From f739850941bc300ed4dc18e22d42cbb670bf69b6 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Thu, 30 Oct 2014 12:42:30 +0000 Subject: staging: comedi: don't allow write() on async command set up for "read" If a Comedi asynchronous command has been set up for data transfer in the "read" direction on the current "write" subdevice (for those subdevices that support both directions), don't allow the "write" file operation as that would mess with the data in the comedi data buffer that is written by the low-level comedi hardware driver. Signed-off-by: Ian Abbott Reviewed-by: H Hartley Sweeten Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/comedi_fops.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/staging/comedi/comedi_fops.c') diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 452121b6a604..0ed6f1f00e7f 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2075,6 +2075,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, retval = -EACCES; goto out; } + if (!(async->cmd.flags & CMDF_WRITE)) { + retval = -EINVAL; + goto out; + } add_wait_queue(&async->wait_head, &wait); on_wait_queue = true; @@ -2146,6 +2150,10 @@ static ssize_t comedi_write(struct file *file, const char __user *buf, retval = -EACCES; break; } + if (!(async->cmd.flags & CMDF_WRITE)) { + retval = -EINVAL; + break; + } continue; } -- cgit v1.2.3-55-g7522