Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932911Ab3D2TtD (ORCPT ); Mon, 29 Apr 2013 15:49:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60587 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758761Ab3D2TC3 (ORCPT ); Mon, 29 Apr 2013 15:02:29 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jiri Slaby , Linus Torvalds Subject: [ 03/42] TTY: fix atime/mtime regression Date: Mon, 29 Apr 2013 12:01:45 -0700 Message-Id: <20130429184752.796052982@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130429184752.435249613@linuxfoundation.org> References: <20130429184752.435249613@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2038 Lines: 73 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby commit 37b7f3c76595e23257f61bd80b223de8658617ee upstream. In commit b0de59b5733d ("TTY: do not update atime/mtime on read/write") we removed timestamps from tty inodes to fix a security issue and waited if something breaks. Well, 'w', the utility to find out logged users and their inactivity time broke. It shows that users are inactive since the time they logged in. To revert to the old behaviour while still preventing attackers to guess the password length, we update the timestamps in one-minute intervals by this patch. Signed-off-by: Jiri Slaby Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/tty/tty_io.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -941,6 +941,14 @@ void start_tty(struct tty_struct *tty) EXPORT_SYMBOL(start_tty); +static void tty_update_time(struct timespec *time) +{ + unsigned long sec = get_seconds(); + sec -= sec % 60; + if ((long)(sec - time->tv_sec) > 0) + time->tv_sec = sec; +} + /** * tty_read - read method for tty device files * @file: pointer to tty file @@ -978,6 +986,9 @@ static ssize_t tty_read(struct file *fil i = -EIO; tty_ldisc_deref(ld); + if (i > 0) + tty_update_time(&inode->i_atime); + return i; } @@ -1078,8 +1089,11 @@ static inline ssize_t do_tty_write( break; cond_resched(); } - if (written) + if (written) { + struct inode *inode = file->f_path.dentry->d_inode; + tty_update_time(&inode->i_mtime); ret = written; + } out: tty_write_unlock(tty); return ret; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/