry %pM (vid: %d): %s\n", tt_global->common.addr, batadv_print_vid(tt_global->common.vid), message); - batadv_hash_remove(bat_priv->tt.global_hash, batadv_compare_tt, - batadv_choose_tt, &tt_global->common); - batadv_tt_global_entry_put(tt_global); + tt_removed_node = batadv_hash_remove(bat_priv->tt.global_hash, + batadv_compare_tt, + batadv_choose_tt, + &tt_global->common); + if (!tt_removed_node) + return; + + /* drop reference of remove hash entry */ + tt_removed_entry = hlist_entry(tt_removed_node, + struct batadv_tt_global_entry, + common.hash_entry); + batadv_tt_global_entry_put(tt_removed_entry); } /** -- cgit v1.2.3 From ca8c3b922e7032aff6cc3fd05548f4df1f3df90e Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Fri, 22 Feb 2019 16:25:54 +0100 Subject: batman-adv: fix warning in function batadv_v_elp_get_throughput MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When CONFIG_CFG80211 isn't enabled the compiler correcly warns about 'sinfo.pertid' may be unused. It can also happen for other error conditions that it not warn about. net/batman-adv/bat_v_elp.c: In function ‘batadv_v_elp_get_throughput.isra.0’: include/net/cfg80211.h:6370:13: warning: ‘sinfo.pertid’ may be used uninitialized in this function [-Wmaybe-uninitialized] kfree(sinfo->pertid); ~~~~~^~~~~~~~ Rework so that we only release '&sinfo' if cfg80211_get_station returns zero. Fixes: 7d652669b61d ("batman-adv: release station info tidstats") Signed-off-by: Anders Roxell Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/bat_v_elp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'net/batman-adv') diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index a9b7919c9de5..d5df0114f08a 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -104,8 +104,10 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) ret = cfg80211_get_station(real_netdev, neigh->addr, &sinfo); - /* free the TID stats immediately */ - cfg80211_sinfo_release_content(&sinfo); + if (!ret) { + /* free the TID stats immediately */ + cfg80211_sinfo_release_content(&sinfo); + } dev_put(real_netdev); if (ret == -ENOENT) { -- cgit v1.2.3 From 438b3d3fae4346a49fe12fa7cc1dc9327f006a91 Mon Sep 17 00:00:00 2001 From: Sven Eckelmann Date: Sun, 3 Mar 2019 19:25:26 +0100 Subject: batman-adv: Fix genl notification for throughput_override The throughput_override sysfs file is not below the meshif but below a hardif. The kobj has therefore not a pointer which can be used to find the batadv_priv data. The pointer stored in the hardif object must be used instead to find the correct meshif private data. Fixes: 7e6f461efe25 ("batman-adv: Trigger genl notification on sysfs config change") Signed-off-by: Sven Eckelmann Signed-off-by: Simon Wunderlich --- net/batman-adv/sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'net/batman-adv') diff --git a/net/batman-adv/sysfs.c b/net/batman-adv/sysfs.c index 0b4b3fb778a6..208655cf6717 100644 --- a/net/batman-adv/sysfs.c +++ b/net/batman-adv/sysfs.c @@ -1116,9 +1116,9 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj, struct attribute *attr, char *buff, size_t count) { - struct batadv_priv *bat_priv = batadv_kobj_to_batpriv(kobj); struct net_device *net_dev = batadv_kobj_to_netdev(kobj); struct batadv_hard_iface *hard_iface; + struct batadv_priv *bat_priv; u32 tp_override; u32 old_tp_override; bool ret; @@ -1147,7 +1147,10 @@ static ssize_t batadv_store_throughput_override(struct kobject *kobj, atomic_set(&hard_iface->bat_v.throughput_override, tp_override); - batadv_netlink_notify_hardif(bat_priv, hard_iface); + if (hard_iface->soft_iface) { + bat_priv = netdev_priv(hard_iface->soft_iface); + batadv_netlink_notify_hardif(bat_priv, hard_iface); + } out: batadv_hardif_put(hard_iface); -- cgit v1.2.3