From 8e4bfca1d1f0de62301dd223675717e7a5f63a27 Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 20 Jul 2012 01:17:26 +0400
Subject: [PATCH] mknod: take sanity checks on mode into the very beginning
Note that applying umask can't affect their results. While
that affects errno in cases like
mknod("/no_such_directory/a", 030000)
yielding -EINVAL (due to impossible mode_t) instead of
-ENOENT (due to inexistent directory), IMO that makes a lot
more sense, POSIX allows to return either and any software
that relies on getting -ENOENT instead of -EINVAL in that
case deserves everything it gets.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/namei.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 5bc6f3d1dc8a..cf362dc9d1fd 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2964,8 +2964,9 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
struct path path;
int error;
- if (S_ISDIR(mode))
- return -EPERM;
+ error = may_mknod(mode);
+ if (error)
+ return error;
dentry = user_path_create(dfd, filename, &path, 0);
if (IS_ERR(dentry))
@@ -2973,9 +2974,6 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
if (!IS_POSIXACL(path.dentry->d_inode))
mode &= ~current_umask();
- error = may_mknod(mode);
- if (error)
- goto out_dput;
error = mnt_want_write(path.mnt);
if (error)
goto out_dput;
--
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