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Commit 14d12b1b authored by Colin Ian King's avatar Colin Ian King Committed by Greg Kroah-Hartman
Browse files

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: 050ac52c ("mac80211: code for on-demand Hybrid Wireless Mesh Protocol")
Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210205175352.208841-1-colin.king@canonical.com


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent d6cd5498

net/mac80211/mesh_hwmp.c

+1 −1
Original line number Diff line number Diff line
@@ -355,7 +355,7 @@ static 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;

}