Commit df93988e authored May 21, 2015 by Jan Kara Committed by Sasha Levin Jul 13, 2015

fs: Fix S_NOSEC handling



[ Upstream commit 2426f3910069ed47c0cc58559a6d088af7920201 ]

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.

CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent c215cf25

fs/inode.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1631,8 +1631,8 @@ 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;
		}