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mac80211: fix potential overflow when multiplying to u32 integers

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The multiplication of the u32 variables tx_time and estimated_retx is
performed using a 32 bit multiplication and the result is stored in
a u64 result. This has a potential u32 overflow issue, so avoid this
by casting tx_time to a u64 to force a 64 bit multiply.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: 050ac52cbe1f ("mac80211: code for on-demand Hybrid Wireless Mesh Protocol")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210205175352.208841-1-colin.king@canonical.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Colin Ian King 2021-02-05 17:53:52 +00:00 committed by Johannes Berg
parent 10cb8e6175
commit 6194f7e647
1 changed files with 1 additions and 1 deletions
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2
net/mac80211/mesh_hwmp.c
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@ -356,7 +356,7 @@ u32 airtime_link_metric_get(struct ieee80211_local *local,
*/
tx_time = (device_constant + 10 * test_frame_len / rate);
estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
return (u32)result;
}