* re: net: stmmac: Add basic EST support for GMAC5+
@ 2019-12-20 23:49 Colin Ian King
2019-12-26 17:14 ` Jose Abreu
0 siblings, 1 reply; 2+ messages in thread
From: Colin Ian King @ 2019-12-20 23:49 UTC (permalink / raw)
To: Jose Abreu, David S. Miller, Giuseppe Cavallaro,
Alexandre Torgue, Maxime Coquelin, netdev, linux-arm-kernel
Cc: linux-kernel
Hi,
Static analysis with Coverity has detected a potential issue with the
following commit:
commit 504723af0d85434be5fb6f2dde0b62644a7f1ead
Author: Jose Abreu <joabreu@synopsys.com>
Date: Wed Dec 18 11:33:05 2019 +0100
net: stmmac: Add basic EST support for GMAC5+
In function dwmac5_est_configure() we have a u64 total_ctr being
assigned as follows:
total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000;
The cfg->ctr[1] is a u32, the multiplication of cfg->ctr[1] is a u32
multiplication operation, so multiplying by 1000000000 can potentially
cause an overflow. Either cfg->ctr[1] needs to be cast to a u64 or
1000000000 should be at least a 1000000000UL to avoid this overflow. I
was going to fix this but on further inspection I was not sure if the
original code was intended as:
total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000UL;
or:
total_ctr = (cfg->ctr[0] + cfg->ctr[1]) * 1000000000UL;
..hence I'm flagging this up as potential error.
Colin
^ permalink raw reply [flat|nested] 2+ messages in thread* RE: net: stmmac: Add basic EST support for GMAC5+
2019-12-20 23:49 net: stmmac: Add basic EST support for GMAC5+ Colin Ian King
@ 2019-12-26 17:14 ` Jose Abreu
0 siblings, 0 replies; 2+ messages in thread
From: Jose Abreu @ 2019-12-26 17:14 UTC (permalink / raw)
To: Colin Ian King, David S. Miller, Giuseppe Cavallaro,
Alexandre Torgue, Maxime Coquelin, netdev, linux-arm-kernel
Cc: linux-kernel
From: Colin Ian King <colin.king@canonical.com>
Date: Dec/20/2019, 23:49:02 (UTC+00:00)
> Hi,
>
> Static analysis with Coverity has detected a potential issue with the
> following commit:
>
> commit 504723af0d85434be5fb6f2dde0b62644a7f1ead
> Author: Jose Abreu <joabreu@synopsys.com>
> Date: Wed Dec 18 11:33:05 2019 +0100
>
> net: stmmac: Add basic EST support for GMAC5+
>
>
> In function dwmac5_est_configure() we have a u64 total_ctr being
> assigned as follows:
>
> total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000;
>
> The cfg->ctr[1] is a u32, the multiplication of cfg->ctr[1] is a u32
> multiplication operation, so multiplying by 1000000000 can potentially
> cause an overflow. Either cfg->ctr[1] needs to be cast to a u64 or
> 1000000000 should be at least a 1000000000UL to avoid this overflow. I
> was going to fix this but on further inspection I was not sure if the
> original code was intended as:
>
> total_ctr = cfg->ctr[0] + cfg->ctr[1] * 1000000000UL;
> or:
> total_ctr = (cfg->ctr[0] + cfg->ctr[1]) * 1000000000UL;
>
> ..hence I'm flagging this up as potential error.
Thanks for the report. The first option is the correct one as ctr[1] is
seconds and ctr[0] is nanoseconds. Can you send a fix-up patch ?
---
Thanks,
Jose Miguel Abreu
^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-12-20 23:49 net: stmmac: Add basic EST support for GMAC5+ Colin Ian King
2019-12-26 17:14 ` Jose Abreu
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