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From: Hans Verkuil <hverkuil@xs4all.nl>
To: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
	Helen Koike <helen.koike@collabora.com>,
	linux-media@vger.kernel.org
Cc: ezequiel@collabora.com, skhan@linuxfoundation.org,
	kernel@collabora.com, dafna3@gmail.com
Subject: Re: [PATCH v5 3/3] media: vimc: use-after-free fix - release vimc in the v4l_device release
Date: Fri, 24 Jan 2020 12:31:19 +0100	[thread overview]
Message-ID: <c2b2f566-0eb6-2cdc-79e8-e2c70a4e9fce@xs4all.nl> (raw)
In-Reply-To: <a32072f9-491a-dc47-ae52-d94a77cbb565@collabora.com>

On 1/23/20 12:36 PM, Dafna Hirschfeld wrote:
> Hi
> 
> On 22.01.20 17:39, Helen Koike wrote:
>> Hi Dafna,
>>
>> Thanks for the patch.
>>
>> On 1/22/20 2:01 PM, Dafna Hirschfeld wrote:
>>> A use-after-free bug occures when unbinding the device while it streams.
>>> The 'struct vimc_ent_device' allocated for the 'Sensor A' is freed
>>> when calling the sensor's 'rm' callback but the freed pointer is
>>> later accessed in the function 'vimc_streamer_pipeline_terminate'.
>>> To fix this bug, move the release callback of the vimc entities
>>> and vimc_device to the release callback of v4l2_device.
>>> The .rm callback of vimc_ent_config is replaced by two callbacks:
>>>
>>> .unregister - this is called upon removing the device and
>>> it unregisters the entity. This is an optional callback since
>>> subdevices don't need to implement it because they are already
>>> unregistered in v4l2_device_unregister.
>>>
>>> .release - this is called from the release callback of v4l2_device
>>> and it frees the entity.
>>>
>>> This ensures that the entities will be released when the last fh
>>> of any of the devices is closed.
>>>
>>> The commands that cause the crash and the KASAN report:
>>>
>>> media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
>>> media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
>>> v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440
>>> v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81
>>> v4l2-ctl --stream-mmap --stream-count=1000 -d /dev/video2 &
>>> sleep 1
>>> echo -n vimc.0 >/sys/bus/platform/drivers/vimc/unbind
>>>
>>> [  188.417934] BUG: KASAN: use-after-free in vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.420182] Read of size 8 at addr ffff8881e9c26008 by task bash/185
>>> [  188.421800]
>>> [  188.422223] CPU: 0 PID: 185 Comm: bash Not tainted 5.5.0-rc1+ #1
>>> [  188.423681] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
>>> [  188.425938] Call Trace:
>>> [  188.426610]  dump_stack+0x75/0xa0
>>> [  188.427519]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.429057]  print_address_description.constprop.6+0x16/0x220
>>> [  188.430462]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.431979]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.433455]  __kasan_report.cold.9+0x1a/0x40
>>> [  188.434518]  ? vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.436010]  kasan_report+0xe/0x20
>>> [  188.436859]  vimc_streamer_pipeline_terminate+0x75/0x140 [vimc]
>>> [  188.438339]  vimc_streamer_s_stream+0x8b/0x3c0 [vimc]
>>> [  188.439576]  vimc_cap_stop_streaming+0x22/0x40 [vimc]
>>> [  188.440863]  __vb2_queue_cancel+0x65/0x560 [videobuf2_common]
>>> [  188.442391]  vb2_core_queue_release+0x19/0x50 [videobuf2_common]
>>> [  188.443974]  vimc_cap_rm+0x10/0x20 [vimc]
>>> [  188.444986]  vimc_rm_subdevs+0x9e/0xe0 [vimc]
>>> [  188.446179]  vimc_remove+0x19/0x70 [vimc]
>>> [  188.447301]  platform_drv_remove+0x2f/0x50
>>> [  188.448468]  device_release_driver_internal+0x133/0x260
>>> [  188.449814]  unbind_store+0x121/0x150
>>> [  188.450726]  kernfs_fop_write+0x142/0x230
>>> [  188.451724]  ? sysfs_kf_bin_read+0x100/0x100
>>> [  188.452826]  vfs_write+0xdc/0x230
>>> [  188.453760]  ksys_write+0xaf/0x140
>>> [  188.454702]  ? __ia32_sys_read+0x40/0x40
>>> [  188.455773]  ? __do_page_fault+0x473/0x620
>>> [  188.456780]  do_syscall_64+0x5e/0x1a0
>>> [  188.457711]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>> [  188.459079] RIP: 0033:0x7f80f1f13504
>>> [  188.459969] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 48 8d 05 f9 61 0d 00 8b 00 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 41 54 49 89
>>> d4 55 48 89 f5 53
>>> [  188.464445] RSP: 002b:00007ffd7e843b58 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
>>> [  188.466276] RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 00007f80f1f13504
>>> [  188.467999] RDX: 0000000000000006 RSI: 000055ef2eb21b10 RDI: 0000000000000001
>>> [  188.469708] RBP: 000055ef2eb21b10 R08: 00007f80f1fe68c0 R09: 00007f80f1e26740
>>> [  188.471407] R10: 000055ef2eade010 R11: 0000000000000246 R12: 00007f80f1fe5760
>>> [  188.473381] R13: 0000000000000006 R14: 00007f80f1fe0760 R15: 0000000000000006
>>> [  188.475107]
>>> [  188.475500] Allocated by task 473:
>>> [  188.476351]  save_stack+0x19/0x80
>>> [  188.477201]  __kasan_kmalloc.constprop.6+0xc1/0xd0
>>> [  188.478507]  vimc_sen_add+0x36/0x309 [vimc]
>>> [  188.479649]  vimc_probe+0x1e2/0x530 [vimc]
>>> [  188.480776]  platform_drv_probe+0x46/0xa0
>>> [  188.481829]  really_probe+0x16c/0x520
>>> [  188.482732]  driver_probe_device+0x114/0x170
>>> [  188.483783]  device_driver_attach+0x85/0x90
>>> [  188.484800]  __driver_attach+0xa8/0x190
>>> [  188.485734]  bus_for_each_dev+0xe4/0x140
>>> [  188.486702]  bus_add_driver+0x223/0x2d0
>>> [  188.487715]  driver_register+0xca/0x140
>>> [  188.488767]  0xffffffffc037003d
>>> [  188.489635]  do_one_initcall+0x86/0x28f
>>> [  188.490702]  do_init_module+0xf8/0x340
>>> [  188.491773]  load_module+0x3766/0x3a10
>>> [  188.492811]  __do_sys_finit_module+0x11a/0x1b0
>>> [  188.494059]  do_syscall_64+0x5e/0x1a0
>>> [  188.495079]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>> [  188.496481]
>>> [  188.496893] Freed by task 185:
>>> [  188.497670]  save_stack+0x19/0x80
>>> [  188.498493]  __kasan_slab_free+0x125/0x170
>>> [  188.499486]  kfree+0x8c/0x230
>>> [  188.500254]  v4l2_subdev_release+0x64/0x70 [videodev]
>>> [  188.501498]  v4l2_device_release_subdev_node+0x1c/0x30 [videodev]
>>> [  188.502976]  device_release+0x3c/0xd0
>>> [  188.503867]  kobject_put+0xf4/0x240
>>> [  188.507802]  vimc_rm_subdevs+0x9e/0xe0 [vimc]
>>> [  188.508846]  vimc_remove+0x19/0x70 [vimc]
>>> [  188.509792]  platform_drv_remove+0x2f/0x50
>>> [  188.510752]  device_release_driver_internal+0x133/0x260
>>> [  188.512006]  unbind_store+0x121/0x150
>>> [  188.512899]  kernfs_fop_write+0x142/0x230
>>> [  188.513874]  vfs_write+0xdc/0x230
>>> [  188.514698]  ksys_write+0xaf/0x140
>>> [  188.515523]  do_syscall_64+0x5e/0x1a0
>>> [  188.516543]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>>> [  188.517710]
>>> [  188.518034] The buggy address belongs to the object at ffff8881e9c26000
>>> [  188.518034]  which belongs to the cache kmalloc-4k of size 4096
>>> [  188.520528] The buggy address is located 8 bytes inside of
>>> [  188.520528]  4096-byte region [ffff8881e9c26000, ffff8881e9c27000)
>>> [  188.523015] The buggy address belongs to the page:
>>> [  188.524357] page:ffffea0007a70800 refcount:1 mapcount:0 mapping:ffff8881f6402140 index:0x0 compound_mapcount: 0
>>> [  188.527058] raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881f6402140
>>> [  188.528983] raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
>>> [  188.530883] page dumped because: kasan: bad access detected
>>> [  188.532336]
>>> [  188.532720] Memory state around the buggy address:
>>> [  188.533871]  ffff8881e9c25f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>> [  188.535631]  ffff8881e9c25f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>>> [  188.537370] >ffff8881e9c26000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>> [  188.538996]                       ^
>>> [  188.539812]  ffff8881e9c26080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>> [  188.541549]  ffff8881e9c26100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>>>
>>> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
>>> ---
>>>   drivers/media/platform/vimc/vimc-capture.c | 12 ++---
>>>   drivers/media/platform/vimc/vimc-common.c  |  2 -
>>>   drivers/media/platform/vimc/vimc-common.h  | 25 ++++-----
>>>   drivers/media/platform/vimc/vimc-core.c    | 61 +++++++++++++++-------
>>>   drivers/media/platform/vimc/vimc-debayer.c | 19 ++-----
>>>   drivers/media/platform/vimc/vimc-scaler.c  | 19 ++-----
>>>   drivers/media/platform/vimc/vimc-sensor.c  | 18 ++-----
>>>   7 files changed, 71 insertions(+), 85 deletions(-)
>>>
>>> diff --git a/drivers/media/platform/vimc/vimc-capture.c b/drivers/media/platform/vimc/vimc-capture.c
>>> index 9a78bb7826a8..c5a645f98c66 100644
>>> --- a/drivers/media/platform/vimc/vimc-capture.c
>>> +++ b/drivers/media/platform/vimc/vimc-capture.c
>>> @@ -325,20 +325,20 @@ static const struct media_entity_operations vimc_cap_mops = {
>>>       .link_validate        = vimc_vdev_link_validate,
>>>   };
>>>   -static void vimc_cap_release(struct video_device *vdev)
>>> +void vimc_cap_release(struct vimc_ent_device *ved)
>>>   {
>>>       struct vimc_cap_device *vcap =
>>> -        container_of(vdev, struct vimc_cap_device, vdev);
>>> +        container_of(ved, struct vimc_cap_device, ved);
>>>         media_entity_cleanup(vcap->ved.ent);
>>>       kfree(vcap);
>>>   }
>>>   -void vimc_cap_rm(struct vimc_device *vimc, struct vimc_ent_device *ved)
>>> +void vimc_cap_unregister(struct vimc_ent_device *ved)
>>>   {
>>> -    struct vimc_cap_device *vcap;
>>> +    struct vimc_cap_device *vcap =
>>> +        container_of(ved, struct vimc_cap_device, ved);
>>>   -    vcap = container_of(ved, struct vimc_cap_device, ved);
>>>       vb2_queue_release(&vcap->queue);
>>>       video_unregister_device(&vcap->vdev);
>>>   }
>>> @@ -449,7 +449,7 @@ struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc,
>>>       vdev = &vcap->vdev;
>>>       vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
>>>       vdev->entity.ops = &vimc_cap_mops;
>>> -    vdev->release = vimc_cap_release;
>>> +    vdev->release = video_device_release_empty;
>>>       vdev->fops = &vimc_cap_fops;
>>>       vdev->ioctl_ops = &vimc_cap_ioctl_ops;
>>>       vdev->lock = &vcap->lock;
>>> diff --git a/drivers/media/platform/vimc/vimc-common.c b/drivers/media/platform/vimc/vimc-common.c
>>> index 16ce9f3b7c75..c95c17c048f2 100644
>>> --- a/drivers/media/platform/vimc/vimc-common.c
>>> +++ b/drivers/media/platform/vimc/vimc-common.c
>>> @@ -327,7 +327,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved,
>>>                u32 function,
>>>                u16 num_pads,
>>>                struct media_pad *pads,
>>> -             const struct v4l2_subdev_internal_ops *sd_int_ops,
>>>                const struct v4l2_subdev_ops *sd_ops)
>>>   {
>>>       int ret;
>>> @@ -337,7 +336,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved,
>>>         /* Initialize the subdev */
>>>       v4l2_subdev_init(sd, sd_ops);
>>> -    sd->internal_ops = sd_int_ops;
>>>       sd->entity.function = function;
>>>       sd->entity.ops = &vimc_ent_sd_mops;
>>>       sd->owner = THIS_MODULE;
>>> diff --git a/drivers/media/platform/vimc/vimc-common.h b/drivers/media/platform/vimc/vimc-common.h
>>> index 1b6ef7196f3c..616d5a6b0754 100644
>>> --- a/drivers/media/platform/vimc/vimc-common.h
>>> +++ b/drivers/media/platform/vimc/vimc-common.h
>>> @@ -125,16 +125,18 @@ struct vimc_device {
>>>    * @name            entity name
>>>    * @ved                pointer to vimc_ent_device (a node in the
>>>    *                    topology)
>>> - * @add                subdev add hook - initializes and registers
>>> - *                    subdev called from vimc-core
>>> - * @rm                subdev rm hook - unregisters and frees
>>> - *                    subdev called from vimc-core
>>> + * @add                initializes and registers
>>> + *                    vim entity - called from vimc-core
>>> + * @unregister            unregisters vimc entity - called from vimc-core
>>> + * @release            releases vimc entity - called from the v4l2_dev
>>> + *                    release callback
>>>    */
>>
>> Did you test the suggestion I gave in last patch?
>> That instead of adding another callback here, to just remove the release functions of the subdevices,
>> and add a check if the release cb isn't null just before calling it.
>> With this, the release functions of the video nodes would be called first.
>>
> I just tested you suggestion, here is the patch: https://gitlab.collabora.com/dafna/linux/commit/f59bc7c6643ce8f88aa33eb5e9f413a1aca99589
> I get a kasan report:
> 
> [   37.736909] BUG: KASAN: use-after-free in v4l2_device_unregister+0xa7/0xf0 [videodev]
> [   37.738110] Read of size 4 at addr ffff8881eb3f00bc by task bash/227
> ...
> 
> What happen is that the function v4l2_device_unregister loops over the subdevices and unregister them:
> 
>   /* Unregister subdevs */
>         list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list) {
>                 v4l2_device_unregister_subdev(sd);
>                 if (sd->flags & V4L2_SUBDEV_FL_IS_I2C)
>                         v4l2_i2c_subdev_unregister(sd);
>                 else if (sd->flags & V4L2_SUBDEV_FL_IS_SPI)
>                         v4l2_spi_subdev_unregister(sd);
>         }
> 
> when unregistering the first subdevice it also immediately calls the release callback because no one holds a fh for
> /dev/v4l2-subdev* , but the release cb releases the memory where the 'sd' in the above loop resides, then when
> referencing it in sd->flags it is after it is already freed.

Urgh. That's a bug in that function. I think the if...else if bit can be moved to
v4l2_subdev_release().

I'm surprised that this hasn't been seen before.

Regards,

	Hans

> 
> Dafna
> 
>> I followed the discussion regarding fhs in media node and video, not that I'm against your changes,
>> but I would like to understand a bit better why the simple fix suggested isn't enough.
>>
>> Thanks
>> Helen
>>
>>>   struct vimc_ent_config {
>>>       const char *name;
>>>       struct vimc_ent_device *(*add)(struct vimc_device *vimc,
>>>                          const char *vcfg_name);
>>> -    void (*rm)(struct vimc_device *vimc, struct vimc_ent_device *ved);
>>> +    void (*unregister)(struct vimc_ent_device *ved);
>>> +    void (*release)(struct vimc_ent_device *ved);
>>>   };
>>>     /**
>>> @@ -145,22 +147,23 @@ struct vimc_ent_config {
>>>    */
>>>   bool vimc_is_source(struct media_entity *ent);
>>>   -/* prototypes for vimc_ent_config add and rm hooks */
>>> +/* prototypes for vimc_ent_config hooks */
>>>   struct vimc_ent_device *vimc_cap_add(struct vimc_device *vimc,
>>>                        const char *vcfg_name);
>>> -void vimc_cap_rm(struct vimc_device *vimc, struct vimc_ent_device *ved);
>>> +void vimc_cap_unregister(struct vimc_ent_device *ved);
>>> +void vimc_cap_release(struct vimc_ent_device *ved);
>>>     struct vimc_ent_device *vimc_deb_add(struct vimc_device *vimc,
>>>                        const char *vcfg_name);
>>> -void vimc_deb_rm(struct vimc_device *vimc, struct vimc_ent_device *ved);
>>> +void vimc_deb_release(struct vimc_ent_device *ved);
>>>     struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
>>>                        const char *vcfg_name);
>>> -void vimc_sca_rm(struct vimc_device *vimc, struct vimc_ent_device *ved);
>>> +void vimc_sca_release(struct vimc_ent_device *ved);
>>>     struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
>>>                        const char *vcfg_name);
>>> -void vimc_sen_rm(struct vimc_device *vimc, struct vimc_ent_device *ved);
>>> +void vimc_sen_release(struct vimc_ent_device *ved);
>>>     /**
>>>    * vimc_pix_map_by_index - get vimc_pix_map struct by its index
>>> @@ -195,7 +198,6 @@ const struct vimc_pix_map *vimc_pix_map_by_pixelformat(u32 pixelformat);
>>>    * @num_pads:    number of pads to initialize
>>>    * @pads:    the array of pads of the entity, the caller should set the
>>>           flags of the pads
>>> - * @sd_int_ops:    pointer to &struct v4l2_subdev_internal_ops
>>>    * @sd_ops:    pointer to &struct v4l2_subdev_ops.
>>>    *
>>>    * Helper function initialize and register the struct vimc_ent_device and struct
>>> @@ -208,7 +210,6 @@ int vimc_ent_sd_register(struct vimc_ent_device *ved,
>>>                u32 function,
>>>                u16 num_pads,
>>>                struct media_pad *pads,
>>> -             const struct v4l2_subdev_internal_ops *sd_int_ops,
>>>                const struct v4l2_subdev_ops *sd_ops);
>>>     /**
>>> diff --git a/drivers/media/platform/vimc/vimc-core.c b/drivers/media/platform/vimc/vimc-core.c
>>> index 1c55e0382f09..306f9c293628 100644
>>> --- a/drivers/media/platform/vimc/vimc-core.c
>>> +++ b/drivers/media/platform/vimc/vimc-core.c
>>> @@ -48,48 +48,51 @@ static struct vimc_ent_config ent_config[] = {
>>>       {
>>>           .name = "Sensor A",
>>>           .add = vimc_sen_add,
>>> -        .rm = vimc_sen_rm,
>>> +        .release = vimc_sen_release,
>>>       },
>>>       {
>>>           .name = "Sensor B",
>>>           .add = vimc_sen_add,
>>> -        .rm = vimc_sen_rm,
>>> +        .release = vimc_sen_release,
>>>       },
>>>       {
>>>           .name = "Debayer A",
>>>           .add = vimc_deb_add,
>>> -        .rm = vimc_deb_rm,
>>> +        .release = vimc_deb_release,
>>>       },
>>>       {
>>>           .name = "Debayer B",
>>>           .add = vimc_deb_add,
>>> -        .rm = vimc_deb_rm,
>>> +        .release = vimc_deb_release,
>>>       },
>>>       {
>>>           .name = "Raw Capture 0",
>>>           .add = vimc_cap_add,
>>> -        .rm = vimc_cap_rm,
>>> +        .unregister = vimc_cap_unregister,
>>> +        .release = vimc_cap_release,
>>>       },
>>>       {
>>>           .name = "Raw Capture 1",
>>>           .add = vimc_cap_add,
>>> -        .rm = vimc_cap_rm,
>>> +        .unregister = vimc_cap_unregister,
>>> +        .release = vimc_cap_release,
>>>       },
>>>       {
>>>           /* TODO: change this to vimc-input when it is implemented */
>>>           .name = "RGB/YUV Input",
>>>           .add = vimc_sen_add,
>>> -        .rm = vimc_sen_rm,
>>> +        .release = vimc_sen_release,
>>>       },
>>>       {
>>>           .name = "Scaler",
>>>           .add = vimc_sca_add,
>>> -        .rm = vimc_sca_rm,
>>> +        .release = vimc_sca_release,
>>>       },
>>>       {
>>>           .name = "RGB/YUV Capture",
>>>           .add = vimc_cap_add,
>>> -        .rm = vimc_cap_rm,
>>> +        .unregister = vimc_cap_unregister,
>>> +        .release = vimc_cap_release,
>>>       },
>>>   };
>>>   @@ -175,13 +178,33 @@ static int vimc_add_subdevs(struct vimc_device *vimc)
>>>       return 0;
>>>   }
>>>   -static void vimc_rm_subdevs(struct vimc_device *vimc)
>>> +static void vimc_release_subdevs(struct vimc_device *vimc)
>>>   {
>>>       unsigned int i;
>>>         for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
>>>           if (vimc->ent_devs[i])
>>> -            vimc->pipe_cfg->ents[i].rm(vimc, vimc->ent_devs[i]);
>>> +            vimc->pipe_cfg->ents[i].release(vimc->ent_devs[i]);
>>> +}
>>> +
>>> +static void vimc_unregister_subdevs(struct vimc_device *vimc)
>>> +{
>>> +    unsigned int i;
>>> +
>>> +    for (i = 0; i < vimc->pipe_cfg->num_ents; i++)
>>> +        if (vimc->ent_devs[i] && vimc->pipe_cfg->ents[i].unregister)
>>> +            vimc->pipe_cfg->ents[i].unregister(vimc->ent_devs[i]);
>>> +}
>>> +
>>> +static void vimc_v4l2_dev_release(struct v4l2_device *v4l2_dev)
>>> +{
>>> +    struct vimc_device *vimc =
>>> +        container_of(v4l2_dev, struct vimc_device, v4l2_dev);
>>> +
>>> +    vimc_release_subdevs(vimc);
>>> +    media_device_cleanup(&vimc->mdev);
>>> +    kfree(vimc->ent_devs);
>>> +    kfree(vimc);
>>>   }
>>>     static int vimc_register_devices(struct vimc_device *vimc)
>>> @@ -195,7 +218,6 @@ static int vimc_register_devices(struct vimc_device *vimc)
>>>               "v4l2 device register failed (err=%d)\n", ret);
>>>           return ret;
>>>       }
>>> -
>>>       /* allocate ent_devs */
>>>       vimc->ent_devs = kcalloc(vimc->pipe_cfg->num_ents,
>>>                    sizeof(*vimc->ent_devs), GFP_KERNEL);
>>> @@ -236,9 +258,9 @@ static int vimc_register_devices(struct vimc_device *vimc)
>>>     err_mdev_unregister:
>>>       media_device_unregister(&vimc->mdev);
>>> -    media_device_cleanup(&vimc->mdev);
>>>   err_rm_subdevs:
>>> -    vimc_rm_subdevs(vimc);
>>> +    vimc_unregister_subdevs(vimc);
>>> +    vimc_release_subdevs(vimc);
>>>       kfree(vimc->ent_devs);
>>>   err_v4l2_unregister:
>>>       v4l2_device_unregister(&vimc->v4l2_dev);
>>> @@ -248,11 +270,9 @@ static int vimc_register_devices(struct vimc_device *vimc)
>>>     static void vimc_unregister(struct vimc_device *vimc)
>>>   {
>>> +    vimc_unregister_subdevs(vimc);
>>>       media_device_unregister(&vimc->mdev);
>>> -    media_device_cleanup(&vimc->mdev);
>>>       v4l2_device_unregister(&vimc->v4l2_dev);
>>> -    kfree(vimc->ent_devs);
>>> -    kfree(vimc);
>>>   }
>>>     static int vimc_probe(struct platform_device *pdev)
>>> @@ -285,7 +305,12 @@ static int vimc_probe(struct platform_device *pdev)
>>>           kfree(vimc);
>>>           return ret;
>>>       }
>>> +    /*
>>> +     * the release cb is set only after successful registration.
>>> +     * if the registration fails, we release directly from probe
>>> +     */
>>>   +    vimc->v4l2_dev.release = vimc_v4l2_dev_release;
>>>       platform_set_drvdata(pdev, vimc);
>>>       return 0;
>>>   }
>>> @@ -296,8 +321,8 @@ static int vimc_remove(struct platform_device *pdev)
>>>         dev_dbg(&pdev->dev, "remove");
>>>   -    vimc_rm_subdevs(vimc);
>>>       vimc_unregister(vimc);
>>> +    v4l2_device_put(&vimc->v4l2_dev);
>>>         return 0;
>>>   }
>>> diff --git a/drivers/media/platform/vimc/vimc-debayer.c b/drivers/media/platform/vimc/vimc-debayer.c
>>> index 34b98b235880..baf6bf9f65b5 100644
>>> --- a/drivers/media/platform/vimc/vimc-debayer.c
>>> +++ b/drivers/media/platform/vimc/vimc-debayer.c
>>> @@ -494,28 +494,16 @@ static const struct v4l2_ctrl_ops vimc_deb_ctrl_ops = {
>>>       .s_ctrl = vimc_deb_s_ctrl,
>>>   };
>>>   -static void vimc_deb_release(struct v4l2_subdev *sd)
>>> +void vimc_deb_release(struct vimc_ent_device *ved)
>>>   {
>>>       struct vimc_deb_device *vdeb =
>>> -                container_of(sd, struct vimc_deb_device, sd);
>>> +        container_of(ved, struct vimc_deb_device, ved);
>>>         v4l2_ctrl_handler_free(&vdeb->hdl);
>>>       media_entity_cleanup(vdeb->ved.ent);
>>>       kfree(vdeb);
>>>   }
>>>   -static const struct v4l2_subdev_internal_ops vimc_deb_int_ops = {
>>> -    .release = vimc_deb_release,
>>> -};
>>> -
>>> -void vimc_deb_rm(struct vimc_device *vimc, struct vimc_ent_device *ved)
>>> -{
>>> -    struct vimc_deb_device *vdeb;
>>> -
>>> -    vdeb = container_of(ved, struct vimc_deb_device, ved);
>>> -    v4l2_device_unregister_subdev(&vdeb->sd);
>>> -}
>>> -
>>>   static const struct v4l2_ctrl_config vimc_deb_ctrl_class = {
>>>       .flags = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY,
>>>       .id = VIMC_CID_VIMC_CLASS,
>>> @@ -563,8 +551,7 @@ struct vimc_ent_device *vimc_deb_add(struct vimc_device *vimc,
>>>       ret = vimc_ent_sd_register(&vdeb->ved, &vdeb->sd, v4l2_dev,
>>>                      vcfg_name,
>>>                      MEDIA_ENT_F_PROC_VIDEO_PIXEL_ENC_CONV, 2,
>>> -                   vdeb->pads,
>>> -                   &vimc_deb_int_ops, &vimc_deb_ops);
>>> +                   vdeb->pads, &vimc_deb_ops);
>>>       if (ret)
>>>           goto err_free_hdl;
>>>   diff --git a/drivers/media/platform/vimc/vimc-scaler.c b/drivers/media/platform/vimc/vimc-scaler.c
>>> index cb2dc24c3e59..7521439747c5 100644
>>> --- a/drivers/media/platform/vimc/vimc-scaler.c
>>> +++ b/drivers/media/platform/vimc/vimc-scaler.c
>>> @@ -464,27 +464,15 @@ static void *vimc_sca_process_frame(struct vimc_ent_device *ved,
>>>       return vsca->src_frame;
>>>   };
>>>   -static void vimc_sca_release(struct v4l2_subdev *sd)
>>> +void vimc_sca_release(struct vimc_ent_device *ved)
>>>   {
>>>       struct vimc_sca_device *vsca =
>>> -                container_of(sd, struct vimc_sca_device, sd);
>>> +        container_of(ved, struct vimc_sca_device, ved);
>>>         media_entity_cleanup(vsca->ved.ent);
>>>       kfree(vsca);
>>>   }
>>>   -static const struct v4l2_subdev_internal_ops vimc_sca_int_ops = {
>>> -    .release = vimc_sca_release,
>>> -};
>>> -
>>> -void vimc_sca_rm(struct vimc_device *vimc, struct vimc_ent_device *ved)
>>> -{
>>> -    struct vimc_sca_device *vsca;
>>> -
>>> -    vsca = container_of(ved, struct vimc_sca_device, ved);
>>> -    v4l2_device_unregister_subdev(&vsca->sd);
>>> -}
>>> -
>>>   struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
>>>                        const char *vcfg_name)
>>>   {
>>> @@ -504,8 +492,7 @@ struct vimc_ent_device *vimc_sca_add(struct vimc_device *vimc,
>>>       ret = vimc_ent_sd_register(&vsca->ved, &vsca->sd, v4l2_dev,
>>>                      vcfg_name,
>>>                      MEDIA_ENT_F_PROC_VIDEO_SCALER, 2,
>>> -                   vsca->pads,
>>> -                   &vimc_sca_int_ops, &vimc_sca_ops);
>>> +                   vsca->pads, &vimc_sca_ops);
>>>       if (ret) {
>>>           kfree(vsca);
>>>           return NULL;
>>> diff --git a/drivers/media/platform/vimc/vimc-sensor.c b/drivers/media/platform/vimc/vimc-sensor.c
>>> index 9788fe291193..92daee58209e 100644
>>> --- a/drivers/media/platform/vimc/vimc-sensor.c
>>> +++ b/drivers/media/platform/vimc/vimc-sensor.c
>>> @@ -279,10 +279,10 @@ static const struct v4l2_ctrl_ops vimc_sen_ctrl_ops = {
>>>       .s_ctrl = vimc_sen_s_ctrl,
>>>   };
>>>   -static void vimc_sen_release(struct v4l2_subdev *sd)
>>> +void vimc_sen_release(struct vimc_ent_device *ved)
>>>   {
>>>       struct vimc_sen_device *vsen =
>>> -                container_of(sd, struct vimc_sen_device, sd);
>>> +        container_of(ved, struct vimc_sen_device, ved);
>>>         v4l2_ctrl_handler_free(&vsen->hdl);
>>>       tpg_free(&vsen->tpg);
>>> @@ -290,18 +290,6 @@ static void vimc_sen_release(struct v4l2_subdev *sd)
>>>       kfree(vsen);
>>>   }
>>>   -static const struct v4l2_subdev_internal_ops vimc_sen_int_ops = {
>>> -    .release = vimc_sen_release,
>>> -};
>>> -
>>> -void vimc_sen_rm(struct vimc_device *vimc, struct vimc_ent_device *ved)
>>> -{
>>> -    struct vimc_sen_device *vsen;
>>> -
>>> -    vsen = container_of(ved, struct vimc_sen_device, ved);
>>> -    v4l2_device_unregister_subdev(&vsen->sd);
>>> -}
>>> -
>>>   /* Image Processing Controls */
>>>   static const struct v4l2_ctrl_config vimc_sen_ctrl_class = {
>>>       .flags = V4L2_CTRL_FLAG_READ_ONLY | V4L2_CTRL_FLAG_WRITE_ONLY,
>>> @@ -365,7 +353,7 @@ struct vimc_ent_device *vimc_sen_add(struct vimc_device *vimc,
>>>       ret = vimc_ent_sd_register(&vsen->ved, &vsen->sd, v4l2_dev,
>>>                      vcfg_name,
>>>                      MEDIA_ENT_F_CAM_SENSOR, 1, &vsen->pad,
>>> -                   &vimc_sen_int_ops, &vimc_sen_ops);
>>> +                   &vimc_sen_ops);
>>>       if (ret)
>>>           goto err_free_tpg;
>>>  


  reply	other threads:[~2020-01-24 11:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-22 16:01 [PATCH v5 0/3] media: vimc: release vimc in release cb of v4l2_device Dafna Hirschfeld
2020-01-22 16:01 ` [PATCH v5 1/3] media: vimc: replace vimc->pdev.dev with vimc->mdev.dev Dafna Hirschfeld
2020-01-22 16:01 ` [PATCH v5 2/3] media: vimc: allocate vimc_device dynamically Dafna Hirschfeld
2020-01-22 16:01 ` [PATCH v5 3/3] media: vimc: use-after-free fix - release vimc in the v4l_device release Dafna Hirschfeld
2020-01-22 16:39   ` Helen Koike
2020-01-23 11:36     ` Dafna Hirschfeld
2020-01-24 11:31       ` Hans Verkuil [this message]
2020-01-24 12:18         ` Dafna Hirschfeld
2020-01-24 13:21           ` Hans Verkuil
2020-01-31 17:41             ` Dafna Hirschfeld

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