[PATCH 5.17 0630/1126] Bluetooth: Fix skb allocation in mgmt_remote_name() & mgmt_device_connected()

Greg Kroah-Hartman
2022-04-05T10:04:41Z

From: Radoslaw Biernacki <rad@semihalf.com>

[ Upstream commit ba17bb62ce415950753c19d16bb43b2bd3701158 ]

This patch fixes skb allocation, as lack of space for ev might push skb
tail beyond its end.
Also introduce eir_precalc_len() that can be used instead of magic
numbers for similar eir operations on skb.

Fixes: cf1bce1de7eeb ("Bluetooth: mgmt: Make use of mgmt_send_event_skb in MGMT_EV_DEVICE_FOUND")
Fixes: e96741437ef0a ("Bluetooth: mgmt: Make use of mgmt_send_event_skb in MGMT_EV_DEVICE_CONNECTED")
Signed-off-by: Angela Czubak <acz@semihalf.com>
Signed-off-by: Marek Maslanka <mm@semihalf.com>
Signed-off-by: Radoslaw Biernacki <rad@semihalf.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/eir.h | 5 +++++
net/bluetooth/mgmt.c | 18 ++++++++----------
2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/net/bluetooth/eir.h b/net/bluetooth/eir.h
index 05e2e917fc25..e5876751f07e 100644
--- a/net/bluetooth/eir.h
+++ b/net/bluetooth/eir.h
@@ -15,6 +15,11 @@ u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr);
u8 eir_append_local_name(struct hci_dev *hdev, u8 *eir, u8 ad_len);
u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len);

+static inline u16 eir_precalc_len(u8 data_len)
+{
+ return sizeof(u8) * 2 + data_len;
+}
+
static inline u16 eir_append_data(u8 *eir, u16 eir_len, u8 type,
u8 *data, u8 data_len)
{
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 230a7a8196c0..15eab8b968ce 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -9086,12 +9086,14 @@ void mgmt_device_connected(struct hci_dev *hdev, struct hci_conn *conn,
u16 eir_len = 0;
u32 flags = 0;

+ /* allocate buff for LE or BR/EDR adv */
if (conn->le_adv_data_len > 0)
skb = mgmt_alloc_skb(hdev, MGMT_EV_DEVICE_CONNECTED,
- conn->le_adv_data_len);
+ sizeof(*ev) + conn->le_adv_data_len);
else
skb = mgmt_alloc_skb(hdev, MGMT_EV_DEVICE_CONNECTED,
- 2 + name_len + 5);
+ sizeof(*ev) + (name ? eir_precalc_len(name_len) : 0) +
+ eir_precalc_len(sizeof(conn->dev_class)));

ev = skb_put(skb, sizeof(*ev));
bacpy(&ev->addr.bdaddr, &conn->dst);
@@ -9707,13 +9709,11 @@ void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
{
struct sk_buff *skb;
struct mgmt_ev_device_found *ev;
- u16 eir_len;
- u32 flags;
+ u16 eir_len = 0;
+ u32 flags = 0;

- if (name_len)
- skb = mgmt_alloc_skb(hdev, MGMT_EV_DEVICE_FOUND, 2 + name_len);
- else
- skb = mgmt_alloc_skb(hdev, MGMT_EV_DEVICE_FOUND, 0);
+ skb = mgmt_alloc_skb(hdev, MGMT_EV_DEVICE_FOUND,
+ sizeof(*ev) + (name ? eir_precalc_len(name_len) : 0));

ev = skb_put(skb, sizeof(*ev));
bacpy(&ev->addr.bdaddr, bdaddr);
@@ -9723,10 +9723,8 @@ void mgmt_remote_name(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 link_type,
if (name) {
eir_len = eir_append_data(ev->eir, 0, EIR_NAME_COMPLETE, name,
name_len);
- flags = 0;
skb_put(skb, eir_len);
} else {
- eir_len = 0;
flags = MGMT_DEV_FOUND_NAME_REQUEST_FAILED;
}

--
2.34.1