From: David van Moolenbroek <david@minix3.org>
Date: Fri, 15 Jul 2016 14:29:16 +0000 (+0000)
Subject: VFS: forbid mknod(2) on symlinks
X-Git-Url: http://zhaoyanbai.com/repos/%22http:/www.isc.org/icons/doc/howto.html?a=commitdiff_plain;h=refs%2Fchanges%2F41%2F3341%2F1;p=minix.git

VFS: forbid mknod(2) on symlinks

As imposed by POSIX.

Extend a random test to verify this behavior.

Change-Id: Ib70550cefaeb9efd54e22312425263a5606fb5e8
---

diff --git a/minix/servers/vfs/open.c b/minix/servers/vfs/open.c
index 0a8f91af6..5fd23b0d9 100644
--- a/minix/servers/vfs/open.c
+++ b/minix/servers/vfs/open.c
@@ -520,7 +520,8 @@ int do_mknod(void)
   mode_bits = job_m_in.m_lc_vfs_mknod.mode;
   dev = job_m_in.m_lc_vfs_mknod.device;
 
-  lookup_init(&resolve, fullpath, PATH_NOFLAGS, &vmp, &vp);
+  /* If the path names a symbolic link, mknod() shall fail with EEXIST. */
+  lookup_init(&resolve, fullpath, PATH_RET_SYMLINK, &vmp, &vp);
   resolve.l_vmnt_lock = VMNT_WRITE;
   resolve.l_vnode_lock = VNODE_WRITE;
 
diff --git a/minix/tests/test61.c b/minix/tests/test61.c
index e70605387..423ec7fe9 100644
--- a/minix/tests/test61.c
+++ b/minix/tests/test61.c
@@ -66,8 +66,12 @@ void dangling_slink(int sub_test, char const slink_to[PATH_MAX])
 
 	/* Cleanup created files */
 	if (unlink(slink_to) == -1) e(18);
-	if (unlink("a") == -1) e(19);
-	if (unlink("c") == -1) e(20);
+	if (unlink("c") == -1) e(19);
+
+	/* Use the dangling symlink to test mknod(2) following symlinks */
+	if (mknod("a", S_IFCHR | 0777, makedev(1, 1)) != -1) e(20);
+	if (errno != EEXIST) e(21);
+	if (unlink("a") == -1) e(22);
 
 	exit(EXIT_SUCCESS);
   } else {