lkml.org 
[lkml]   [2021]   [Mar]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH][next] nvmem: core: Fix unintentional sign extension issue
From
Date


On 11/03/2021 09:53, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The shifting of the u8 integer buf[3] by 24 bits to the left will
> be promoted to a 32 bit signed int and then sign-extended to a
> u64. In the event that the top bit of buf[3] is set then all
> then all the upper 32 bits of the u64 end up as also being set
> because of the sign-extension. Fix this by casting buf[i] to
> a u64 before the shift.
>
> Addresses-Coverity: ("Unintended sign extension")
> Fixes: 097eb1136ebb ("nvmem: core: Add functions to make number reading easy")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---

Applied thanks,

--srini

> drivers/nvmem/core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 635e3131eb5f..bca671ff4e54 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -1693,7 +1693,7 @@ int nvmem_cell_read_variable_le_u64(struct device *dev, const char *cell_id,
> /* Copy w/ implicit endian conversion */
> *val = 0;
> for (i = 0; i < len; i++)
> - *val |= buf[i] << (8 * i);
> + *val |= (uint64_t)buf[i] << (8 * i);
>
> kfree(buf);
>
>

\
 
 \ /
  Last update: 2021-03-11 18:53    [W:0.054 / U:0.668 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site