linux-kernel - [PATCH] tty/n_gsm.c: fix a memory leak when gsmtty is removed

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <551111B9.3000008@intel.com>
Date:	Tue, 24 Mar 2015 15:26:49 +0800
From:	Pan Xinhui <xinhuix.pan@...el.com>
To:	gregkh@...uxfoundation.org, jslaby@...e.cz,
	linux-kernel@...r.kernel.org
CC:	yanmin_zhang@...ux.intel.com, mnipxh@...i.com
Subject: [PATCH] tty/n_gsm.c: fix a memory leak when gsmtty is removed

In gsmtty_remove, we will put dlci. when dlci's ref-count is zero,
tty_port_destructor will be called, and it will check if port->itty is NULL.
However port->itty will be set to NULL in release_tty after gsmtty_remove.
that may cause memory leak. so we use queue_work to put the dlci later.

Signed-off-by: xinhui.pan <xinhuix.pan@...el.com>
---
  drivers/tty/n_gsm.c | 16 ++++++++++++++--
  1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c434376..50f4660 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -135,6 +135,7 @@ struct gsm_dlci {
  #define DLCI_OPEN		2	/* SABM/UA complete */
  #define DLCI_CLOSING		3	/* Sending DISC not seen UA/DM */
  	struct mutex mutex;
+	struct work_struct putself_work;
  
  	/* Link layer */
  	spinlock_t lock;	/* Protects the internal state */
@@ -3170,14 +3171,25 @@ static int gsmtty_break_ctl(struct tty_struct *tty, int state)
  	return gsmtty_modem_update(dlci, encode);
  }
  
-static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
+static void put_gsm_dlci(struct work_struct *work)
  {
-	struct gsm_dlci *dlci = tty->driver_data;
+	struct gsm_dlci *dlci =
+		container_of(work, struct gsm_dlci, putself_work);
  	struct gsm_mux *gsm = dlci->gsm;
  
+	mutex_lock(&gsm->mutex);
  	dlci_put(dlci);
  	dlci_put(gsm->dlci[0]);
+	mutex_unlock(&gsm->mutex);
  	mux_put(gsm);
+}
+
+static void gsmtty_remove(struct tty_driver *driver, struct tty_struct *tty)
+{
+	struct gsm_dlci *dlci = tty->driver_data;
+
+	INIT_WORK(&dlci->putself_work, put_gsm_dlci);
+	schedule_work(&dlci->putself_work);
  	driver->ttys[tty->index] = NULL;
  }
  
-- 
1.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/