Since the new_metric and last_hop_metric variables can reach
the MAX_METRIC(0xffffffff) value, an integer overflow may occur
when multiplying them by 10/9. It can lead to incorrect behavior.
Found by InfoTeCS on behalf of Linux Verification Center
(linuxtesting.org) with SVACE.
Fixes: a8d418d9ac25 ("mac80211: mesh: only switch path when new metric is at least 10% better")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ilia Gavrilov <Ilia.Gavrilov@xxxxxxxxxxx>
---
net/mac80211/mesh_hwmp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c
index 4e9546e998b6..7d367ff1efc2 100644
--- a/net/mac80211/mesh_hwmp.c
+++ b/net/mac80211/mesh_hwmp.c
@@ -458,7 +458,7 @@ static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
(mpath->sn == orig_sn &&
(rcu_access_pointer(mpath->next_hop) !=
sta ?
- mult_frac(new_metric, 10, 9) :
+ mult_frac((u64)new_metric, 10, 9) :
new_metric) >= mpath->metric)) {
process = false;
fresh_info = false;
@@ -533,7 +533,7 @@ static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
if ((mpath->flags & MESH_PATH_FIXED) ||
((mpath->flags & MESH_PATH_ACTIVE) &&
((rcu_access_pointer(mpath->next_hop) != sta ?
- mult_frac(last_hop_metric, 10, 9) :
+ mult_frac((u64)last_hop_metric, 10, 9) :
last_hop_metric) > mpath->metric)))
fresh_info = false;
} else {
--
2.39.5
