[PATCH 5.6 024/194] net: stmmac: gmac5+: fix potential integer overflow on 32 bit multiply

Greg Kroah-Hartman
2020-05-18T18:00:46Z

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 44d95cc6b10ff7439d45839c96c581cb4368c088 ]

The multiplication of cfg->ctr[1] by 1000000000 is performed using a
32 bit multiplication (since cfg->ctr[1] is a u32) and this can lead
to a potential overflow. Fix this by making the constant a ULL to
ensure a 64 bit multiply occurs.

Fixes: 504723af0d85 ("net: stmmac: Add basic EST support for GMAC5+")
Addresses-Coverity: ("Unintentional integer overflow")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/stmicro/stmmac/dwmac5.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac5.c b/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
index 494c859b4ade8..67ba67ed0cb99 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac5.c
@@ -624,7 +624,7 @@ int dwmac5_est_configure(void __iomem *ioaddr, struct stmmac_est *cfg,
total_offset += offset;
}

- total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000;
+ total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000ULL;
total_ctr += total_offset;

ctr_low = do_div(total_ctr, 1000000000);
--
2.20.1