This is a note to let you know that I've just added the patch titled mac80211: fix potential overflow when multiplying to u32 integers to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mac80211-fix-potential-overflow-when-multiplying-to-.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit da4c0942b1cb55fd4a2baa494b3ff9a934b8bc02 Author: Colin Ian King <colin.king@xxxxxxxxxxxxx> Date: Fri Feb 5 17:53:52 2021 +0000 mac80211: fix potential overflow when multiplying to u32 integers [ Upstream commit 6194f7e6473be78acdc5d03edd116944bdbb2c4e ] 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@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210205175352.208841-1-colin.king@xxxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/mac80211/mesh_hwmp.c b/net/mac80211/mesh_hwmp.c index aa5150929996d..b5b728a71ab53 100644 --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -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; }