2020-09-09 19:57:17

by Alex Dewar

Subject: [PATCH] staging: media: atomisp: Use kvfree_sensitive in a few places

In the file pci/sh_css_params.c, there are a number of places where
memset+kvfree is used, where kvfree_sensitive could be used instead. Fix
these occurrences.

Issue identified with Coccinelle.

Signed-off-by: Alex Dewar <[email protected]>
---
.../staging/media/atomisp/pci/sh_css_params.c | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/sh_css_params.c b/drivers/staging/media/atomisp/pci/sh_css_params.c
index 2c67c23b3700..d1b5d6608d52 100644
--- a/drivers/staging/media/atomisp/pci/sh_css_params.c
+++ b/drivers/staging/media/atomisp/pci/sh_css_params.c
@@ -4378,8 +4378,7 @@ ia_css_3a_statistics_free(struct ia_css_3a_statistics *me)
if (me) {
kvfree(me->rgby_data);
kvfree(me->data);
- memset(me, 0, sizeof(struct ia_css_3a_statistics));
- kvfree(me);
+ kvfree_sensitive(me, sizeof(struct ia_css_3a_statistics));
}
}

@@ -4417,8 +4416,7 @@ ia_css_dvs_statistics_free(struct ia_css_dvs_statistics *me)
if (me) {
kvfree(me->hor_proj);
kvfree(me->ver_proj);
- memset(me, 0, sizeof(struct ia_css_dvs_statistics));
- kvfree(me);
+ kvfree_sensitive(me, sizeof(struct ia_css_dvs_statistics));
}
}

@@ -4459,8 +4457,7 @@ ia_css_dvs_coefficients_free(struct ia_css_dvs_coefficients *me)
if (me) {
kvfree(me->hor_coefs);
kvfree(me->ver_coefs);
- memset(me, 0, sizeof(struct ia_css_dvs_coefficients));
- kvfree(me);
+ kvfree_sensitive(me, sizeof(struct ia_css_dvs_coefficients));
}
}

@@ -4551,8 +4548,7 @@ ia_css_dvs2_statistics_free(struct ia_css_dvs2_statistics *me)
kvfree(me->ver_prod.odd_imag);
kvfree(me->ver_prod.even_real);
kvfree(me->ver_prod.even_imag);
- memset(me, 0, sizeof(struct ia_css_dvs2_statistics));
- kvfree(me);
+ kvfree_sensitive(me, sizeof(struct ia_css_dvs2_statistics));
}
}

@@ -4635,8 +4631,7 @@ ia_css_dvs2_coefficients_free(struct ia_css_dvs2_coefficients *me)
kvfree(me->ver_coefs.odd_imag);
kvfree(me->ver_coefs.even_real);
kvfree(me->ver_coefs.even_imag);
- memset(me, 0, sizeof(struct ia_css_dvs2_coefficients));
- kvfree(me);
+ kvfree_sensitive(me, sizeof(struct ia_css_dvs2_coefficients));
}
}

@@ -4710,8 +4705,8 @@ ia_css_dvs2_6axis_config_free(struct ia_css_dvs_6axis_config *dvs_6axis_config)
kvfree(dvs_6axis_config->ycoords_y);
kvfree(dvs_6axis_config->xcoords_uv);
kvfree(dvs_6axis_config->ycoords_uv);
- memset(dvs_6axis_config, 0, sizeof(struct ia_css_dvs_6axis_config));
- kvfree(dvs_6axis_config);
+ kvfree_sensitive(dvs_6axis_config,
+ sizeof(struct ia_css_dvs_6axis_config));
}
}

--
2.28.0

2020-09-09 20:09:44

by Dan Carpenter

Subject: Re: [PATCH] staging: media: atomisp: Use kvfree_sensitive in a few places

On Wed, Sep 09, 2020 at 08:53:50PM +0100, Alex Dewar wrote:
> In the file pci/sh_css_params.c, there are a number of places where
> memset+kvfree is used, where kvfree_sensitive could be used instead. Fix
> these occurrences.

This doesn't say *why* the commit is doing it. There are two reasons:
The worry with these is that the compiler could optimize away the memset
because it sees the kfree(). Second using kvfree_sensitive() is more
clear and readable.

>
> Issue identified with Coccinelle.
>
> Signed-off-by: Alex Dewar <[email protected]>
> ---
> .../staging/media/atomisp/pci/sh_css_params.c | 19 +++++++------------
> 1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/media/atomisp/pci/sh_css_params.c b/drivers/staging/media/atomisp/pci/sh_css_params.c
> index 2c67c23b3700..d1b5d6608d52 100644
> --- a/drivers/staging/media/atomisp/pci/sh_css_params.c
> +++ b/drivers/staging/media/atomisp/pci/sh_css_params.c
> @@ -4378,8 +4378,7 @@ ia_css_3a_statistics_free(struct ia_css_3a_statistics *me)
> if (me) {
> kvfree(me->rgby_data);
> kvfree(me->data);
> - memset(me, 0, sizeof(struct ia_css_3a_statistics));
> - kvfree(me);
> + kvfree_sensitive(me, sizeof(struct ia_css_3a_statistics));

I don't think ia_css_3a_statistics are sensitive at all. What we're
trying to protect are things like passwords. Just delete the memset.

Looking below, I don't think any of these are sensitive so just delete
all the memsets.

regards,
dan carpenter

2020-09-09 20:43:53

by Alex Dewar

Subject: Re: [PATCH] staging: media: atomisp: Use kvfree_sensitive in a few places

On 2020-09-09 21:06, Dan Carpenter wrote:
> On Wed, Sep 09, 2020 at 08:53:50PM +0100, Alex Dewar wrote:
>> In the file pci/sh_css_params.c, there are a number of places where
>> memset+kvfree is used, where kvfree_sensitive could be used instead. Fix
>> these occurrences.
> This doesn't say *why* the commit is doing it. There are two reasons:
> The worry with these is that the compiler could optimize away the memset
> because it sees the kfree(). Second using kvfree_sensitive() is more
> clear and readable.
Good point :)
>
>> Issue identified with Coccinelle.
>>
>> Signed-off-by: Alex Dewar <[email protected]>
>> ---
>> .../staging/media/atomisp/pci/sh_css_params.c | 19 +++++++------------
>> 1 file changed, 7 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/staging/media/atomisp/pci/sh_css_params.c b/drivers/staging/media/atomisp/pci/sh_css_params.c
>> index 2c67c23b3700..d1b5d6608d52 100644
>> --- a/drivers/staging/media/atomisp/pci/sh_css_params.c
>> +++ b/drivers/staging/media/atomisp/pci/sh_css_params.c
>> @@ -4378,8 +4378,7 @@ ia_css_3a_statistics_free(struct ia_css_3a_statistics *me)
>> if (me) {
>> kvfree(me->rgby_data);
>> kvfree(me->data);
>> - memset(me, 0, sizeof(struct ia_css_3a_statistics));
>> - kvfree(me);
>> + kvfree_sensitive(me, sizeof(struct ia_css_3a_statistics));
> I don't think ia_css_3a_statistics are sensitive at all. What we're
> trying to protect are things like passwords. Just delete the memset.
>
> Looking below, I don't think any of these are sensitive so just delete
> all the memsets.
This makes sense. I'll send a new patch. Thanks for the feedback!

Alex
>
> regards,
> dan carpenter
>