tee: qcom: prevent potential off by one read

[PATCH next] tee: qcom: prevent potential off by one read

Posted by Dan Carpenter 3 months ago

Re-order these checks to check if "i" is a valid array index before using
it.  This prevents a potential off by one read access.

Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
 drivers/tee/qcomtee/call.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
index cc17a48d0ab7..ac134452cc9c 100644
--- a/drivers/tee/qcomtee/call.c
+++ b/drivers/tee/qcomtee/call.c
@@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
 	}
 
 	/* Release any IO and OO objects not processed. */
-	for (; u[i].type && i < num_params; i++) {
+	for (; i < num_params && u[i].type; i++) {
 		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
 		    u[i].type == QCOMTEE_ARG_TYPE_IO)
 			qcomtee_object_put(u[i].o);
-- 
2.51.0

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Amirreza Zarrabi 2 months, 3 weeks ago

On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> Re-order these checks to check if "i" is a valid array index before using
> it.  This prevents a potential off by one read access.
> 
> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>  drivers/tee/qcomtee/call.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> index cc17a48d0ab7..ac134452cc9c 100644
> --- a/drivers/tee/qcomtee/call.c
> +++ b/drivers/tee/qcomtee/call.c
> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
>  	}
>  
>  	/* Release any IO and OO objects not processed. */
> -	for (; u[i].type && i < num_params; i++) {
> +	for (; i < num_params && u[i].type; i++) {
>  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
>  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
>  			qcomtee_object_put(u[i].o);

This is not required, considering the sequence of clean up, this
would never happen. `i` at least have been accessed once in the
switch above.

Regards,
Amir

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Dan Carpenter 2 months, 3 weeks ago

On Wed, Sep 24, 2025 at 08:48:29AM +1000, Amirreza Zarrabi wrote:
> On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> > Re-order these checks to check if "i" is a valid array index before using
> > it.  This prevents a potential off by one read access.
> > 
> > Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > ---
> >  drivers/tee/qcomtee/call.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> > index cc17a48d0ab7..ac134452cc9c 100644
> > --- a/drivers/tee/qcomtee/call.c
> > +++ b/drivers/tee/qcomtee/call.c
> > @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> >  	}
> >  
> >  	/* Release any IO and OO objects not processed. */
> > -	for (; u[i].type && i < num_params; i++) {
> > +	for (; i < num_params && u[i].type; i++) {
> >  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> >  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
> >  			qcomtee_object_put(u[i].o);
> 
> This is not required, considering the sequence of clean up, this
> would never happen. `i` at least have been accessed once in the
> switch above.

Only the first iteration has been accessed.  The rest no.

regards,
dan carpenter

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Amirreza Zarrabi 2 months, 3 weeks ago


On 9/24/2025 8:48 AM, Amirreza Zarrabi wrote:
> On 9/18/2025 7:50 PM, Dan Carpenter wrote:
>> Re-order these checks to check if "i" is a valid array index before using
>> it.  This prevents a potential off by one read access.
>>
>> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
>> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
>> ---
>>  drivers/tee/qcomtee/call.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
>> index cc17a48d0ab7..ac134452cc9c 100644
>> --- a/drivers/tee/qcomtee/call.c
>> +++ b/drivers/tee/qcomtee/call.c
>> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
>>  	}
>>  
>>  	/* Release any IO and OO objects not processed. */
>> -	for (; u[i].type && i < num_params; i++) {
>> +	for (; i < num_params && u[i].type; i++) {
>>  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
>>  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
>>  			qcomtee_object_put(u[i].o);
> 
> This is not required, considering the sequence of clean up, this
> would never happen. `i` at least have been accessed once in the
> switch above.
> 
> Regards,
> Amir
> 
>

Also, size of u is always num_params + 1 for the ending 0.
(basically means `i < num_params` can be removed).

Anyway, it does not hurt :).

Regards,
Amir

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Dan Carpenter 2 months, 3 weeks ago

On Wed, Sep 24, 2025 at 08:58:45AM +1000, Amirreza Zarrabi wrote:
> 
> 
> On 9/24/2025 8:48 AM, Amirreza Zarrabi wrote:
> > On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> >> Re-order these checks to check if "i" is a valid array index before using
> >> it.  This prevents a potential off by one read access.
> >>
> >> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> >> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> >> ---
> >>  drivers/tee/qcomtee/call.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> >> index cc17a48d0ab7..ac134452cc9c 100644
> >> --- a/drivers/tee/qcomtee/call.c
> >> +++ b/drivers/tee/qcomtee/call.c
> >> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> >>  	}
> >>  
> >>  	/* Release any IO and OO objects not processed. */
> >> -	for (; u[i].type && i < num_params; i++) {
> >> +	for (; i < num_params && u[i].type; i++) {
> >>  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> >>  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
> >>  			qcomtee_object_put(u[i].o);
> > 
> > This is not required, considering the sequence of clean up, this
> > would never happen. `i` at least have been accessed once in the
> > switch above.
> > 
> > Regards,
> > Amir
> > 
> >
> 
> Also, size of u is always num_params + 1 for the ending 0.
> (basically means `i < num_params` can be removed).
> 

Yes.  This is true.

regards,
dan carpenter

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Jens Wiklander 2 months, 3 weeks ago

On Wed, Sep 24, 2025 at 9:36 AM Dan Carpenter <dan.carpenter@linaro.org> wrote:
>
> On Wed, Sep 24, 2025 at 08:58:45AM +1000, Amirreza Zarrabi wrote:
> >
> >
> > On 9/24/2025 8:48 AM, Amirreza Zarrabi wrote:
> > > On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> > >> Re-order these checks to check if "i" is a valid array index before using
> > >> it.  This prevents a potential off by one read access.
> > >>
> > >> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> > >> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > >> ---
> > >>  drivers/tee/qcomtee/call.c | 2 +-
> > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > >>
> > >> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> > >> index cc17a48d0ab7..ac134452cc9c 100644
> > >> --- a/drivers/tee/qcomtee/call.c
> > >> +++ b/drivers/tee/qcomtee/call.c
> > >> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> > >>    }
> > >>
> > >>    /* Release any IO and OO objects not processed. */
> > >> -  for (; u[i].type && i < num_params; i++) {
> > >> +  for (; i < num_params && u[i].type; i++) {
> > >>            if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> > >>                u[i].type == QCOMTEE_ARG_TYPE_IO)
> > >>                    qcomtee_object_put(u[i].o);
> > >
> > > This is not required, considering the sequence of clean up, this
> > > would never happen. `i` at least have been accessed once in the
> > > switch above.
> > >
> > > Regards,
> > > Amir
> > >
> > >
> >
> > Also, size of u is always num_params + 1 for the ending 0.
> > (basically means `i < num_params` can be removed).
> >
>
> Yes.  This is true.

So this patch isn't needed. I'll drop it if no one objects.

Cheers,
Jens

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Dan Carpenter 2 months, 3 weeks ago

On Wed, Sep 24, 2025 at 11:21:34AM +0200, Jens Wiklander wrote:
> On Wed, Sep 24, 2025 at 9:36 AM Dan Carpenter <dan.carpenter@linaro.org> wrote:
> >
> > On Wed, Sep 24, 2025 at 08:58:45AM +1000, Amirreza Zarrabi wrote:
> > >
> > >
> > > On 9/24/2025 8:48 AM, Amirreza Zarrabi wrote:
> > > > On 9/18/2025 7:50 PM, Dan Carpenter wrote:
> > > >> Re-order these checks to check if "i" is a valid array index before using
> > > >> it.  This prevents a potential off by one read access.
> > > >>
> > > >> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> > > >> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > > >> ---
> > > >>  drivers/tee/qcomtee/call.c | 2 +-
> > > >>  1 file changed, 1 insertion(+), 1 deletion(-)
> > > >>
> > > >> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> > > >> index cc17a48d0ab7..ac134452cc9c 100644
> > > >> --- a/drivers/tee/qcomtee/call.c
> > > >> +++ b/drivers/tee/qcomtee/call.c
> > > >> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> > > >>    }
> > > >>
> > > >>    /* Release any IO and OO objects not processed. */
> > > >> -  for (; u[i].type && i < num_params; i++) {
> > > >> +  for (; i < num_params && u[i].type; i++) {
> > > >>            if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> > > >>                u[i].type == QCOMTEE_ARG_TYPE_IO)
> > > >>                    qcomtee_object_put(u[i].o);
> > > >
> > > > This is not required, considering the sequence of clean up, this
> > > > would never happen. `i` at least have been accessed once in the
> > > > switch above.
> > > >
> > > > Regards,
> > > > Amir
> > > >
> > > >
> > >
> > > Also, size of u is always num_params + 1 for the ending 0.
> > > (basically means `i < num_params` can be removed).
> > >
> >
> > Yes.  This is true.
> 
> So this patch isn't needed. I'll drop it if no one objects.

The patch makes the code better though...  It never really makes sense
to use a variable first and then check if it's valid later.  In this
case the check isn't required.

Ideally the code would only have one limit.  We could either do:

	for (; i < num_params; i++) {
Or:
	for (; u[i].type != QCOMTEE_ARG_TYPE_INV; i++) {

Either way works...

regards,
dan carpenter

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Sumit Garg 3 months ago

On Thu, Sep 18, 2025 at 12:50:26PM +0300, Dan Carpenter wrote:
> Re-order these checks to check if "i" is a valid array index before using
> it.  This prevents a potential off by one read access.
> 
> Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
>  drivers/tee/qcomtee/call.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>

-Sumit

> 
> diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> index cc17a48d0ab7..ac134452cc9c 100644
> --- a/drivers/tee/qcomtee/call.c
> +++ b/drivers/tee/qcomtee/call.c
> @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
>  	}
>  
>  	/* Release any IO and OO objects not processed. */
> -	for (; u[i].type && i < num_params; i++) {
> +	for (; i < num_params && u[i].type; i++) {
>  		if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
>  		    u[i].type == QCOMTEE_ARG_TYPE_IO)
>  			qcomtee_object_put(u[i].o);
> -- 
> 2.51.0
> 
>

Re: [PATCH next] tee: qcom: prevent potential off by one read

Posted by Jens Wiklander 3 months ago

On Fri, Sep 19, 2025 at 7:21 AM Sumit Garg <sumit.garg@kernel.org> wrote:
>
> On Thu, Sep 18, 2025 at 12:50:26PM +0300, Dan Carpenter wrote:
> > Re-order these checks to check if "i" is a valid array index before using
> > it.  This prevents a potential off by one read access.
> >
> > Fixes: d6e290837e50 ("tee: add Qualcomm TEE driver")
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > ---
> >  drivers/tee/qcomtee/call.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>

Applied.

/Jens

>
> -Sumit
>
> >
> > diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
> > index cc17a48d0ab7..ac134452cc9c 100644
> > --- a/drivers/tee/qcomtee/call.c
> > +++ b/drivers/tee/qcomtee/call.c
> > @@ -308,7 +308,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
> >       }
> >
> >       /* Release any IO and OO objects not processed. */
> > -     for (; u[i].type && i < num_params; i++) {
> > +     for (; i < num_params && u[i].type; i++) {
> >               if (u[i].type == QCOMTEE_ARG_TYPE_OO ||
> >                   u[i].type == QCOMTEE_ARG_TYPE_IO)
> >                       qcomtee_object_put(u[i].o);
> > --
> > 2.51.0
> >
> >