Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763211AbYJMJwc (ORCPT ); Mon, 13 Oct 2008 05:52:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760983AbYJMJlI (ORCPT ); Mon, 13 Oct 2008 05:41:08 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:50971 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761101AbYJMJlG (ORCPT ); Mon, 13 Oct 2008 05:41:06 -0400 From: Alan Cox Subject: [PATCH 51/80] pty: If the administrator creates a device for a ptmx slave we should not error To: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org Date: Mon, 13 Oct 2008 10:41:03 +0100 Message-ID: <20081013094058.21645.99384.stgit@localhost.localdomain> In-Reply-To: <20081013092758.21645.2359.stgit@localhost.localdomain> References: <20081013092758.21645.2359.stgit@localhost.localdomain> User-Agent: StGIT/0.14.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2896 Lines: 90 From: Alan Cox The open path for ptmx slaves is via the ptmx device. Opening them any other way is not allowed. Vegard Nossum found that previously this was not the case and mknod foo c 128 42; cat foo would produce nasty diagnostics Signed-off-by: Alan Cox --- drivers/char/tty_io.c | 18 ++++++++++++------ 1 files changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index f40298e..2e96ce0 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1227,7 +1227,8 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p) * init_dev - initialise a tty device * @driver: tty driver we are opening a device on * @idx: device index - * @tty: returned tty structure + * @ret_tty: returned tty structure + * @first_ok: ok to open a new device (used by ptmx) * * Prepare a tty device. This may not be a "new" clean device but * could also be an active device. The pty drivers require special @@ -1248,7 +1249,7 @@ static void tty_line_name(struct tty_driver *driver, int index, char *p) */ static int init_dev(struct tty_driver *driver, int idx, - struct tty_struct **ret_tty) + struct tty_struct **ret_tty, int first_ok) { struct tty_struct *tty, *o_tty; struct ktermios *tp, **tp_loc, *o_tp, **o_tp_loc; @@ -1279,6 +1280,11 @@ static int init_dev(struct tty_driver *driver, int idx, } if (tty) goto fast_track; + if (driver->subtype == PTY_TYPE_MASTER && + (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) { + retval = -EIO; + goto end_init; + } /* * First time open is complex, especially for PTY devices. * This code guarantees that either everything succeeds and the @@ -1413,7 +1419,7 @@ static int init_dev(struct tty_driver *driver, int idx, if (retval) goto release_mem_out; - goto success; + goto success; /* * This fast open can be used if the tty is already open. @@ -1795,7 +1801,7 @@ static void release_dev(struct file *filp) } /** - * tty_open - open a tty device + * __tty_open - open a tty device * @inode: inode of device file * @filp: file pointer to tty * @@ -1874,7 +1880,7 @@ retry_open: return -ENODEV; } got_driver: - retval = init_dev(driver, index, &tty); + retval = init_dev(driver, index, &tty, 0); mutex_unlock(&tty_mutex); if (retval) return retval; @@ -1971,7 +1977,7 @@ static int __ptmx_open(struct inode *inode, struct file *filp) return index; mutex_lock(&tty_mutex); - retval = init_dev(ptm_driver, index, &tty); + retval = init_dev(ptm_driver, index, &tty, 1); mutex_unlock(&tty_mutex); if (retval) -- 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/