linux-kernel - [PATCH 3.12 093/124] fs: Fix S

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Message-Id: <d4109d0f177aeb2fd34627a0b98c7ac2b4fa784b.1438076484.git.jslaby@suse.cz>
Date:	Tue, 28 Jul 2015 11:43:47 +0200
From:	Jiri Slaby <jslaby@...e.cz>
To:	stable@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, Jan Kara <jack@...e.cz>,
	Al Viro <viro@...iv.linux.org.uk>, Jiri Slaby <jslaby@...e.cz>
Subject: [PATCH 3.12 093/124] fs: Fix S_NOSEC handling

From: Jan Kara <jack@...e.cz>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

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@...e.cz>
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 fs/inode.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index d9134a0f5dd9..9ec57cb0aacd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1599,8 +1599,8 @@ 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;
 }
-- 
2.4.6

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