From: Jan Kara <jack@suse.cz>
Date: Thu, 21 May 2015 14:05:52 +0000 (+0200)
Subject: fs: Fix S_NOSEC handling
X-Git-Tag: firefly_0821_release~3679^2~316
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9b9724dc865428f0bc900f653b636456e81d8e3b;p=firefly-linux-kernel-4.4.55.git

fs: Fix S_NOSEC handling

commit 2426f3910069ed47c0cc58559a6d088af7920201 upstream.

file_remove_suid() could mistakenly set S_NOSEC inode bit when root was
modifying the file. As a result following writes to the file by ordinary
user would avoid clearing suid or sgid bits.

Fix the bug by checking actual mode bits before setting S_NOSEC.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/inode.c b/fs/inode.c
index 1b300a06b8be..17f95b417955 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1628,8 +1628,8 @@ int file_remove_suid(struct file *file)
 		error = security_inode_killpriv(dentry);
 	if (!error && killsuid)
 		error = __remove_suid(dentry, killsuid);
-	if (!error && (inode->i_sb->s_flags & MS_NOSEC))
-		inode->i_flags |= S_NOSEC;
+	if (!error)
+		inode_has_no_xattr(inode);
 
 	return error;
 }