From: Pauli Virtanen <pav@iki.fi> mainline inclusion from mainline-v7.3-rc1 commit 2b66c83ff1751d6bd3201b3017206262ab46dc05 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19458 CVE: CVE-2026-90256 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via hci_conn_timeout (disc_work) -> hci_proto_disconn_ind -> l2cap_disconn_ind. This is UAF if the l2cap_conn is deleted concurrently. disc_work is disabled sync in hci_conn_del(), so we cannot take hci_dev_lock in disc_work. Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock which is held in other access paths. Fixes: ab4eedb790ca ("Bluetooth: L2CAP: Fix corrupted list in hci_chan_del") Reported-by: syzbot+9c40ad7c6ed7165e46e8@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=9c40ad7c6ed7165e46e8 Signed-off-by: Pauli Virtanen <pav@iki.fi> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> Co-authored-by: BackportAgent@deepseek-v4.1-flash Signed-off-by: Hulk Robot <hulkrobot@huawei.com> Signed-off-by: Tang Hui <tanghui20@huawei.com> --- net/bluetooth/l2cap_core.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index e00c7e6ef04d3..dd0dc271d0b3d 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -1819,7 +1819,10 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) hci_chan_del(conn->hchan); conn->hchan = NULL; + spin_lock(&hcon->proto_lock); hcon->l2cap_data = NULL; + spin_unlock(&hcon->proto_lock); + mutex_unlock(&conn->lock); l2cap_conn_put(conn); } @@ -7074,8 +7077,6 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) } kref_init(&conn->ref); - hcon->l2cap_data = conn; - conn->hcon = hci_conn_get(hcon); conn->hchan = hchan; BT_DBG("hcon %p conn %p hchan %p", hcon, conn, hchan); @@ -7104,6 +7105,11 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon) conn->disc_reason = HCI_ERROR_REMOTE_USER_TERM; + spin_lock(&hcon->proto_lock); + conn->hcon = hci_conn_get(hcon); + hcon->l2cap_data = conn; + spin_unlock(&hcon->proto_lock); + return conn; } @@ -7493,13 +7499,18 @@ static void l2cap_connect_cfm(struct hci_conn *hcon, u8 status) int l2cap_disconn_ind(struct hci_conn *hcon) { - struct l2cap_conn *conn = hcon->l2cap_data; + struct l2cap_conn *conn; + int ret = HCI_ERROR_REMOTE_USER_TERM; BT_DBG("hcon %p", hcon); - if (!conn) - return HCI_ERROR_REMOTE_USER_TERM; - return conn->disc_reason; + spin_lock(&hcon->proto_lock); + conn = hcon->l2cap_data; + if (conn) + ret = conn->disc_reason; + spin_unlock(&hcon->proto_lock); + + return ret; } static void l2cap_disconn_cfm(struct hci_conn *hcon, u8 reason) -- 2.34.1