From 5a404946700fc485ddc81aa41a97bbe6333ac014 Mon Sep 17 00:00:00 2001
From: markj <markj@FreeBSD.org>
Date: Sat, 12 Jan 2019 17:00:54 +0000
Subject: [PATCH] MFC r342787: Add a bounds check to the tws(4) passthrough
 ioctl handler.

admbug:		825
---
 sys/dev/tws/tws_user.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/sys/dev/tws/tws_user.c b/sys/dev/tws/tws_user.c
index 5c93a4b93f78..f3eb09201ba6 100644
--- a/sys/dev/tws/tws_user.c
+++ b/sys/dev/tws/tws_user.c
@@ -90,9 +90,13 @@ tws_passthru(struct tws_softc *sc, void *buf)
     struct tws_request *req;
     struct tws_ioctl_no_data_buf *ubuf = (struct tws_ioctl_no_data_buf *)buf;
     int error;
+    u_int32_t buffer_length;
     u_int16_t lun4;
 
-
+    buffer_length = roundup2(ubuf->driver_pkt.buffer_length, 512);
+    if ( buffer_length > TWS_MAX_IO_SIZE ) {
+        return(EINVAL);
+    }
     if ( tws_get_state(sc) != TWS_ONLINE) {
         return(EBUSY);
     }
@@ -116,7 +120,7 @@ tws_passthru(struct tws_softc *sc, void *buf)
         }
     } while(1);
 
-    req->length = (ubuf->driver_pkt.buffer_length + 511) & ~511;
+    req->length = buffer_length;
     TWS_TRACE_DEBUG(sc, "datal,rid", req->length, req->request_id);
     if ( req->length ) {
         req->data = sc->ioctl_data_mem;