From 2a4b99ffcda9f6739d4deb7bd7d2e0ed8444dda7 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Fri, 5 Feb 2021 17:53:52 +0000 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20210205175352.208841-1-colin.king@canonical.com Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin --- net/mac80211/mesh_hwmp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/mac80211/mesh_hwmp.c +++ b/net/mac80211/mesh_hwmp.c @@ -355,7 +355,7 @@ static u32 airtime_link_metric_get(struc */ 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; }