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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tyler Hicks <tyhicks@canonical.com>,
        Seth Arnold <seth.arnold@canonical.com>,
        Stefan Bader <stefan.bader@canonical.com>
Subject: [PATCH 4.14 107/115] irda: Fix memory leak caused by repeated binds of irda socket
Date:   Thu, 13 Sep 2018 15:32:07 +0200
Message-Id: <20180913131829.906753548@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tyler Hicks <tyhicks@canonical.com>

The irda_bind() function allocates memory for self->ias_obj without
checking to see if the socket is already bound. A userspace process
could repeatedly bind the socket, have each new object added into the
LM-IAS database, and lose the reference to the old object assigned to
the socket to exhaust memory resources. This patch errors out of the
bind operation when self->ias_obj is already assigned.

CVE-2018-6554

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reviewed-by: Seth Arnold <seth.arnold@canonical.com>
Reviewed-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/irda/net/af_irda.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/staging/irda/net/af_irda.c
+++ b/drivers/staging/irda/net/af_irda.c
@@ -775,6 +775,13 @@ static int irda_bind(struct socket *sock
 		return -EINVAL;
 
 	lock_sock(sk);
+
+	/* Ensure that the socket is not already bound */
+	if (self->ias_obj) {
+		err = -EINVAL;
+		goto out;
+	}
+
 #ifdef CONFIG_IRDA_ULTRA
 	/* Special care for Ultra sockets */
 	if ((sk->sk_type == SOCK_DGRAM) &&