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batman-adv: Fix integer overflow in batadv_iv_ogm_calc_tq

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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 <sven.eckelmann@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sven Eckelmann 2020-03-18 00:26:52 +01:00 committed by Greg Kroah-Hartman
parent 7ba476d56b
commit b0e7f6a27e
1 changed files with 3 additions and 2 deletions
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5
net/batman-adv/bat_iv_ogm.c
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@ -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();