[PATCH 0/2] media: pci: Fix invalid access to file *

[PATCH 0/2] media: pci: Fix invalid access to file *

[Jacopo Mondi]

Since commits
7b9eb53e8591 ("media: cx18: Access v4l2_fh from file")
9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file")

All the ioctl handlers access their private data structures
from file *

The ivtv and cx18 drivers call the ioctl handlers from their
DVB layer without a valid file *, causing invalid memory access.

The issue has been reported by smatch in
"[bug report] media: cx18: Access v4l2_fh from file"

Fix this by providing wrappers for the ioctl handlers to be
used by the DVB layer that do not require a valid file *.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
Jacopo Mondi (2):
      media: cx18: Fix invalid access to file *
      media: ivtv: Fix invalid access to file *

 drivers/media/pci/cx18/cx18-driver.c |  6 +++---
 drivers/media/pci/cx18/cx18-ioctl.c  | 26 ++++++++++++++++++++------
 drivers/media/pci/cx18/cx18-ioctl.h  |  8 +++++---
 drivers/media/pci/ivtv/ivtv-driver.c |  4 ++--
 drivers/media/pci/ivtv/ivtv-ioctl.c  | 22 +++++++++++++++++-----
 drivers/media/pci/ivtv/ivtv-ioctl.h  |  6 ++++--
 6 files changed, 51 insertions(+), 21 deletions(-)
---
base-commit: a75b8d198c55e9eb5feb6f6e155496305caba2dc
change-id: 20250818-cx18-v4l2-fh-7eaa6199fdde

Best regards,
-- 
Jacopo Mondi <jacopo.mondi@ideasonboard.com>

[PATCH 1/2] media: cx18: Fix invalid access to file *

[Jacopo Mondi]

Sice commit 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file")
all ioctl handlers have been ported to operate on the file * first
function argument.

The cx18 DVB layer calls cx18_init_on_first_open() when the driver needs
to start streaming. This function calls the s_input(), s_std() and
s_frequency() ioctl handlers directly, but being called from the driver
context, it doesn't have a valid file * to pass them. This causes
the ioctl handlers to deference an invalid pointer.

Fix this by wrapping the ioctl handlers implementation in helper
functions which accepts a cx18_open_id pointer as first argument
and make the cx18_init_on_first_open() function call the helpers
without going through the ioctl handlers.

The bug has been reported by Smatch:

--> 1223         cx18_s_input(NULL, &fh, video_input);
The patch adds a new dereference of "file" but some of the callers pass a
NULL pointer.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aKL4OMWsESUdX8KQ@stanley.mountain/
Fixes: 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file")
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 drivers/media/pci/cx18/cx18-driver.c |  6 +++---
 drivers/media/pci/cx18/cx18-ioctl.c  | 26 ++++++++++++++++++++------
 drivers/media/pci/cx18/cx18-ioctl.h  |  8 +++++---
 3 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/drivers/media/pci/cx18/cx18-driver.c b/drivers/media/pci/cx18/cx18-driver.c
index 743fcc9613744bfc1edeffc51e908fe88520405a..e1798850ff78a50d7930148622c87d9303033c45 100644
--- a/drivers/media/pci/cx18/cx18-driver.c
+++ b/drivers/media/pci/cx18/cx18-driver.c
@@ -1220,14 +1220,14 @@ int cx18_init_on_first_open(struct cx18 *cx)
 
 	video_input = cx->active_input;
 	cx->active_input++;	/* Force update of input */
-	cx18_s_input(NULL, &fh, video_input);
+	cx18_do_s_input(&fh, video_input);
 
 	/* Let the VIDIOC_S_STD ioctl do all the work, keeps the code
 	   in one place. */
 	cx->std++;		/* Force full standard initialization */
 	std = (cx->tuner_std == V4L2_STD_ALL) ? V4L2_STD_NTSC_M : cx->tuner_std;
-	cx18_s_std(NULL, &fh, std);
-	cx18_s_frequency(NULL, &fh, &vf);
+	cx18_do_s_std(&fh, std);
+	cx18_do_s_frequency(&fh, &vf);
 	return 0;
 }
 
diff --git a/drivers/media/pci/cx18/cx18-ioctl.c b/drivers/media/pci/cx18/cx18-ioctl.c
index bf16d36448f888d9326b5f4a8f9c8f0e13d0c3a1..507df0d885e0dd2df7446aaef9e066592496d215 100644
--- a/drivers/media/pci/cx18/cx18-ioctl.c
+++ b/drivers/media/pci/cx18/cx18-ioctl.c
@@ -521,9 +521,8 @@ static int cx18_g_input(struct file *file, void *fh, unsigned int *i)
 	return 0;
 }
 
-int cx18_s_input(struct file *file, void *fh, unsigned int inp)
+int cx18_do_s_input(struct cx18_open_id *id, unsigned int inp)
 {
-	struct cx18_open_id *id = file2id(file);
 	struct cx18 *cx = id->cx;
 	v4l2_std_id std = V4L2_STD_ALL;
 	const struct cx18_card_video_input *card_input =
@@ -558,6 +557,11 @@ int cx18_s_input(struct file *file, void *fh, unsigned int inp)
 	return 0;
 }
 
+static int cx18_s_input(struct file *file, void *fh, unsigned int inp)
+{
+	return cx18_do_s_input(file2id(file), inp);
+}
+
 static int cx18_g_frequency(struct file *file, void *fh,
 				struct v4l2_frequency *vf)
 {
@@ -570,9 +574,9 @@ static int cx18_g_frequency(struct file *file, void *fh,
 	return 0;
 }
 
-int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf)
+int cx18_do_s_frequency(struct cx18_open_id *id,
+			const struct v4l2_frequency *vf)
 {
-	struct cx18_open_id *id = file2id(file);
 	struct cx18 *cx = id->cx;
 
 	if (vf->tuner != 0)
@@ -585,6 +589,12 @@ int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *v
 	return 0;
 }
 
+static int cx18_s_frequency(struct file *file, void *fh,
+			    const struct v4l2_frequency *vf)
+{
+	return cx18_do_s_frequency(file2id(file), vf);
+}
+
 static int cx18_g_std(struct file *file, void *fh, v4l2_std_id *std)
 {
 	struct cx18 *cx = file2id(file)->cx;
@@ -593,9 +603,8 @@ static int cx18_g_std(struct file *file, void *fh, v4l2_std_id *std)
 	return 0;
 }
 
-int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
+int cx18_do_s_std(struct cx18_open_id *id, v4l2_std_id std)
 {
-	struct cx18_open_id *id = file2id(file);
 	struct cx18 *cx = id->cx;
 
 	if ((std & V4L2_STD_ALL) == 0)
@@ -642,6 +651,11 @@ int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
 	return 0;
 }
 
+static int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
+{
+	return cx18_do_s_std(file2id(file), std);
+}
+
 static int cx18_s_tuner(struct file *file, void *fh, const struct v4l2_tuner *vt)
 {
 	struct cx18_open_id *id = file2id(file);
diff --git a/drivers/media/pci/cx18/cx18-ioctl.h b/drivers/media/pci/cx18/cx18-ioctl.h
index 221e2400fb3e2d817eaff7515fa89eb94f2d7f8a..bd0e6e5ac4e4a66f747789fd45b1d026c6905601 100644
--- a/drivers/media/pci/cx18/cx18-ioctl.h
+++ b/drivers/media/pci/cx18/cx18-ioctl.h
@@ -12,6 +12,8 @@ u16 cx18_service2vbi(int type);
 void cx18_expand_service_set(struct v4l2_sliced_vbi_format *fmt, int is_pal);
 u16 cx18_get_service_set(struct v4l2_sliced_vbi_format *fmt);
 void cx18_set_funcs(struct video_device *vdev);
-int cx18_s_std(struct file *file, void *fh, v4l2_std_id std);
-int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf);
-int cx18_s_input(struct file *file, void *fh, unsigned int inp);
+
+struct cx18_open_id;
+int cx18_do_s_std(struct cx18_open_id *id, v4l2_std_id std);
+int cx18_do_s_frequency(struct cx18_open_id *id, const struct v4l2_frequency *vf);
+int cx18_do_s_input(struct cx18_open_id *id, unsigned int inp);

-- 
2.50.1

Re: [PATCH 1/2] media: cx18: Fix invalid access to file *

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCH 1/2] media: cx18: Fix invalid access to file *
Link: https://lore.kernel.org/stable/20250818-cx18-v4l2-fh-v1-1-6fe153760bce%40ideasonboard.com

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH 1/2] media: cx18: Fix invalid access to file *

[Laurent Pinchart]

On Mon, Aug 18, 2025 at 02:40:11PM +0200, Jacopo Mondi wrote:
> Sice commit 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file")
> all ioctl handlers have been ported to operate on the file * first
> function argument.
> 
> The cx18 DVB layer calls cx18_init_on_first_open() when the driver needs
> to start streaming. This function calls the s_input(), s_std() and
> s_frequency() ioctl handlers directly, but being called from the driver
> context, it doesn't have a valid file * to pass them. This causes
> the ioctl handlers to deference an invalid pointer.
> 
> Fix this by wrapping the ioctl handlers implementation in helper
> functions which accepts a cx18_open_id pointer as first argument
> and make the cx18_init_on_first_open() function call the helpers
> without going through the ioctl handlers.
> 
> The bug has been reported by Smatch:
> 
> --> 1223         cx18_s_input(NULL, &fh, video_input);
> The patch adds a new dereference of "file" but some of the callers pass a
> NULL pointer.
> 
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/all/aKL4OMWsESUdX8KQ@stanley.mountain/
> Fixes: 7b9eb53e8591 ("media: cx18: Access v4l2_fh from file")
> Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> ---
>  drivers/media/pci/cx18/cx18-driver.c |  6 +++---
>  drivers/media/pci/cx18/cx18-ioctl.c  | 26 ++++++++++++++++++++------
>  drivers/media/pci/cx18/cx18-ioctl.h  |  8 +++++---
>  3 files changed, 28 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/media/pci/cx18/cx18-driver.c b/drivers/media/pci/cx18/cx18-driver.c
> index 743fcc9613744bfc1edeffc51e908fe88520405a..e1798850ff78a50d7930148622c87d9303033c45 100644
> --- a/drivers/media/pci/cx18/cx18-driver.c
> +++ b/drivers/media/pci/cx18/cx18-driver.c
> @@ -1220,14 +1220,14 @@ int cx18_init_on_first_open(struct cx18 *cx)
>  
>  	video_input = cx->active_input;
>  	cx->active_input++;	/* Force update of input */
> -	cx18_s_input(NULL, &fh, video_input);
> +	cx18_do_s_input(&fh, video_input);
>  
>  	/* Let the VIDIOC_S_STD ioctl do all the work, keeps the code
>  	   in one place. */
>  	cx->std++;		/* Force full standard initialization */
>  	std = (cx->tuner_std == V4L2_STD_ALL) ? V4L2_STD_NTSC_M : cx->tuner_std;
> -	cx18_s_std(NULL, &fh, std);
> -	cx18_s_frequency(NULL, &fh, &vf);
> +	cx18_do_s_std(&fh, std);
> +	cx18_do_s_frequency(&fh, &vf);
>  	return 0;
>  }
>  
> diff --git a/drivers/media/pci/cx18/cx18-ioctl.c b/drivers/media/pci/cx18/cx18-ioctl.c
> index bf16d36448f888d9326b5f4a8f9c8f0e13d0c3a1..507df0d885e0dd2df7446aaef9e066592496d215 100644
> --- a/drivers/media/pci/cx18/cx18-ioctl.c
> +++ b/drivers/media/pci/cx18/cx18-ioctl.c
> @@ -521,9 +521,8 @@ static int cx18_g_input(struct file *file, void *fh, unsigned int *i)
>  	return 0;
>  }
>  
> -int cx18_s_input(struct file *file, void *fh, unsigned int inp)
> +int cx18_do_s_input(struct cx18_open_id *id, unsigned int inp)

As id is only used to access id->cx, I would pass a cx18 pointer to this
function. Same for cx18_do_s_std() and cx18_do_s_frequency(). This will
allow dropping the fake fh variable from cx18_init_on_first_open().

>  {
> -	struct cx18_open_id *id = file2id(file);
>  	struct cx18 *cx = id->cx;
>  	v4l2_std_id std = V4L2_STD_ALL;
>  	const struct cx18_card_video_input *card_input =
> @@ -558,6 +557,11 @@ int cx18_s_input(struct file *file, void *fh, unsigned int inp)
>  	return 0;
>  }
>  
> +static int cx18_s_input(struct file *file, void *fh, unsigned int inp)
> +{
> +	return cx18_do_s_input(file2id(file), inp);
> +}
> +
>  static int cx18_g_frequency(struct file *file, void *fh,
>  				struct v4l2_frequency *vf)
>  {
> @@ -570,9 +574,9 @@ static int cx18_g_frequency(struct file *file, void *fh,
>  	return 0;
>  }
>  
> -int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf)
> +int cx18_do_s_frequency(struct cx18_open_id *id,
> +			const struct v4l2_frequency *vf)
>  {
> -	struct cx18_open_id *id = file2id(file);
>  	struct cx18 *cx = id->cx;
>  
>  	if (vf->tuner != 0)
> @@ -585,6 +589,12 @@ int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *v
>  	return 0;
>  }
>  
> +static int cx18_s_frequency(struct file *file, void *fh,
> +			    const struct v4l2_frequency *vf)
> +{
> +	return cx18_do_s_frequency(file2id(file), vf);
> +}
> +
>  static int cx18_g_std(struct file *file, void *fh, v4l2_std_id *std)
>  {
>  	struct cx18 *cx = file2id(file)->cx;
> @@ -593,9 +603,8 @@ static int cx18_g_std(struct file *file, void *fh, v4l2_std_id *std)
>  	return 0;
>  }
>  
> -int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
> +int cx18_do_s_std(struct cx18_open_id *id, v4l2_std_id std)
>  {
> -	struct cx18_open_id *id = file2id(file);
>  	struct cx18 *cx = id->cx;
>  
>  	if ((std & V4L2_STD_ALL) == 0)
> @@ -642,6 +651,11 @@ int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
>  	return 0;
>  }
>  
> +static int cx18_s_std(struct file *file, void *fh, v4l2_std_id std)
> +{
> +	return cx18_do_s_std(file2id(file), std);
> +}
> +
>  static int cx18_s_tuner(struct file *file, void *fh, const struct v4l2_tuner *vt)
>  {
>  	struct cx18_open_id *id = file2id(file);
> diff --git a/drivers/media/pci/cx18/cx18-ioctl.h b/drivers/media/pci/cx18/cx18-ioctl.h
> index 221e2400fb3e2d817eaff7515fa89eb94f2d7f8a..bd0e6e5ac4e4a66f747789fd45b1d026c6905601 100644
> --- a/drivers/media/pci/cx18/cx18-ioctl.h
> +++ b/drivers/media/pci/cx18/cx18-ioctl.h
> @@ -12,6 +12,8 @@ u16 cx18_service2vbi(int type);
>  void cx18_expand_service_set(struct v4l2_sliced_vbi_format *fmt, int is_pal);
>  u16 cx18_get_service_set(struct v4l2_sliced_vbi_format *fmt);
>  void cx18_set_funcs(struct video_device *vdev);
> -int cx18_s_std(struct file *file, void *fh, v4l2_std_id std);
> -int cx18_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf);
> -int cx18_s_input(struct file *file, void *fh, unsigned int inp);
> +
> +struct cx18_open_id;
> +int cx18_do_s_std(struct cx18_open_id *id, v4l2_std_id std);
> +int cx18_do_s_frequency(struct cx18_open_id *id, const struct v4l2_frequency *vf);
> +int cx18_do_s_input(struct cx18_open_id *id, unsigned int inp);
> 

-- 
Regards,

Laurent Pinchart

[PATCH 2/2] media: ivtv: Fix invalid access to file *

[Jacopo Mondi]

Since commit 9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file")
all ioctl handlers have been ported to operate on the file * first
function argument.

The ivtv DVB layer calls ivtv_init_on_first_open() when the driver
needs to start streaming. This function calls the s_input() and
s_frequency() ioctl handlers directly, but being called from the driver
context, it doesn't have a valid file * to pass them. This causes the
ioctl handlers to deference an invalid pointer.

Fix this by wrapping the ioctl handlers implementation in helper
functions which accepts a ivtv_open_id pointer as first argument
and make the ivtv_init_on_first_open() function call the helpers
without going through the ioctl handlers.

The bug has been reported by Smatch.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/aKL4OMWsESUdX8KQ@stanley.mountain/
Fixes: 9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file")
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 drivers/media/pci/ivtv/ivtv-driver.c |  4 ++--
 drivers/media/pci/ivtv/ivtv-ioctl.c  | 22 +++++++++++++++++-----
 drivers/media/pci/ivtv/ivtv-ioctl.h  |  6 ++++--
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/drivers/media/pci/ivtv/ivtv-driver.c b/drivers/media/pci/ivtv/ivtv-driver.c
index ecc20cd89926fe2ce4e472526a6b5fc0857615dd..bcbb03271047df9b127039759dbfefbaae67f9c3 100644
--- a/drivers/media/pci/ivtv/ivtv-driver.c
+++ b/drivers/media/pci/ivtv/ivtv-driver.c
@@ -1310,13 +1310,13 @@ int ivtv_init_on_first_open(struct ivtv *itv)
 
 	video_input = itv->active_input;
 	itv->active_input++;	/* Force update of input */
-	ivtv_s_input(NULL, &fh, video_input);
+	ivtv_do_s_input(&fh, video_input);
 
 	/* Let the VIDIOC_S_STD ioctl do all the work, keeps the code
 	   in one place. */
 	itv->std++;		/* Force full standard initialization */
 	itv->std_out = itv->std;
-	ivtv_s_frequency(NULL, &fh, &vf);
+	ivtv_do_s_frequency(&fh, &vf);
 
 	if (itv->card->v4l2_capabilities & V4L2_CAP_VIDEO_OUTPUT) {
 		/* Turn on the TV-out: ivtv_init_mpeg_decoder() initializes
diff --git a/drivers/media/pci/ivtv/ivtv-ioctl.c b/drivers/media/pci/ivtv/ivtv-ioctl.c
index 8077a71d4850ec773caa20c3fca08f92f3117d69..ba1fce42a8d6d7d9a3779bfc9dfd310060e61103 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.c
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.c
@@ -974,9 +974,9 @@ static int ivtv_g_input(struct file *file, void *fh, unsigned int *i)
 	return 0;
 }
 
-int ivtv_s_input(struct file *file, void *fh, unsigned int inp)
+int ivtv_do_s_input(struct ivtv_open_id *id, unsigned int inp)
 {
-	struct ivtv *itv = file2id(file)->itv;
+	struct ivtv *itv = id->itv;
 	v4l2_std_id std;
 	int i;
 
@@ -1017,6 +1017,11 @@ int ivtv_s_input(struct file *file, void *fh, unsigned int inp)
 	return 0;
 }
 
+static int ivtv_s_input(struct file *file, void *fh, unsigned int inp)
+{
+	return ivtv_do_s_input(file2id(file), inp);
+}
+
 static int ivtv_g_output(struct file *file, void *fh, unsigned int *i)
 {
 	struct ivtv *itv = file2id(file)->itv;
@@ -1065,10 +1070,11 @@ static int ivtv_g_frequency(struct file *file, void *fh, struct v4l2_frequency *
 	return 0;
 }
 
-int ivtv_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf)
+int ivtv_do_s_frequency(struct ivtv_open_id *id,
+			const struct v4l2_frequency *vf)
 {
-	struct ivtv *itv = file2id(file)->itv;
-	struct ivtv_stream *s = &itv->streams[file2id(file)->type];
+	struct ivtv *itv = id->itv;
+	struct ivtv_stream *s = &itv->streams[id->type];
 
 	if (s->vdev.vfl_dir)
 		return -ENOTTY;
@@ -1082,6 +1088,12 @@ int ivtv_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *v
 	return 0;
 }
 
+static int ivtv_s_frequency(struct file *file, void *fh,
+			    const struct v4l2_frequency *vf)
+{
+	return ivtv_do_s_frequency(file2id(file), vf);
+}
+
 static int ivtv_g_std(struct file *file, void *fh, v4l2_std_id *std)
 {
 	struct ivtv *itv = file2id(file)->itv;
diff --git a/drivers/media/pci/ivtv/ivtv-ioctl.h b/drivers/media/pci/ivtv/ivtv-ioctl.h
index 42c2516379fcbbd0640820ab0e3abe9bf00b57ea..7c91b8963b420761c2afcab1dece4d19a4ec0322 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.h
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.h
@@ -17,7 +17,9 @@ int ivtv_set_speed(struct ivtv *itv, int speed);
 void ivtv_set_funcs(struct video_device *vdev);
 void ivtv_s_std_enc(struct ivtv *itv, v4l2_std_id std);
 void ivtv_s_std_dec(struct ivtv *itv, v4l2_std_id std);
-int ivtv_s_frequency(struct file *file, void *fh, const struct v4l2_frequency *vf);
-int ivtv_s_input(struct file *file, void *fh, unsigned int inp);
+
+struct ivtv_open_id;
+int ivtv_do_s_frequency(struct ivtv_open_id *id, const struct v4l2_frequency *vf);
+int ivtv_do_s_input(struct ivtv_open_id *id, unsigned int inp);
 
 #endif

-- 
2.50.1