From mboxrd@z Thu Jan 1 00:00:00 1970 From: ben.hutchings@codethink.co.uk (Ben Hutchings) Date: Fri, 09 Dec 2016 00:36:21 +0000 Subject: [cip-dev] [PATCH 4.4-cip 13/23] batman-adv: Fix integer overflow in batadv_iv_ogm_calc_tq In-Reply-To: <1481243545.1860.156.camel@codethink.co.uk> References: <1481243545.1860.156.camel@codethink.co.uk> Message-ID: <1481243781.1860.169.camel@codethink.co.uk> To: cip-dev@lists.cip-project.org List-Id: cip-dev.lists.cip-project.org From: Sven Eckelmann commit d285f52cc0f23564fd61976d43fd5b991b4828f6 upstream. The undefined behavior sanatizer detected an signed integer overflow in a setup with near perfect link quality UBSAN: Undefined behaviour in net/batman-adv/bat_iv_ogm.c:1246:25 signed integer overflow: 8713350 * 255 cannot be represented in type 'int' The problems happens because the calculation of mixed unsigned and signed integers resulted in an integer multiplication. batadv_ogm_packet::tq (u8 255) * tq_own (u8 255) * tq_asym_penalty (int 134; max 255) * tq_iface_penalty (int 255; max 255) The tq_iface_penalty, tq_asym_penalty and inv_asym_penalty can just be changed to unsigned int because they are not expected to become negative. Fixes: c039876892e3 ("batman-adv: add WiFi penalty") Signed-off-by: Sven Eckelmann Signed-off-by: Marek Lindner Signed-off-by: Antonio Quartulli [bwh: Backported to 4.4: adjust context] Signed-off-by: Ben Hutchings --- net/batman-adv/bat_iv_ogm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c index 912d9c36fb1c..3fb6e9e8df7e 100644 --- a/net/batman-adv/bat_iv_ogm.c +++ b/net/batman-adv/bat_iv_ogm.c @@ -1140,9 +1140,10 @@ static int batadv_iv_ogm_calc_tq(struct batadv_orig_node *orig_node, u8 total_count; u8 orig_eq_count, neigh_rq_count, neigh_rq_inv, tq_own; unsigned int neigh_rq_inv_cube, neigh_rq_max_cube; - int tq_asym_penalty, inv_asym_penalty, if_num, ret = 0; + int if_num, ret = 0; + unsigned int tq_asym_penalty, inv_asym_penalty; unsigned int combined_tq; - int tq_iface_penalty; + unsigned int tq_iface_penalty; /* find corresponding one hop neighbor */ rcu_read_lock(); -- 2.10.2 -- Ben Hutchings Software Developer, Codethink Ltd.