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Subject[Linux-kernel-mentees] [PATCH] net: bluetooth: Fix null pointer deref in hci_phy_link_complete_evt
Date
Fix null pointer deref in hci_phy_link_complete_evt, there was no 
checking there for the hcon->amp_mgr->l2cap_conn->hconn, and also
in hci_cmd_work, for hdev->sent_cmd.

To fix this issue Add pointer checking in hci_cmd_work and
hci_phy_link_complete_evt.
[Linux-next-20200827]

This patch corrected some mistakes from previous patch.

Reported-by: syzbot+0bef568258653cff272f@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=0d93140da5a82305a66a136af99b088b75177b99
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
---
net/bluetooth/hci_core.c | 5 ++++-
net/bluetooth/hci_event.c | 4 ++++
2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 68bfe57b6625..996efd654e7a 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -4922,7 +4922,10 @@ static void hci_cmd_work(struct work_struct *work)

kfree_skb(hdev->sent_cmd);

- hdev->sent_cmd = skb_clone(skb, GFP_KERNEL);
+ if (hdev->sent_cmd) {
+ hdev->sent_cmd = skb_clone(skb, GFP_KERNEL);
+ }
+
if (hdev->sent_cmd) {
if (hci_req_status_pend(hdev))
hci_dev_set_flag(hdev, HCI_CMD_PENDING);
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 4b7fc430793c..1e7d9bee9111 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4941,6 +4941,10 @@ static void hci_phy_link_complete_evt(struct hci_dev *hdev,
hci_dev_unlock(hdev);
return;
}
+ if (!(hcon->amp_mgr->l2cap_conn->hcon)) {
+ hci_dev_unlock(hdev);
+ return;
+ }

bredr_hcon = hcon->amp_mgr->l2cap_conn->hcon;

--
2.28.0
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