diff options
| author | Johan Hedberg <johan.hedberg@intel.com> | 2013-10-10 13:33:37 +0200 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2013-10-10 05:00:34 -0700 |
| commit | c4e5bafa661126b7b42459ad32d4c2cc589ef8fb (patch) | |
| tree | b0647af6398962acb3532679c71221a37fc6eb6e | |
| parent | 9ecb3e24258f1ff4b9937602962ae12e3b57f98d (diff) | |
Bluetooth: Fix potential double-frees of L2CAP skbs
The l2cap_recv_frame function is expected to take ownership and
eventually free the skb passed to it. We need to ensure that the
conn->rx_skb pointer is no longer reachable when calling
l2cap_recv_frame so that no other function, such as l2cap_conn_del, may
think that it can free conn->rx_skb.
An actual situation when this can happen is when smp_sig_channel (called
from l2cap_recv_frame) fails and l2cap_conn_del gets called as a
consequence. The l2cap_conn_del function would then try to free
conn->rx_skb, but as the same skb was just passed to smp_sig_channel and
freed we get a double-free.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | net/bluetooth/l2cap_core.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index a9a7df6639a7..06e7173c2d13 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -6798,9 +6798,13 @@ int l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags) conn->rx_len -= skb->len; if (!conn->rx_len) { - /* Complete frame received */ - l2cap_recv_frame(conn, conn->rx_skb); + /* Complete frame received. l2cap_recv_frame + * takes ownership of the skb so set the global + * rx_skb pointer to NULL first. + */ + struct sk_buff *rx_skb = conn->rx_skb; conn->rx_skb = NULL; + l2cap_recv_frame(conn, rx_skb); } break; } |