This is a note to let you know that I've just added the patch titled
Bluetooth: SCO: Fix UAF on sco_sock_timeout
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bluetooth-sco-fix-uaf-on-sco_sock_timeout.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8fb5a15137bd3199ea1df4d0abc285242e9466ef
Author: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Date: Tue Oct 22 12:31:08 2024 -0400
Bluetooth: SCO: Fix UAF on sco_sock_timeout
[ Upstream commit 1bf4470a3939c678fb822073e9ea77a0560bc6bb ]
conn->sk maybe have been unlinked/freed while waiting for sco_conn_lock
so this checks if the conn->sk is still valid by checking if it part of
sco_sk_list.
Reported-by: syzbot+4c0d0c4cde787116d465@xxxxxxxxxxxxxxxxxxxxxxxxx
Tested-by: syzbot+4c0d0c4cde787116d465@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=4c0d0c4cde787116d465
Fixes: ba316be1b6a0 ("Bluetooth: schedule SCO timeouts with delayed_work")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
index 5d655e109b2c0..f66bc85c6411d 100644
--- a/include/net/bluetooth/bluetooth.h
+++ b/include/net/bluetooth/bluetooth.h
@@ -403,6 +403,7 @@ int bt_sock_register(int proto, const struct net_proto_family *ops);
void bt_sock_unregister(int proto);
void bt_sock_link(struct bt_sock_list *l, struct sock *s);
void bt_sock_unlink(struct bt_sock_list *l, struct sock *s);
+bool bt_sock_linked(struct bt_sock_list *l, struct sock *s);
struct sock *bt_sock_alloc(struct net *net, struct socket *sock,
struct proto *prot, int proto, gfp_t prio, int kern);
int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c
index e39fba5565c5d..0b4d0a8bd3614 100644
--- a/net/bluetooth/af_bluetooth.c
+++ b/net/bluetooth/af_bluetooth.c
@@ -185,6 +185,28 @@ void bt_sock_unlink(struct bt_sock_list *l, struct sock *sk)
}
EXPORT_SYMBOL(bt_sock_unlink);
+bool bt_sock_linked(struct bt_sock_list *l, struct sock *s)
+{
+ struct sock *sk;
+
+ if (!l || !s)
+ return false;
+
+ read_lock(&l->lock);
+
+ sk_for_each(sk, &l->head) {
+ if (s == sk) {
+ read_unlock(&l->lock);
+ return true;
+ }
+ }
+
+ read_unlock(&l->lock);
+
+ return false;
+}
+EXPORT_SYMBOL(bt_sock_linked);
+
void bt_accept_enqueue(struct sock *parent, struct sock *sk, bool bh)
{
const struct cred *old_cred;
diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c
index a5ac160c592eb..1c7252a368669 100644
--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -76,6 +76,16 @@ struct sco_pinfo {
#define SCO_CONN_TIMEOUT (HZ * 40)
#define SCO_DISCONN_TIMEOUT (HZ * 2)
+static struct sock *sco_sock_hold(struct sco_conn *conn)
+{
+ if (!conn || !bt_sock_linked(&sco_sk_list, conn->sk))
+ return NULL;
+
+ sock_hold(conn->sk);
+
+ return conn->sk;
+}
+
static void sco_sock_timeout(struct work_struct *work)
{
struct sco_conn *conn = container_of(work, struct sco_conn,
@@ -87,9 +97,7 @@ static void sco_sock_timeout(struct work_struct *work)
sco_conn_unlock(conn);
return;
}
- sk = conn->sk;
- if (sk)
- sock_hold(sk);
+ sk = sco_sock_hold(conn);
sco_conn_unlock(conn);
if (!sk)
@@ -194,9 +202,7 @@ static void sco_conn_del(struct hci_conn *hcon, int err)
/* Kill socket */
sco_conn_lock(conn);
- sk = conn->sk;
- if (sk)
- sock_hold(sk);
+ sk = sco_sock_hold(conn);
sco_conn_unlock(conn);
if (sk) {
