[src/trunk]: src/sys/netsmb Reject negative offset/count for smb read/write.

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

details:   https://anonhg.NetBSD.org/src/rev/29f401c8d836
branches:  trunk
changeset: 825697:29f401c8d836
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jul 28 14:45:59 2017 +0000

description:
Reject negative offset/count for smb read/write.

Not clear that this is actually a problem for the kernel -- might
overwrite user's buffers or return garbage to user, but that's their
own damn fault.  But it's hard to imagine that negative offset/count
ever makes sense, and I haven't ruled out a problem for the kernel.

diffstat:

 sys/netsmb/smb_dev.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (27 lines):

diff -r 62b53375ff67 -r 29f401c8d836 sys/netsmb/smb_dev.c
--- a/sys/netsmb/smb_dev.c      Fri Jul 28 14:40:42 2017 +0000
+++ b/sys/netsmb/smb_dev.c      Fri Jul 28 14:45:59 2017 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: smb_dev.c,v 1.49 2016/07/18 21:03:01 pgoyette Exp $    */
+/*     $NetBSD: smb_dev.c,v 1.50 2017/07/28 14:45:59 riastradh Exp $   */
 
 /*
  * Copyright (c) 2000-2001 Boris Popov
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: smb_dev.c,v 1.49 2016/07/18 21:03:01 pgoyette Exp $");
+__KERNEL_RCSID(0, "$NetBSD: smb_dev.c,v 1.50 2017/07/28 14:45:59 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -345,6 +345,8 @@
                struct uio auio;
                struct iovec iov;
 
+               if (rwrq->ioc_cnt < 0 || rwrq->ioc_offset < 0)
+                       return EINVAL;
                if ((ssp = sdp->sd_share) == NULL)
                        return ENOTCONN;
                iov.iov_base = rwrq->ioc_base;