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