1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index d8a7d8323414..ebaebdf30f98 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -902,7 +902,9 @@ isdn_tty_send_msg(modem_info *info, atemu *m, char *msg)
         int j;
         int l;
 
-        l = strlen(msg);
+        l = min(strlen(msg), sizeof(cmd.parm) - sizeof(cmd.parm.cmsg)
+                + sizeof(cmd.parm.cmsg.para) - 2);
+
         if (!l) {
                 isdn_tty_modem_result(RESULT_ERROR, info);
                 return;