From: Luiz Augusto von Dentz luiz.von.dentz@intel.com
mainline inclusion from mainline-v5.10 commit f19425641cb2572a33cb074d5e30283720bd4d22 category: bugfix bugzilla: NA CVE: CVE-2020-12351
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Only sockets will have the chan->data set to an actual sk, channels like A2MP would have its own data which would likely cause a crash when calling sk_filter, in order to fix this a new callback has been introduced so channels can implement their own filtering if necessary.
Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Marcel Holtmann marcel@holtmann.org Conflicts: net/bluetooth/l2cap_sock.c [yyl: adjust context] Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- include/net/bluetooth/l2cap.h | 2 ++ net/bluetooth/l2cap_core.c | 7 ++++--- net/bluetooth/l2cap_sock.c | 14 ++++++++++++++ 3 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h index 0697fd413087..21dbd38f724d 100644 --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -619,6 +619,8 @@ struct l2cap_ops { struct sk_buff *(*alloc_skb) (struct l2cap_chan *chan, unsigned long hdr_len, unsigned long len, int nb); + int (*filter) (struct l2cap_chan * chan, + struct sk_buff *skb); };
struct l2cap_conn { diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index c04107d44601..f1ff83321023 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -6683,9 +6683,10 @@ static int l2cap_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb) goto drop; }
- if ((chan->mode == L2CAP_MODE_ERTM || - chan->mode == L2CAP_MODE_STREAMING) && sk_filter(chan->data, skb)) - goto drop; + if (chan->ops->filter) { + if (chan->ops->filter(chan, skb)) + goto drop; + }
if (!control->sframe) { int err; diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 5572042f0453..2a85dc3be8bf 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1476,6 +1476,19 @@ static void l2cap_sock_suspend_cb(struct l2cap_chan *chan) sk->sk_state_change(sk); }
+static int l2cap_sock_filter(struct l2cap_chan *chan, struct sk_buff *skb) +{ + struct sock *sk = chan->data; + + switch (chan->mode) { + case L2CAP_MODE_ERTM: + case L2CAP_MODE_STREAMING: + return sk_filter(sk, skb); + } + + return 0; +} + static const struct l2cap_ops l2cap_chan_ops = { .name = "L2CAP Socket Interface", .new_connection = l2cap_sock_new_connection_cb, @@ -1490,6 +1503,7 @@ static const struct l2cap_ops l2cap_chan_ops = { .set_shutdown = l2cap_sock_set_shutdown_cb, .get_sndtimeo = l2cap_sock_get_sndtimeo_cb, .alloc_skb = l2cap_sock_alloc_skb_cb, + .filter = l2cap_sock_filter, };
static void l2cap_sock_destruct(struct sock *sk)