From: Gavin Li <git@xxxxxxxxxxxxxx>
After creating a socket(AF_INET, SOCK_STREAM, BTPROTO_L2CAP) socket and
connect()'ing to a LE device with default settings (no setsockopt), upon
the first sendmsg, the following BUG occurs because chan->mode==L2CAP_MODE_ERTM,
causing l2cap_ertm_send() -> __set_retrans_timer() -> schedule_delayed_work()
on l2cap_chan.retrans_timer, which was never initialized because
l2cap_ertm_init() was never called to initialize it.
Call Trace:
queue_delayed_work_on+0x36/0x40
l2cap_ertm_send.isra.0+0x14d/0x2d0 [bluetooth]
l2cap_tx+0x361/0x510 [bluetooth]
l2cap_chan_send+0xb26/0xb50 [bluetooth]
l2cap_sock_sendmsg+0xc9/0x100 [bluetooth]
sock_sendmsg+0x5e/0x60
sock_write_iter+0x97/0x100
new_sync_write+0x1d3/0x1f0
vfs_write+0x1b4/0x270
ksys_write+0xaf/0xe0
do_syscall_64+0x33/0x40
entry_SYSCALL_64_after_hwframe+0x44/0xa9
This patch ensures that when connecting to a LE device, chan->mode will
always be corrected to L2CAP_MODE_LE_FLOWCTL if it is invalid for LE.
Signed-off-by: Gavin Li <git@xxxxxxxxxxxxxx>
---
net/bluetooth/l2cap_sock.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 160c016a5dfb9..58c06ef32656c 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -78,6 +78,17 @@ static int l2cap_validate_le_psm(u16 psm)
return 0;
}
+static bool l2cap_mode_supports_le(u8 mode)
+{
+ switch (mode) {
+ case L2CAP_MODE_LE_FLOWCTL:
+ case L2CAP_MODE_EXT_FLOWCTL:
+ return true;
+ default:
+ return false;
+ }
+}
+
static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
{
struct sock *sk = sock->sk;
@@ -161,7 +172,7 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
break;
}
- if (chan->psm && bdaddr_type_is_le(chan->src_type))
+ if (chan->psm && bdaddr_type_is_le(la.l2_bdaddr_type) && !l2cap_mode_supports_le(chan->mode))
chan->mode = L2CAP_MODE_LE_FLOWCTL;
chan->state = BT_BOUND;
@@ -240,7 +251,7 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr,
return -EINVAL;
}
- if (chan->psm && bdaddr_type_is_le(chan->src_type) && !chan->mode)
+ if (chan->psm && bdaddr_type_is_le(la.l2_bdaddr_type) && !l2cap_mode_supports_le(chan->mode))
chan->mode = L2CAP_MODE_LE_FLOWCTL;
err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
--
2.34.1
