@@ -38,7 +38,6 @@ struct skb_cb {
struct in6_addr addr;
struct in6_addr gw;
struct l2cap_chan *chan;
- int status;
};
#define lowpan_cb(skb) ((struct skb_cb *)((skb)->cb))
@@ -528,7 +527,7 @@ static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
}
if (!err)
- err = lowpan_cb(skb)->status;
+ err = (!chan->tx_credits ? -EAGAIN : 0);
if (err < 0) {
if (err == -EAGAIN)
@@ -964,26 +963,12 @@ static struct sk_buff *chan_alloc_skb_cb(struct l2cap_chan *chan,
static void chan_suspend_cb(struct l2cap_chan *chan)
{
- struct sk_buff *skb = chan->data;
-
- BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
-
- if (!skb)
- return;
-
- lowpan_cb(skb)->status = -EAGAIN;
+ BT_DBG("chan %p suspend", chan);
}
static void chan_resume_cb(struct l2cap_chan *chan)
{
- struct sk_buff *skb = chan->data;
-
- BT_DBG("chan %p conn %p skb %p", chan, chan->conn, skb);
-
- if (!skb)
- return;
-
- lowpan_cb(skb)->status = 0;
+ BT_DBG("chan %p resume", chan);
}
static long chan_get_sndtimeo_cb(struct l2cap_chan *chan)
A status field in the skb_cb struct was storing a channel status based on channel suspend/resume events. This stored status was then used to return EAGAIN if there were packet sending issues in snd_pkt(). The issue is that the skb has been freed by the time the callback to 6lowpan's suspend/resume was called. So, this generates a "use after free" issue that was noticed while running kernel tests with KASAN debug enabled. Let's eliminate the status field entirely as we can use the channel tx_credits to indicate whether we should return EAGAIN when handling packets. Signed-off-by: Michael Scott <michael.scott@linaro.org> --- net/bluetooth/6lowpan.c | 21 +++------------------ 1 file changed, 3 insertions(+), 18 deletions(-) -- 2.11.0