* [PATCH] staging: iio: ade7759: fix signed extension bug on shift of a u8
@ 2017-09-13 17:02 Colin King
2017-09-30 20:14 ` Jonathan Cameron
0 siblings, 1 reply; 2+ messages in thread
From: Colin King @ 2017-09-13 17:02 UTC (permalink / raw)
To: Lars-Peter Clausen, Michael Hennerich, Jonathan Cameron,
Hartmut Knaack, Peter Meerwald-Stadler, Greg Kroah-Hartman,
linux-iio, devel
Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
The current shift of st->rx[2] left shifts a u8 24 bits left,
promotes the integer to a an int and then to a unsigned u64. If
the top bit of st->rx[2] is set then we end up with all the upper
bits being set to 1. Fix this by casting st->rx[2] to a u64 before
the 24 bit left shift.
Detected by CoverityScan CID#144940 ("Unintended sign extension")
Fixes: 2919fa54ef64 ("staging: iio: meter: new driver for ADE7759 devices")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
drivers/staging/iio/meter/ade7759.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/iio/meter/ade7759.c b/drivers/staging/iio/meter/ade7759.c
index 1691760339da..02573c517d9d 100644
--- a/drivers/staging/iio/meter/ade7759.c
+++ b/drivers/staging/iio/meter/ade7759.c
@@ -172,7 +172,7 @@ static int ade7759_spi_read_reg_40(struct device *dev,
reg_address);
goto error_ret;
}
- *val = ((u64)st->rx[1] << 32) | (st->rx[2] << 24) |
+ *val = ((u64)st->rx[1] << 32) | ((u64)st->rx[2] << 24) |
(st->rx[3] << 16) | (st->rx[4] << 8) | st->rx[5];
error_ret:
--
2.14.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] staging: iio: ade7759: fix signed extension bug on shift of a u8
2017-09-13 17:02 [PATCH] staging: iio: ade7759: fix signed extension bug on shift of a u8 Colin King
@ 2017-09-30 20:14 ` Jonathan Cameron
0 siblings, 0 replies; 2+ messages in thread
From: Jonathan Cameron @ 2017-09-30 20:14 UTC (permalink / raw)
To: Colin King
Cc: Lars-Peter Clausen, Michael Hennerich, Hartmut Knaack,
Peter Meerwald-Stadler, Greg Kroah-Hartman, linux-iio, devel,
kernel-janitors, linux-kernel
On Wed, 13 Sep 2017 18:02:02 +0100
Colin King <colin.king@canonical.com> wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The current shift of st->rx[2] left shifts a u8 24 bits left,
> promotes the integer to a an int and then to a unsigned u64. If
> the top bit of st->rx[2] is set then we end up with all the upper
> bits being set to 1. Fix this by casting st->rx[2] to a u64 before
> the 24 bit left shift.
>
> Detected by CoverityScan CID#144940 ("Unintended sign extension")
>
> Fixes: 2919fa54ef64 ("staging: iio: meter: new driver for ADE7759 devices")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
Applied to the fixes-togreg branch of iio.git.
Thanks,
Jonathan
> ---
> drivers/staging/iio/meter/ade7759.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/iio/meter/ade7759.c b/drivers/staging/iio/meter/ade7759.c
> index 1691760339da..02573c517d9d 100644
> --- a/drivers/staging/iio/meter/ade7759.c
> +++ b/drivers/staging/iio/meter/ade7759.c
> @@ -172,7 +172,7 @@ static int ade7759_spi_read_reg_40(struct device *dev,
> reg_address);
> goto error_ret;
> }
> - *val = ((u64)st->rx[1] << 32) | (st->rx[2] << 24) |
> + *val = ((u64)st->rx[1] << 32) | ((u64)st->rx[2] << 24) |
> (st->rx[3] << 16) | (st->rx[4] << 8) | st->rx[5];
>
> error_ret:
^ permalink raw reply [flat|nested] 2+ messages in thread
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