2021-11-11 08:06:21

by Christophe JAILLET

Subject: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

If 'map->name' can't be allocated, 'map' must be released before returning.

Fixes: 70fa906d6fce ("media: uvcvideo: Use control names from framework")
Signed-off-by: Christophe JAILLET <[email protected]>
---
drivers/media/usb/uvc/uvc_v4l2.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4e4aff8ddf7..5aa76a9a6080 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -44,8 +44,10 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
if (v4l2_ctrl_get_name(map->id) == NULL) {
map->name = kmemdup(xmap->name, sizeof(xmap->name),
GFP_KERNEL);
- if (!map->name)
+ if (!map->name) {
+ kfree(map);
return -ENOMEM;
+ }
}
memcpy(map->entity, xmap->entity, sizeof(map->entity));
map->selector = xmap->selector;
--
2.30.2

2021-11-11 08:12:45

by Ricardo Ribalda

Subject: Re: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

Hi Christophe

I believe this is a dup of:
https://lore.kernel.org/lkml/[email protected]/

Thanks

On Thu, 11 Nov 2021 at 09:06, Christophe JAILLET
<[email protected]> wrote:
>
> If 'map->name' can't be allocated, 'map' must be released before returning.
>
> Fixes: 70fa906d6fce ("media: uvcvideo: Use control names from framework")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> drivers/media/usb/uvc/uvc_v4l2.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index f4e4aff8ddf7..5aa76a9a6080 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -44,8 +44,10 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> if (v4l2_ctrl_get_name(map->id) == NULL) {
> map->name = kmemdup(xmap->name, sizeof(xmap->name),
> GFP_KERNEL);
> - if (!map->name)
> + if (!map->name) {
> + kfree(map);
> return -ENOMEM;
> + }
> }
> memcpy(map->entity, xmap->entity, sizeof(map->entity));
> map->selector = xmap->selector;
> --
> 2.30.2
>


--
Ricardo Ribalda

2021-11-11 08:24:06

by Christophe JAILLET

Subject: Re: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

Le 11/11/2021 à 09:12, Ricardo Ribalda a écrit :
> Hi Christophe
>
> I believe this is a dup of:
> https://lore.kernel.org/lkml/[email protected]/

Yes it is, and Colin's proposal is cleaner than mine.

Sorry for the noise.

CJ

>
> Thanks
>
> On Thu, 11 Nov 2021 at 09:06, Christophe JAILLET
> <[email protected]> wrote:
>>
>> If 'map->name' can't be allocated, 'map' must be released before returning.
>>
>> Fixes: 70fa906d6fce ("media: uvcvideo: Use control names from framework")
>> Signed-off-by: Christophe JAILLET <[email protected]>
>> ---
>> drivers/media/usb/uvc/uvc_v4l2.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
>> index f4e4aff8ddf7..5aa76a9a6080 100644
>> --- a/drivers/media/usb/uvc/uvc_v4l2.c
>> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
>> @@ -44,8 +44,10 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
>> if (v4l2_ctrl_get_name(map->id) == NULL) {
>> map->name = kmemdup(xmap->name, sizeof(xmap->name),
>> GFP_KERNEL);
>> - if (!map->name)
>> + if (!map->name) {
>> + kfree(map);
>> return -ENOMEM;
>> + }
>> }
>> memcpy(map->entity, xmap->entity, sizeof(map->entity));
>> map->selector = xmap->selector;
>> --
>> 2.30.2
>>
>
>

2021-11-11 10:33:41

by Dan Carpenter

Subject: Re: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

On Thu, Nov 11, 2021 at 09:06:11AM +0100, Christophe JAILLET wrote:
> If 'map->name' can't be allocated, 'map' must be released before returning.
>
> Fixes: 70fa906d6fce ("media: uvcvideo: Use control names from framework")
> Signed-off-by: Christophe JAILLET <[email protected]>
> ---
> drivers/media/usb/uvc/uvc_v4l2.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index f4e4aff8ddf7..5aa76a9a6080 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -44,8 +44,10 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> if (v4l2_ctrl_get_name(map->id) == NULL) {
> map->name = kmemdup(xmap->name, sizeof(xmap->name),
> GFP_KERNEL);
> - if (!map->name)
> + if (!map->name) {
> + kfree(map);
> return -ENOMEM;
> + }

Your patch is fine but there is a second issue. The error handling
should free "map->name" as well. The problem is that this function
frees everything on the success path at all, but freeing map->name on
the success path will lead to a crash so you have to do something
weird like:

diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
index f4e4aff8ddf7..953a5cbf7945 100644
--- a/drivers/media/usb/uvc/uvc_v4l2.c
+++ b/drivers/media/usb/uvc/uvc_v4l2.c
@@ -90,6 +90,9 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
ret = uvc_ctrl_add_mapping(chain, map);

kfree(map->menu_info);
+free_name:
+ if (ret)
+ kfree(map->name);
free_map:
kfree(map);

2021-11-11 10:40:52

by Ricardo Ribalda

Subject: Re: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

I belive this is also addressed by this patch that is under review:

https://patchwork.linuxtv.org/project/linux-media/patch/[email protected]/

On Thu, 11 Nov 2021 at 11:33, Dan Carpenter <[email protected]> wrote:
>
> On Thu, Nov 11, 2021 at 09:06:11AM +0100, Christophe JAILLET wrote:
> > If 'map->name' can't be allocated, 'map' must be released before returning.
> >
> > Fixes: 70fa906d6fce ("media: uvcvideo: Use control names from framework")
> > Signed-off-by: Christophe JAILLET <[email protected]>
> > ---
> > drivers/media/usb/uvc/uvc_v4l2.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> > index f4e4aff8ddf7..5aa76a9a6080 100644
> > --- a/drivers/media/usb/uvc/uvc_v4l2.c
> > +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> > @@ -44,8 +44,10 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> > if (v4l2_ctrl_get_name(map->id) == NULL) {
> > map->name = kmemdup(xmap->name, sizeof(xmap->name),
> > GFP_KERNEL);
> > - if (!map->name)
> > + if (!map->name) {
> > + kfree(map);
> > return -ENOMEM;
> > + }
>
> Your patch is fine but there is a second issue. The error handling
> should free "map->name" as well. The problem is that this function
> frees everything on the success path at all, but freeing map->name on
> the success path will lead to a crash so you have to do something
> weird like:
>
> diff --git a/drivers/media/usb/uvc/uvc_v4l2.c b/drivers/media/usb/uvc/uvc_v4l2.c
> index f4e4aff8ddf7..953a5cbf7945 100644
> --- a/drivers/media/usb/uvc/uvc_v4l2.c
> +++ b/drivers/media/usb/uvc/uvc_v4l2.c
> @@ -90,6 +90,9 @@ static int uvc_ioctl_ctrl_map(struct uvc_video_chain *chain,
> ret = uvc_ctrl_add_mapping(chain, map);
>
> kfree(map->menu_info);
> +free_name:
> + if (ret)
> + kfree(map->name);
> free_map:
> kfree(map);
>
>


--
Ricardo Ribalda

2021-11-11 11:08:51

by Dan Carpenter

Subject: Re: [PATCH] media: uvcvideo: Fix a memory leak in an error handling path of 'uvc_ioctl_ctrl_map()'

On Thu, Nov 11, 2021 at 11:40:32AM +0100, Ricardo Ribalda wrote:
> I belive this is also addressed by this patch that is under review:
>
> https://patchwork.linuxtv.org/project/linux-media/patch/[email protected]/
>

Ah perfect. My approach was quite lazy and that's a better way. Thanks!

regards,
dan carpenter