[PATCH 4.9 116/191] media: dvb_frontend: Add commands implementation for compat ioct

Sasha Levin
2020-06-29T19:26:53Z

From: Jaedon Shin <jaedon.shin@gmail.com>

commit 18192a77f0810933ab71a46c1b260d230d7352ee upstream

The dtv_properties structure and the dtv_property structure are
different sizes in 32-bit and 64-bit system. This patch provides
FE_SET_PROPERTY and FE_GET_PROPERTY ioctl commands implementation for
32-bit user space applications.

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/media/dvb-core/dvb_frontend.c | 131 ++++++++++++++++++++++++++
1 file changed, 131 insertions(+)

diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
index c0a25cd6ccb8b..34f55a2ba071d 100644
--- a/drivers/media/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb-core/dvb_frontend.c
@@ -1983,9 +1983,140 @@ static long dvb_frontend_ioctl(struct file *file, unsigned int cmd,
}

#ifdef CONFIG_COMPAT
+struct compat_dtv_property {
+ __u32 cmd;
+ __u32 reserved[3];
+ union {
+ __u32 data;
+ struct dtv_fe_stats st;
+ struct {
+ __u8 data[32];
+ __u32 len;
+ __u32 reserved1[3];
+ compat_uptr_t reserved2;
+ } buffer;
+ } u;
+ int result;
+} __attribute__ ((packed));
+
+struct compat_dtv_properties {
+ __u32 num;
+ compat_uptr_t props;
+};
+
+#define COMPAT_FE_SET_PROPERTY _IOW('o', 82, struct compat_dtv_properties)
+#define COMPAT_FE_GET_PROPERTY _IOR('o', 83, struct compat_dtv_properties)
+
+static int dvb_frontend_handle_compat_ioctl(struct file *file, unsigned int cmd,
+ unsigned long arg)
+{
+ struct dvb_device *dvbdev = file->private_data;
+ struct dvb_frontend *fe = dvbdev->priv;
+ struct dvb_frontend_private *fepriv = fe->frontend_priv;
+ int i, err = 0;
+
+ if (cmd == COMPAT_FE_SET_PROPERTY) {
+ struct compat_dtv_properties prop, *tvps = NULL;
+ struct compat_dtv_property *tvp = NULL;
+
+ if (copy_from_user(&prop, compat_ptr(arg), sizeof(prop)))
+ return -EFAULT;
+
+ tvps = &prop;
+
+ /*
+ * Put an arbitrary limit on the number of messages that can
+ * be sent at once
+ */
+ if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
+ return -EINVAL;
+
+ tvp = memdup_user(compat_ptr(tvps->props), tvps->num * sizeof(*tvp));
+ if (IS_ERR(tvp))
+ return PTR_ERR(tvp);
+
+ for (i = 0; i < tvps->num; i++) {
+ err = dtv_property_process_set(fe, file,
+ (tvp + i)->cmd,
+ (tvp + i)->u.data);
+ if (err < 0) {
+ kfree(tvp);
+ return err;
+ }
+ }
+ kfree(tvp);
+ } else if (cmd == COMPAT_FE_GET_PROPERTY) {
+ struct compat_dtv_properties prop, *tvps = NULL;
+ struct compat_dtv_property *tvp = NULL;
+ struct dtv_frontend_properties getp = fe->dtv_property_cache;
+
+ if (copy_from_user(&prop, compat_ptr(arg), sizeof(prop)))
+ return -EFAULT;
+
+ tvps = &prop;
+
+ /*
+ * Put an arbitrary limit on the number of messages that can
+ * be sent at once
+ */
+ if (!tvps->num || (tvps->num > DTV_IOCTL_MAX_MSGS))
+ return -EINVAL;
+
+ tvp = memdup_user(compat_ptr(tvps->props), tvps->num * sizeof(*tvp));
+ if (IS_ERR(tvp))
+ return PTR_ERR(tvp);
+
+ /*
+ * Let's use our own copy of property cache, in order to
+ * avoid mangling with DTV zigzag logic, as drivers might
+ * return crap, if they don't check if the data is available
+ * before updating the properties cache.
+ */
+ if (fepriv->state != FESTATE_IDLE) {
+ err = dtv_get_frontend(fe, &getp, NULL);
+ if (err < 0) {
+ kfree(tvp);
+ return err;
+ }
+ }
+ for (i = 0; i < tvps->num; i++) {
+ err = dtv_property_process_get(
+ fe, &getp, (struct dtv_property *)tvp + i, file);
+ if (err < 0) {
+ kfree(tvp);
+ return err;
+ }
+ }
+
+ if (copy_to_user((void __user *)compat_ptr(tvps->props), tvp,
+ tvps->num * sizeof(struct compat_dtv_property))) {
+ kfree(tvp);
+ return -EFAULT;
+ }
+ kfree(tvp);
+ }
+
+ return err;
+}
+
static long dvb_frontend_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
+ struct dvb_device *dvbdev = file->private_data;
+ struct dvb_frontend *fe = dvbdev->priv;
+ struct dvb_frontend_private *fepriv = fe->frontend_priv;
+ int err;
+
+ if (cmd == COMPAT_FE_SET_PROPERTY || cmd == COMPAT_FE_GET_PROPERTY) {
+ if (down_interruptible(&fepriv->sem))
+ return -ERESTARTSYS;
+
+ err = dvb_frontend_handle_compat_ioctl(file, cmd, arg);
+
+ up(&fepriv->sem);
+ return err;
+ }
+
return dvb_frontend_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif
--
2.25.1