Staging: rspiusb: Fix buffer overflow

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@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/rspiusb/rspiusb.c b/drivers/staging/rspiusb/rspiusb.c
index 2f8155c1968b31652f63f781c0e15071fd25afe6..04e2f92c0f6293292d55d5a56822a936d0a4ba52 100644 (file)
--- 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] =