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 moving the implementation of those ioctls to functions that take a cx18 pointer instead of a file pointer, and turn the V4L2 ioctl handlers into wrappers that get the cx18 from the file. When calling from cx18_init_on_first_open(), pass the cx18 pointer directly. This allows removing the fake fh in cx18_init_on_first_open().

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") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/stable/20250818-cx18-v4l2-fh-v1-1-6fe153760bce%40ide... Reviewed-by: Laurent Pinchart laurent.pinchart+renesas@ideasonboard.com Signed-off-by: Jacopo Mondi jacopo.mondi@ideasonboard.com --- drivers/media/pci/cx18/cx18-driver.c | 9 +++------ drivers/media/pci/cx18/cx18-ioctl.c | 30 +++++++++++++++++++----------- drivers/media/pci/cx18/cx18-ioctl.h | 8 +++++--- 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/drivers/media/pci/cx18/cx18-driver.c b/drivers/media/pci/cx18/cx18-driver.c index 743fcc9613744bfc1edeffc51e908fe88520405a..cd84dfcefcf971a7adb9aac2bafb9089dbe0f33f 100644 --- a/drivers/media/pci/cx18/cx18-driver.c +++ b/drivers/media/pci/cx18/cx18-driver.c @@ -1136,11 +1136,8 @@ int cx18_init_on_first_open(struct cx18 *cx) int video_input; int fw_retry_count = 3; struct v4l2_frequency vf; - struct cx18_open_id fh; v4l2_std_id std;

- fh.cx = cx; - if (test_bit(CX18_F_I_FAILED, &cx->i_flags)) return -ENXIO;

@@ -1220,14 +1217,14 @@ 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(cx, 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(cx, std); + cx18_do_s_frequency(cx, &vf); return 0; }

diff --git a/drivers/media/pci/cx18/cx18-ioctl.c b/drivers/media/pci/cx18/cx18-ioctl.c index bf16d36448f888d9326b5f4a8f9c8f0e13d0c3a1..6e869c43cbd520feb720a71d8eb2dd60c05b0ae9 100644 --- a/drivers/media/pci/cx18/cx18-ioctl.c +++ b/drivers/media/pci/cx18/cx18-ioctl.c @@ -521,10 +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 *cx, 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 = cx->card->video_inputs + inp; @@ -558,6 +556,11 @@ 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)->cx, inp); +} + static int cx18_g_frequency(struct file *file, void *fh, struct v4l2_frequency *vf) { @@ -570,11 +573,8 @@ 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 *cx, const struct v4l2_frequency *vf) { - struct cx18_open_id *id = file2id(file); - struct cx18 *cx = id->cx; - if (vf->tuner != 0) return -EINVAL;

@@ -585,6 +585,12 @@ 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)->cx, vf); +} + static int cx18_g_std(struct file *file, void *fh, v4l2_std_id *std) { struct cx18 *cx = file2id(file)->cx; @@ -593,11 +599,8 @@ 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 *cx, v4l2_std_id std) { - struct cx18_open_id *id = file2id(file); - struct cx18 *cx = id->cx; - if ((std & V4L2_STD_ALL) == 0) return -EINVAL;

@@ -642,6 +645,11 @@ 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)->cx, 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..7a42ac99312ab6502e1abe4f3d5c88c9c7f144f3 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; +int cx18_do_s_std(struct cx18 *cx, v4l2_std_id std); +int cx18_do_s_frequency(struct cx18 *cx, const struct v4l2_frequency *vf); +int cx18_do_s_input(struct cx18 *cx, unsigned int inp);