git.ipfire.org Git - thirdparty/openwrt.git/blob

   1 From 2a4b99ffcda9f6739d4deb7bd7d2e0ed8444dda7 Mon Sep 17 00:00:00 2001
   2 From: Colin Ian King <colin.king@canonical.com>
   3 Date: Fri, 5 Feb 2021 17:53:52 +0000
   4 Subject: [PATCH] mac80211: fix potential overflow when multiplying to u32
   5  integers
   6
   7 [ Upstream commit 6194f7e6473be78acdc5d03edd116944bdbb2c4e ]
   8
   9 The multiplication of the u32 variables tx_time and estimated_retx is
  10 performed using a 32 bit multiplication and the result is stored in
  11 a u64 result. This has a potential u32 overflow issue, so avoid this
  12 by casting tx_time to a u64 to force a 64 bit multiply.
  13
  14 Addresses-Coverity: ("Unintentional integer overflow")
  15 Fixes: 050ac52cbe1f ("mac80211: code for on-demand Hybrid Wireless Mesh Protocol")
  16 Signed-off-by: Colin Ian King <colin.king@canonical.com>
  17 Link: https://lore.kernel.org/r/20210205175352.208841-1-colin.king@canonical.com
  18 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
  19 Signed-off-by: Sasha Levin <sashal@kernel.org>
  20 ---
  21  net/mac80211/mesh_hwmp.c | 2 +-
  22  1 file changed, 1 insertion(+), 1 deletion(-)
  23
  24 --- a/net/mac80211/mesh_hwmp.c
  25 +++ b/net/mac80211/mesh_hwmp.c
  26 @@ -355,7 +355,7 @@ static u32 airtime_link_metric_get(struc
  27          */
  28         tx_time = (device_constant + 10 * test_frame_len / rate);
  29         estimated_retx = ((1 << (2 * ARITH_SHIFT)) / (s_unit - err));
  30 -       result = (tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
  31 +       result = ((u64)tx_time * estimated_retx) >> (2 * ARITH_SHIFT);
  32         return (u32)result;
  33  }
  34