isdn: avoid copying too long drvid

"cfg->drvid" comes from the user so there is a possibility they
didn't NUL terminate it properly.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/isdn/i4l/isdn_net.c b/drivers/isdn/i4l/isdn_net.c
index 1f73d7f..2339d73 100644 (file)
--- a/drivers/isdn/i4l/isdn_net.c
+++ b/drivers/isdn/i4l/isdn_net.c
@@ -2756,6 +2756,9 @@ isdn_net_setcfg(isdn_net_ioctl_cfg * cfg)
                        char *c,
                        *e;
 
+                       if (strnlen(cfg->drvid, sizeof(cfg->drvid)) ==
+                                       sizeof(cfg->drvid))
+                               return -EINVAL;
                        drvidx = -1;
                        chidx = -1;
                        strcpy(drvid, cfg->drvid);