2018-06-17 10:34:19

by Stefan Agner

Subject: [PATCH] brcm80211: fix wrap around in conversion from constant to s16

The last value in the log_table wraps around to a negative value
since s16 has a value range of -32768 to 32767. This is not what
the table intends to represent. Use the closest positive value
32767.

This fixes a warning seen with clang:
drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c:216:2: warning:
implicit conversion from 'int' to 's16' (aka 'short') changes
value from 32768
to -32768 [-Wconstant-conversion]
32768
^~~~~
1 warning generated.

Fixes: 4c0bfeaae9f9 ("brcmsmac: fix array out-of-bounds access in qm_log10")
Cc: Tobias Regnery <[email protected]>
Signed-off-by: Stefan Agner <[email protected]>
---
.../net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c b/drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c
index b9672da24a9d..b24bc57ca91b 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c
@@ -213,7 +213,7 @@ static const s16 log_table[] = {
30498,
31267,
32024,
- 32768
+ 32767
};

#define LOG_TABLE_SIZE 32 /* log_table size */
--
2.17.1

2018-06-27 15:57:07

by Kalle Valo

Subject: Re: brcmsmac: fix wrap around in conversion from constant to s16

Stefan Agner <[email protected]> wrote:

> The last value in the log_table wraps around to a negative value
> since s16 has a value range of -32768 to 32767. This is not what
> the table intends to represent. Use the closest positive value
> 32767.
>
> This fixes a warning seen with clang:
> drivers/net/wireless/broadcom/brcm80211/brcmsmac/phy/phy_qmath.c:216:2: warning:
> implicit conversion from 'int' to 's16' (aka 'short') changes
> value from 32768
> to -32768 [-Wconstant-conversion]
> 32768
> ^~~~~
> 1 warning generated.
>
> Fixes: 4c0bfeaae9f9 ("brcmsmac: fix array out-of-bounds access in qm_log10")
> Cc: Tobias Regnery <[email protected]>
> Signed-off-by: Stefan Agner <[email protected]>

Patch applied to wireless-drivers-next.git, thanks.

c9a61469fc97 brcmsmac: fix wrap around in conversion from constant to s16

--
https://patchwork.kernel.org/patch/10468755/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches