[PATCH 5/5] Staging: rspiusb: Fix buffer overflow

[Greg Kroah-Hartman]

From: Roel Kluin <roel.kluin at gmail.com>

usb_buffer_map_sg() may return -1. This will result in a read from
pdx->PixelUrb[frameInfo][-1]

Signed-off-by: Roel Kluin <roel.kluin at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at suse.de>
---
 drivers/staging/rspiusb/rspiusb.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/rspiusb/rspiusb.c b/drivers/staging/rspiusb/rspiusb.c
index 2f8155c..04e2f92 100644
--- a/drivers/staging/rspiusb/rspiusb.c
+++ b/drivers/staging/rspiusb/rspiusb.c
@@ -716,6 +716,8 @@ static int MapUserBuffer(struct ioctl_struct *io, struct device_extension *pdx)
 		pdx->PixelUrb[frameInfo][i]->transfer_flags =
 		    URB_NO_TRANSFER_DMA_MAP | URB_NO_INTERRUPT;
 	}
+	if (i == 0)
+		return -EINVAL;
 	/* only interrupt when last URB completes */
 	pdx->PixelUrb[frameInfo][--i]->transfer_flags &= ~URB_NO_INTERRUPT;
 	pdx->pendedPixelUrbs[frameInfo] =
-- 
1.6.3.2