[PATCH 2/3] media: gspca/sunplus: fix zero-length control requests

[PATCH 2/3] media: gspca/sunplus: fix zero-length control requests

[Johan Hovold]

The direction of the pipe argument must match the request-type direction
bit or control requests may fail depending on the host-controller-driver
implementation.

Control transfers without a data stage are treated as OUT requests by
the USB stack and should be using usb_sndctrlpipe(). Failing to do so
will now trigger a warning.

Fix the single zero-length control request which was using the
read-register helper, and update the helper so that zero-length reads
fail with an error message instead.

Fixes: 6a7eba24e4f0 ("V4L/DVB (8157): gspca: all subdrivers")
Cc: stable@vger.kernel.org      # 2.6.27
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/usb/gspca/sunplus.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/media/usb/gspca/sunplus.c b/drivers/media/usb/gspca/sunplus.c
index ace3da40006e..971dee0a56da 100644
--- a/drivers/media/usb/gspca/sunplus.c
+++ b/drivers/media/usb/gspca/sunplus.c
@@ -242,6 +242,10 @@ static void reg_r(struct gspca_dev *gspca_dev,
 		gspca_err(gspca_dev, "reg_r: buffer overflow\n");
 		return;
 	}
+	if (len == 0) {
+		gspca_err(gspca_dev, "reg_r: zero-length read\n");
+		return;
+	}
 	if (gspca_dev->usb_err < 0)
 		return;
 	ret = usb_control_msg(gspca_dev->dev,
@@ -250,7 +254,7 @@ static void reg_r(struct gspca_dev *gspca_dev,
 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 			0,		/* value */
 			index,
-			len ? gspca_dev->usb_buf : NULL, len,
+			gspca_dev->usb_buf, len,
 			500);
 	if (ret < 0) {
 		pr_err("reg_r err %d\n", ret);
@@ -727,7 +731,7 @@ static int sd_start(struct gspca_dev *gspca_dev)
 		case MegaImageVI:
 			reg_w_riv(gspca_dev, 0xf0, 0, 0);
 			spca504B_WaitCmdStatus(gspca_dev);
-			reg_r(gspca_dev, 0xf0, 4, 0);
+			reg_w_riv(gspca_dev, 0xf0, 4, 0);
 			spca504B_WaitCmdStatus(gspca_dev);
 			break;
 		default:
-- 
2.26.3

[PATCH 3/3] media: rtl28xxu: fix zero-length control request

[Johan Hovold]

The direction of the pipe argument must match the request-type direction
bit or control requests may fail depending on the host-controller-driver
implementation.

Control transfers without a data stage are treated as OUT requests by
the USB stack and should be using usb_sndctrlpipe(). Failing to do so
will now trigger a warning.

Fix the zero-length i2c-read request used for type detection by
attempting to read a single byte instead.

Reported-by: syzbot+faf11bbadc5a372564da@syzkaller.appspotmail.com
Fixes: d0f232e823af ("[media] rtl28xxu: add heuristic to detect chip type")
Cc: stable@vger.kernel.org      # 4.0
Cc: Antti Palosaari <crope@iki.fi>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
index 97ed17a141bb..2c04ed8af0e4 100644
--- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
+++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
@@ -612,8 +612,9 @@ static int rtl28xxu_read_config(struct dvb_usb_device *d)
 static int rtl28xxu_identify_state(struct dvb_usb_device *d, const char **name)
 {
 	struct rtl28xxu_dev *dev = d_to_priv(d);
+	u8 buf[1];
 	int ret;
-	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 0, NULL};
+	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 1, buf};
 
 	dev_dbg(&d->intf->dev, "\n");
 
-- 
2.26.3

Re: [PATCH 3/3] media: rtl28xxu: fix zero-length control request

[Johan Hovold]

On Mon, May 24, 2021 at 01:09:20PM +0200, Johan Hovold wrote:
> The direction of the pipe argument must match the request-type direction
> bit or control requests may fail depending on the host-controller-driver
> implementation.
> 
> Control transfers without a data stage are treated as OUT requests by
> the USB stack and should be using usb_sndctrlpipe(). Failing to do so
> will now trigger a warning.
> 
> Fix the zero-length i2c-read request used for type detection by
> attempting to read a single byte instead.
> 
> Reported-by: syzbot+faf11bbadc5a372564da@syzkaller.appspotmail.com
> Fixes: d0f232e823af ("[media] rtl28xxu: add heuristic to detect chip type")
> Cc: stable@vger.kernel.org      # 4.0
> Cc: Antti Palosaari <crope@iki.fi>
> Signed-off-by: Johan Hovold <johan@kernel.org>
> ---
>  drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> index 97ed17a141bb..2c04ed8af0e4 100644
> --- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> +++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> @@ -612,8 +612,9 @@ static int rtl28xxu_read_config(struct dvb_usb_device *d)
>  static int rtl28xxu_identify_state(struct dvb_usb_device *d, const char **name)
>  {
>  	struct rtl28xxu_dev *dev = d_to_priv(d);
> +	u8 buf[1];
>  	int ret;
> -	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 0, NULL};
> +	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 1, buf};
>  
>  	dev_dbg(&d->intf->dev, "\n");

As reported here

	https://lore.kernel.org/r/YLSVsrhMZ2oOL1vM@hovoldconsulting.com

this patch is causing the chip type to no longer be detected correctly,
so please drop this one for now until this has been resolved.

Johan

Re: [PATCH 3/3] media: rtl28xxu: fix zero-length control request

[Johan Hovold]

On Mon, May 31, 2021 at 09:55:39AM +0200, Johan Hovold wrote:
> On Mon, May 24, 2021 at 01:09:20PM +0200, Johan Hovold wrote:
> > The direction of the pipe argument must match the request-type direction
> > bit or control requests may fail depending on the host-controller-driver
> > implementation.
> > 
> > Control transfers without a data stage are treated as OUT requests by
> > the USB stack and should be using usb_sndctrlpipe(). Failing to do so
> > will now trigger a warning.
> > 
> > Fix the zero-length i2c-read request used for type detection by
> > attempting to read a single byte instead.
> > 
> > Reported-by: syzbot+faf11bbadc5a372564da@syzkaller.appspotmail.com
> > Fixes: d0f232e823af ("[media] rtl28xxu: add heuristic to detect chip type")
> > Cc: stable@vger.kernel.org      # 4.0
> > Cc: Antti Palosaari <crope@iki.fi>
> > Signed-off-by: Johan Hovold <johan@kernel.org>
> > ---
> >  drivers/media/usb/dvb-usb-v2/rtl28xxu.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > index 97ed17a141bb..2c04ed8af0e4 100644
> > --- a/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > +++ b/drivers/media/usb/dvb-usb-v2/rtl28xxu.c
> > @@ -612,8 +612,9 @@ static int rtl28xxu_read_config(struct dvb_usb_device *d)
> >  static int rtl28xxu_identify_state(struct dvb_usb_device *d, const char **name)
> >  {
> >  	struct rtl28xxu_dev *dev = d_to_priv(d);
> > +	u8 buf[1];
> >  	int ret;
> > -	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 0, NULL};
> > +	struct rtl28xxu_req req_demod_i2c = {0x0020, CMD_I2C_DA_RD, 1, buf};
> >  
> >  	dev_dbg(&d->intf->dev, "\n");
> 
> As reported here
> 
> 	https://lore.kernel.org/r/YLSVsrhMZ2oOL1vM@hovoldconsulting.com
> 
> this patch is causing the chip type to no longer be detected correctly,
> so please drop this one for now until this has been resolved.

Looks like this one was applied to the media tree a couple of days after
I sent this nonetheless.

Can you drop this one in favour of the v2 posted here:

	 https://lore.kernel.org/r/20210531094434.12651-4-johan@kernel.org

or do you want me to send an incremental fix instead?

Johan