From e1dee2c1de2b4dd00eb44004a4bda6326ed07b59 Mon Sep 17 00:00:00 2001
From: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Date: Tue, 10 Aug 2021 12:14:10 +0800
Subject: [PATCH] Bluetooth: fix repeated calls to sco_sock_kill
Git-commit: e1dee2c1de2b4dd00eb44004a4bda6326ed07b59
Patch-mainline: v5.15-rc1
References: git-fixes

In commit 4e1a720d0312 ("Bluetooth: avoid killing an already killed
socket"), a check was added to sco_sock_kill to skip killing a socket
if the SOCK_DEAD flag was set.

This was done after a trace for a use-after-free bug showed that the
same sock pointer was being killed twice.

Unfortunately, this check prevents sco_sock_kill from running on any
socket. sco_sock_kill kills a socket only if it's zapped and orphaned,
however sock_orphan announces that the socket is dead before detaching
it. i.e., orphaned sockets have the SOCK_DEAD flag set.

To fix this, we remove the check for SOCK_DEAD, and avoid repeated
calls to sco_sock_kill by removing incorrect calls in:

1. sco_sock_timeout. The socket should not be killed on timeout as
further processing is expected to be done. For example,
sco_sock_connect sets the timer then waits for the socket to be
connected or for an error to be returned.

2. sco_conn_del. This function should clean up resources for the
connection, but the socket itself should be cleaned up in
sco_sock_release.

3. sco_sock_close. Calls to sco_sock_close in sco_sock_cleanup_listen
and sco_sock_release are followed by sco_sock_kill. Hence the
duplicated call should be removed.

Fixes: 4e1a720d0312 ("Bluetooth: avoid killing an already killed socket")
Signed-off-by: Desmond Cheong Zhi Xi <desmondcheongzx@gmail.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/bluetooth/sco.c |    7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

--- a/net/bluetooth/sco.c
+++ b/net/bluetooth/sco.c
@@ -83,8 +83,6 @@ static void sco_sock_timeout(unsigned lo
 	sk->sk_err = ETIMEDOUT;
 	sk->sk_state_change(sk);
 	release_sock(sk);
-
-	sco_sock_kill(sk);
 	sock_put(sk);
 }
 
@@ -196,7 +196,6 @@ static void sco_conn_del(struct hci_conn
 		sco_sock_clear_timer(sk);
 		sco_chan_del(sk, err);
 		release_sock(sk);
-		sco_sock_kill(sk);
 		sock_put(sk);
 
 		/* Ensure no more work items will run before freeing conn. */
@@ -378,8 +375,7 @@ static void sco_sock_cleanup_listen(stru
  */
 static void sco_sock_kill(struct sock *sk)
 {
-	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket ||
-	    sock_flag(sk, SOCK_DEAD))
+	if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)
 		return;
 
 	BT_DBG("sk %p state %d", sk, sk->sk_state);
@@ -431,7 +427,6 @@ static void sco_sock_close(struct sock *
 	lock_sock(sk);
 	__sco_sock_close(sk);
 	release_sock(sk);
-	sco_sock_kill(sk);
 }
 
 static void sco_sock_init(struct sock *sk, struct sock *parent)