From patchwork Tue Jun 11 14:50:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edward Adam Davis X-Patchwork-Id: 803296 Received: from out162-62-58-216.mail.qq.com (out162-62-58-216.mail.qq.com [162.62.58.216]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 904F02868D; Tue, 11 Jun 2024 15:02:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.62.58.216 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718118176; cv=none; b=IWH98dlPHrDmttp2UEYPgq8QUWUzm4ElUBhOaO5oKQp8wkuaqMdzOEccqiHrkczg9o4SR5Tq83pSgEst2wCsWvv/22Dq1YT1g5l/1atU6ouTZ1VCrNyuNYPZSSIZdZfVYH3toUHu7PSIUJV18Z8Isc3L9CMbw+CCaqnamCMLWr4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718118176; c=relaxed/simple; bh=SD9Ox2uEgLQshHdPNaSlBqTcE1dEXOGR6zfPNYTOHgQ=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=gRg0h3g8AMpgDt+iiNFVrobDSQs7LXwU0Y4T73GRULf9WYk67jSoOMk1Ylqx/8w7/Oj/dudX+2LaTgid8DbTDg2aYLWJjMYFRR4wkVZtNbiu5iID89hHTVDrRqCYNNNoCNvXqEbeplWvNaKLppCcsLdwNnQuA7ixG5KkfELJxD4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=f42GHxX+; arc=none smtp.client-ip=162.62.58.216 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="f42GHxX+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1718118165; bh=EYZJeMpHWJRkQqovyVl3G5DqtUj1NtUFyItaVN67Ogk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=f42GHxX+j+2EYRXI3DgQqOOzhfCb1/4MUj2V49+H5LEvRrxnPjG9SJL3EvyuQGROY fHxwfiQK+gIAouaqOYeYLQHeI2KmfWjrix+fUP3lVf20Kql43B4glSyVYJZvV29OxT Kfmena5swtfEepp8mvkTVJ6CmbqvqzhGj2tp8EBs= Received: from pek-lxu-l1.wrs.com ([111.198.228.153]) by newxmesmtplogicsvrsza29-0.qq.com (NewEsmtp) with SMTP id C9107ACF; Tue, 11 Jun 2024 22:50:17 +0800 X-QQ-mid: xmsmtpt1718117417tpy0idpsl Message-ID: X-QQ-XMAILINFO: MB5+LsFw85NotV1rPa9aT9fXzjVDRjmoVre1tPCLpk+PR3dw+8o/OClgcieWx/ Z+J5aQb0hcyNQhrKegLlWcSOX1GZT+vxFZChIuE9eoFfdg8zrOdWFS45YmTJ1zxgm49m2a5Yv597 ayyBDbo595mOsHMJG253NmqW2lX91Y1WXnha9C1NdTJ9+aT5y8rrRGataNf1TqhDOVqC8YC5EBvg j8Rh1bP5ieC+tMEDRD9jogUAKLrFFnS4/Xiy4XoZPQ5ukc22+2YfjFoNofsOe07X//cghIuYcUkG 1QgFad5EkH57Nhoa2lukc8qcxFFH4CnSrB5Fx/v11Pi1BUwj6TZ1/7irlxVF3BsfAlCSMmiFnZIA weQoZ88Y6+NjeMyqKbnL6NHmEvTMo5aBfq2Gt25MZSPBBhuGBZNiRDhm9YhZqbbGVS7oslzoHvdL CpI0MUeQzrTJNFVNuYO+CmuEVgtIeZp/RdWW2ATCXFf+BPHJk5fL5kHQv3hS8OYTlHRmmyqVzYQC bOeHuPDBrQI9h0oT6+NP4h92rTJCfmeHvW5BUMW6ItkgUhiZhINnrnRFM7qIMHcajXPY6K1WLtOx mgH3/Vx32vYLjMyK7H+2EY3uWDCOhqiExPVKfLnM7QljgC7RnRob6nIVL+nUKcZBaaFVgjsLukiR OmY9M9eRpQlzLuKoPdaE9+t5yysAT9cZmOkj6A4st8wCsSRv5JJTmEMn1eYFqvGk06yl6+tDrnD7 omiAWwxi7fdqAL/Q31TAT4PeMzl6NUoYGKRg8HVv/JyIi9GwJcO2Z6WeowkdGoTtFAiOD1BZx8CD FgKuiaL+FnsEJ9xhgYPruS3mJFuvxXbVPxvDX9adD+bRDJ+MdtCWHzs2yeTXElhe2U0/QqAhNvZ5 +/RF+6PmJ4ubmXwi2AXDmDrr9LhAXrIhE1TG5oHOn0tE/q/X8ecCrIcw/xT1U2uAMtsvipmo2K X-QQ-XMRINFO: OD9hHCdaPRBwq3WW+NvGbIU= From: Edward Adam Davis To: syzbot+b7f6f8c9303466e16c8a@syzkaller.appspotmail.com Cc: johan.hedberg@gmail.com, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, luiz.dentz@gmail.com, marcel@holtmann.org, syzkaller-bugs@googlegroups.com Subject: [PATCH] bluetooth/l2cap: sync sock recv cb and release Date: Tue, 11 Jun 2024 22:50:17 +0800 X-OQ-MSGID: <20240611145016.2085712-2-eadavis@qq.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <000000000000b0906d061a468b93@google.com> References: <000000000000b0906d061a468b93@google.com> Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The problem occurs between the system call to close the sock and hci_rx_work, where the former releases the sock and the latter accesses it without lock protection. CPU0 CPU1 ---- ---- sock_close hci_rx_work l2cap_sock_release hci_acldata_packet l2cap_sock_kill l2cap_recv_frame sk_free l2cap_conless_channel l2cap_sock_recv_cb If hci_rx_work processes the data that needs to be received before the sock is closed, then everything is normal; Otherwise, the work thread may access the released sock when receiving data. Add a chan mutex in the rx callback of the sock to achieve synchronization between the sock release and recv cb. Reported-and-tested-by: syzbot+b7f6f8c9303466e16c8a@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis --- net/bluetooth/l2cap_sock.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 6db60946c627..f3e9236293e1 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1413,6 +1413,8 @@ static int l2cap_sock_release(struct socket *sock) l2cap_chan_hold(chan); l2cap_chan_lock(chan); + if (refcount_read(&sk->sk_refcnt) == 1) + chan->data = NULL; sock_orphan(sk); l2cap_sock_kill(sk); @@ -1481,12 +1483,22 @@ static struct l2cap_chan *l2cap_sock_new_connection_cb(struct l2cap_chan *chan) static int l2cap_sock_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb) { - struct sock *sk = chan->data; - struct l2cap_pinfo *pi = l2cap_pi(sk); + struct sock *sk; + struct l2cap_pinfo *pi; int err; - lock_sock(sk); + l2cap_chan_hold(chan); + l2cap_chan_lock(chan); + sk = chan->data; + + if (!sk) { + l2cap_chan_unlock(chan); + l2cap_chan_put(chan); + return -ENXIO; + } + pi = l2cap_pi(sk); + lock_sock(sk); if (chan->mode == L2CAP_MODE_ERTM && !list_empty(&pi->rx_busy)) { err = -ENOMEM; goto done; @@ -1535,6 +1547,8 @@ static int l2cap_sock_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb) done: release_sock(sk); + l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return err; }