[PATCH 5.4 77/87] Bluetooth: RFCOMM: Replace use of memcpy_from_msg with bt_skb_sendmmsg

Greg Kroah-Hartman
2022-07-27T16:44:55Z

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

commit 81be03e026dc0c16dc1c64e088b2a53b73caa895 upstream.

This makes use of bt_skb_sendmmsg instead using memcpy_from_msg which
is not considered safe to be used when lock_sock is held.

Also make rfcomm_dlc_send handle skb with fragments and queue them all
atomically.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/bluetooth/rfcomm/core.c | 50 +++++++++++++++++++++++++++++++++++++-------
net/bluetooth/rfcomm/sock.c | 50 ++++++++++----------------------------------
2 files changed, 55 insertions(+), 45 deletions(-)

--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -553,22 +553,58 @@ struct rfcomm_dlc *rfcomm_dlc_exists(bda
return dlc;
}

+static int rfcomm_dlc_send_frag(struct rfcomm_dlc *d, struct sk_buff *frag)
+{
+ int len = frag->len;
+
+ BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
+
+ if (len > d->mtu)
+ return -EINVAL;
+
+ rfcomm_make_uih(frag, d->addr);
+ __skb_queue_tail(&d->tx_queue, frag);
+
+ return len;
+}
+
int rfcomm_dlc_send(struct rfcomm_dlc *d, struct sk_buff *skb)
{
- int len = skb->len;
+ unsigned long flags;
+ struct sk_buff *frag, *next;
+ int len;

if (d->state != BT_CONNECTED)
return -ENOTCONN;

- BT_DBG("dlc %p mtu %d len %d", d, d->mtu, len);
+ frag = skb_shinfo(skb)->frag_list;
+ skb_shinfo(skb)->frag_list = NULL;

- if (len > d->mtu)
- return -EINVAL;
+ /* Queue all fragments atomically. */
+ spin_lock_irqsave(&d->tx_queue.lock, flags);
+
+ len = rfcomm_dlc_send_frag(d, skb);
+ if (len < 0 || !frag)
+ goto unlock;
+
+ for (; frag; frag = next) {
+ int ret;
+
+ next = frag->next;
+
+ ret = rfcomm_dlc_send_frag(d, frag);
+ if (ret < 0) {
+ kfree_skb(frag);
+ goto unlock;
+ }
+
+ len += ret;
+ }

- rfcomm_make_uih(skb, d->addr);
- skb_queue_tail(&d->tx_queue, skb);
+unlock:
+ spin_unlock_irqrestore(&d->tx_queue.lock, flags);

- if (!test_bit(RFCOMM_TX_THROTTLED, &d->flags))
+ if (len > 0 && !test_bit(RFCOMM_TX_THROTTLED, &d->flags))
rfcomm_schedule();
return len;
}
--- a/net/bluetooth/rfcomm/sock.c
+++ b/net/bluetooth/rfcomm/sock.c
@@ -578,47 +578,21 @@ static int rfcomm_sock_sendmsg(struct so
lock_sock(sk);

sent = bt_sock_wait_ready(sk, msg->msg_flags);
- if (sent)
- goto done;
-
- while (len) {
- size_t size = min_t(size_t, len, d->mtu);
- int err;
-
- skb = sock_alloc_send_skb(sk, size + RFCOMM_SKB_RESERVE,
- msg->msg_flags & MSG_DONTWAIT, &err);
- if (!skb) {
- if (sent == 0)
- sent = err;
- break;
- }
- skb_reserve(skb, RFCOMM_SKB_HEAD_RESERVE);
-
- err = memcpy_from_msg(skb_put(skb, size), msg, size);
- if (err) {
- kfree_skb(skb);
- if (sent == 0)
- sent = err;
- break;
- }
-
- skb->priority = sk->sk_priority;
-
- err = rfcomm_dlc_send(d, skb);
- if (err < 0) {
- kfree_skb(skb);
- if (sent == 0)
- sent = err;
- break;
- }
-
- sent += size;
- len -= size;
- }

-done:
release_sock(sk);

+ if (sent)
+ return sent;
+
+ skb = bt_skb_sendmmsg(sk, msg, len, d->mtu, RFCOMM_SKB_HEAD_RESERVE,
+ RFCOMM_SKB_TAIL_RESERVE);
+ if (IS_ERR_OR_NULL(skb))
+ return PTR_ERR(skb);
+
+ sent = rfcomm_dlc_send(d, skb);
+ if (sent < 0)
+ kfree_skb(skb);
+
return sent;
}