From 560bef609fa5992745929e8d7d458b9d88dd2830 Mon Sep 17 00:00:00 2001 From: Hang Nan <2122295973@qq.com> Date: Wed, 19 Aug 2026 08:57:58 +0800 Subject: [PATCH] Bluetooth: ISO: fix use-after-free of listener socket in iso_conn_ready iso_conn_ready() looks up the BIS listener socket with iso_get_sock(), which takes a reference, and then, without re-checking its state, creates a child socket from it: parent = iso_get_sock(hdev, ...); if (!parent) return; lock_sock(parent); sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, ...); ... iso_chan_add(conn, sk, parent); ... release_sock(parent); sock_put(parent); If the listener socket is closed concurrently, between iso_get_sock() and lock_sock(), the reference taken by iso_get_sock() may be the last one: the close path drops the link-list reference, and once iso_conn_ready() drops its own reference at the end of the function the socket is freed. The child socket, however, is already linked to the freed parent, and a later disconnect of the child runs iso_chan_del() -> bt_accept_unlink(), which dereferences the dangling parent pointer into the freed accept queue (a use-after-free). The same dangling pointer is also dereferenced through parent->***() in iso_chan_del(). Fix it the same way the connected (non-BIS) path was fixed in commit 0d255e63fcf3 ("Bluetooth: ISO: hold sk properly in iso_conn_ready"): after taking the socket lock, re-check that the parent is still a listening, alive socket, and bail out otherwise. Fixes: ccf74f2390d60 ("Bluetooth: Add BTPROTO_ISO socket type") Cc: stable@vger.kernel.org Signed-off-by: Hang Nan <2122295973@qq.com> Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/iso.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index aa2ce78f56a2..75bfd5938b2e 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -2277,6 +2277,14 @@ static void iso_conn_ready(struct iso_conn *conn) lock_sock(parent); + /* The listener may have been closed concurrently. */ + if (parent->sk_state != BT_LISTEN || + sock_flag(parent, SOCK_ZAPPED)) { + release_sock(parent); + sock_put(parent); + return; + } + sk = iso_sock_alloc(sock_net(parent), NULL, BTPROTO_ISO, GFP_ATOMIC, 0); if (!sk) {