irda: Fix memory leak caused by repeated binds of irda socket

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>

diff --git a/net/irda/af_irda.c b/net/irda/af_irda.c
index 101ed6c..b85fa22 100644 (file)
--- a/net/irda/af_irda.c
+++ b/net/irda/af_irda.c
@@ -774,6 +774,13 @@ static int irda_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
                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) &&