Hi Mat,
> When configuring an ERTM or streaming mode connection, remote devices
> are expected to send an RFC option in a successful config response. A
> misbehaving remote device might not send an RFC option, and the L2CAP
> code should not access uninitialized data in this case.
>
> Signed-off-by: Mat Martineau <mathewm@xxxxxxxxxxxxxx>
> ---
> net/bluetooth/l2cap_core.c | 16 +++++++++++++++-
> 1 files changed, 15 insertions(+), 1 deletions(-)
>
> diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
> index 5ea94a1..49ae7df 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -2152,7 +2152,7 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len, voi
> void *ptr = req->data;
> int type, olen;
> unsigned long val;
> - struct l2cap_conf_rfc rfc;
> + struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_BASIC };
>
> BT_DBG("chan %p, rsp %p, len %d, req %p", chan, rsp, len, data);
>
> @@ -2205,6 +2205,9 @@ static int l2cap_parse_conf_rsp(struct l2cap_chan *chan, void *rsp, int len, voi
> break;
> case L2CAP_MODE_STREAMING:
> chan->mps = le16_to_cpu(rfc.max_pdu_size);
> + break;
> + default:
> + break;
Adding a BT_ERR here would be a good idea.
> }
> }
>
> @@ -2271,6 +2274,14 @@ static void l2cap_conf_rfc_get(struct l2cap_chan *chan, void *rsp, int len)
> }
> }
>
> + /* Use sane default values in case a misbehaving remote device
> + * did not send an RFC option.
> + */
> + rfc.mode = chan->mode;
> + rfc.retrans_timeout = cpu_to_le16(chan->retrans_timeout);
> + rfc.monitor_timeout = cpu_to_le16(chan->monitor_timeout);
> + rfc.max_pdu_size = cpu_to_le16(chan->mps);
> +
> done:
> switch (rfc.mode) {
> case L2CAP_MODE_ERTM:
> @@ -2280,6 +2291,9 @@ done:
> break;
> case L2CAP_MODE_STREAMING:
> chan->mps = le16_to_cpu(rfc.max_pdu_size);
> + break;
> + default:
> + break;
Also adding a BT_ERR seems like the right thing to do.
Otherwise patch looks good to me.
Regards
Marcel
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