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Message-Id: <20250819-cx18-v4l2-fh-v4-2-9db1635d6787@ideasonboard.com>
Date: Tue, 19 Aug 2025 09:07:04 +0200
From: Jacopo Mondi <jacopo.mondi@...asonboard.com>
To: Andy Walls <awalls@...metrocast.net>,
Mauro Carvalho Chehab <mchehab@...nel.org>,
Hans Verkuil <hverkuil+cisco@...nel.org>,
Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
Cc: Dan Carpenter <dan.carpenter@...aro.org>, stable@...r.kernel.org,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
Jacopo Mondi <jacopo.mondi@...asonboard.com>
Subject: [PATCH v4 2/2] media: ivtv: Fix invalid access to file *
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 moving the implementation of those ioctls to two helper
functions.
The ivtv_do_s_input() helper accepts a struct ivtv * as first argument,
which is easily accessible in ivtv_init_on_first_open() as well as from
the file * argument of the ioctl handler.
The ivtv_s_frequency() takes an ivtv_stream * instead. The stream * can
safely be accessed in ivtv_init_on_first_open() where it is hard-coded
to the IVTV_ENC_STREAM_TYPE_MPG stream type, as well as from the ioctl
handler as a valid stream type is associated to each open file handle
depending on which video device node has been opened in the ivtv_open()
file operation.
The bug has been reported by Smatch.
Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Closes: https://lore.kernel.org/all/aKL4OMWsESUdX8KQ@stanley.mountain/
Fixes: 9ba9d11544f9 ("media: ivtv: Access v4l2_fh from file")
Cc: stable@...r.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@...asonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@...asonboard.com>
---
drivers/media/pci/ivtv/ivtv-driver.c | 11 ++++-------
drivers/media/pci/ivtv/ivtv-ioctl.c | 22 +++++++++++++++++-----
drivers/media/pci/ivtv/ivtv-ioctl.h | 6 ++++--
3 files changed, 25 insertions(+), 14 deletions(-)
diff --git a/drivers/media/pci/ivtv/ivtv-driver.c b/drivers/media/pci/ivtv/ivtv-driver.c
index ecc20cd89926fe2ce4e472526a6b5fc0857615dd..7e2fb98cfccf02f701ceb4484dd1d330dd1dc867 100644
--- a/drivers/media/pci/ivtv/ivtv-driver.c
+++ b/drivers/media/pci/ivtv/ivtv-driver.c
@@ -1260,15 +1260,12 @@ static int ivtv_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
int ivtv_init_on_first_open(struct ivtv *itv)
{
- struct v4l2_frequency vf;
/* Needed to call ioctls later */
- struct ivtv_open_id fh;
+ struct ivtv_stream *s = &itv->streams[IVTV_ENC_STREAM_TYPE_MPG];
+ struct v4l2_frequency vf;
int fw_retry_count = 3;
int video_input;
- fh.itv = itv;
- fh.type = IVTV_ENC_STREAM_TYPE_MPG;
-
if (test_bit(IVTV_F_I_FAILED, &itv->i_flags))
return -ENXIO;
@@ -1310,13 +1307,13 @@ 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(itv, 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(s, &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..dfbc842b22453868a2075935a81db7ae313ee46c 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.c
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.c
@@ -974,9 +974,8 @@ 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 *itv, unsigned int inp)
{
- struct ivtv *itv = file2id(file)->itv;
v4l2_std_id std;
int i;
@@ -1017,6 +1016,11 @@ 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)->itv, inp);
+}
+
static int ivtv_g_output(struct file *file, void *fh, unsigned int *i)
{
struct ivtv *itv = file2id(file)->itv;
@@ -1065,10 +1069,9 @@ 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_stream *s, const struct v4l2_frequency *vf)
{
- struct ivtv *itv = file2id(file)->itv;
- struct ivtv_stream *s = &itv->streams[file2id(file)->type];
+ struct ivtv *itv = s->itv;
if (s->vdev.vfl_dir)
return -ENOTTY;
@@ -1082,6 +1085,15 @@ 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)
+{
+ struct ivtv_open_id *id = file2id(file);
+ struct ivtv *itv = id->itv;
+
+ return ivtv_do_s_frequency(&itv->streams[id->type], 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..edc05eb8e060fd64d7ff94f8f7f5c315a2fa6298 100644
--- a/drivers/media/pci/ivtv/ivtv-ioctl.h
+++ b/drivers/media/pci/ivtv/ivtv-ioctl.h
@@ -9,6 +9,8 @@
#ifndef IVTV_IOCTL_H
#define IVTV_IOCTL_H
+struct ivtv;
+
u16 ivtv_service2vbi(int type);
void ivtv_expand_service_set(struct v4l2_sliced_vbi_format *fmt, int is_pal);
u16 ivtv_get_service_set(struct v4l2_sliced_vbi_format *fmt);
@@ -17,7 +19,7 @@ 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);
+int ivtv_do_s_frequency(struct ivtv_stream *s, const struct v4l2_frequency *vf);
+int ivtv_do_s_input(struct ivtv *itv, unsigned int inp);
#endif
--
2.50.1
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