[rtems commit] b1553rt.c: Fix Deference before null check (CID #1399830)

[Joel Sherrill]

Module:    rtems
Branch:    master
Commit:    4edcdf43c7c4d0ac2314ff3518643c2a80eb3e19
Changeset: http://git.rtems.org/rtems/commit/?id=4edcdf43c7c4d0ac2314ff3518643c2a80eb3e19

Author:    Ryan Long <ryan.long at oarcorp.com>
Date:      Tue Feb 16 16:41:25 2021 -0500

b1553rt.c: Fix Deference before null check (CID #1399830)

CID 1399830: Dereference before null check in rt_control().

Closes #4251

---

 bsps/shared/grlib/1553/b1553rt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/bsps/shared/grlib/1553/b1553rt.c b/bsps/shared/grlib/1553/b1553rt.c
index d7257e4..df72ada 100644
--- a/bsps/shared/grlib/1553/b1553rt.c
+++ b/bsps/shared/grlib/1553/b1553rt.c
@@ -619,7 +619,7 @@ static rtems_device_driver rt_write(rtems_device_major_number major, rtems_devic
 static rtems_device_driver rt_control(rtems_device_major_number major, rtems_device_minor_number minor, void *arg)
 {
     rtems_libio_ioctl_args_t *ioarg = (rtems_libio_ioctl_args_t *) arg;
-    unsigned int *data = ioarg->buffer;
+    unsigned int *data;
 
     rt_priv *rt;
     struct drvmgr_dev *dev;
@@ -636,6 +636,8 @@ static rtems_device_driver rt_control(rtems_device_major_number major, rtems_dev
         return RTEMS_INVALID_NAME;
     }
 
+    data = ioarg->buffer;
+
     ioarg->ioctl_return = 0;
     switch (ioarg->command) {