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authorRuihan Li <lrh2000@pku.edu.cn>2023-05-03 21:39:35 +0800
committerLuiz Augusto von Dentz <luiz.von.dentz@intel.com>2023-05-19 15:37:45 -0700
commit2910431ab0e500dfc5df12299bb15eef0f30b43e (patch)
tree0e8602d8977512314b7d7780f3d119c1df38675f /net/bluetooth
parentca1fd42e7dbfcb34890ffbf1f2f4b356776dab6f (diff)
Bluetooth: Refcnt drop must be placed last in hci_conn_unlink
If hci_conn_put(conn->parent) reduces conn->parent's reference count to zero, it can immediately deallocate conn->parent. At the same time, conn->link->list has its head in conn->parent, causing use-after-free problems in the latter list_del_rcu(&conn->link->list). This problem can be easily solved by reordering the two operations, i.e., first performing the list removal with list_del_rcu and then decreasing the refcnt with hci_conn_put. Reported-by: Luiz Augusto von Dentz <luiz.dentz@gmail.com> Closes: https://lore.kernel.org/linux-bluetooth/CABBYNZ+1kce8_RJrLNOXd_8=Mdpb=2bx4Nto-hFORk=qiOkoCg@mail.gmail.com/ Fixes: 06149746e720 ("Bluetooth: hci_conn: Add support for linking multiple hcon") Signed-off-by: Ruihan Li <lrh2000@pku.edu.cn> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'net/bluetooth')
-rw-r--r--net/bluetooth/hci_conn.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 70e1655a9df6..44d0643fc681 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -1102,12 +1102,12 @@ static void hci_conn_unlink(struct hci_conn *conn)
if (!conn->link)
return;
- hci_conn_put(conn->parent);
- conn->parent = NULL;
-
list_del_rcu(&conn->link->list);
synchronize_rcu();
+ hci_conn_put(conn->parent);
+ conn->parent = NULL;
+
kfree(conn->link);
conn->link = NULL;
}