From: Ben Gras <ben@minix3.org>
Date: Mon, 29 Mar 2010 11:39:54 +0000 (+0000)
Subject: fix null deref; vmnt->mounted_on is NULL legitimately for root.
X-Git-Tag: v3.1.7~195
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/man.named.html?a=commitdiff_plain;h=bc0e36f40281ab9b304fc11d9ce8fa73c375dcf1;p=minix.git

fix null deref; vmnt->mounted_on is NULL legitimately for root.

changed check+panic to assert().

added assert().
---

diff --git a/servers/vfs/path.c b/servers/vfs/path.c
index 05706f7b8..1d2f65299 100644
--- a/servers/vfs/path.c
+++ b/servers/vfs/path.c
@@ -11,6 +11,7 @@
 #include <minix/const.h>
 #include <minix/endpoint.h>
 #include <unistd.h>
+#include <assert.h>
 #include <minix/vfsif.h>
 #include "fproc.h"
 #include "vmnt.h"
@@ -43,6 +44,8 @@ int flags;
   struct vmnt *vmp;
   struct node_details res;
 
+  assert(dirp);
+
   /* Get a free vnode */
   if((new_vp = get_free_vnode()) == NIL_VNODE) return(NIL_VNODE);
   
@@ -238,7 +241,7 @@ node_details_t *node;
 		dir_vp = 0;
 		/* Start node is now the mounted partition's root node */
 		for (vmp = &vmnt[0]; vmp != &vmnt[NR_MNTS]; ++vmp) {
-			if (vmp->m_dev != NO_DEV) {
+			if (vmp->m_dev != NO_DEV && vmp->m_mounted_on) {
 			   if (vmp->m_mounted_on->v_inode_nr == res.inode_nr &&
 			       vmp->m_mounted_on->v_fs_e == res.fs_e) {
 				dir_vp = vmp->m_root_node;
@@ -246,10 +249,7 @@ node_details_t *node;
 			   }
 			}
 		}
-
-		if (!dir_vp) {
-			panic("VFS lookup: can't find mounted partition");
-		}
+		assert(dir_vp);
 	} else {
 		/* Climbing up mount */
 		/* Find the vmnt that represents the partition on