linux-kernel - Ensure FMODE_NONOTIFY is not set by userspace

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Message-ID: <20101029100217.GC26242@lsanfilippo.unix.rd.tt.avira.com>
Date:	Fri, 29 Oct 2010 12:02:17 +0200
From:	Lino Sanfilippo <LinoSanfilippo@....de>
To:	eparis@...hat.com
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Ensure FMODE_NONOTIFY is not set by userspace


    In fsnotify_open() ensure that FMODE_NONOTIFY is never set by userspace.
    Also always call fsnotify_parent and fsnotify.

Signed-off-by: Lino Sanfilippo <LinoSanfilippo@....de>
---
This patch applies against commit 3970d817558a426cc2f53eaa01182eb9452e0cb1
of branch 'origin/for-next' from git.infradead.org/users/eparis/notify.git


diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index ecb43b3..5c185fa 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -235,10 +235,11 @@ static inline void fsnotify_open(struct file *file)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_ISDIR;
 
-	if (!(file->f_mode & FMODE_NONOTIFY)) {
-		fsnotify_parent(path, NULL, mask);
-		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
-	}
+	/* FMODE_NONOTIFY must never be set from user */
+	file->f_mode &= ~FMODE_NONOTIFY;
+
+	fsnotify_parent(path, NULL, mask);
+	fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 }
 
 /*
--
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