From: Johan Hovold johan@kernel.org
commit b4bb4d425b7b02424afea2dfdcd77b3b4794175e upstream.
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 Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+huawei@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/media/usb/gspca/sunplus.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/media/usb/gspca/sunplus.c +++ b/drivers/media/usb/gspca/sunplus.c @@ -251,6 +251,10 @@ static void reg_r(struct gspca_dev *gspc PERR("reg_r: buffer overflow\n"); return; } + if (len == 0) { + PERR("reg_r: zero-length read\n"); + return; + } if (gspca_dev->usb_err < 0) return; ret = usb_control_msg(gspca_dev->dev, @@ -259,7 +263,7 @@ static void reg_r(struct gspca_dev *gspc 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); @@ -734,7 +738,7 @@ static int sd_start(struct gspca_dev *gs 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: