[src/trunk]: src/sys/dev Put in a litany of judicious bounds checks around vn...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/782d26a9191c
branches:  trunk
changeset: 355410:782d26a9191c
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jul 28 16:19:20 2017 +0000

description:
Put in a litany of judicious bounds checks around vnd headers.

Thought I was done with this crap after I rewrote vndcompress(1)!

>From Ilja Van Sprundel.

diffstat:

 sys/dev/vnd.c |  26 +++++++++++++++++++++-----
 1 files changed, 21 insertions(+), 5 deletions(-)

diffs (65 lines):

diff -r 0a8afc08c5aa -r 782d26a9191c sys/dev/vnd.c
--- a/sys/dev/vnd.c     Fri Jul 28 16:11:03 2017 +0000
+++ b/sys/dev/vnd.c     Fri Jul 28 16:19:20 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vnd.c,v 1.259 2017/03/25 07:00:33 pgoyette Exp $       */
+/*     $NetBSD: vnd.c,v 1.260 2017/07/28 16:19:20 riastradh Exp $      */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 2008 The NetBSD Foundation, Inc.
@@ -91,7 +91,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vnd.c,v 1.259 2017/03/25 07:00:33 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vnd.c,v 1.260 2017/07/28 16:19:20 riastradh Exp $");
 
 #if defined(_KERNEL_OPT)
 #include "opt_vnd.h"
@@ -1284,6 +1284,13 @@
                                goto close_and_exit;
                        }
 
+                       if (ntohl(ch->block_size) == 0 ||
+                           ntohl(ch->num_blocks) > UINT32_MAX - 1) {
+                               free(ch, M_TEMP);
+                               VOP_UNLOCK(nd.ni_vp);
+                               goto close_and_exit;
+                       }
+
                        /* save some header info */
                        vnd->sc_comp_blksz = ntohl(ch->block_size);
                        /* note last offset is the file byte size */
@@ -1294,20 +1301,29 @@
                                error = EINVAL;
                                goto close_and_exit;
                        }
-                       if (sizeof(struct vnd_comp_header) +
-                         sizeof(u_int64_t) * vnd->sc_comp_numoffs >
-                         vattr.va_size) {
+                       KASSERT(0 < vnd->sc_comp_blksz);
+                       KASSERT(0 < vnd->sc_comp_numoffs);
+                       if ((SIZE_MAX/sizeof(uint64_t) <
+                               vnd->sc_comp_numoffs) ||
+                           (vattr.va_size < sizeof(struct vnd_comp_header)) ||
+                           (vattr.va_size - sizeof(struct vnd_comp_header) <
+                               sizeof(uint64_t)*vnd->sc_comp_numoffs) ||
+                           (UQUAD_MAX/vnd->sc_comp_blksz <
+                               vnd->sc_comp_numoffs - 1)) {
                                VOP_UNLOCK(nd.ni_vp);
                                error = EINVAL;
                                goto close_and_exit;
                        }
 
                        /* set decompressed file size */
+                       KASSERT(vnd->sc_comp_numoffs - 1 <=
+                           UQUAD_MAX/vnd->sc_comp_blksz);
                        vattr.va_size =
                            ((u_quad_t)vnd->sc_comp_numoffs - 1) *
                             (u_quad_t)vnd->sc_comp_blksz;
 
                        /* allocate space for all the compressed offsets */
+                       __CTASSERT(UINT32_MAX <= UQUAD_MAX/sizeof(uint64_t));
                        vnd->sc_comp_offsets =
                        malloc(sizeof(u_int64_t) * vnd->sc_comp_numoffs,
                        M_DEVBUF, M_WAITOK);