2023-05-29 06:22:00

by Christophe JAILLET

Subject: [PATCH] media: v4l2-core: Fix a potential resource leak in v4l2_fwnode_parse_link()

'fwnode is known to be NULL, at this point, so fwnode_handle_put() is a
no-op.

Release the reference taken from a previous fwnode_graph_get_port_parent()
call instead.

Fixes: ca50c197bd96 ("[media] v4l: fwnode: Support generic fwnode for parsing standardised properties")
Signed-off-by: Christophe JAILLET <[email protected]>
---
/!\ THIS PATCH IS SPECULATIVE /!\
review with care
---
drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 049c2f2001ea..b7dd467c53fd 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -571,7 +571,7 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,

fwnode = fwnode_graph_get_remote_endpoint(fwnode);
if (!fwnode) {
- fwnode_handle_put(fwnode);
+ fwnode_handle_put(link->local_node);
return -ENOLINK;
}

--
2.34.1

2023-06-13 11:11:19

by Sakari Ailus

Subject: Re: [PATCH] media: v4l2-core: Fix a potential resource leak in v4l2_fwnode_parse_link()

Hi Christophe,

On Mon, May 29, 2023 at 08:17:18AM +0200, Christophe JAILLET wrote:
> 'fwnode is known to be NULL, at this point, so fwnode_handle_put() is a
> no-op.
>
> Release the reference taken from a previous fwnode_graph_get_port_parent()
> call instead.
>
> Fixes: ca50c197bd96 ("[media] v4l: fwnode: Support generic fwnode for parsing standardised properties")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> /!\ THIS PATCH IS SPECULATIVE /!\
> review with care
> ---
> drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> index 049c2f2001ea..b7dd467c53fd 100644
> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> @@ -571,7 +571,7 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>
> fwnode = fwnode_graph_get_remote_endpoint(fwnode);
> if (!fwnode) {
> - fwnode_handle_put(fwnode);
> + fwnode_handle_put(link->local_node);

link->local_node also needs to be non-NULL for the successful case. The
condition should take that into account. Could you send v2 with that?

> return -ENOLINK;
> }
>

--
Kind regards,

Sakari Ailus

2023-06-13 17:23:09

by Christophe JAILLET

Subject: Re: [PATCH] media: v4l2-core: Fix a potential resource leak in v4l2_fwnode_parse_link()

Le 13/06/2023 à 12:55, Sakari Ailus a écrit :
> Hi Christophe,
>
> On Mon, May 29, 2023 at 08:17:18AM +0200, Christophe JAILLET wrote:
>> 'fwnode is known to be NULL, at this point, so fwnode_handle_put() is a
>> no-op.
>>
>> Release the reference taken from a previous fwnode_graph_get_port_parent()
>> call instead.
>>
>> Fixes: ca50c197bd96 ("[media] v4l: fwnode: Support generic fwnode for parsing standardised properties")
>> Signed-off-by: Christophe JAILLET <[email protected]>
>> ---
>> /!\ THIS PATCH IS SPECULATIVE /!\
>> review with care
>> ---
>> drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
>> index 049c2f2001ea..b7dd467c53fd 100644
>> --- a/drivers/media/v4l2-core/v4l2-fwnode.c
>> +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
>> @@ -571,7 +571,7 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
>>
>> fwnode = fwnode_graph_get_remote_endpoint(fwnode);
>> if (!fwnode) {
>> - fwnode_handle_put(fwnode);
>> + fwnode_handle_put(link->local_node);
>
> link->local_node also needs to be non-NULL for the successful case. The
> condition should take that into account. Could you send v2 with that?
>
>> return -ENOLINK;
>> }
>>
>

Hi,
something like below?

@@ -568,19 +568,25 @@ int v4l2_fwnode_parse_link(struct fwnode_handle
*fwnode,
link->local_id = fwep.id;
link->local_port = fwep.port;
link->local_node = fwnode_graph_get_port_parent(fwnode);
+ if (!link->local_node)
+ return -ENOLINK;

fwnode = fwnode_graph_get_remote_endpoint(fwnode);
- if (!fwnode) {
- fwnode_handle_put(fwnode);
- return -ENOLINK;
- }
+ if (!fwnode)
+ goto err_put_local_node;

fwnode_graph_parse_endpoint(fwnode, &fwep);
link->remote_id = fwep.id;
link->remote_port = fwep.port;
link->remote_node = fwnode_graph_get_port_parent(fwnode);
+ if (!link->remote_node)
+ goto err_put_local_node;

return 0;
+
+err_put_local_node:
+ fwnode_handle_put(link->local_node);
+ return -ENOLINK;
}
EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_link);


CJ

2023-06-14 08:19:01

by Sakari Ailus

Subject: Re: [PATCH] media: v4l2-core: Fix a potential resource leak in v4l2_fwnode_parse_link()

Hi Christophe,

On Tue, Jun 13, 2023 at 07:15:40PM +0200, Christophe JAILLET wrote:
> Le 13/06/2023 ? 12:55, Sakari Ailus a ?crit?:
> > Hi Christophe,
> >
> > On Mon, May 29, 2023 at 08:17:18AM +0200, Christophe JAILLET wrote:
> > > 'fwnode is known to be NULL, at this point, so fwnode_handle_put() is a
> > > no-op.
> > >
> > > Release the reference taken from a previous fwnode_graph_get_port_parent()
> > > call instead.
> > >
> > > Fixes: ca50c197bd96 ("[media] v4l: fwnode: Support generic fwnode for parsing standardised properties")
> > > Signed-off-by: Christophe JAILLET <[email protected]>
> > > ---
> > > /!\ THIS PATCH IS SPECULATIVE /!\
> > > review with care
> > > ---
> > > drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
> > > index 049c2f2001ea..b7dd467c53fd 100644
> > > --- a/drivers/media/v4l2-core/v4l2-fwnode.c
> > > +++ b/drivers/media/v4l2-core/v4l2-fwnode.c
> > > @@ -571,7 +571,7 @@ int v4l2_fwnode_parse_link(struct fwnode_handle *fwnode,
> > > fwnode = fwnode_graph_get_remote_endpoint(fwnode);
> > > if (!fwnode) {
> > > - fwnode_handle_put(fwnode);
> > > + fwnode_handle_put(link->local_node);
> >
> > link->local_node also needs to be non-NULL for the successful case. The
> > condition should take that into account. Could you send v2 with that?
> >
> > > return -ENOLINK;
> > > }
> >
>
> Hi,
> something like below?

Ah, remote_node must be non-NULL, too, indeed. It was surprisingly broken.

>
> @@ -568,19 +568,25 @@ int v4l2_fwnode_parse_link(struct fwnode_handle
> *fwnode,
> link->local_id = fwep.id;
> link->local_port = fwep.port;
> link->local_node = fwnode_graph_get_port_parent(fwnode);
> + if (!link->local_node)
> + return -ENOLINK;
>
> fwnode = fwnode_graph_get_remote_endpoint(fwnode);
> - if (!fwnode) {
> - fwnode_handle_put(fwnode);
> - return -ENOLINK;
> - }
> + if (!fwnode)
> + goto err_put_local_node;

On error, fwnode needs to be put from this onwards, too.

But you can use a single label: fwnode_handle_put() is NULL-safe.

>
> fwnode_graph_parse_endpoint(fwnode, &fwep);
> link->remote_id = fwep.id;
> link->remote_port = fwep.port;
> link->remote_node = fwnode_graph_get_port_parent(fwnode);
> + if (!link->remote_node)
> + goto err_put_local_node;
>
> return 0;
> +
> +err_put_local_node:
> + fwnode_handle_put(link->local_node);
> + return -ENOLINK;
> }
> EXPORT_SYMBOL_GPL(v4l2_fwnode_parse_link);

--
Kind regards,

Sakari Ailus