[src/trunk]: src/sys/netsmb Since "len" has changed to (unsinged) size_t, the...

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

details:   https://anonhg.NetBSD.org/src/rev/9c21a4e67f10
branches:  trunk
changeset: 779217:9c21a4e67f10
user:      nakayama <nakayama%NetBSD.org@localhost>
date:      Fri May 11 14:51:39 2012 +0000

description:
Since "len" has changed to (unsinged) size_t, the while loop
condition (len > 0) became less able to detect its underflow.
So check the subtrahend to avoid the underflow.

Should fix PR kern/44092.

diffstat:

 sys/netsmb/subr_mchain.c |  8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diffs (36 lines):

diff -r 1a90146045ac -r 9c21a4e67f10 sys/netsmb/subr_mchain.c
--- a/sys/netsmb/subr_mchain.c  Fri May 11 04:05:54 2012 +0000
+++ b/sys/netsmb/subr_mchain.c  Fri May 11 14:51:39 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_mchain.c,v 1.20 2010/12/17 13:05:29 pooka Exp $   */
+/*     $NetBSD: subr_mchain.c,v 1.21 2012/05/11 14:51:39 nakayama Exp $        */
 
 /*
  * Copyright (c) 2000, 2001 Boris Popov
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_mchain.c,v 1.20 2010/12/17 13:05:29 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_mchain.c,v 1.21 2012/05/11 14:51:39 nakayama Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -66,7 +66,7 @@
                 }
         }
         mp->m_len = 0;
-        len -= M_TRAILINGSPACE(mp);
+        len -= min(len, M_TRAILINGSPACE(mp));
 
         if (m != NULL)
                 for (mtail = m; mtail->m_next != NULL; mtail = mtail->m_next);
@@ -88,7 +88,7 @@
                 }
 
                 mp->m_len = 0;
-                len -= M_TRAILINGSPACE(mp);
+                len -= min(len, M_TRAILINGSPACE(mp));
         }
 
         if (mtail != NULL)