5.15-stable review patch. If anyone has any objections, please let me know.
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From: Hyunwoo Kim v4bel@theori.io
[ Upstream commit 2e07e8348ea454615e268222ae3fc240421be768 ]
This can cause a race with bt_sock_ioctl() because bt_sock_recvmsg() gets the skb from sk->sk_receive_queue and then frees it without holding lock_sock. A use-after-free for a skb occurs with the following flow. ``` bt_sock_recvmsg() -> skb_recv_datagram() -> skb_free_datagram() bt_sock_ioctl() -> skb_peek() ``` Add lock_sock to bt_sock_recvmsg() to fix this issue.
Cc: stable@vger.kernel.org Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim v4bel@theori.io Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/af_bluetooth.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/af_bluetooth.c b/net/bluetooth/af_bluetooth.c index ce744b14d1a98..b7498e890f0b0 100644 --- a/net/bluetooth/af_bluetooth.c +++ b/net/bluetooth/af_bluetooth.c @@ -263,11 +263,14 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, if (flags & MSG_OOB) return -EOPNOTSUPP;
+ lock_sock(sk); + skb = skb_recv_datagram(sk, flags, noblock, &err); if (!skb) { if (sk->sk_shutdown & RCV_SHUTDOWN) - return 0; + err = 0;
+ release_sock(sk); return err; }
@@ -293,6 +296,8 @@ int bt_sock_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
skb_free_datagram(sk, skb);
+ release_sock(sk); + if (flags & MSG_TRUNC) copied = skblen;